Apparatus and method for producing activated irradiation targets in the instrumentation tubing system of a nuclear reactor

Abstract

The decay station (30) comprises a housing (50) having a radiation shield (54), the housing (50) defining a decay duct (52) intended to receive irradiation targets (16) in a predetermined linear sequence, the decay duct (52) comprising: a decay duct inlet (56) intended to be connected to a structure (12) of a core (10) of a nuclear reactor to receive the irradiation targets (16) therefrom; a decay duct outlet (58) intended to be connected to an irradiation target discharge system (27) to discharge the irradiation targets (16) from the decay station (30), the decay station (30) further comprising: an inlet distributor (68) located at the decay duct inlet (56) and configured for discharging irradiation targets (16) from the decay station (30) to the core (10) of the nuclear reactor. The structure (12) of the core (10) releases only a predetermined amount of irradiation targets (16) at a time, the inlet distributor (68) being configured to release the irradiation targets (16) closest to the decay duct inlet (56) while keeping the remaining irradiation targets (16) in the decay duct (52); an inlet counter (96) being configured to count the number of irradiation targets (16) entering or leaving the decay duct (52) through the decay duct inlet (56), the inlet counter (96) being located at the decay duct inlet (56); and an outlet radiation detector (102) being configured to measure radiation emitted by the irradiation targets (16) located at the decay duct outlet (58).

Description

Technical Field

[0001] The present invention relates to a decay station configured for receiving irradiated irradiation targets from a structure within the core of a nuclear reactor, a diverter of an apparatus for producing activated irradiation targets in a nuclear reactor, and an apparatus and method for producing activated irradiation targets in an instrument tube system of a nuclear reactor. Background Art

[0002] Radionuclides are used in various technical and scientific fields, as well as for medical purposes. They are produced in research reactors or cyclotrons. However, since the number of facilities for commercial radionuclide production is limited and expected to decrease, there is a need to provide alternative production sites.

[0003] Neutron flux density in commercial nuclear reactor cores is measured, inter alia, by introducing solid spherical detectors into instrumentation tubes extending through the reactor core. Therefore, it is recommended that the instrumentation tubes of commercial nuclear reactors be used to generate radionuclides while the reactor is in power generation operation. In particular, one or more instrumentation tubes of a commercial nuclear reactor's aero-ball measurement system can be used, and existing components of the aero-ball measurement system can be modified and / or supplemented to enable efficient generation of radionuclides during reactor operation.

[0004] In this context, patent applications EP 3326175 A1 or WO 2019 / 086329 A1 describe a device and a method for producing radionuclides in an instrument tube system of a nuclear reactor.

[0005] However, these devices are not entirely satisfactory.

[0006] In practice, the delivery interval of the radionuclides requested by the customer is typically shorter than the time required to generate the radionuclides by exposure to the neutron flux in the nuclear reactor core. Since only a few instrument tubes are available for generating radionuclides, the use of the above-described radionuclide generation device cannot reduce the generation interval and provide radionuclides at the frequency requested by the customer.

[0007] Furthermore, activation of the irradiation target within a nuclear reactor core results in the production of the desired radionuclide, but also in the production of short-lived, highly radioactive isotopes as byproducts. For example, the production of lutetium-177 within a nuclear reactor core results in the formation of highly radioactive isotopes of ytterbium as byproducts. Furthermore, when the irradiation target includes a blanket containing aluminum, highly radioactive isotopes of aluminum are also formed as byproducts.

[0008] Due to their high radioactivity, these byproduct isotopes should not be handled by conventional radionuclide removal systems described in the aforementioned patent applications, as this would result in unacceptably high radiation transfer to the environment, as these removal systems are designed for radionuclides with less radioactivity that will be produced by the device, not for these byproduct isotopes.

[0009] One approach to discharging activated irradiation targets containing desired radionuclides (or one or more) and short-lived byproducts into conventional storage containers is to add a high-level radioactive material work shielding room for receiving the activated irradiation targets before discharging them into the storage container. However, such a high-level radioactive material work shielding room is very expensive to construct and occupies a large amount of space, making it difficult to provide such a high-level radioactive material work shielding room in commercial nuclear reactors where available space is limited. Summary of the Invention

[0010] It is therefore an object of the present invention to provide a system that allows the delivery of radionuclides with a delivery interval that is shorter than the activation time required for their production in a nuclear reactor core, and that also enables the activated irradiated targets to be discharged from the structure of the nuclear reactor core in a cost-effective and compact manner while minimizing the risks to the environment.

[0011] To this end, the present invention relates to a decay station configured for receiving irradiation targets from a structure of a core of a nuclear reactor in a predetermined linear sequence, the decay station comprising a housing including a radiation shield configured for protecting the environment of the decay station from radiation emitted by the irradiation targets housed in the decay station,

[0012] The housing defines a decay duct intended to house the irradiation targets in a predetermined linear sequence, the decay duct comprising:

[0013] - a decay duct inlet intended to be connected to a structure of the core of a nuclear reactor in order to receive an irradiation target therefrom;

[0014] - a decay duct outlet intended to be connected to an irradiation target discharge system for discharging the irradiated target from the decay station;

[0015] The decay station also includes:

[0016] an inlet distributor located at the inlet of the decay duct and configured to release only a predetermined amount of irradiated targets at a time from the decay station to the structure of the core of the nuclear reactor, the inlet distributor being configured to release the irradiated targets closest to the inlet of the decay duct while retaining the remaining irradiated targets in the decay duct;

[0017] an entry counter configured to count the number of irradiated targets entering or leaving the decay duct through the decay duct entry, the entry counter being located at the decay duct entry; and

[0018] - an exit radiation detector configured for measuring radiation emitted by the irradiation target located at the exit of the decay conduit.

[0019] The decay station according to the present invention allows a specific amount of irradiated targets to be transferred into the decay station for temporary storage of partially activated irradiated targets or for allowing short-lived radioactive isotopes of activated irradiated targets to decay to an acceptable level before the activated irradiated targets are discharged into a storage container.

[0020] By means of an inlet distributor and an associated counter, a specific quantity of irradiated targets housed in a decay station can be transferred back into the core of a nuclear reactor, which allows batches of radioisotopes to be produced with a delivery interval that is shorter than the activation time required for producing the radioisotopes in the core within the same instrument finger. For example, batches of radioisotopes can be produced with a delivery interval that corresponds to half the activation time required for producing the radioisotopes in the core.

[0021] In particular, the decay station can receive a batch of partially activated irradiated targets (having spent only a portion of the required activation time in the core) and a batch of fully activated irradiated targets (having spent the required activation time in the core) in this linear sequence from the inlet to the outlet of the decay station. The inlet distributor then allows, after a certain number of non-activated irradiated targets have been introduced into the core, the selective transfer of only the partially activated irradiated targets back into the core, while retaining the fully activated irradiated targets in the decay station to further decay short-lived byproduct isotopes before the fully activated irradiated targets are discharged into a storage container via an appropriate discharge system.

[0022] Thus, by allowing the intermediate storage of fully activated irradiated targets within the system's discharge circuit for a duration sufficient to reduce the activity of short-lived radioactive isotopes to an acceptable level, the decay station also allows the fully activated irradiated targets to be discharged into conventional storage containers without the need for a high-level radioactive material work shielded room or manipulator. Once the activity level has decreased below a predetermined threshold, the activated irradiated targets can be automatically transferred from the decay station to the discharge system of the device for generating the activated irradiated targets.

[0023] Transfers to and from the decay station can occur automatically without any manual handling, as would be required in the case of a shielded room for working with highly radioactive materials, for example.

[0024] Furthermore, the decay station according to the present invention can be directly integrated into existing radionuclide production facilities with minimal additional effort, while allowing for the safe decay of short-lived, highly radioactive byproduct isotopes. In this regard, the decay station can be inserted anywhere along the path of the irradiation target from the core of the nuclear reactor to the exhaust system, thus providing a high degree of flexibility.

[0025] The decay station according to the invention therefore constitutes a cost-effective and compact solution for discharging activated irradiated targets from the core of a nuclear reactor while minimizing the risks to the environment.

[0026] The decay station may also include one or more of the following features, taken individually or in any technically possible combination:

[0027] - the decay station further comprises a pressurized gas supply source connected to the decay duct outlet to introduce pressurized gas into the decay duct from the decay duct outlet;

[0028] The inlet distributor comprises, in order from the decay duct inlet toward the decay duct outlet:

[0029] a locking element displaceable between a locking position, in which the locking element prevents the irradiation target from being removed from the decay duct through the decay duct inlet, and a release position, in which the locking element allows a predetermined amount of the irradiation target to be removed from the decay duct through the decay duct inlet; and

[0030] a holder displaceable between a retracted position, in which the holder allows the passage of the irradiation target, and an extended position, in which the holder at least partially extends into the decay duct, the holder being configured to abut against the irradiation target in the extended position so as to prevent the irradiation target from moving towards the decay duct inlet,

[0031] And the inlet distributor also includes:

[0032] a first actuator configured to displace the locking element between a locking position and a release position; and

[0033] a second actuator configured for displacing the holder between an extended position and a retracted position, the first actuator and / or the second actuator being for example a pneumatic actuator, a magnetic actuator or a hydraulic actuator;

[0034] - the locking element comprises a locking pin configured to extend radially through the decay conduit in a locked position of the locking element, and the holder comprises a retaining pin configured to extend radially partially into the decay conduit in an extended position of the holder, and a spring element connected to the retaining pin;

[0035] The decay station further comprises a controller configured to control the release of a predetermined amount of irradiation targets by the inlet dispenser by controlling a release sequence comprising the following steps:

[0036] - displacing the locking element from the release position to the locking position by means of a first actuator;

[0037] - activating a pressurized gas supply source so as to obtain a pressurized gas flow through the decay duct from the outlet end of the decay duct, the pressurized gas flow being configured to push irradiation targets housed in the decay duct toward the inlet end of the decay duct until they abut against a locking element positioned in a locking position;

[0038] - displacing the holder by means of a second actuator from a retracted position to an extended position in which the holder is able to rest on an irradiation target housed in the decay guide;

[0039] - displacing the locking element from the locking position to the releasing position by means of the first actuator, so that a predetermined amount of irradiation targets corresponding to the irradiation targets located downstream of the holder in the direction of the pressurized gas flow is conveyed out of the decay duct through the decay duct inlet, while the remaining irradiation targets are retained in the decay duct by means of the holder positioned in the extended position;

[0040] - the controller is further adapted to repeat the release sequence a number of times depending on the total amount of irradiated targets to be released from the decay station through the decay conduit inlet;

[0041] - the predetermined amount of irradiation targets is equal to one irradiation target, the dispenser being configured to release the irradiation targets one by one from the decay station to the structure of the core of the nuclear reactor;

[0042] the decay station further comprises at least one intermediate irradiation target counter, the at least one intermediate irradiation target counter being configured for counting the number of irradiation targets present in the decay duct and being located between the inlet counter and the decay duct outlet of the decay duct, the at least one intermediate irradiation target counter being, for example, a temperature sensor, a pressure sensor or a radiation sensor, for example a gamma radiation sensor;

[0043] - the decay station further comprising at least one intermediate radiation detector configured for measuring radiation emitted by an irradiation target housed in the decay duct and located between the exit radiation detector and the decay duct inlet;

[0044] - the decay station comprises one intermediate radiation detector or one exit radiation detector for each irradiation target accommodated in the decay station;

[0045] -The decay station also includes an outlet distributor, which is located at the outlet of the decay duct and is configured to release only a predetermined amount of irradiation targets from the decay station through the outlet of the decay duct at a time, the outlet distributor being configured to release the irradiation targets closest to the outlet of the decay duct while keeping the remaining irradiation targets in the decay duct.

[0046] - the decay duct is a straight duct that preferably slopes downwards from the decay duct inlet to the decay duct outlet;

[0047] the decay duct is substantially U-shaped and comprises a first decay duct section, a second decay duct section and a bottom formed at a junction between the first decay duct section and the second decay duct section, the first decay duct section and the second decay duct section extending upwardly from the bottom;

[0048] - the decay station further comprising a controller configured to discharge at least some of the irradiated targets from the decay station after a predetermined decay duration;

[0049] - the decay station further comprises a controller configured to discharge only irradiated targets that emit radiation below a predetermined threshold, the emitted radiation being measured by the exit radiation detector and / or by the optional intermediate radiation detector;

[0050] - the decay station further comprising a controller configured for ejecting at least some of the irradiated targets when the radiation measured by the exit radiation detector and optionally by the intermediate radiation detector has fallen below a predetermined threshold;

[0051] -The core structure of a nuclear reactor is the instrument tube system of the nuclear reactor.

[0052] The present invention also relates to a diverter for a device for producing activated irradiation targets in a nuclear reactor, the diverter having a first configuration and a second configuration, wherein in the first configuration the diverter defines a path for displacing the irradiation targets between the structure of the core of the nuclear reactor, in particular the instrument pipe system, and the irradiation target discharge system for discharging the activated irradiation targets, and in the second configuration the diverter defines a path for displacing the irradiation targets between the irradiation target supply system and the structure of the core of the nuclear reactor.

[0053] The steering gear includes:

[0054] - a first connector intended to be connected to an irradiation target extraction system;

[0055] - a second connector intended to be connected to the irradiation target supply system;

[0056] - a third connector intended to be connected to a structure of the core of a nuclear reactor;

[0057] - at least one diverter guide tube movable between:

[0058] - a first position in which the diverter conduit connects one of the first and second connectors to the third connector so as to define a path for irradiating the target from the one of the first and second connectors to the third connector; and

[0059] - a second position, in which the diverter conduit does not connect one of the first connector and the second connector to the third connector;

[0060] the or each diverter conduit being shaped so as to cause two changes of direction of an irradiation target intended to circulate therein along its length; and

[0061] - an actuator configured for displacing the or each diverter conduit between its first position and its second position.

[0062] Such a diverter is advantageous because it is compact and allows for selective transfer of targets directly (ie, without the need for additional intermediate transfer operations) to different destinations.

