Systems and methods for in-core component handling

Abstract

The in-core fuel transfer machine may be permanently fixed to the reactor and remain in place during power operation. The in-core fuel transfer machine may include a pantograph machine that positions a grapple to access any fuel socket location within the core and move any core assembly between the core, an in-core fuel storage area, and a fuel elevator. The grapple may be positioned through a combination of movements, such as rotating a rotating plug assembly, rotating the in-core fuel transfer machine, extending the pantograph arm, and reciprocating the grapple along its legs. The grapple may be compliant to accommodate a deformed core assembly, configured to pivot for close alignment with an eccentric core assembly handling socket, or movable in a horizontal plane to accommodate a deformed core assembly during insertion or extraction.

Description

Detailed Description of the Invention

[0001] [Government Licensing Rights] This invention was made with government support under DOE Cooperative Agreement No. DE-NE0009054 awarded by the U.S. Department of Energy. The government has certain rights in this invention.

[0002] Field of the Disclosure The present disclosure relates to an in-vessel core component handling system configured to insert, remove, and rearrange core components (e.g., fuel assemblies, reflectors, absorbers, and other core components).

[0003] 〔background〕 Nuclear reactors typically have means for moving core components within the core to load and unload fuel, rearrange reflectors or neutron absorbers along with other core components, etc. Fuel handling machines are typically inserted into the core during power shutdowns to remove fuel rods and to refuel the reactor. This necessitates shutting down the reactor for refueling or re-arranging core components. The downtime required to swap or remove core components increases capital, operating, and maintenance costs.

[0004] Additionally, core components may deform due to exposure to the core environment. For example, thermomechanical stresses within the core cause microstructural deformations and macroscopic responses. Such core component responses may include creep, swelling, cracking, and fuel-clad interactions. The fuel transfer machine must be able to account for core component deformations so that additional eccentric loads on the core components during removal from the core are reduced or eliminated.

[0005] It would be advantageous to provide a fuel handling machine that addresses these deficiencies and promotes more efficient nuclear reactors with reduced power outages. These and other advantages will become readily apparent to those skilled in the art upon review of the following description and drawings.

[0006] 〔overview〕 According to some embodiments, an in-reactor fuel transfer machine includes: a drive assembly configured to be mounted above a reactor head of a nuclear reactor; a telescoping guide tube operatively coupled to the drive assembly, the telescoping guide tube extending through the reactor head; a pantograph mechanism coupled to the telescoping guide tube, the pantograph mechanism including: an upper arm having a first upper arm end and a second upper arm end, the upper arm operatively coupled to the telescoping guide tube at the first upper arm end; a lower arm having a first lower arm end and a second lower arm end, the lower arm operatively coupled to the telescoping guide tube at the first lower arm end; legs coupled to the second upper arm end and the second lower arm end, the legs defining a path; and a grapple coupled to the legs, the grapple configured to move on the path.

[0007] In some embodiments, the in-reactor fuel transfer machine may further include a pantograph driveline selectively engageable with the upper arm and the lower arm, and the drive assembly may be configured to rotate the upper arm and the lower arm away from the telescopic guide tube.

[0008] In some embodiments, the legs are configured to be moved away from the telescoping guide tube by actuation of the upper and lower arms, and the legs are further configured to maintain parallelism with the telescoping guide tube during actuation of the upper and lower arms. In some cases, the legs remain upright or substantially upright while the pantograph is moved and manipulated.

[0009] In some embodiments, the grapple is configured to float by disengaging the pantograph drive line and allowing the grapple to move in a horizontal plane in response to an external force applied to the grapple. The external force may be applied by a deformed core assembly, and the grapple may be allowed to float to reduce forces from the deformed core assembly on adjacent core assemblies during insertion or extraction from a core socket.

[0010] According to some embodiments, the grapple includes fingers biased in a parallel orientation relative to the legs, for example, the fingers may be biased downward to facilitate insertion of the core assembly into the core handling socket.

[0011] The grapple may include a shaft configured to be slidable to spread the fingers outward. For example, the shaft may slide across a cam that spreads the fingers once they are in the core handling socket.

[0012] In some embodiments, the telescoping guide tube may define a longitudinal axis, and a rotational motor may be configured to rotate the intracore fuel transfer machine about the guide tube longitudinal axis.