[0063] The diverter may also include one or more of the following features, taken alone or in any technically possible combination:

[0064] - the or each steering duct comprises a substantially straight end section at each end of the steering duct and an intermediate section extending between these end sections;

[0065] - the middle section of each diverter duct is straight, the absolute value of the angle between the end section and the middle section of the diverter duct being, for example, comprised between 2° and 5°;

[0066] - the middle section of the or each diverter duct is curved, the radius of curvature of the or each diverter duct at the junction with each end section being, for example, comprised between 200 and 800 mm;

[0067] - the third connector is spaced apart from the first connector and the second connector in the horizontal direction;

[0068] - the first connector and the second connector are substantially aligned in the vertical direction, and / or the third connector is located at an intermediate height between the height of the first connector and the height of the second connector;

[0069] - an actuator configured for displacing the or each diverter guide tube between its first position and its second position by translation or rotation;

[0070] - the steering gear further comprises a first steering gear conduit and a second steering gear conduit,

[0071] a first diverter conduit connecting the first connector to the third connector in its first position so as to define a path for displacing the irradiation target from the first connector to the third connector; and

[0072] a second diverter conduit connecting the second connector to the third connector in its first position so as to define a path for displacement of the irradiation target from the second connector to the third connector;

[0073] - the diverter is configured such that when the second diverter conduit is in its second position, the first diverter conduit is in its first position, and vice versa;

[0074] -The steering gear also includes a piston defining a first steering gear duct and a second steering gear duct therein, the piston being movable between a first position and a second position, wherein in the first position of the piston the first steering gear duct is in its first position and the second steering gear duct is in its second position, and in the second position of the piston the first steering gear duct is in its second position and the second steering gear duct is in its first position.

[0075] The steering gear further comprises a steering gear housing, in which the piston is received so as to be able to slide therein along the displacement direction.

[0076] -The steering gear housing also includes:

[0077] - a first chamber and a second chamber formed between the piston and the steering gear housing, the first chamber and the second chamber being located on both sides of the piston along the displacement direction of the piston;

[0078] an inlet port in fluid communication with the first chamber and intended to introduce pressurized fluid into the first chamber in order to displace the piston from its first position to its second position; and

[0079] - an outlet port in fluid communication with the second chamber and intended to allow removal of air from the second chamber during displacement of the piston along its displacement direction;

[0080] - the piston is configured to return to its first position in the absence of pressurized fluid in the first chamber;

[0081] - the steering gear housing comprises a first wall and a second wall spaced apart from each other in the longitudinal direction of the steering gear duct, the first and second connectors being provided on the first wall, and the third connector being provided on the second wall;

[0082] - the first diverter duct and the second diverter duct are symmetrical with respect to a mid-plane between the two ducts;

[0083] the diverter comprises a single diverter conduit which, in a first position thereof, connects the first connector to the third connector and, in a second position thereof, connects the second connector to the third connector, the diverter conduit being rotatable between the first position and the second position;

[0084] -The diverter also includes a support member and a rotatable catheter carrier, the first connector and the second connector are arranged on the support member, the rotatable catheter carrier is mounted on the support member in a manner that can rotate relative to the support member around a rotation axis, one end of the diverter catheter is mounted on the rotatable catheter carrier, so that rotation of the rotatable catheter carrier causes the diverter catheter to be displaced between its first position and its second position.

[0085] The invention also relates to a device for producing an activated irradiation target in an instrument tube system of a nuclear reactor, the device comprising:

[0086] - an irradiation target supply system configured to provide a non-activated irradiation target;

[0087] - an instrument tube system configured for receiving irradiated targets from an irradiated target supply system in view of activation of the irradiated targets by exposure to a neutron flux in the nuclear reactor;

[0088] a decay station as described above, wherein a decay duct inlet of the decay duct is connected to the instrument tube system, and an inlet distributor of the decay station is configured to release a predetermined amount of irradiation targets from the decay station to the instrument tube system at a time, the inlet distributor being configured to release the irradiation targets closest to the instrument tube system while keeping the remaining irradiation targets in the decay station;

[0089] - an irradiation target exhaust system comprising a target outlet port configured to be coupled to a target storage container, the exhaust system comprising an inlet end connected to a decay conduit outlet of a decay station;

[0090] a diverter displaceable between a first position in which the diverter defines a path for displacement of the irradiation target between the irradiation target supply system and the instrument tube system, and a second position in which the diverter defines a path for displacement of the irradiation target between the instrument tube system and the decay station; and

[0091] - an irradiation target drive system configured for transporting at least some of the irradiation targets through the apparatus, the irradiation target drive system comprising a pressurized gas supply to the decay station.

[0092] The apparatus may further include a controller configured to control the following steps performed by the apparatus:

[0093] - using the target drive system to transfer q1 number of inactivated irradiation targets from the irradiation target supply system to the instrument tube system;

[0094] - exposing the q1 number of non-activated irradiation targets to the neutron flux in the instrument tube system for a predetermined irradiation duration d1, which is strictly less than the minimum activation time for complete conversion of the precursor material contained in the irradiation targets into the desired radionuclide, so as to obtain q1 number of partially activated irradiation targets;

[0095] - using the target drive system to transfer q1 partially activated irradiated targets from the instrument tube system to the decay station;

[0096] - using the target drive system to transfer q2 non-activated irradiation targets from the irradiation target supply system to the instrument tube system;

[0097] - Using the target drive system to transfer q1 partially activated irradiated targets from the decay station back to the instrument tube system;

[0098] - exposing q1 number of partially activated irradiated targets and q2 number of non-activated irradiated targets to a neutron flux in the instrument tube system for a predetermined irradiation duration d2 to obtain q1 number of partially activated or fully activated irradiated targets and q2 number of partially activated irradiated targets; and

[0099] - Discharging at least some of the irradiated targets, and preferably fully activated irradiated targets, from the decay station into a target storage container.

[0100] The diverter may be as described above.

[0101] The present invention also relates to a method for producing an activated irradiation target in an instrument tube system of a nuclear reactor using a device as described above, the method comprising:

[0102] - transferring q1 number of inactivated irradiation targets from the irradiation target supply system to the instrument piping system;

[0103] - exposing the q1 number of non-activated irradiation targets to a neutron flux in the instrument tube system for a predetermined irradiation duration d1, so as to obtain q1 number of partially activated irradiation targets, the predetermined irradiation duration d1 being less than or equal to the minimum activation time for complete conversion of the precursor material of the irradiation targets into the desired radionuclide; and

[0104] - transferring q1 irradiation targets from the instrument tube system to the decay station; and

[0105] - Discharging at least some of the irradiated targets from the decay station into a target storage container.

[0106] The method may further comprise one or more of the following features, taken alone or in any technically possible combination:

[0107] - the method further comprising maintaining at least some of the irradiated targets in the decay station for a predetermined decay duration before discharging the irradiated targets from the decay station into a target storage container;

[0108] the predetermined duration d1 is less than the minimum activation time for complete conversion of the precursor material of the irradiation targets into the desired radionuclide, so that the number q1 of irradiation targets obtained and delivered to the instrument tube system at the end of the exposure step is the number q1 of partially activated irradiation targets;

[0109] Between the step of transferring the q1 number of partially activated irradiated targets from the instrument tube system into the decay station and the step of discharging at least some of the irradiated targets from the decay station into the target storage container, the method further comprises the following steps:

[0110] - delivering q2 inactive irradiation targets into the instrument tube system;

[0111] - transferring q1 partially activated irradiated targets from the decay station back to the instrument tube system;

[0112] - exposing q1 number of partially activated irradiation targets and q2 number of non-activated irradiation targets to a neutron flux in the instrument tube system for a predetermined irradiation duration d2 to obtain q1 number of partially activated or fully activated irradiation targets and q2 number of partially activated irradiation targets;

[0113] The method comprises the following steps: before discharging the irradiation targets from the decay station, the radiation, in particular the dose rate, emitted by the q1 number of irradiation targets present in the discharge duct is measured, the irradiation targets being discharged only if their measured radiation, in particular the dose rate, is below a predetermined threshold value.

[0114] According to another aspect, the present invention also relates to a device for producing an activated irradiation target in an instrument tube system of a nuclear reactor, the device comprising:

[0115] - an irradiation target supply system configured to provide a non-activated irradiation target;

[0116] - an instrument tube system configured for receiving irradiated targets from an irradiated target supply system in view of activation of the irradiated targets by exposure to a neutron flux in the nuclear reactor;

[0117] - an irradiation target exhaust system comprising a target outlet port configured to be coupled to a target storage container,

[0118] - a diverter as described above, configured to selectively define a path for displacement of an irradiation target between an irradiation target supply system and an instrument tube system or between the instrument tube system and an irradiation target exhaust system, the first connector being connected to the irradiation target exhaust system, the second connector being connected to the irradiation target supply system, and the third connector being connected to the instrument tube system; and

[0119] - an irradiation target drive system configured for transporting at least some of the irradiation targets through the apparatus.

[0120] According to a specific aspect, the device further comprises a decay station arranged on a path of the irradiation target between the instrument tube system and the irradiation target discharge system and configured to hold the activated irradiation target before the activated irradiation target is discharged from the device through the irradiation target discharge system, the first connector being connected to the irradiation target discharge system via the decay station. BRIEF DESCRIPTION OF THE DRAWINGS

[0121] The invention will be better understood on reading the following description which is given by way of example only with reference to the accompanying drawings in which:

[0122] - Figure 1 is a schematic diagram of an apparatus for producing an activated irradiation target 16 in a nuclear reactor;

[0123] - Figure 2 yes Figure 1 Another schematic diagram of an apparatus for producing an activated irradiation target in a nuclear reactor;

[0124] - Figure 3 According to the first embodiment Figure 1 Schematic diagram of the decay station of the device;

[0125] - Figure 4 According to the second embodiment Figure 1 Schematic diagram of the decay station of the device;

[0126] - Figure 5 is a schematic cross-sectional view of a steering gear according to a first embodiment;

[0127] - Figure 6 is a schematic cross-sectional view of a steering gear according to a second embodiment; and

[0128] - Figure 7 is a schematic diagram of a method for producing an activated irradiation target in an instrument tube system of a nuclear reactor. DETAILED DESCRIPTION

[0129] The present invention contemplates that commercial nuclear reactors can be used to produce artificial radioisotopes or radionuclides during reactor operation. In particular, conventional pneumatic ball measurement systems or other systems including tubes (e.g., instrument tubes) extending into and / or through the reactor core of a commercial reactor can be modified and / or supplemented to achieve effective and efficient production of radionuclides when the reactor is in energy generation mode.

[0130] For example, some guide tubes of commercial pneumatic ball measurement systems or transportable in-core probe (TIP) systems are used to guide irradiation targets containing precursors of the desired radionuclide into instrument tubes in the reactor core and to guide activated irradiation targets out of the reactor core.

[0131] Figure 1 There is shown an apparatus 6 for producing an activated irradiated target 16 within a commercial nuclear power plant 8. In contrast to research reactors, the purpose of commercial nuclear reactors is to produce electricity. Commercial nuclear reactors typically have a power rating of 100+ megawatts of electricity.

[0132] The basis of the device 6 for producing an activated irradiation target described in the exemplary embodiment is derived from a conventional aerodynamic ball measurement system (AMS) for measuring the neutron flux density in the core 10 of a nuclear reactor.

[0133] The pneumatic ball measurement system includes a pneumatically operated drive system configured to insert the pneumatic ball into the instrument finger and remove the pneumatic ball from the corresponding instrument finger after activation. Typically, the instrument finger extends into the reactor core 10 and extends through the entire axial length of the core 10. Multiple pneumatic balls are arranged in a linear sequence within the instrument finger, forming a pneumatic ball cylinder. Pneumatic balls are essentially spherical or circular probes, but may have other forms, such as ellipsoids or cylinders, as long as they are capable of moving through the conduits of the instrument tube system.

[0134] Reference Figure 1 , a commercial nuclear reactor includes an instrumentation tube system 12 including at least one instrumentation finger 14 that passes through the reactor core 10 of the nuclear reactor. The instrumentation tube system 12 is configured to allow insertion and removal of an irradiation target 16 in the instrumentation finger 14.

[0135] The irradiation target 16 includes a cladding enclosing a core made of a non-fissile material and including suitable precursor materials for producing radionuclides to be used for medical and / or other purposes.

[0136] The blanket encloses the core in a gas-tight manner. For example, it is made of a material that is not activated by the neutron flux, such as a material including polyetheretherketone (PEEK). The blanket may preferably include portions made of metallic material, in order to allow for improved detection, for example using inductive sensors.

[0137] The core comprises in particular the precursor material in powder form.

[0138] More preferably, the irradiation target 16 is composed of a precursor material that is converted to the desired radionuclide when activated by exposure to the neutron flux present in the reactor core 10 of an operating commercial nuclear reactor. Useful precursor materials are Mo-98, Yb-176, and Lu-176, which are converted to Mo-99 and Lu-177, respectively. However, it should be understood that the present invention is not limited to the use of a particular precursor material.

[0139] The guide tubes 13 of the instrument tube system 12 penetrate the reactor's entry barrier 11 and are coupled to one or more instrument fingers 14. Preferably, the instrument fingers 14 penetrate the pressure vessel cover of the nuclear reactor, wherein the instrument fingers 14 extend from the top to the bottom over substantially the entire axial length of the reactor core 10. The respective lower ends of the instrument fingers 14 at the bottom of the reactor core 10 are closed and / or provided with stops, so that the irradiation targets 16 inserted into the instrument fingers 14 form a cylinder, wherein each target 16 is in a predetermined axial position.

[0140] Preferably, activation of the target 16 is optimized by positioning the irradiation target 16 in a predetermined region of the reactor core having a neutron flux sufficient to completely convert the matrix material in the irradiation target 16 to the desired radionuclide.

[0141] Proper positioning of the irradiation target 16 can be achieved with the aid of a dummy target 18 made of an inert material, preferably a magnetic material, and sequencing the dummy target 18 and the irradiation target 16 in the instrument tube system 12 so as to form a column of targets 16, 18 within the instrument finger 14. In practice, the irradiation target 16 is at a pre-calculated optimal axial position in the reactor core 10, and other positions are occupied by the inert dummy target 18 or remain empty. However, it is preferred that as many positions as possible within the instrument finger 14 be used for the irradiation target 16 rather than the dummy target 18 to produce as many radionuclides as possible.

[0142] The optional dummy target 18 is made of an inert material that is substantially inactive under the conditions found in the reactor core 10 of an operating nuclear reactor. Preferably, the dummy target 18 can be made of an inexpensive inert material and can be reused after a short decay time, further reducing the amount of radioactive waste. More preferably, the dummy target is magnetic.

[0143] The device 6 is suitable for processing irradiation targets 16 and dummy targets 18 having a circular, cylindrical, elliptical or spherical shape and having a diameter corresponding to the gap of the instrument fingers 14 of the pneumatic ball measurement system.

[0144] The targets 16, 18 are preferably round, preferably spherical or cylindrical, so that they slide smoothly through and can be easily guided in the instrument tube system 12 by pressurized gas (e.g., air or nitrogen) and / or under gravity.

[0145] Preferably, the diameter of the targets 16, 18 is in the range of 1 to 3 mm, preferably about 1.7 mm.

[0146] According to a preferred embodiment, the commercial nuclear reactor is a pressurized water reactor. More preferably, the instrument tube system 12 is derived from a reactor such as an EPR. TM Pressurized water reactor (PWR) or Siemens TM Conventional pneumatic ball measurement system for PWR nuclear reactors.

[0147] However, those skilled in the art will recognize that the present invention is not limited to use with a pneumatic ball measurement system for PWR reactors. Rather, the invention may also be used with instrument tubes of a transportable in-core probe (TIP) system for a boiling water reactor (BWR), observation ports of a CANDU reactor, and temperature measurement and / or neutron flux channels in a heavy water reactor.

[0148] like Figure 1 As shown, the apparatus 6 includes an irradiation target supply system 21 configured to provide non-activated irradiation targets 16 to the instrument tube system 12 .

[0149] The irradiation target supply system 21 includes a supply tube 23 including an outlet end intended to be connected to the instrument tube system 12. The irradiation target supply system 21 also includes a supply unit 22 configured to supply the irradiation targets 16 and, optionally, the dummy targets 18 to the apparatus 6. The supply unit 22 is configured to be connected to an inlet end of the supply tube 23. The supply unit 22 includes, for example, a container, a funnel, or a box that accommodates the non-activated irradiation targets 16 and / or the dummy targets 18.

[0150] exist Figure 1 In the example shown, the irradiation target supply system 21 further includes a stop 20 configured to prevent movement of the irradiation target 16 and optional dummy target 18 through the supply tube 23. The stop 20 may be a magnetically or pneumatically operated pin.

[0151] The irradiation targets 16 provided by the irradiation target supply system 21 are inactive irradiation targets 16 , ie, irradiation targets 16 that have not been subjected to any irradiation in the core 10 of the nuclear reactor and do not contain any radioactive isotopes.

[0152] like Figure 2 As shown, the apparatus 6 further includes a target drive system 25 configured to transport the irradiation target 16 and optional dummy target 18 through the apparatus 6 .

[0153] The target drive system 25 is specifically configured to drive the targets 16 , 18 from the supply system 21 into the instrument fingers 14 in a predetermined linear sequence and force the irradiated targets 16 and dummy targets 18 out of the instrument fingers 14 , thereby maintaining the linear sequence of the targets 16 , 18 .

[0154] Preferably, the target drive system 25 is pneumatically operated using a pressurized gas such as nitrogen or air. Such a system allows for rapid processing of the irradiation target 16 and optional dummy target 18.

[0155] More preferably, the target drive system 25 includes one or more pneumatically operated valve cells (not shown) for individually controlling the insertion and transport of the irradiation target 16 and the optional dummy target 18 into the instrument tube system 12. The valve cells of the target drive system 25 can be implemented as an additional subsystem in addition to the valve cells of a conventional pneumatic ball measurement system, or a separate target drive system 25 can be installed.

[0156] Within the supply system 21 , the transfer of the irradiation targets 16 and optional dummy targets 18 from the supply unit 22 into the supply tube 23 may occur under the effect of gravity or may be driven by a target drive system 25 .

[0157] The apparatus 6 also includes an irradiation target discharge system 27 configured to receive irradiation targets 16 from the instrument piping system 12 and discharge these irradiation targets 16 into a shielded storage container 34. Figure 1 The irradiation target discharge system 27 is described in more detail.

[0158] The device 6 according to the invention further comprises a decay station 30 connected between the instrument tube system 12 and the irradiation target discharge system 27 .

[0159] The decay station 30 is configured to receive partially or fully activated irradiation targets 16 driven from the structure of the nuclear reactor core and, in particular, from the instrument tube system 12 .

[0160] The decay station 30 is particularly intended to hold fully activated irradiation targets 16 for a predetermined time in order to allow a predetermined decay of the activity of these fully activated irradiation targets 16 before they are discharged into a storage container 34 by means of the irradiation target discharge system 27 .

[0161] Preferably, the decay station 30 is located outside the reactor core 10, but preferably within an accessible area within the reactor containment vessel. Figure 1 and Figure 3 The decay station 30 is described in more detail.

[0162] exist Figure 1 In the illustrated embodiment, the apparatus 6 further includes a diverter 32 configured to alternatively create a path for the irradiation target 16 and, optionally, the dummy target 18 to be displaced between the irradiation target supply system 21 and the instrument tube system 12, or between the instrument tube system 12 and the decay station 30. More specifically, the diverter 32 has a first configuration in which the diverter 32 defines a path for the irradiation target 16 and, optionally, the dummy target 18 to be displaced from the instrument tube system 12 to the decay station 30, and a second configuration in which the diverter 32 defines a path for the irradiation target 16 and, optionally, the dummy target 18 to be displaced from the irradiation target supply system 21 to the instrument tube system 12.

[0163] The displacement of the irradiation target 16 and the optional dummy target through the diverter 32 is driven by the target drive system 25 .

[0164] The device 6 further comprises a switching unit 40 configured for placing the diverter 32 in the first configuration or the second configuration as required.

[0165] The following will refer to Figure 5 and Figure 6 The diverter 32 is described in more detail.

[0166] Reference Figure 2 The device 6 also includes an instrument and control unit (ICU) 42 connected to the irradiation target supply system 21, the instrument tube system 12, the target drive system 25, the switching unit 40, the decay station 30 and the irradiation target discharge system 27.

[0167] Preferably, the ICU 42 is also connected to the pneumatic ball measuring system fault monitoring system 28 for reporting any errors. The fault monitoring system 28 can also be designed not to be connected to the existing pneumatic ball measuring system but to be connected directly to the main control room.

[0168] Furthermore, the apparatus 6 comprises an online core monitoring system 26 for controlling the activation of the irradiation targets 16 .

[0169] According to one embodiment, the core monitoring system 26 and the instrument and control unit 24 are configured so that the activation process for converting the irradiated target 16 into the desired radionuclide is optimized by taking into account the actual state of the reactor, in particular the current neutron flux, fuel burnup, reactor power, and / or load. Thus, the optimal axial irradiation position and irradiation time can be calculated to achieve the best results. However, it is not important whether the actual calculations are performed in the ICU 42 or by the core monitoring system 26 of the pneumatic ball measurement system.

[0170] Now refer to Figure 3 The decay station 30 according to the first embodiment is described in more detail.

[0171] The decay station 30 according to the first embodiment is preferably configured for receiving a cylindrical irradiation target 16, preferably having a circular base. As mentioned above, the irradiation target 16 preferably has a diameter comprised between 1 mm and 3 mm and preferably equal to about 1.7 mm.

[0172] The length of each cylindrical irradiation target 16 is preferably greater than or equal to twice the diameter of the irradiation target 16. The upper limit of the length of the cylindrical irradiation target 16 is particularly limited by the radius of curvature of the guide tube of the device 6. The length of each cylindrical irradiation target 16 is, for example, comprised between 60 mm and 75 mm, more particularly equal to 70 mm.

[0173] The decay station 30 comprises a housing 50 defining a decay conduit 52 intended to house the irradiation target 16 and more particularly a partially or fully activated irradiation target.

[0174] The linear sequence of irradiated targets 16 in the instrument tube system 12 is maintained in a decay station 30 .

[0175] The apparatus 6 may include a separation device 53 positioned along the path of the targets 16, 18 from the instrument tube system 12 to the decay station 30 (at Figure 3 16 is shown in the figure to remove the optional pseudo target 18 so that only the irradiated target 16 is conveyed into the decay station 30. Preferably, the pseudo target 18 is magnetic and the irradiated target 16 is non-magnetic, and the separation device 53 includes an optional magnetic device, such as an electromagnet, arranged along the path of the targets 16, 18 from the instrument tube system 12 to the decay station 30 and configured to retain only the pseudo target 18. In this regard, when the pseudo target 18 is present, the pseudo target 18 is typically arranged below the irradiated target 16 in the instrument finger 14 so that the irradiated target 16 is located in front of the pseudo target 18 when the targets 16, 18 are driven from the instrument tube system 12 toward the decay station 30. The pseudo target 18 and the separation device 53 are optional.

[0176] The decay conduit 52 preferably has a circular cross section. The inner diameter of the decay conduit 52 substantially corresponds to the outer diameter of the irradiation target 16.

[0177] The housing 50 includes a radiation shield 54 configured to protect the environment of the decay station 30 from radiation emitted by a partially or fully activated irradiation target 16 housed therein, and in particular to limit the amount of radiation radiated from the interior of the decay station 30 into its environment.

[0178] The radiation shield 54 is made of a material suitable for absorbing or reflecting radiation, and in particular absorbing or reflecting alpha, gamma and / or beta radiation. According to an example, the radiation shield 54 is made of lead or tungsten or a combination thereof.

[0179] The thickness of the radiation shield 54 is selected in particular according to the nature of the radionuclides to be received in the decay station 30 and in particular according to the amount of radiation emitted. Preferably, the thickness of the radiation shield 54 is selected so as to obtain a dose less than or equal to a predetermined threshold in the external environment of the decay station 30. For example, the predetermined threshold is equal to 25 μSv / h at a distance of 50 cm from the decay station 30.

[0180] The radiation shield 54 preferably extends over the entire circumferential outer surface of the housing 50. In particular, the radiation shield 54 forms a wall of the housing 50 that delimits the decay duct 52.

[0181] The decay conduit 52 comprises:

[0182] a decay duct inlet 56 intended to be connected to the instrument tube system 12 in order to receive the irradiation target 16 therefrom;

[0183] A decay duct outlet 58 , which is intended to be connected to the irradiation target discharge system 27 for discharging the irradiation target 16 from the decay station 30 .

[0184] The decay duct inlet 56 forms the inlet of the decay station 30 , while the decay duct outlet 58 forms the outlet of the decay station 30 .

[0185] The decay conduit inlet 56 is more particularly intended to be connected to the instrument tubing 12 in the first configuration of the diverter 32 .

[0186] Preferably, the length of the decay duct 52 between its inlet 56 and outlet 58 is equal to or greater than the length of the activation region of the instrument tube system 12, so that all irradiation targets 16 activated in the instrument tube system 12 fit into the decay duct 52. The activation region corresponds to the region of the instrument tube system 12 intended to receive the irradiation targets 16 in the core for their activation. In particular, the length of the decay duct 52 between its inlet 56 and outlet 58 is greater than or equal to the length of the instrument finger 14.

[0187] exist Figure 3 In the first embodiment shown, the decay duct 52 extends in a straight line from a decay duct inlet 56 to a decay duct outlet 58 .

[0188] like Figure 3 As shown, the decay duct 52 is preferably sloped downward from the decay duct inlet 56 to the decay duct outlet 58. This slope prevents the irradiation target 16 from moving toward the decay duct inlet 56 without an additional force directed thereto.

[0189] According to an alternative (not shown), the decay duct 52 extends substantially horizontally.

[0190] The housing 50 is, for example, substantially cylindrical.

[0191] Decay Station 30 additionally includes:

[0192] a first pressurized gas supply 60 connected to the decay duct outlet 58 to introduce pressurized gas from the outlet 58 of the decay duct 52 into the decay duct 52 ; and

[0193] a second pressurized gas supply 62 connected to the decay duct inlet 56 to introduce pressurized gas into the decay duct 52 from the inlet 56 of the decay duct 52 .

[0194] The first pressurized gas supply source 60 and the second pressurized gas supply source 62 are Figure 2 It is only shown schematically.

[0195] The first and second pressurized gas supply sources 60, 62 are in particular part of the irradiation target drive system 25. For example, the first and second pressurized gas supply sources 60, 62 are connected to a common pressurized gas supply source 63 of the irradiation target drive system 25.

[0196] like Figure 1 As shown, the decay station 30 further includes an inlet distributor 68, which is located at the decay duct inlet 56 and is configured to release only a predetermined amount of irradiation targets 16 from the decay station 30 to the instrument tube system 12 at a time, while keeping at least some irradiation targets 16, in particular the remaining number of irradiation targets 16, in the decay station 30. The inlet distributor 68 is configured to release the irradiation targets 16 closest to the decay duct inlet 56.

[0197] The inlet distributor 68 is configured for clamping the irradiation target 16 within the decay conduit 52 so as to retain the irradiation target 16 against the flow of pressurized gas circulating through the decay conduit 52 .

[0198] The predetermined amount of irradiation targets 16 is less than the total number of irradiation targets 16 that can be received in the decay station 30 .

[0199] The inlet distributor 68 is preferably configured to release only a predetermined amount of irradiation targets 16 from the decay station 30 to the instrument tube system 12 at a time, and to maintain at least some of the irradiation targets 16, in particular the remaining number of irradiation targets 16, in the decay station 30 regardless of the magnetic properties of the irradiation targets 16, and in particular through mechanical operation.

[0200] More specifically, the inlet distributor 68 includes, in order from the decay duct inlet 56 toward the decay duct outlet 58:

[0201] a locking element 70 that is displaceable between a locked position, in which the locking element 70 prevents the irradiation target 16 from being removed from the decay duct 52 through the decay duct inlet 56, and a released position, in which the locking element 70 allows a predetermined amount of the irradiation target 16 to be removed from the decay duct 52 through the decay duct inlet 56;

[0202] a holder 72 that is displaceable between a retracted position, in which the holder 72 allows the passage of the irradiation target 16 , and an extended position in which the holder 72 at least partially extends into the decay duct 52 so as to abut against the irradiation target 16 and prevent the same from moving toward the decay duct inlet 56 .

[0203] The inlet distributor 68 also includes:

[0204] a first actuator 74 configured for displacing the locking element 70 between a locking position and a release position; and

[0205] A second actuator 76 configured for displacing the retainer 72 between an extended position and a retracted position.

[0206] The locking element 70 and retainer 72 are configured to allow gas to flow therethrough in the locked position of the locking element 70 or the extended position of the retainer 72 .

[0207] For example, the locking element 70 includes a locking pin 73 that is configured to extend radially through the decay duct 52 in a locked position to prevent passage of the irradiation target 16. More specifically, the locking pin includes an actuating end connected to a first actuator 74 and a free end opposite the actuating end. In the extended position, the free end of the locking pin 73 rests against the inner surface of the decay duct 52. In the extended position, the locking pin 73 extends along the diameter of the decay duct 52 from one side to the opposite side thereof. In particular, the length of the locking pin 73 is greater than or equal to the diameter of the decay duct 52.

[0208] In the released position, the locking element 70 is preferably retracted into the housing 50 and does not protrude into the decay conduit 52 .

[0209] The first actuator 74 is, for example, a pneumatic actuator, a magnetic actuator, or a hydraulic actuator.

[0210] In the extended position, the retainer 72 clamps the irradiation target 16, which rests against the inner wall of the decay duct 52. The retainer 72 is configured to apply a force, particularly a radial force, to the irradiation target 16, which is sufficient to hold the irradiation target 16 against the irradiation target 16 in the extended position, while the retainer 72 rests against the irradiation target 16.

[0211] The second actuator 76 is, for example, a pneumatic actuator, a magnetic actuator, or a hydraulic actuator.