[0013] According to some embodiments, the pantograph is configured to remain within the reactor vessel during power operation of the reactor. For example, the pantograph may be permanently installed in a position that leaves the pantograph at least partially immersed in a pool of sodium, while a drive assembly operatively coupled to the pantograph may remain above the sodium (e.g., above the reactor head).

[0014] In some cases, a force sensor is coupled to the grapple and configured to sense one or more forces applied to the grapple. An encoder may be coupled to the drive assembly and configured to operate the drive assembly to move the pantograph in response to one or more forces applied to the grapple. The encoder may be configured to move the grapple to reduce the force applied to the grapple by a deformed core assembly. For example, when a deformed core assembly is removed from a core socket, a side load is applied to the grapple by a bowed core assembly. In response, the grapple may move laterally (e.g., in a horizontal plane) to accommodate the side load and the bowed core assembly. The grapple may be free-floating and move in response to an applied force, or in some cases, an applied force may be determined by a sensor and the grapple may be moved by the IVTM drive assembly to accommodate the bowed core assembly.

[0015] In some cases, the encoder is configured to move the grapple in a circuitous path while removing a deformed core assembly from a core socket within the nuclear reactor core.

[0016] The grapple may further include a ball joint that allows the grapple to pivot freely within predetermined angular limits (e.g., 0.25°, 0.5°, 0.675°, 0.75°, 1°, or more).

[0017] In some embodiments, a ball screw actuator is provided for extending and retracting the telescoping guide tube. The ball screw actuator may be mounted above the reactor head and may include a sliding shaft that penetrates the reactor head at a penetration and a sliding shaft seal at the penetration.

[0018] According to some embodiments, a method for extracting a deformed core assembly from a nuclear reactor core includes positioning a grapple of a pantograph in-core fuel transfer machine above a selected core assembly; disengaging a pantograph drive line to allow the pantograph to float in a horizontal plane; driving the grapple into a handling socket of the selected core assembly; extending grapple fingers within the handling socket; extracting the selected core assembly from the reactor core while the pantograph drive line is disengaged; and after a predetermined extraction distance, engaging the pantograph drive line to complete the extraction of the selected core assembly.

[0019] The method may include removing the selected core assembly from the reactor core, including moving the grapple along a circuitous path.

[0020] The method may further include determining a side load on the grapple from the deformed core assembly.

[0021] The method may further include moving the grapple in a horizontal plane based at least in part on the side load.

[0022] The method may include identifying the deformed core assembly with a mechanical core component identification system. The method may include engaging claws with an outer periphery of the core assembly and rotating the core assembly. The claws may follow a shape of the outer periphery of the core assembly and determine a unique identifier associated with the core assembly based at least in part on the shape of the outer periphery of the core assembly. The claws may follow a series of surface features formed in a surface of the outer periphery of the core assembly. The core assembly may have surface features formed as grooves, protrusions, lands, valleys, bumps, indentations, or any other surface features that cause the claws to move to generate a signal indicative of a surface condition that can be used to determine the unique identifier of the core assembly. The core assembly may have a longitudinal axis, and the claws may be moved radially relative to the longitudinal axis by the surface features.

[0023] The disclosed methods, IVTM operation, grapple operation, and other movements may be performed under the control of one or more computers that may be programmed with instructions that, when executed, cause the system to perform the methods and steps described herein.

[0024] The above and other features and advantages will become more apparent from the following detailed description taken in conjunction with the drawings.

[0025] BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates various components of a nuclear reactor, according to some embodiments.

[0026] FIG. 2 illustrates an in-reactor fuel handling machine, according to some embodiments.

[0027] FIG. 3 illustrates an internal fuel transfer machine that may form a component of an internal fuel handling machine, according to some embodiments.

[0028] FIG. 4A is a top view of an exemplary intracore fuel transfer machine, according to some embodiments.

[0029] FIG. 4B is a side view of the intracore fuel transfer machine of FIG. 4A, according to some embodiments.

[0030] FIG. 5 is a top view of a rotating plug assembly, an in-core storage system, a fuel elevator, and an in-core fuel transfer machine, according to some embodiments.

[0031] FIG. 6 is a side view of a pantograph and grapple mechanism of an intracore fuel transfer machine, according to some embodiments.

[0032] FIG. 7A shows a grapple head with the fingers retracted, according to some embodiments.