[0212] For example, the retainer 72 includes a retaining pin 75 configured to extend radially into the decay conduit 52 in an extended position and a spring element (not shown) connected to the retaining pin 75. The spring element reduces the risk of damaging the irradiation target 16 against which the retaining pin 75 abuts when the retainer 72 is moved to its extended position. According to a specific example, the second actuator 76 is configured to perform a linear movement that is transmitted to a spring, the force of which acts on the irradiation target 16. The second actuator 76 also includes a stopper that limits the range of linear movement of the second actuator 76 to a predetermined range. Therefore, the force exerted by the retaining pin 75 on the irradiation target 16 is limited by the stiffness of the spring and the predetermined range of movement of the second actuator 76. It is particularly independent of the force exerted by the second actuator 76.

[0213] The distance between the locking element 70 and the retainer 72 is selected so that only a predetermined number of irradiation targets 16 can be accommodated between the locking element 70 and the retainer 72. More specifically, the distance between the locking element 70 and the retainer 72 is strictly greater than the cumulative length of the predetermined number of irradiation targets 16 and strictly less than the cumulative length of the predetermined number of irradiation targets 16 plus one irradiation target 16. In this case, when the locking element 70 is in its locked position and the retainer 72 is in its extended position, the predetermined number of irradiation targets 16 can be accommodated in the portion of the decay duct 52 located between the locking element 70 and the retainer 72, and the retainer 72 abuts against an irradiation target 16 located immediately adjacent to an irradiation target 16 of the predetermined number of irradiation targets 16 that is farthest from the decay duct inlet 56.

[0214] According to a preferred embodiment, the predetermined amount of irradiation targets 16 dispensed by inlet dispenser 68 is equal to one. In this case, inlet dispenser 68 is configured to release irradiation targets 16 from decay station 30 to instrument tube system 12 one by one. Furthermore, the distance between locking element 70 and retainer 72 is preferably selected so that only one irradiation target 16 can be accommodated between locking element 70 and retainer 72. More specifically, the distance between locking element 70 and retainer 72 is strictly greater than the length of one irradiation target 16 and strictly less than the length of two irradiation targets 16. In this case, when locking element 70 is in its locked position and retainer 72 is in its extended position, only one irradiation target 16 can be accommodated in the portion of decay conduit 52 located between locking element 70 and retainer 72, with retainer 72 resting against the irradiation target 16 immediately adjacent to it. For example, the distance between locking element 70 and retainer 72 is equal to approximately 1.5 times the length of irradiation target 16.

[0215] The decay station 30 also includes a controller 80 (see Figure 2 ), which is configured to control the release of a predetermined amount of irradiation target 16 by the inlet distributor 68 by controlling the release sequence, the control sequence comprising the following series of steps:

[0216] - displacement of the locking element 70 from the release position to the locking position by means of the first actuator 74;

[0217] - activating the first pressurized gas supply source 60 so as to obtain a pressurized gas flow through the decay duct 52 from the outlet end of the decay duct 52 , the pressurized gas flow being configured to push the irradiation targets 16 housed in the decay duct 52 towards the inlet end of the decay duct 52 until they come into abutment against the locking element 70 positioned in the locking position;

[0218] - displacing the holder 72 by means of the second actuator 76 from the retracted position into an extended position in which the holder 72 can bear against the irradiation target 16 facing the holder 72 in the decay duct 52 ;

[0219] - The locking element 72 is displaced from the locking position to the released position by means of the first actuator 74, so that a predetermined amount of irradiation targets 16 corresponding to the irradiation targets 16 located downstream of the holder 72 in the direction of the pressurized gas flow are transported out of the decay duct 52 through the decay duct inlet 56 by the pressurized gas flow, while the irradiation targets 16 located at or upstream of the holder 72 are retained in the decay duct 52 by means of the holder 72 positioned in the extended position.

[0220] The release sequence described above results in only a predetermined amount of the irradiated targets 16 being released from the decay station 30 through the decay conduit inlet 56 , while the remaining irradiated targets 16 are retained in the decay station 30 .

[0221] According to a specific example, the controller 80 is configured to repeat the release sequence a number of times depending on the total amount of irradiated targets 16 to be released from the decay station 30 through the decay conduit inlet 56 .

[0222] For example, in the preferred example where the predetermined number of irradiation targets 16 is equal to 1, if a number of irradiation targets 16 equal to N are to be released from the decay station 30 via the inlet distributor 68, the controller 80 is configured to repeat the above sequence of steps N times, where N is different from 1.

[0223] The controller 80 may in particular be part of the above-mentioned ICU 42 .

[0224] To introduce the irradiation target 16 from the instrument tube system 12 into the decay station 30, the locking element 70 and retainer 72 are positioned in their released or retracted positions.

[0225] The decay station 30 also includes an entry counter 96 located at the decay duct inlet 56 and configured to count the number of irradiation targets 16 that pass through the entry counter 96. Thus, the entry counter 96 is configured to count the number of irradiation targets 16 that enter or exit the decay duct 52 through the decay duct inlet 56.

[0226] The entrance counter 96 is a device capable of detecting the passage of the irradiation target 16 in front of the entrance counter 96. In particular, it is selected from an inductive sensor capable of measuring the change in the inductive or dielectric field of the passing irradiation target 16, a pressure sensor capable of measuring the pressure difference occurring when the irradiation target 16 passes, an optical sensor (for example, a laser sensor or a contrast sensor) capable of optically detecting the passage of the irradiation target 16, a dielectric sensor, or a radiation sensor capable of detecting the difference in radiation intensity occurring when the irradiation target 16 passes.

[0227] The number of irradiated targets 16 counted by the entry counter 96 is preferably compared to a preset value to ensure that the required number of irradiated targets 16 have entered or exited the decay station 30 through the decay conduit entry 56 .

[0228] exist Figures 1 to 3 In the illustrated embodiment, the decay station 30 further includes an exit stop 84 located at an outlet end thereof, the exit stop 84 being configured to prevent the irradiation target 16 from moving out of the decay station 30 through the decay duct outlet 58. The exit stop 84 helps ensure that the irradiation target 16 housed in the decay duct 52 remains in a predetermined position within the decay duct 52 in the absence of a force exerted on the irradiation target 16 directed toward the decay duct inlet 56, particularly in the absence of a flow of pressurized gas in a direction from the decay duct outlet 58 toward the decay duct inlet 56.

[0229] In the first embodiment where the decay duct 52 is downwardly inclined from its inlet 56 towards its outlet 58 , the irradiation target 16 rests against the outlet stop 84 under the action of gravity, which also contributes to a well-defined positioning of the irradiation target 16 in the decay duct 52 .

[0230] The exit block 84 can be moved between a stop position and a release position. In the stop position, the exit block 84 prevents the irradiation target 16 from moving out of the decay station 30 through the decay duct outlet 58, while in the release position, the exit block 84 allows the irradiation target 16 to move out of the decay station 30 through the decay duct outlet 58.

[0231] In the stopped position, outlet block 84 preferably allows gas to flow therethrough.

[0232] The exit stopper 84 has a structure similar to the locking element 70 of the inlet distributor 68. For example, it includes a stop pin 86 configured to extend radially through the decay duct 52 in the stop position of the exit stopper 84 to prevent the passage of the irradiation target 16, and a stop pin actuator 88 configured to displace the stop pin 86 between the stop position and the release position.

[0233] More specifically, the stop pin 86 includes an actuated end connected to the stop pin actuator 88 and a free end opposite the actuated end. In the extended position of the stopper 84, the free end of the stop pin 86 rests against the inner surface of the decay duct 52. In the extended position, the stop pin 86 extends from one side of the decay duct 52 to the opposite side along the diameter of the decay duct 52. In particular, the length of the stop pin 86 is greater than or equal to the diameter of the decay duct 52.

[0234] In the retracted position, the stop pin 86 is preferably retracted into the housing 50 and does not protrude into the decay conduit 52 .

[0235] The detent pin actuator 88 is, for example, a pneumatic actuator, a magnetic actuator, or a hydraulic actuator.

[0236] Optionally, when considering the flow of the irradiation target 16 from the inlet toward the outlet, the decay station 30 further includes an inlet blocker 90 located at the decay duct inlet 56 upstream of the inlet distributor 68. The inlet blocker 90 is configured to prevent the irradiation target 16 from moving out of the decay station 30 through the decay duct inlet 56, and in particular, back into the instrument tube system 12.

[0237] The entrance barrier 90 has the same structure as the exit barrier 84 , with the only difference being that, in the stopped position, it prevents the irradiation target 16 from moving out of the decay conduit 52 through the entrance of the decay conduit 52 .

[0238] Optionally, the decay station 30 further includes an outlet distributor 92 located at the decay duct outlet 58 and configured to release only a predetermined amount of irradiated targets 16 from the decay station 30 through the decay duct outlet 58 at a time and to retain the remaining irradiated targets 16 in the decay duct 52 .

[0239] The outlet distributor 92 is Figure 3 It is shown schematically only and is not described in Figure 1 . The outlet distributor 92 has the same structure as the inlet distributor 68, except that the locking elements and the retainers of the outlet distributor 92 are arranged in a sequence from the decay duct outlet 58 toward the decay duct inlet 56. In addition, in the case of the outlet distributor 92, the roles of the inlet and outlet are reversed compared to the inlet distributor 68, and the first pressurized gas supply source 60 is replaced by the second pressurized gas supply source 62, and the controller 80 is configured to activate the second pressurized gas supply source 62 in order to obtain a pressurized gas flow through the decay duct 52 from the inlet end of the decay duct 52.

[0240] Optionally, the decay station 30 further includes an exit counter 98, which is located at the decay duct outlet 58 and is configured to count the number of irradiation targets 16 that pass through it (i.e., in particular, exit the decay duct 52 through the decay duct outlet 58). The exit counter 98 is a device capable of detecting the passage of an irradiation target 16 in front of the exit counter 98. It has the same structure as the entrance counter 92.

[0241] Further optionally, the decay station 30 includes at least one intermediate irradiation target counter 100, for example, a plurality of intermediate irradiation target counters 100, arranged along the decay duct 52 between the decay duct inlet 56 and the decay duct outlet 58, and the intermediate irradiation target counter 100 is configured to count the number of irradiation targets 16 present in the decay duct 52 at a given time.

[0242] The intermediate irradiation target counter(s) 100 are particularly selected among temperature sensors and gamma radiation measurement sensors.

[0243] In particular, because the irradiation targets 16 have a specific temperature due to their activation in the core, the presence of the irradiation targets 16 in the decay conduit 52 can be detected based on temperature measurements. Specifically, if the temperature measured by the temperature sensor is greater than or equal to a predetermined threshold value (depending on the characteristics of the radionuclides contained in the irradiation targets 16), then the irradiation targets 16 in the core are detected.

[0244] Alternatively, the presence of irradiation targets 16 in the decay conduit 52 can be detected based on gamma radiation measurements, with each irradiation target 16 present in the decay conduit 52 emitting a specific amount of gamma radiation that depends specifically on the characteristics of the radionuclides contained in the irradiation target 16 and the characteristics of the cladding of the irradiation target 16.

[0245] According to an example and Figure 3 As shown schematically, the decay station 30 includes one intermediate irradiation target counter 100 facing each irradiation target 16 in the decay duct 52. In particular, adjacent intermediate irradiation target counters 100 are spaced apart from each other along the length of the decay duct 52 by a distance corresponding to the length of the irradiation target 16 intended to be accommodated in the decay duct 52. For example, adjacent intermediate irradiation target counters 100 are spaced apart by a distance comprised between 60 mm and 70 mm, for example, equal to approximately 70 mm.

[0246] According to an alternative, the number of intermediate irradiation target counters 100 can be less than the total number of irradiation targets 16 in the decay conduit 52, particularly in the case where homogeneous material is activated in all irradiation targets 16. In fact, in the case where homogeneous material is activated in the irradiation targets 16, the values ​​measured by the intermediate irradiation target counters 100 for some irradiation targets 16 can be extrapolated for other irradiation targets 16.

[0247] The intermediate irradiation target counter(s) 100 serve as a means of confirming the counts performed by the entry counter 96 and / or the optional exit counter 98. They differ from the entry counter 96 and the optional exit counter 98 in that the entry counter 96 and the exit counter 98 are configured to count moving targets, whereas the intermediate counters 100 are configured to count stationary targets housed in the decay conduit 52.

[0248] exist Figure 3 In the illustrated embodiment, the decay station 30 further includes an exit radiation detector 102 configured to measure radiation emitted by an irradiation target 16 located in the decay conduit 52 at the decay conduit exit 58 and, for example, against the exit barrier 84 .

[0249] The exit radiation detector 102 may be located in a wall of the housing 50 of the decay station 30 or outside the housing 50 , in particular above or below the housing 50 .

[0250] The exit radiation detector 102 is located at a distance from the exit barrier 84 that is less than or equal to the length of one irradiation target 16 , measured along the length of the decay conduit 52 .

[0251] exist Figure 3 In the illustrated embodiment, the exit radiation detector 102 is located at a fixed position at the decay conduit exit 58 .

[0252] Optionally, the decay station 30 further includes at least one, for example a plurality of, intermediate radiation detectors 104 configured to measure radiation emitted by the irradiation target 16 at various locations along the length of the decay conduit 52 between its entrance 56 and exit 58 .

[0253] For example, the decay station 30 includes one radiation detector 102, 104 facing each irradiation target 16 in the decay duct 52. In this case, adjacent intermediate radiation detectors 102, 104 are in particular spaced apart from one another by a distance corresponding to the length of the irradiation target 16 intended to be housed in the decay duct 52. For example, adjacent radiation detectors 102, 104 are spaced apart by a distance comprised between 60 mm and 70 mm, for example equal to approximately 70 mm.

[0254] The optional intermediate radiation detector 104 is preferably located in a wall of the housing 50 of the decay station 30 or outside the housing 50 , in particular above or below the housing 50 .

[0255] Radiation detectors 102 , 104 may be particularly useful for confirming that radiation (eg, dose rate) has dropped below a predetermined threshold, thereby allowing the activated irradiation target 16 to be safely transferred from the decay station 30 into the irradiation target exhaust system 27 , which is less shielded than the decay station 30 .

[0256] Compared to embodiments including fewer radiation detectors 102 , 104 , using one radiation detector 102 , 104 per irradiation target 16 allows for observing individual activation deviations of the irradiation targets 16 .

[0257] Alternatively, the total number of radiation detectors 104 can be less than the total number of irradiation targets 16 in the decay conduit 52, particularly if homogeneous material is activated in all irradiation targets 16. Indeed, if homogeneous material is activated in the irradiation targets 16, the values ​​measured by the radiation detectors 102, 104 for some irradiation targets 16 can be extrapolated for other irradiation targets 16.

[0258] The exit radiation detector and / or the intermediate radiation detector 104 may be gamma radiation measuring sensors.

[0259] The intermediate radiation detector 104 may serve as an intermediate irradiation target counter 100 . In particular, the intermediate radiation detector 104 may be a gamma radiation measuring sensor that may be used to measure radiation emitted by the irradiation target 16 and to detect the presence of the irradiation target 16 .

[0260] According to an alternative (not shown), the exit radiation detector 102 is displaceable along the decay duct 52 between the decay duct inlet 56 and the decay duct outlet 58 so as to be able to measure radiation emitted by the irradiation target 16 at different locations along the length of the decay duct 52. The exit radiation detector 102 is particularly displaceable to a position at the decay duct outlet 58 so as to be able to measure radiation emitted by the irradiation target 16 located in the decay duct 52 at the decay duct outlet 58 and, in particular, against the exit barrier 84.

[0261] Radiation detectors 102, 104 are configured for monitoring the decay of irradiation targets 16 housed in decay station 30. They allow discharge from the decay station of only those irradiation targets 26 that have sufficiently decayed such that the radiation they emit is below a predetermined threshold.

[0262] The radiation detectors 102 , 104 are particularly configured for measuring a dose rate emitted by the irradiation target 16 .

[0263] The controller 80 is preferably configured to control the displacement of the exit block 84 from a stop position to a release position according to the measurement results of the exit radiation detector 102, for example, when the measured radiation is equal to or below a predetermined threshold, the exit block 84 is displaced to its release position.

[0264] One possible purpose of the decay station 30 is to allow radioactive decay of the irradiation targets 16 before transferring them to a less shielded area of ​​the apparatus 6 (e.g., the irradiation target exhaust system 27), a feature that allows the irradiation targets 16 to be exhausted from the decay station 30 only when the radiation emitted by the irradiation targets 16 (particularly their dose rate) has decreased to a predetermined level.

[0265] exist Figure 4 A decay station 30' according to a second embodiment is shown in . This decay station 30' has the same features as described above in relation to the first embodiment, the only difference being the shape of the decay station 30'.

[0266] As in Figure 4 As can be seen in the figure, in this embodiment, the decay duct 52 is not straight as in the first embodiment. In the second embodiment, the decay duct 52 is U-shaped. It includes a first decay duct section 110, a second decay duct section 112, and a bottom 114 formed at the junction between the first decay duct section 110 and the second decay duct section 112. The first decay duct section 110 and the second decay duct section 112 extend upward from the bottom 114.

[0267] In this second embodiment, the housing 50 of the decay station 30' is U-shaped, the walls of the housing 50 delimiting the decay duct 52 being formed in particular by a radiation shield 54. The U-shape of the decay duct 52 ensures safe storage of the irradiation targets 16 in the decay duct 52.

[0268] The decay station 30' according to the second embodiment is preferably configured for receiving a spherical irradiation target 16. The spherical irradiation target 16 has in particular a diameter comprised between 1 mm and 3 mm and preferably equal to approximately 1.7 mm.

[0269] Now refer to Figure 1 The irradiation target discharge system 27 is described in more detail.

[0270] As in Figure 1 As can be seen in FIG, the irradiation target exhaust system 27 includes an exhaust conduit 120 including an inlet end connected to the decay conduit outlet 58 of the decay station 30 and a target outlet port 124 configured to be coupled to the target storage container 34.

[0271] The linear order of irradiated targets 16 discharged from decay station 30 is maintained in discharge conduit 120 .

[0272] Preferably, the drain conduit 120 is located outside the reactor core 10, but preferably within an accessible area within the reactor containment vessel.

[0273] The outlet port 124 is located at the free end of the exhaust conduit 120. Figure 1 In the example shown, it includes a shut-off valve 126 for pressure-tight sealing of the exhaust conduit 120 .

[0274] The outlet port 124 may be positioned above the storage container 34 to be filled, or may be coupled and / or removably connected to a dispensed storage container 34. At least one storage container 34 preferably has shielding to minimize operator exposure to radiation from an activated irradiation target 16.

[0275] The irradiation target discharge system 27 further includes a discharge stopper 128 configured to prevent the irradiation target 16 from moving toward the storage container 34. The discharge stopper 128 is movable between a stop position, in which the discharge stopper 128 prevents the irradiation target 16 from moving into the storage container 34, and a release position, in which the discharge stopper 128 allows the irradiation target 16 to move into the storage container 34. The discharge stopper 128 is, for example, a magnetically or mechanically operated restriction element, preferably a pin that intersects the discharge conduit 120.

[0276] Alternatively, or upstream of the discharge blocker 128, the irradiation target discharge system 27 may include a discharge distributor (not shown) located at the outlet port 124 and configured to release only a predetermined amount of irradiation targets 16 into the storage container 34 at a time, the discharge distributor being configured to release the irradiation target 16 closest to the outlet port 124 and to retain the remaining targets in the discharge conduit 120. Preferably, the predetermined amount of irradiation targets 16 is equal to one target, so that the discharge distributor is configured to release only one irradiation target 16 from the discharge conduit 120 at a time. The structure of the optional discharge distributor is the same as that of the inlet distributor 68 of the decay station 30 and will not be described in detail herein.

[0277] exist Figure 1 In the embodiment shown, the exhaust conduit 120 is substantially straight. In this embodiment, the inclination of the exhaust conduit 120 is selected so that when the exhaust stop 128 is in the released position, the irradiation target 16 is discharged from the exhaust conduit 120 under the action of gravity.

[0278] According to an alternative embodiment (not shown), drain duct 120 is formed into an inverted U-shape and includes a first drain duct section, a second drain duct section, and an apex formed at the junction of the first and second drain duct sections. The apex is the highest point of drain duct 120, and the first and second drain duct sections lead downward from the apex. This type of U-shaped drain duct is described, for example, in patent application EP3326175A1 filed by the applicant.

[0279] Other profiles for the exhaust conduit 120 are possible.

[0280] The irradiation target exhaust system 27 further includes at least one pressurized gas inlet opening 130 formed in the wall of the exhaust conduit 120. Figure 1 In the embodiment shown, the pressurized gas inlet opening 130 is located between the shut-off valve 126 and the exhaust stop 128. It is connected to a pressurized gas source, for example the pressurized gas source 63, and forms part of the irradiation target drive system 25 of the apparatus 6.

[0281] Optionally, the irradiation target exhaust system 27 further includes a radiation detector 134 configured to measure radiation emitted by the irradiation target 16 housed in the exhaust duct 120 , and in particular, to measure a radiation dose rate emitted by the irradiation target 16 housed in the exhaust duct 120 .

[0282] Optionally, the irradiation target discharge system 27 may include a discharge counter 140 configured to count the number of irradiation targets 16 that are moved from the decay station 30 into the discharge duct. The discharge counter 140 is configured to count the number of irradiation targets 16 that pass through the discharge counter 140. The discharge counter 140 is a device capable of detecting the passage of an irradiation target 16 in front of the discharge counter 140. The discharge counter 140 has the same structure as the above-mentioned inlet counter 96.

[0283] Optionally, the apparatus 6 further includes an instrument tube system target counter 144, which is arranged at the entrance of the instrument tube system 12 downstream of the diverter 30 with respect to the displacement direction of the targets 16, 18 into the instrument tube system 12, and is configured to count the number of irradiation targets 16 or dummy targets 18 that are moved into or out of the instrument tube system 12. The instrument tube system target counter 144 is, in particular, a device capable of detecting the passage of a magnetic target, such as a dummy target 18, in front of the counter 144.

[0284] Preferably, the instrument tubing target counter 144 is positioned upstream of an isolation valve of the instrument tubing 12 that is configured for a pressure-tight seal with the instrument tubing 12 .

[0285] Optionally, the irradiation target supply system 12 may further include a target counter (not shown) which is arranged upstream of the diverter 30 with respect to the displacement direction of the targets 16 , 18 into the instrument tube system 12 .

[0286] In the above description, the decay station 30 is described as being connected to the instrument tube system 12 of the core of the nuclear reactor. However, the decay station 30 can be connected to other structures of the core of the nuclear reactor instead of the instrument tube system 12 as needed, with the same advantages.

[0287] Now refer to Figure 5 The diverter 32 according to the first embodiment will be described.

[0288] like Figure 5 As shown in FIG, the diverter 32 according to the first embodiment includes:

[0289] a first connector 150 intended to be connected to the irradiation target extraction system 27 ;

[0290] a second connector 152 intended to be connected to the irradiation target supply system 21 ; and

[0291] A third connector 154 intended to be connected to the instrument tubing system 12 .

[0292] More specifically, each connector 150, 152, 154 is intended to be connected to a corresponding conduit for displacement of the targets 16, 18. For example, the first connector 150 is intended to be connected to the decay conduit 52 of the decay station 30, the second connector 152 is intended to be connected to the supply tube 23 of the irradiation target supply system 21, and the third connector 154 is intended to be connected to the conduit 13 of the instrument tube system 12.

[0293] The first connector 150 may be direct (i.e., without the interposition of an intermediate system between the irradiation target exhaust system 27 and the diverter 32) or indirect (e.g., by connecting to the decay station 30, such as in Figure 1 ) is connected to the irradiation target discharge system 27.

[0294] The third connector 154 is spaced apart from the first connector 150 and the second connector 152 in the horizontal direction. Figure 5 In the example shown, the first connector 150 and the second connector 152 are substantially aligned in the vertical direction. The third connector 154 is located at an intermediate height between the height of the first connector 150 and the height of the second connector 152, for example.

[0295] The displacement of the targets 16 , 18 by the diverter 32 is driven by the target drive system 25 described above.

[0296] The diverter 32 includes at least one diverter conduit 156 that can move between a first position and a second position, in which the diverter conduit 156 connects one of the first connector 150 and the second connector 152 to the third connector 154 so as to define a path for the target 16, 18 from one of the first connector 150 and the second connector 152 to the third connector 154, and in the second position, it does not connect one of the first connector 150 and the second connector 152 to the third connector 150.

[0297] More specifically, in Figure 5 In the example shown, the diverter 32 includes a first diverter conduit 156A and a second diverter conduit 156B.

[0298] The geometry of the diverter conduits 156A, 156B is selected to minimize the size of the diverter 32. Specifically, each diverter conduit 156A, 156B is shaped so that it causes two changes in direction of the targets 16, 18 intended to circulate therein along its length. This particular shape of the diverter conduits 156A, 156B provides a more compact diverter 32 than, for example, an embodiment in which the diverter conduits 156A, 156B are straight along their entire length. This compact shape is important because the space available for the diverter 32 within a nuclear reactor is limited.

[0299] Each change of direction occurs at a distance from the longitudinal end of the diverter conduits 156A, 156B.

[0300] More specifically, each diverter duct 156A, 156B comprises a substantially straight end section 158, 159 at each end of the diverter duct 156A, 156B and an intermediate section 160 extending between the end sections 158, 159. The end sections 158, 159 are preferably parallel to each other and, in particular, extend substantially horizontally. For example, the central axes of the end sections 158, 159 are offset from each other in a direction perpendicular to their longitudinal direction, and in particular in a vertical direction. The offset x is strictly greater than zero, for example, comprised between 10 and 50 mm.

[0301] exist Figure 5 In the embodiment shown, the intermediate section 160 is curved. Preferably, for each diverter conduit 156A, 156B, the transition between the curved intermediate section 160 and each of the substantially straight end sections 158, 159 is continuous, i.e., without angles. Preferably, in this embodiment, the central axes of the diverter conduits 156A, 156 form a continuous line. Figure 5 In the example shown, the intermediate section 160 bends continuously between its ends. This continuous bending of the diverter conduits 156A, 156B and the absence of angles along their lengths allow for particularly smooth displacement of the targets 16, 18 through the diverter conduits 156A, 156B despite the change in direction.

[0302] exist Figure 5 In the example shown, the intermediate section 160 preferably includes a concave section and a convex section separated by an inflection point. In particular, the inflection point is located at the geometric middle of the central axis of the intermediate section 160 measured along the central axis of the intermediate section 160.

[0303] The radius of curvature of each diverter conduit 156A, 156B and its diameter are selected based on the length and diameter of the target 16, 18 so as to result in smooth displacement of the target 16, 18 through the conduits 156A, 156B.

[0304] Preferably, the radius of curvature of each diverter duct 156A, 156B at the junction between each end section 158 and the middle section 160 is comprised between 200 and 800 mm. Tests performed by the inventors have shown that this particular radius of curvature results in a particularly small size of the diverter 32 combined with a substantially unresisting displacement of the targets 16, 18 through the diverter ducts 156A, 156B. This geometry is particularly advantageous in the case of cylindrical targets 16, 18 having a circular base with a diameter comprised between 9 mm and 12 mm and a length comprised between 9 mm and 80 mm.

[0305] According to an alternative embodiment (not shown), the middle section 160 is straight instead of Figure 5 Compared to the embodiment with a curved middle section 160, this embodiment has the advantage of being easier to manufacture.

[0306] For each diverter conduit 156A, 156B, the absolute value of the angle between the orientation of the end segments 158, 159 and the central axis of the middle segment 160 and the diameter of the diverter conduits 156A, 156B are selected based on the length and diameter of the targets 16, 18 so as to result in smooth displacement of the targets 16, 18 through the conduits 156A, 156B.

[0307] In this embodiment, for each diverter duct 156A, 156B, the absolute value of the angle between the orientation of the end segments 158, 159 and the central axis of the intermediate segment 160 is comprised between 2° and 5°. Tests performed by the inventors have shown that this particular inclination angle of the intermediate segment 160 results in a particularly small size of the diverter 32 combined with a substantially unimpeded displacement of the targets 16, 18 through the diverter ducts 156A, 156B. This geometry is particularly advantageous in the case of cylindrical targets 16, 18 having a circular base with a diameter comprised between 9 mm and 12 mm and a length comprised between 9 mm and 80 mm.

[0308] The first and second diverter conduits 156A, 156B are preferably symmetrical about a mid-plane between the two conduits 156A, 156B. The first diverter conduit 156A extends downward from the first connector 150 to the third connector 154, while the second diverter conduit 156B extends upward from the second connector 152 to the third connector 156.

[0309] The first diverter conduit 156A connects the first connector 150 to the third connector 154 in its first position so as to define a path for the targets 16, 18 to be displaced from the first connector 150 to the third connector 154. Figures 1 to 4 In the example shown, the first diverter conduit 156A defines a path for the targets 16, 18 to be displaced between the decay station 30 and the instrument tube system 12. Figure 5 In the illustrated configuration of the diverter 32 , the first diverter conduit 156A is in its first position.

[0310] More specifically, in the first position, the ends of the first diverter conduit 156A are aligned with the first connector 150 and the third connector 154 , respectively.

[0311] In the second position of the first diverter conduit 156A, the first diverter conduit 156A does not connect the first connector 150 to the third connector 154. For example, in the second position, the end of the first diverter conduit 156A is not aligned with the first connector 150 and the third connector 154. Therefore, no displacement of the targets 16, 18 is possible between the first connector 150 and the third connector 154, and therefore, in this particular example, between the decay station 30 and the instrument tube system 12.