[0033] FIG. 7B shows a grapple head with fingers extended within a handling socket of a core assembly according to some embodiments.

[0034] FIG. 7C illustrates a grapple head with fingers engaged within a handling socket of a core assembly according to some embodiments.

[0035] FIG. 8 illustrates a grapple assembly, according to some embodiments.

[0036] FIG. 9 illustrates a modified core assembly having a primary deformation, according to some embodiments.

[0037] FIG. 10 illustrates a deformed core assembly being removed from a core socket, according to some embodiments.

[0038] FIG. 11 illustrates a floating or compliant grapple configured to move in a horizontal plane, according to some embodiments.

[0039] FIG. 12 is a process flow diagram for extraction of a deformed core assembly according to some embodiments.

[0040] FIG. 13 is a process flow diagram for extraction of a deformed core assembly according to some embodiments.

[0041] FIG. 14A illustrates a core component identification system including a claw attached to a guide tube, according to some embodiments.

[0042] FIG. 14B is a top cross-sectional view illustrating surface features formed into a core component and tabs that engage the surface features to determine the unique identity of the core component, according to some embodiments.

[0043] FIG. 15A illustrates a core component identification system including a claw attached to a pantograph, according to some embodiments.

[0044] FIG. 15B is a top cross-sectional view illustrating surface features formed into a core component and tabs that engage the surface features to determine a unique identifier of the core component, according to some embodiments.

[0045] Detailed Description The present disclosure generally relates to methods and systems for handling core components in a nuclear reactor. In some cases, a fuel handling machine is disposed within the reactor vessel and configured to insert, remove, and replace core components. The fuel handling machine may be a pantograph configuration that allows radial, axial, and rotational movement about one or more axes. As used herein, a pantograph refers to a parallelogram-based mechanical linkage in which opposing arms remain parallel even as the angle forming the parallelogram structure changes.

[0046] Referring to FIG. 1 , many of the components and subassemblies of a nuclear reactor 100 are illustrated. For example, in addition to the reactor head 102, reactor vessel, and protective vessel 104, many auxiliary reactor components are illustrated, such as structural members, flanges, cover plates, piping, rails, frames, connecting rods, and supports. While the illustrated reactor 100 is a sodium fast reactor (SFR), it should be understood that the components and embodiments described herein could be applied to any suitable reactor configuration. For example, many of the systems, components, assemblies, and subassemblies described herein could be utilized in any nuclear reactor that utilizes core components that can be inserted, removed, or replaced within the core.

[0047] The nuclear reactor 100 is designed to hold a number of nuclear fuel pins (not shown) within a core 108 located at the bottom of the reactor vessel and protective vessel 104. A reactor head 102 seals the radioactive materials within the reactor vessel 106 and the protective vessel 104. In the illustrated embodiment, the core 108 is accessible only through the reactor head 102. For example, an in-reactor fuel handling machine 116 is provided. The fuel handling machine 116 allows the fuel pins and other core components and equipment to be lifted from the core 108 and removed from the vessel 106 via a set of large and small rotating plugs 118 located in the reactor head 102. This design allows the reactor vessel 106 to be a single unit with no penetrations.

[0048] Sodium is the primary coolant for removing heat from the reactor core 108. At the reactor's operating temperature, sodium is liquid. The reactor vessel 106 is partially filled with sodium, which is circulated through the reactor core 108 using pumps 110. In some embodiments, two or more sodium pumps 110 are provided. The two or more sodium pumps 110 may be electromagnetic pumps. In some cases, one or more pumps 110 may include an impeller that may extend through the reactor head 102 to a motor located above the reactor head 102.

[0049] In some embodiments, pumps 110 are configured to circulate sodium through one or more intermediate heat exchangers 112 disposed within reactor vessel 106. Sodium from cold pool 122 is pumped up into core 108, where it is heated by nuclear fission reactions. The heated sodium leaves the core and rises into hot pool 124. Because the heated sodium is less dense than the cold sodium in the cold pool, it flows upward due to natural circulation and also due to forced pressure from one or more pumps 110. The heated sodium in the hot pool is drawn into intermediate heat exchanger 112, which transfers heat from the primary sodium coolant to the secondary coolant. Fresh secondary coolant is routed through one or more heat transport loop pipes 120 through reactor head 102 to intermediate heat exchanger 112, where it is heated. The heated secondary coolant then flows out of the reactor head 102 through the heat transport loop piping 120. In some embodiments, the heated secondary coolant is used to generate steam that is transferred to the power generation system. The secondary coolant may be a sodium coolant or a salt coolant (e.g., magnesium sodium coolant).