[0312] The second diverter conduit 156B connects the second connector 152 to the third connector 154 in its first position so as to define a path for the irradiation targets 16, 18 to be displaced from the second connector 152 to the third connector 154. Figures 1 to 4 In the example shown, the second diverter conduit 156B defines a path for displacement of the targets 16 , 18 between the irradiation target supply system 21 and the instrument tube system 12 .

[0313] More specifically, in the first position, the ends of the second diverter conduit 156B are aligned with the second connector 152 and the third connector 154, respectively.

[0314] In the second position of second diverter conduit 156B, second diverter conduit 156B does not connect second connector 150 to third connector 154. For example, in the second position, the end of second diverter conduit 156B is not aligned with second connector 152 and third connector 154. Therefore, no displacement of targets 16, 18 is possible between second connector 152 and third connector 154, and therefore, in this particular example, between irradiation target supply system 21 and instrument tube system 12.

[0315] exist Figure 5 In the illustrated configuration, the second diverter conduit 156B is in its second position.

[0316] Figure 5 The configuration of the diverter 32 shown corresponds to the first configuration of the diverter 32. Figure 5 In the illustrated configuration, the diverter 32 defines a path for the targets 16 , 18 to be displaced from the decay station 30 to the instrument tube system 12 .

[0317] The configuration of the diverter 32 with the first diverter conduit 156A in the second position and the second diverter conduit 156B in the second position corresponds to a second configuration of the diverter 32. In this configuration, the diverter 32 defines a path for displacement of the targets 16, 18 between the irradiation target supply system 21 and the instrument tube system 12.

[0318] Due to its structure, in the first construction of the diverter 32, the diverter 32 allows the targets 16, 18 to be transferred directly from the conduit connected to the first connector 150 (e.g., the decay conduit 52) ​​to the conduit connected to the third connector 156 (e.g., the conduit 13 of the instrument conduit system 12), that is, in the first construction of the diverter 32, there is a direct connection between these conduits through the diverter 32.

[0319] In the second construction of the diverter 32, the diverter 32 allows the targets 16, 18 to be transferred directly from the conduit connected to the second connector 152 (for example, the supply conduit 23 of the irradiation target supply system 21) to the conduit connected to the third connector 156 (for example, the conduit 13 of the instrument tube system 12), that is, in the second construction of the diverter 32, there is a direct connection between these conduits through the diverter 32.

[0320] The diverter 32 also includes an actuator configured to displace at least one diverter tube 156 from the second position to the first position and / or from the first position to the second position, such as by rotation or translation.

[0321] exist Figure 5 In the example shown, the actuator includes a piston 168. In this example, the piston 168 defines the first diverter conduit 156A and the second diverter conduit 156B therein.

[0322] Piston 168 can Figure 5 The diverter 32 is configured to move between a first position shown and a second position (not shown), wherein in the first position of the piston 168, the first diverter conduit 156A is in its first position and the second diverter conduit 156B is in its second position, and in the second position of the piston 168, the first diverter conduit 156A is in its second position and the second diverter conduit 156B is in its first position. The diverter 32 is configured such that when the second diverter conduit 156B is in its second position, the first diverter conduit 156A is in its first position, and vice versa.

[0323] The piston 168 is preferably a pneumatic piston.

[0324] More specifically, in Figure 5 In the example shown, the diverter 32 includes a diverter housing 170 including a first wall 172 and a second wall 174 spaced apart from each other, with the diverter conduits 156A, 156B extending from the first wall 172 to the second wall 174. Figure 5 In the example shown, the first wall 172 and the second wall 174 are substantially parallel. The first connector 150 and the second connector 152 are disposed on the first wall 172, and the third connector 156 is disposed on the second wall 174, for example.

[0325] The piston 168 is received in the housing 170 so as to be slidable therein relative to the housing 170 along a displacement direction X. The displacement direction X is in particular perpendicular to the axis of the end sections 158, 159 of the diverter ducts 156A, 156B and is more particularly vertical.

[0326] A first chamber 176 and a second chamber 178 are defined between the piston 168 and the housing 170 , and these chambers 176 , 178 are located on either side of the piston 168 along the displacement direction X of the piston 168 .

[0327] The diverter housing 170 also includes an inlet port 180 intended to introduce pressurized fluid into the first chamber 176 in order to displace the piston 168 from its first position to its second position, and an outlet port 182 intended to allow air to be removed from the second chamber 178 during displacement of the piston 168 .

[0328] The piston 168 is configured to return to its first position in the absence of pressurized fluid in the first chamber 176. In this embodiment, the first position of the piston 168 corresponds to a passively safe position because it connects the instrument tube system 12 to the decay station 30 and, therefore, to an area with strong radiation shielding.

[0329] exist Figure 5 In the example shown, the first diverter conduit 156A is located above the second diverter conduit 156B, and the piston 168 is configured to move upward from a first position to a second position and downward from the second position to the first position.

[0330] The diverter 32 preferably includes a sealing arrangement 177 configured for sealing the space between the piston 168 and the first and second walls 172, 174 of the diverter housing 170. The sealing arrangement 177 is provided in the form of a sealing ring extending around the circumference of the piston 168, for example.

[0331] The longest dimension of the piston 168 in a plane perpendicular to the displacement direction of the piston 168 depends on the offset x between the end sections 158, 159 of the conduits 156A, 156B and the geometry of each conduit 156A, 156B, in particular on the angle between the end sections 158, 159 and the middle section 160 or the radius of curvature at the junction between the end sections 158, 159 and the middle section 160.

[0332] The steering gear housing 170 is, in particular, cylindrical, for example, with a circular bottom surface. In this case, the first connector 150 and the second connector 152 are formed, for example, on one bottom surface of the cylinder, and the third connector 154 is formed on the opposite bottom surface of the cylinder. The piston 168 has a shape corresponding to that of the steering gear housing 170, in particular, a cylindrical shape with a circular bottom surface, the diameter of which substantially corresponds to the diameter of the steering gear housing 170.

[0333] In this embodiment, the actuator also includes a supply of pressurized gas for displacing the piston 168 .

[0334] The switching unit 40 is configured to control the supply of a predetermined amount of pressurized gas to the first chamber 176 in order to displace the piston 168 from its first position to its second position and thus place the diverter 32 in its second configuration. The displacement of the piston 168 from the second position to the first position is achieved without injecting pressurized gas into the first chamber 176.

[0335] Now refer to Figure 6 A diverter 32' according to a second embodiment is described. In this figure, the diverter 32 according to the first embodiment is shown. Figure 5 Elements that are identical to the elements shown are denoted by the same reference numerals.

[0336] The diverter 32′ according to the second embodiment differs from the diverter 32 according to the first embodiment in that there is only one diverter conduit 156. More specifically, the diverter conduit 156 connects the first connector 150 to the third connector 154 in its first position and connects the second connector 152 to the third connector 154 in its second position.

[0337] In this embodiment, the diverter tube 156 is rotatable between a first position and a second position.

[0338] More specifically, in this embodiment, the diverter 32' includes a support member 180 and a rotatable catheter carrier 182, the support member 180 is, for example, a plate, the first connector 150 and the second connector 152 are arranged on the support member 180, and the rotatable catheter carrier 182 is, for example, a disk, which is mounted on the support member 180 in a manner that it can rotate relative to the support member 180 around a rotation axis R perpendicular to the plane of the support member 180.

[0339] One end 184 of the steering conduit 156 is mounted to the rotatable conduit carrier 182 such that rotation of the rotatable conduit carrier 182 displaces the steering conduit 156 between its first position and its second position. The rotation axis R is aligned with the axis of the end segment 159 of the steering conduit 156, which is located opposite the end of the steering conduit 156 mounted to the rotatable conduit carrier 182.

[0340] Depending on the angular position of the rotatable catheter carrier 182, the end section 158 of the diverter catheter 156 closest to the support member 180 is aligned with the first connector 150 or with the second connector 152, respectively defining a path for the targets 16, 18 to move from the first connector 150 to the third connector 154 or from the second connector 152 to the third connector 154.

[0341] The position of the end section 159 of the diverter conduit 156 does not change during rotation of the rotatable conduit carrier 182 .

[0342] For example, in Figure 6 In the example shown, in which the first connector 150 is positioned above and vertically aligned with the second connector 152, the diverter conduit 156 is rotated 180 degrees about the rotational axis R in a first rotational direction D to move the diverter conduit 156 from its first position to its second position, and the diverter conduit 156 is rotated 180 degrees about the rotational axis R in a second direction opposite to the first rotational direction D to move the diverter conduit 156 from its second position to its first position.

[0343] The third connector 154 is in particular fixedly received in a fixed support structure (not shown). The fixed support structure is formed, for example, by a plate, which in particular extends parallel to the plate forming the support 180. The fixed support structure and the support 180 can in particular be part of a steering housing which further comprises at least one connecting wall connecting the fixed support structure to the support 180. The steering housing can be similar to the one in Figure 5 The steering gear housing is shown in FIG.

[0344] The end section 159 of the steering tube 156 is connected to the third connector 154 via an intermediate connector 185, which allows relative rotation of the steering tube 156 relative to the third connector 154. The intermediate connector 185 is, for example, a quick-connect system including two separate components 185A and 185B that are rotatable relative to each other and thus allow relative rotation of the steering tube 156 relative to the third connector 154.

[0345] In this embodiment, for example, the actuator includes a motor configured to rotate the diverter tube 156 by a predetermined angle in the first rotational direction or the second rotational direction so as to displace the diverter tube 156 between the first position and the second position. More specifically, the motor is connected to the rotatable tube carrier 182 by any suitable means so as to drive the rotatable tube carrier 182 to rotate by the predetermined angle in the first rotational direction or the second rotational direction.

[0346] The switching unit 40 is configured to control the motor as needed.

[0347] The geometry of the diverter conduit 156 is the same as that described for diverter conduits 156A, 156B.

[0348] The method for producing an activated irradiation target 16 using the above-described apparatus 6 comprises the following steps:

[0349] - transferring 200 a number of q1 non-activated irradiation targets 16 from the irradiation target supply system 21 to the instrument tube system 12;

[0350] - exposing 202 the q1 number of non-activated irradiation targets 16 to a neutron flux in the instrument tube system 12 for a predetermined irradiation duration d1, so as to obtain q1 number of partially activated irradiation targets 16, the predetermined irradiation duration d1 being less than or equal to a minimum activation time for complete conversion of the precursor material of the irradiation targets (16) into the desired radionuclide; and

[0351] - transferring 204 a number q1 of irradiation targets 16 from the instrument tube system 12 to the decay station 30; and

[0352] Discharging 214 at least some of the irradiated targets 16 from the decay station 30 into a target storage container 34 , in particular via the discharge system 27 .

[0353] Now refer to Figure 7 The method according to the first embodiment will be described in more detail.

[0354] According to a first embodiment, the predetermined irradiation duration d1 is strictly shorter than the minimum activation time required for complete conversion of the precursor material contained in the irradiation target 16 into the desired radionuclide.

[0355] Thus, the q1 first number of irradiation targets 16 obtained at the end of step 204 is q1 first number of partially activated irradiation targets 16. During step 206, the q1 first number of partially activated irradiation targets 16 are transferred from the instrument tube system 12 to the decay station 30.

[0356] The method according to this embodiment further comprises the following consecutive steps between steps 206 and 214:

[0357] - transferring 208 a number q2 of non-activated irradiation targets 16 from the irradiation target supply system 21 to the instrument tube system 12;

[0358] - transferring 210 a number q1 of partially activated irradiated targets 16 from the decay station 30 back to the instrument tube system 12;

[0359] - Exposing q1 number of partially activated irradiation targets 16 and q2 number of non-activated irradiation targets 16 to the neutron flux in the instrument tube system 12 for a predetermined irradiation duration d2 to obtain q1 number of partially activated or fully activated irradiation targets 16 and q2 number of partially activated irradiation targets 16.

[0360] Preferably, the irradiated targets 16 discharged from the decay station 30 into the target storage container 34 during step 214 are fully activated irradiated targets 16 .

[0361] The above-mentioned “transfer” step is performed by the target driving system 25 .

[0362] During step 210 , the partially activated irradiation targets 16 are conveyed out of the decay station 30 through the inlet distributor 68 , which lets only a predetermined amount of irradiation targets 16 pass through at a time while retaining the remaining irradiation targets 16 in the decay station 30 .

[0363] More specifically, in order to release a predetermined amount A of irradiated target 16, the following steps are performed:

[0364] - Step a1: Displacing the locking element 70 from the release position to the locking position by means of the first actuator 74;

[0365] Step a2: activating the pressurized gas supply source 60 so as to obtain a pressurized gas flow through the decay duct 52 from the outlet 58 of the decay duct 52 , said pressurized gas flow pushing the irradiation targets 16 housed in the decay duct 52 towards the inlet 56 of the decay duct 52 until they come into contact with the locking element 70 positioned in the locking position;

[0366] - step a3: displacing the holder 72 by means of the second actuator 76 from the retracted position to an extended position in which the holder 72 rests on the irradiation target 16 housed in the decay duct 52;

[0367] - Step a4: displacing the locking element 70 from the locking position to the releasing position by means of the first actuator 74, so that a predetermined amount of irradiation targets 16 corresponding to the irradiation targets 16 located downstream of the holder 72 in the direction of the pressurized gas flow are transported out of the decay duct 52 through the decay duct inlet 56 by the pressurized gas flow, while the remaining irradiation targets 16 (i.e., the irradiation targets 16 against which the holder 72 abuts and the irradiation targets 16 located upstream thereof) are retained in the decay duct 52 by means of the holder 72 positioned in the extended position.

[0368] Preferably, the flow of pressurized gas remains activated throughout steps a2 to a4.

[0369] More specifically, during step a3 , the holder 72 rests against the irradiation targets 16 facing the holder 72 , which extend on either side of the holder 72 along the length of the decay conduit 52 .

[0370] The quantity q1 is preferably a multiple of the predetermined amount A of the irradiated target, such that q1 = m*A, where m is an integer greater than or equal to 1, and preferably strictly greater than 1.

[0371] In the case where m is strictly greater than 1, during a step 210 , steps a1 to a4 of the above sequence are repeated m times, so that a number q1 of irradiation targets 16 is released from the decay station 30 .

[0372] In the preferred example where the predetermined amount A of irradiation target 16 is equal to 1, the above sequence of steps a1 to a4 is repeated q1 times.

[0373] Preferably, during step 210 , the entry counter 96 counts the number of irradiation targets 16 transferred from the decay station 30 into the instrument tube system 12 and repeats the above sequence of steps a1 to a4 until q1 number of irradiation targets 16 have been transferred to the instrument tube system 12 .

[0374] During step 210, the q1 number of partially activated irradiation targets 16 are transferred from the decay station 30 to the instrument finger 14 which houses the q2 number of irradiation targets 16 transferred to the instrument finger 14 during step 208 and occupy positions in the instrument finger 14 above the q2 number of inactivated irradiation targets 16.

[0375] Thus, at the end of step 210 , the instrument finger 14 contains a number q 2 of non-activated irradiation targets and a number q 1 of partially activated irradiation targets 16 in the direction from its bottom to its top.

[0376] Step 214 is a step of discharging q1 number of fully activated irradiation targets 16 from the decay station 30 .

[0377] During this step, a quantity q1 is discharged through the decay station outlet 58 of the decay station 30 and transferred into the discharge system 27 by means of the target drive system 25 .

[0378] According to one example, during step 214, the exit block 84 is opened and the irradiation targets 16 are conveyed into the exhaust conduit 120 by a flow of pressurized gas flowing in a direction from the inlet 56 to the outlet 58 of the decay conduit 52 until they abut against the exhaust block 128. The exhaust block 128 is then opened so that the irradiation targets 16 can be exhausted into the corresponding exhaust receptacles 34.

[0379] In an embodiment in which the decay station 30 includes an outlet distributor 92, a quantity q1 corresponding to the predetermined amount is discharged in batches through the decay station outlet 58 by performing steps a1 to a4 as described above, replacing "inlet" with "outlet" and replacing "outlet" with "inlet".

[0380] Optionally, before the irradiation targets 16 are discharged from the decay station 30, the radiation (particularly the dose rate) emitted by the q1 number of irradiation targets 16 present in the discharge duct 52 is measured by the exit radiation detector 102 and / or the optional intermediate radiation detector 104, and the irradiation targets 16 are discharged only when the measured radiation (particularly the dose rate) is below a predetermined threshold.

[0381] During step 214, only q1 number of fully activated irradiation targets 16 are discharged from the decay station 30. According to a preferred embodiment, only q1 number of irradiation targets 16 are present in the decay station 30 when the q1 number of fully activated irradiation targets 16 are discharged.

[0382] Preferably, the method comprises, between steps 212 and 214 , a step 216 of transferring the q1 number of fully or partially activated irradiation targets 16 and the q2 number of partially activated irradiation targets 16 to the decay station 30 .

[0383] Step 216 is performed by the target drive system 25. During step 216, the first quantity of irradiation targets 16 and the second quantity of irradiation targets 16 are preferably driven into the decay station 30 by the irradiation target drive system 25 until they abut against the exit stop 84 of the decay station 30 or, if an exit distributor 92 is present, against a locking element of the exit distributor 92.

[0384] The linear order of the irradiation targets 16 is maintained during this step so that the q1 number of fully or partially activated irradiation targets 16 are closer to the decay conduit outlet 52 than the q2 number of partially activated irradiation targets 16 .

[0385] After step 216, q1 number of non-activated irradiation targets 16 are transferred to the instrument tube system 12 (step 218), and q2 number of partially activated irradiation targets 16 are transferred back to the instrument tube system 12 using the target drive system 25 through the implementation of the above-mentioned steps a1 to a4 (step 220).

[0386] At the end of step 220 , the instrument finger 14 contains, in a direction from its bottom to its top, a number q1 of non-activated irradiation targets 16 and a number q2 of partially activated irradiation targets 16 .

[0387] After step 220, the method includes step 222 of exposing the irradiation targets 16 housed in the instrument fingers 14 to the neutron flux in the core 10 of the nuclear reactor for a predetermined irradiation duration d3 to obtain a number q1 of partially activated irradiation targets 16 and a number q2 of fully activated irradiation targets.

[0388] Steps 216, 218, 220, and 222 may be repeated multiple times, with each repetition resulting in a batch of fully activated irradiated targets 16. Each batch of fully activated irradiated targets 16 is discharged from the decay station via step 214.

[0389] Optionally, the method includes the steps of displacing the diverter 32 to the second configuration before transferring the irradiation target 16 from the irradiation target supply system 21 to the instrument tube system 12 during steps 200, 208, and 218; and displacing the diverter 32 from the second configuration to the first configuration before transferring the irradiation target 16 from the instrument tube system 12 to the decay station 30 during steps 206, 210, and 220.

[0390] Preferably, in steps 206 , 210 , 216 and 220 , the entry counter 96 counts the number of irradiation targets 16 transferred from the instrument tube system 12 into the decay station 30 or from the decay station 30 into the instrument tube system 12 .

[0391] The quantity q1 is preferably equal to the quantity q2.

[0392] Preferably, all irradiation durations (eg, d1 , d2 , and d3 ) for exposing the irradiation target 16 to the neutron flux in the core of the nuclear reactor are the same.

[0393] According to one example, each of these irradiation durations is equal to half the minimum activation time for complete conversion of the precursor material contained in the irradiation targets 16 into the desired radionuclide. In this case, the q1 number of irradiation targets 16 obtained at the end of step 212 and the quantity of irradiation targets 16 located on top of the instrument finger 14 at the end of step 222 are fully activated irradiation targets 16. Thus, these fully activated irradiation targets can be retrieved from the device 6 with a retrieval period corresponding to half the activation time of the desired radionuclide.

[0394] In fact, each of these irradiation durations can correspond to a fraction (equal to 1 / M) of the minimum activation time for complete conversion of the precursor material contained in the irradiation target 16 into the desired radionuclide. The integer M is selected based on the relationship between the required retrieval interval and the minimum activation time for complete conversion of the precursor material contained in the irradiation target 16 into the desired radionuclide. In this case, the instrument finger 14 includes or can include M irradiation targets 16 in different activation stages at the end of step 222, and each batch of irradiation targets 16 must be exposed to the neutron flux in the core 10 M times before being fully activated. In this case, the q1 number of irradiation targets 16 obtained at the end of step 212 are only partially activated, and these irradiation targets 16 must be returned to the instrument finger 14 to be exposed to the neutron flux the number of times required to achieve the minimum activation time.

[0395] Optionally, after step 216 and before discharging the fully activated irradiation target 16 in step 214 , the method further comprises the step of maintaining the fully activated irradiation target 16 in the decay station 30 for a decay duration d4 .

[0396] The decay duration d4 corresponds to the time required for the radiation (particularly the dose rate) emitted by the q1 number of fully activated irradiation targets 16 to fall below a predetermined threshold. According to one example, the decay duration d4 is predetermined based on the properties of the material contained in the irradiation targets 16. According to an alternative embodiment, the decay duration d4 depends on the measurement of the radiation (particularly the dose rate) by the exit radiation detector 102 and / or the optional intermediate radiation detector 104.

[0397] According to this option, step 214 is performed after the aforementioned number of fully activated irradiation targets 16 have remained in the decay station 30 for the decay duration d3.

[0398] According to a specific example, multiple batches N of irradiation targets are delivered with a delivery interval equal to half the minimum activation time for complete conversion of the precursor material contained in the irradiation targets 16 into the desired radionuclide, which delivery interval is optionally increased by the decay duration d4 required for the radiation emitted by the q1 number of fully activated irradiation targets 16, in particular the dose rate, to drop below a predetermined threshold.

[0399] In this particular example, all predetermined irradiation durations are equal to 50% of the minimum activation time for complete conversion of the precursor material contained in the irradiation target 16 into the desired radionuclide.

[0400] In step 200 of the method, N inactive irradiation targets 16 are transferred from the irradiation target supply system 21 to the instrument finger 14 .

[0401] In step 204 , the N non-activated irradiation targets 16 are subjected to a neutron flux in a nuclear reactor core for a time equal to half the minimum activation time for complete conversion of the precursor material contained in the irradiation targets 16 .

[0402] In step 206 , the N partially activated irradiated targets 16 are transferred to the decay station 30 .

[0403] In step 208 , N inactive irradiation targets 16 are transferred from the irradiation target supply system 21 to the instrument fingers 14 .

[0404] In step 210 , N partially activated irradiation targets 16 are transferred from the decay station 30 into the instrument finger 14 such that the instrument finger contains N inactivated irradiation targets 16 and N partially activated irradiation targets 16 from bottom to top.

[0405] In step 212, the irradiation targets 16 contained in the instrument fingers 14 are subjected to a neutron flux in the nuclear reactor core for a time equal to half the minimum activation time for complete conversion of the precursor material contained in the irradiation targets 16 so as to obtain N fully activated irradiation targets 16 and N partially activated irradiation targets 16.

[0406] In step 216, the N fully activated irradiation targets 16 and the N partially activated irradiation targets 16 are transferred from the instrument fingers 14 to the decay station 30, preserving the linear order of the irradiation targets 16. Thus, the N fully activated irradiation targets 16 are closer to the exit of the decay station 30 than the N partially activated irradiation targets 16.

[0407] Then, in step 214, the N fully activated irradiated targets 16 are discharged into the discharge container 34. Optionally, before they are discharged in step 214, they remain in the decay station 30 for a predetermined decay duration d4.

[0408] In step 218 , N inactive irradiation targets 16 are transferred from the irradiation target supply system 21 to the instrument fingers 14 .

[0409] In step 220 , N partially activated irradiation targets 16 stored in decay station 30 are transferred from decay station 30 to instrument finger 14 so that the instrument finger contains N inactivated irradiation targets 16 and N partially activated irradiation targets 16 from bottom to top.

[0410] In step 222, the irradiation targets 16 contained in the instrument fingers 14 are subjected to a neutron flux in the nuclear reactor core for a time equal to half the minimum activation time for complete conversion of the precursor material contained in the irradiation targets 16 so as to obtain N fully activated irradiation targets 16 and N partially activated irradiation targets 16.

[0411] Steps 216 to 222 can be repeated as often as desired, with each repetition of these steps resulting in the production of a batch of N fully activated irradiation targets 16, the production duration of which is equal to half the minimum activation time for complete conversion of the precursor material contained in the irradiation targets 16 into the desired radionuclide. The batch can then be discharged by step 214 after a selectable decay duration d4 in the decay station 30.

[0412] The apparatus 6 preferably includes a controller 160 configured to implement the method.

[0413] In particular, the apparatus 6 for generating activated irradiation targets (e.g., the ICU 42) optionally includes a controller 160 configured to control the following steps performed by the apparatus 6:

[0414] - using the target drive system 25 to transfer q1 number of non-activated irradiation targets 16 from the irradiation target supply system 21 to the instrument tube system 12;

[0415] - exposing the q1 number of non-activated irradiation targets 16 to the neutron flux in the instrument tube system 12 for a predetermined irradiation duration d1, so as to obtain q1 number of partially activated irradiation targets 16, the predetermined irradiation duration d1 being strictly less than the minimum activation time for complete conversion of the precursor material contained in the irradiation targets 16 into the desired radionuclide;

[0416] - using the target drive system 25 to transfer q1 number of partially activated irradiation targets 16 from the instrument tube system 12 to the decay station 30;

[0417] - using the target drive system 25 to transfer q2 number of non-activated irradiation targets 16 from the irradiation target supply system 21 to the instrument tube system 12;

[0418] - using the target drive system 25 to transfer q1 number of partially activated irradiation targets 16 from the decay station 30 back to the instrument tube system 12;

[0419] - exposing q1 number of partially activated irradiation targets 16 and q2 number of non-activated irradiation targets 16 to a neutron flux in the instrument tube system for a predetermined irradiation duration d2 to obtain q1 number of partially activated or fully activated irradiation targets 16 and q2 number of partially activated irradiation targets 16; and

[0420] Discharging at least some of the irradiated targets 16 , and more particularly fully activated irradiated targets 16 , from the decay station 30 into a target storage container 34 .

[0421] The decay station 30 and the device 6 described above are advantageous.

[0422] In practice, the decay station 30 allows a predetermined amount of irradiated targets 16 to be transferred into the decay station 30 for temporary storage of partially activated irradiated targets 16 before being transferred back into the core 10 of the nuclear reactor for further activation with the aid of the inlet distributor 68, or for decaying the activated short-lived radioactive isotopes to an acceptable level before they are discharged into the storage container 34.

[0423] A predetermined quantity of irradiated targets 16 housed in the decay station 30 can be transferred back to the core 10 provided by the decay station 30, which allows for the production of multiple batches of radioisotopes with a delivery interval that is less than the activation time of the radioisotopes in the core within the same instrument tube system 12. For example, multiple batches of radioisotopes can be produced with a delivery interval that corresponds to half the activation time of the radioisotopes in the core.

[0424] In particular, the decay station 30 can receive a batch of partially activated irradiated targets 16 (having spent only a portion of the required activation time in the core) and a batch of fully activated irradiated targets (having spent the required activation time in the core) in this linear sequence from the decay station's inlet to its outlet. The inlet distributor 68 and associated inlet counter 96 then allow for the selective transfer of only the partially activated radioisotopes back into the core 10 while maintaining the fully activated irradiated targets 16 in the decay station 30.

[0425] By allowing the fully activated irradiated targets 16 to be stored temporarily within the discharge loop of the device 6 for a duration sufficient to reduce the activity of the short-lived radioactive isotopes to an acceptable level, the decay station 30 also allows the fully activated irradiated targets 16 to be discharged into conventional storage containers 34 without the need for a highly radioactive material work shielded room or manipulator. Once the activity level is reduced to below a predetermined threshold, the activated irradiated targets 27 can be automatically transferred from the decay station 30 to the discharge system 27 of the device 6. In addition, the decay station 30 can be directly integrated into existing radionuclide generation systems with little additional effort, while allowing for the safe decay of short-lived highly radioactive byproduct isotopes.

[0426] The decay station 30 thus constitutes a cost-effective and compact solution for removing activated irradiation targets 16 from the core 10 of a nuclear reactor while minimizing risks to the environment.

[0427] The method according to the invention allows to reduce the delivery interval of the radioisotopes contained in the fully activated irradiated targets 16. In fact, at each moment, the instrument finger 14 contains at least two batches of irradiated targets 16 in different activation stages. The decay station 30 serves as an intermediate storage for the partially activated batches while a new batch of non-activated targets 16 is introduced into the instrument finger 14. Once the new batch has been introduced into the instrument finger 14, the batch of partially activated irradiated targets 16 can be transferred back into the instrument finger 14 for further exposure to the neutron flux. The specific structure of the decay station 30 with the inlet distributor 68 and the associated inlet counter 96 makes it possible to transfer only one of the two batches of irradiated targets back into the instrument finger 14, while the other batch remains in the decay station 30 before being discharged into the corresponding discharge container, possibly after a decay time d3 in the decay station 30 that allows sufficient decay of the short-lived highly radioactive isotope.