[0050] FIG. 2 illustrates an example of an in-vessel fuel handling system 200 that includes an in-vessel transfer machine 116 ("IVTM"). According to some embodiments, the in-vessel fuel handling system 200 includes a pantograph-type IVTM. The in-vessel fuel handling system 200 may further include a rotating plug assembly 202 ("RPA") (or simply "rotating plug"), an upper internal structure 204 ("UIS"), a fuel transfer port, and an in-vessel storage system 206.

[0051] The UIS 204 may be coupled to the underside of the rotating plug 202 and may provide support for many of the components that extend below or through the rotating plug 202. The UIS 204 may have a vertical (lengthwise) slot formed therethrough to provide clearance for the IVTM 116.

[0052] In some cases, the IVTM 116 can exchange fuel assemblies and may store spent assemblies and other core components in an in-vessel storage system 206 ("IVS"). The spent assemblies and other core components can ultimately be removed from the reactor vessel by a fuel elevator 208. The fuel elevator may be of any suitable configuration and may be positioned around the reactor vessel by a rotating plug assembly 202. In some cases, the rotating plug 202 is configured to rotate about a central axis, and any components secured to the rotating plug 202 (e.g., the fuel elevator 208) can be moved around the reactor vessel by the rotating plug 202. In some cases, the fuel elevator 208 is configured to selectively couple to core components stored in the IVS 206 to move the core components to a position above the reactor head 102.

[0053] In some embodiments, the fuel elevator 208 is stationary, and the IVTM 116 can selectively deposit fuel assemblies and other core components into the fuel elevator 208 and remove core components or fuel assemblies from the fuel elevator 208.

[0054] In use, the IVTM 116 can remove the core assembly 210 from the core 212 as desired. Additionally, the IVTM 116 can rearrange, add, or remove the core assembly (e.g., reactivity control elements, fuel elements (which may include fissile fuel elements and / or fertile fuel elements), control rods, neutron reflectors, neutron absorbers, etc.) from the core 212. In some cases, the IVTM 116 is responsible for exchanging core components between the core 212 and the IVS 206.

[0055] As described below, the IVTM 116 is configured to be positioned relative to, and thereby coupled to, any core component within the core by a combination of rotating the IVTM 116 about its longitudinal axis, extending and retracting the pantograph arms radially relative to the longitudinal axis of the IVTM, and rotating the rotating plug 202.

[0056] Control rod drive system 214 may be configured to drive control rods 216 down from a position above core 212 into core 212. In some cases, control rod drive system 214 is coupled to control rods 216 by one or more electromagnetic linkages. Thus, in some embodiments, in the event of a loss of power, the control rods will fall by gravity into core 212, reducing reactivity.

[0057] 3 illustrates an exemplary embodiment of the IVTM 116. Shown are a pantograph 302 and a grapple 304. The IVTM 116 includes an IVTM drive assembly 306, an IVTM bearing housing 308, an IVTM shield plug 310, and an IVTM subassembly 312.

[0058] An IVTM drive assembly provides linkage for driving at least a portion of the motion of the IVTM 116. Through one or more motors, gears, splines, or other linkages, the IVTM 116 can be manipulated to be positioned above any core assembly within the reactor core 212 or IVS 206. As used herein, the terms “core assembly” and “core component” are broad terms and are used interchangeably to refer to any device that can be inserted or removed from the core. The terms “core assembly” and “core component” include, but are not limited to, fuel assemblies, control rods, reflectors, neutron absorbers, etc. In many cases, fuel assemblies and other core components share similar or identical geometric structures and therefore can be interchanged in multiple locations within the core, such as sockets. Fuel assemblies and other core components may have identical handling sockets that allow these devices to be manipulated by the IVTM 116 and interact with the IVS 206 and / or fuel elevator 208.

[0059] In some cases, the pantograph 302 mechanism allows the IVTM 116 to have a smaller volume envelope than conventional intra-reactor transfer machines. This allows the overall reactor vessel 106 to be smaller than reactors utilizing other known IVTM technologies (e.g., offset arm configurations). Furthermore, in typical reactors, the IVTM is inserted into the reactor vessel only during a power outage event, and then removed from the reactor vessel prior to power operation. In contrast, some embodiments disclosed herein are configured to allow the IVTM 116 to remain within the reactor vessel 106 during power operation. Configuring the IVTM 116 in this manner results in more efficient maintenance, operations, and reduced downtime.

[0060] With continued reference to FIG. 3 and additionally to FIGS. 4A and 4B, an exemplary IVTM 116 is illustrated, along with some of its components and couplings. According to some embodiments, the IVTM 116 incorporates a guide tube 320 along which a pantograph 302 can move. While this structure is referred to as a guide tube 320, it need not be so limited, and those skilled in the art will readily appreciate that other structures (e.g., rails, pipes, channels, or any other suitable structure) may provide similar advantages and freedom of movement for the pantograph 302. The pantograph 302 may be formed from an upper arm 322, a lower arm 324, and legs 326. The upper arm 322 and the lower arm 324 may be pivotally coupled to and / or slidably engaged with the guide tube 320. Thus, the upper and lower arms 322, 324 can pivot to move generally parallel or parallel to the guide tube 320, and can also pivot to move away from the guide tube 320. In some cases, the legs 326 are pivotally coupled to the upper and lower arms 322, 324 such that pivoting movement of the upper and lower arms 322, 324 results in the legs 326 moving toward or away from the guide tube 320. In some cases, the legs 326 remain parallel to the guide tube. In other words, regardless of the orientation of the upper and lower arms 322, 324, the longitudinal axes of the legs remain parallel to the longitudinal axis of the guide tube. The legs 326 may nest within recesses or cutouts formed in the guide tube 320. For example, the legs 326 may reside within the guide tube 320 when fully retracted (retracted). This allows the IVTM to be compact and reduces the penetration size of the IVTM 116 required for the RPA 202.

[0061] The legs 326 may carry a grapple 304. The grapple 304 may be configured to couple to one or more core components through any suitable coupling mechanism. The grapple 304 may include a grapple head 402 that is slidable along the legs 326. The legs 326 may define a path along which the grapple 304 may travel back and forth. In other words, the grapple may move from a first position to a second position along the path, or to any position between the first and second positions.

[0062] In some cases, guide tube 320 is configured as a telescoping tube so that its overall length can be varied, for example, to position pantograph 302 in a vertical position. For simplicity, the remainder of this disclosure will refer to guide tube 320 as upright, and therefore legs 326 as upright throughout the movement of upper arm 322 and lower arm 324. Guide tube 320 may be telescopic in the vertical direction to reposition pantograph 302 within the reactor vessel. Pantograph 302 may be coupled to guide tube 320 by rollers so that pantograph 302 can move up and down guide tube 320.

[0063] One or more pantograph drivelines 328 may operatively couple the pantograph 302 to the IVTM drive assembly 306 and transmit motion to the components of the pantograph 302. The pantograph drivelines 328 may be coupled via one or more universal joints 330 a, 330 b, which allow for variable angular relationships between the drivelines and the guide tube 320 and legs 326. In some embodiments, the grapple 304 may move up and down the legs 326, for example, through any suitable mechanism (e.g., power screws, rollers, channels, wheels, belts, and / or chains) or combination of mechanisms. Thus, vertical positioning of grapple 304 may be achieved through any of a variety of methods, such as, for example, manipulating telescoping-length guide tube 320, moving pantograph 302 up and down guide tube 320, driving grapple along legs 326, and combinations of movements. Link 330 may provide motion input to upper arm 322 and / or lower arm 324 to extend and retract legs 326 relative to guide tube 320. In some embodiments, pantograph mechanism 302 allows legs 326 to remain parallel to guide tube 320 while being steered radially toward or away from guide tube 320.

[0064] The movement of the IVTM 116 and its components may be under the control of a control unit and one or more actuators. For example, the systems and / or methods described herein may be under the control of one or more processors. The one or more processors may have access to a computer-readable storage medium (“CRSM”). The CRSM may be any available physical medium accessible by the processor(s) to execute instructions stored in the CRSM. In one basic implementation, the CRSM may include random access memory (“RAM”) and flash memory. In other implementations, the CRSM may include, but is not limited to, read-only memory (“ROM”), electrically erasable programmable read-only memory (“EEPROM”), or any other medium usable to store desired information and accessible by the processor(s). In some cases, the memory storing instructions is non-transitory memory, and the instructions, when executed, cause the processor to take actions that result in control of the systems described herein.