[0428] According to a second embodiment, the method for producing an activated irradiation target 16 using the device 6 described above comprises the following steps:

[0429] - transferring the non-activated irradiation target 16 from the irradiation target supply system 21 to the instrument tube system 12;

[0430] - exposing the irradiation target 16 to the neutron flux in the instrument tube system 12 for a predetermined irradiation duration corresponding to the minimum activation time required for complete conversion of the precursor material contained in the irradiation target 16 into the desired radionuclide, so as to obtain a fully activated irradiation target 16;

[0431] - Transferring the fully activated irradiation target 16 from the instrument tube system 12 to the decay station 30;

[0432] - Maintaining the fully activated irradiated target 16 in the decay station 30 for the decay duration

[0433] Discharge of the irradiated targets 16 from the decay station 30 into the target storage container 34 .

[0434] The decay duration corresponds to the time required for the radiation (particularly the dose rate) emitted by the q1 number of fully activated irradiation targets 16 to fall below a predetermined threshold. According to one example, the decay duration is predetermined based on the properties of the material contained in the irradiation targets 16. According to an alternative embodiment, the decay duration depends on the measurement of the radiation (particularly the dose rate) by the exit radiation detector 102 and / or the optional intermediate radiation detector 104.

[0435] Optionally, the method includes the steps of: displacing the diverter 32 to the second configuration before transferring the irradiation target 16 from the irradiation target supply system 21 to the instrument tube system 12; and displacing the diverter 32 from the second configuration to the first configuration before transferring the irradiation target 16 from the instrument tube system 12 to the decay station 30.

[0436] Preferably, an entry counter 96 counts the number of irradiated targets 16 transferred from the instrument tube system 12 into the decay station 30 .

[0437] The method according to this alternative results in the production of radionuclides with a delivery interval equal to the minimum activation time-extended decay duration of the desired radionuclide.

[0438] The method according to this alternative is advantageous. Because the irradiation target enters container 34 only after the highly radioactive isotope byproducts have decayed, it improves safety and reduces radiation contamination of the environment and personnel. Furthermore, it can be performed automatically, eliminating the need for additional, separate equipment, such as a shielded room for handling highly radioactive materials. Therefore, it is easy to implement and requires minimal space.

[0439] In the above description, the diverter 32 is described as being part of an apparatus including the decay station 30. In this case, it is indirectly connected to the irradiation target discharge system 27 via the decay station 30. However, the diverter 32 may also be part of an apparatus that does not include the decay station 30 and then be directly connected to the irradiation target discharge system 27 without the decay station 30 interposed therebetween.

[0440] Additionally, the diverter 32 is described as being connected to the instrumentation tubing 12 of the nuclear reactor core. However, if desired, the diverter 32 can be connected to other structures within the nuclear reactor core instead of the instrumentation tubing 12 with the same advantages.

[0441] The present application also relates to an apparatus for producing an activated irradiation target 16 in an instrument tube system 12 of a nuclear reactor, the apparatus comprising:

[0442] - an irradiation target supply system 21 as described above, which is configured to provide non-activated irradiation targets 16;

[0443] - an instrument tube system 12 as described above, configured for receiving irradiation targets 16 from an irradiation target supply system 21 on account of their activation by exposure to a neutron flux in a nuclear reactor;

[0444] an irradiation target exhaust system 27 comprising a target outlet port configured to be coupled to a target storage container 34,

[0445] a diverter 32 as described above, configured to selectively define a path for displacement of the irradiation target 16 between the irradiation target supply system 21 and the instrument tube system 12 or between the instrument tube system 12 and the irradiation target exhaust system 27, the first connector 150 being connected to the irradiation target exhaust system 27, the second connector 152 being connected to the irradiation target supply system 21, and the third connector 154 being connected to the instrument tube system 12; and

[0446] An irradiation target drive system 25 configured for transporting at least some of the irradiation targets 16 through the apparatus 6 .

Claims

1. A decay station (30) configured to receive irradiation targets (16) from a structure (12) of a core (10) of a nuclear reactor in a predetermined linear sequence, the decay station (30) comprising a housing (50), the housing (50) including a radiation shield (54), the radiation shield (54) configured to protect an environment of the decay station (30) from radiation emitted by the irradiation targets (16) housed in the decay station (30), The housing (50) defines a decay conduit (52) intended to receive the irradiation targets (16) in the predetermined linear sequence, the decay conduit (52) comprising: - a decay conduit inlet (56) intended to be connected to a structure (12) of the core (10) of said nuclear reactor in order to receive said irradiation target (16) from said structure (12); a decay duct outlet (58) intended to be connected to an irradiation target discharge system (27) for discharging the irradiation target (16) from the decay station (30), The decay station (30) further comprises: an inlet distributor (68) located at the decay duct inlet (56) and configured to release only a predetermined amount of irradiation targets (16) at a time from the decay station (30) to the structure (12) of the core (10) of the nuclear reactor, the inlet distributor (68) being configured to release the irradiation targets (16) closest to the decay duct inlet (56) while retaining the remaining irradiation targets (16) in the decay duct (52); an entry counter (96) configured to count the number of irradiation targets (16) entering or leaving the decay duct (52) through the decay duct entry (56), the entry counter (96) being located at the decay duct entry (56), and - an exit radiation detector (102) configured to measure radiation emitted by an irradiation target (16) located at the decay conduit exit (58).

2. The decay station (30) according to claim 1, further comprising a pressurized gas supply source connected to the decay duct outlet (58) to introduce pressurized gas into the decay duct (52) from the outlet (58) of the decay duct (52).

3. The decay station (30) according to claim 2, wherein The inlet distributor (68) includes, in order from the decay duct inlet (56) toward the decay duct outlet (58): a locking element (70) displaceable between a locked position in which the locking element (70) prevents the irradiation target (16) from being removed from the decay duct (52) through the decay duct inlet (56) and a released position in which the locking element (70) allows a predetermined amount of the irradiation target (16) to be removed from the decay duct (52) through the decay duct inlet (56); and a retainer (72) displaceable between a retracted position, in which the retainer (72) allows the passage of the irradiation target (16), and an extended position, in which the retainer (72) at least partially extends into the decay duct (52), the retainer being configured to abut against the irradiation target in the extended position so as to prevent the irradiation target from moving toward the decay duct inlet (56), And wherein the inlet distributor (68) further comprises: - a first actuator (74) configured for displacing the locking element between the locking position and the release position; and - a second actuator (76) configured for displacing the retainer (72) between the extended position and the retracted position.

4. The decay station (30) according to claim 3, wherein The locking element (70) includes a locking pin (73) configured to extend radially through the decay duct (52) in the locked position of the locking element (70), and wherein the retainer (72) includes a retaining pin (75) configured to radially partially extend into the decay duct (52) in the extended position of the retainer (72), and a spring element connected to the retaining pin (75).

5. The decay station (30) of claim 3 or 4, further comprising a controller (80) configured to control the release of a predetermined amount of irradiation targets (16) by the inlet dispenser (68) by controlling a release sequence, the release sequence comprising the following steps: - displacing the locking element (70) from the release position to the locking position by means of the first actuator (74); - activating the pressurized gas supply source so as to obtain a pressurized gas flow through the decay duct (52) from the outlet end of the decay duct (52), the pressurized gas flow being configured to push the irradiation targets (16) housed in the decay duct (52) towards the inlet end of the decay duct (52) until they abut against the locking element (70) positioned in the locking position; - displacing the holder (72) from the retracted position to the extended position by means of the second actuator (76), in which the holder is capable of resting on an irradiation target housed in the decay duct (52); - displacing the locking element (70) from the locking position to the releasing position by means of the first actuator (74) so ​​that a predetermined amount of irradiation targets (16) corresponding to the irradiation targets (16) located downstream of the holder in the direction of the pressurized gas flow are conveyed out of the decay duct (52) through the decay duct inlet (56), while the remaining irradiation targets (16) are retained in the decay duct (52) by means of the holder positioned in the extended position.

6. The decay station (30) according to claim 5, wherein The controller (80) is further adapted to repeat the release sequence a number of times depending on the total amount of irradiated targets (16) to be released from the decay station (30) through the decay conduit inlet (56).

7. The decay station (30) according to claim 1 or 2, wherein: The predetermined amount of irradiation targets (16) is equal to one irradiation target (16), and the dispenser is configured to release the irradiation targets (16) one by one from the decay station (30) to the structure of the core (10) of the nuclear reactor.

8. The decay station (30) of claim 1 or 2, further comprising at least one intermediate irradiation target counter (100), the at least one intermediate irradiation target counter (100) being configured to count the number of irradiation targets (16) present in the decay duct (52) and being located between the entry counter (96) and the decay duct outlet (58) of the decay duct (52).

9. The decay station (30) of claim 1 or 2, further comprising at least one intermediate radiation detector (104) configured to measure radiation emitted by an irradiation target (16) housed in the decay duct (52) and located between the exit radiation detector (100) and the decay duct inlet (56).

10. The decay station (30) according to claim 1 or 2, further comprising an outlet distributor (92), the outlet distributor (92) being located at the decay duct outlet (58) and being configured to release only a predetermined amount of irradiation targets (16) from the decay station (30) through the outlet of the decay duct (52) at a time, the outlet distributor (92) being configured to release the irradiation target (16) closest to the decay duct outlet (58) while keeping the remaining irradiation targets (16) in the decay duct (52).

11. The decay station (30) according to claim 1 or 2, wherein The decay conduit (52) is a straight conduit.

12. The decay station (30) according to claim 1 or 2, wherein The decay duct (52) is substantially U-shaped and includes a first decay duct section (110), a second decay duct section (112), and a bottom (114) formed at a junction between the first decay duct section and the second decay duct section, the first decay duct section and the second decay duct section extending upwardly from the bottom.

13. A decay station (30) according to claim 1 or 2, comprising a controller (80) configured to discharge at least some of the irradiation targets (16) from the decay station (30) after a predetermined decay duration and / or when the radiation measured by the exit radiation detector (102) has dropped below a predetermined threshold.

14. The decay station (30) according to claim 1 or 2, wherein The structure of the core (10) of the nuclear reactor is the instrument tube system (12) of the nuclear reactor.

15. An apparatus for producing an activated irradiation target (16) in an instrument tube system (12) of a nuclear reactor, the apparatus comprising: - an irradiation target supply system (21) configured to provide non-activated irradiation targets (16); - an instrument tube system (12) configured to receive the irradiation target (16) from the irradiation target supply system (21) in view of the activation of the irradiation target (16) by exposure to the neutron flux in the nuclear reactor; - The decay station (30) according to claim 1 or 2, wherein a decay duct inlet (56) of a decay duct (52) is connected to the instrument tube system (12), and an inlet distributor (68) of the decay station (30) is configured to release a predetermined amount of irradiation targets (16) from the decay station (30) to the instrument tube system at a time, the inlet distributor (68) being configured to release the irradiation target (16) closest to the instrument tube system (12) while keeping the remaining irradiation targets (16) in the decay station (30); - an irradiation target exhaust system (27) comprising a target outlet port configured to be coupled to a target storage container (34), said exhaust system comprising an inlet end connected to a decay conduit outlet (58) of said decay station (30); a diverter (32) displaceable between a first position, in which the diverter defines a path for displacement of the irradiation target (16) between the irradiation target supply system (21) and the instrument tube system (12), and a second position, in which the diverter (32) defines a path for displacement of the irradiation target (16) between the instrument tube system (12) and the decay station (30); as well as - an irradiation target drive system (25) configured for transporting at least some of the irradiation targets (16) through the apparatus (6), the irradiation target drive system (25) comprising a pressurized gas supply (60) to the decay station (30).

16. The apparatus (6) according to claim 15, further comprising a controller (160), the controller (160) being configured to control the following steps performed by the apparatus (6): - using the target drive system (25) to transfer q1 number of non-activated irradiation targets (16) from the irradiation target supply system (21) to the instrument tube system (12); - exposing the q1 number of non-activated irradiation targets (16) to a neutron flux in the instrument tube system (12) for a predetermined irradiation duration d1, so as to obtain q1 number of partially activated irradiation targets (16), said predetermined irradiation duration d1 being strictly less than a minimum activation time for complete conversion of the precursor material contained in the irradiation targets (16) into the desired radionuclide; - transferring q1 number of partially activated irradiation targets (16) from the instrument tube system (12) to the decay station (30) using the target drive system (25); - using the target drive system (25) to transfer q2 number of non-activated irradiation targets (16) from the irradiation target supply system (21) to the instrument tube system (12); - transferring q1 number of partially activated irradiated targets (16) from the decay station (30) back to the instrument tube system (12) using the target drive system; - exposing q1 number of partially activated irradiation targets (16) and q2 number of non-activated irradiation targets (16) to a neutron flux in the instrument tube system (12) for a predetermined irradiation duration d2 to obtain q1 number of partially activated or fully activated irradiation targets (16) and q2 number of partially activated irradiation targets (16); and - discharging at least some of the irradiated targets (16) from the decay station (30) into the target storage container (34).

17. A method for producing an activated irradiation target (16) using the device (6) according to claim 15, the method comprising: - transferring (200) a number of q1 non-activated irradiation targets (16) from the irradiation target supply system (21) to the instrument tube system (12); - exposing (202) the q1 number of non-activated irradiation targets (16) to a neutron flux in the instrument tube system (12) for a predetermined irradiation duration d1 to obtain q1 number of partially activated irradiation targets (16), the predetermined irradiation duration d1 being less than or equal to a minimum activation time for complete conversion of precursor material of the irradiation targets (16) into desired radionuclides; as well as - transferring (204) a number q1 of irradiation targets (16) from the instrument tube system (12) to the decay station (30); and - discharging (214) at least some of the irradiated targets (16) from the decay station (30) into a target storage container (34).

18. The method of claim 17, further comprising maintaining at least some of the irradiated targets (16) in the decay station (30) for a predetermined decay duration before discharging the irradiated targets (16) from the decay station (30) into the target storage container (34).

19. The method according to claim 17, wherein The predetermined irradiation duration d1 is less than a minimum activation time for complete conversion of the precursor material of the irradiation targets (16) into the desired radionuclide, so that the q1 number of irradiation targets (16) obtained and delivered to the instrument tube system (12) at the end of the exposure step is q1 number of partially activated irradiation targets (16); wherein, between the step of transferring (204) q1 number of partially activated irradiation targets (16) from the instrument tube system (12) to the decay station (30) and the step of discharging (214) at least some of the irradiation targets (16) from the decay station (30) into the target storage container (34), the method further comprises the following steps: - delivering (208) a number q2 of non-activated irradiation targets (16) into the instrument tube system (12); - transferring q1 number of partially activated irradiated targets (16) from the decay station (30) back to the instrument tube system (12); - exposing (212) a number q1 of partially activated irradiation targets (16) and a number q2 of non-activated irradiation targets (16) to a neutron flux in the instrument tube system (12) for a predetermined irradiation duration d2 to obtain a number q1 of partially activated or fully activated irradiation targets (16) and a number q2 of partially activated irradiation targets (16).

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