[0065] 4A and 4B show top and cross-sectional views, respectively, of the IVTM assembly 116. The drive assembly 306 may be typically cylindrical and may house a portion of the mechanical actuator that controls the IVTM (including the pantograph and grapple). In some cases, the drive assembly 306 is centrally disposed relative to the guide tube 320, with a central axis 404 extending through the drive assembly 306 and the guide tube 320. A rotating plug-through shield plug 310 provides a sealing engagement between the RPA 202 (of FIG. 1) and the IVTM 116 where the IVTM extends through the RPA.

[0066] Driveline shield plugs 406 provide a seal between the drivelines of the IVTMs 116 where they penetrate the RPA. In some embodiments, a plug is installed at each penetration through the RPA and reactor head. A pantograph actuation driveline 408 extends along the guide tube 320. In some cases, the pantograph actuation driveline 408 extends through the hollow center of the guide tube 320 and transfers mechanical energy (e.g., to extend the pantograph 302 and actuate the grapple 304, for travel strokes, or to engage / disengage the core assembly 210) from the drive assembly 306 to the pantograph. In some embodiments, the pantograph actuation driveline 408 is selectively engageable with the pantograph 302. Thus, the pantograph 302 may be driven by the pantograph actuation driveline 408 when the pantograph driveline 408 is engaged with the pantograph 302, or the pantograph 302 may be free-floating and able to move in a horizontal plane (transverse plane) when the pantograph actuation driveline 408 is not engaged. For example, as described later herein, when the pantograph 302 is in a free-floating configuration, the pantograph may move in response to external forces.

[0067] 4B shows core assembly 210 coupled to grapple 304. In some cases, the act of extracting a core assembly imparts a frictional force to adjacent core assemblies, causing a liftoff force on the adjacent core assemblies. In some embodiments, hold-down feet 410 are provided as part of pantograph 302 to secure one or more adjacent core assemblies against the frictional liftoff force exerted on the adjacent core assemblies by core assembly extraction during operation by IVTM 116.

[0068] FIG. 5 illustrates a top view of the rotating plug assembly 202, the IVTM 116, and the fuel elevator 208 and their relative positions, according to some embodiments. In some cases, the reactor has a core center 502. The core center 502 may coincide with the center of the reactor vessel. While these reactor components may be concentric, in some embodiments, the RPA 202 may not be concentric with the core and thus has its own RPA axis 504 about which it rotates. Similarly, the IVTM 116 has a guide tube central axis 404 about which it rotates. In many cases, the guide tube central axis 404 is not concentric with either the RPA axis 504 or the core center 502. In some cases, the in-core reservoir 206 is circular and may be concentric with the reactor vessel, as shown in FIG. 6. However, this is not necessary, and the in-reactor reservoir 206 may be offset or located at another location, or configured as a shape other than generally circular.

[0069] IVTM 116 is configured to be moved to grasp a core assembly from any socket within the core and further configured to be moved to any location in in-core storage 206 and fuel elevator 208. By rotating RPA 202, rotating IVTM 116, and / or extending the pantograph, grapple 304 can travel an arcuate eccentric path to reach any core assembly located within the core, IVS 206, or fuel elevator 208. These movements can be controlled by a fuel handler controller, which is programmed with instructions to reposition the core assembly by engaging linkages to effect such movements. The linkages can include, but are not limited to, motors, ball screws, drivelines, channels, chains, rollers, or other types of linkages that can be electrically controlled.

[0070] 6 illustrates the IVTM 116 seating / unseating the core assembly 408a from the core. As shown, the RPA 202 and IVTM 116 can be rotated and the pantograph 302 can be extended so that the grapple 304 can reach any core assembly within the core. Once the core assembly 408a is removed from the core, the IVTM can place the core assembly 408a into the IVS 206 at any available position (e.g., the position shown by core assembly 408b). In some cases, the fuel elevator 208 is spaced from the IVTM 116 so that the IVT can freely rotate 360° without interfering with the fuel elevator 208. The pantograph 302 can be extended to reach the fuel elevator 208, for example, to exchange a core assembly with respect to the fuel elevator 208.

[0071] The pantograph 302 can be raised and lowered by extending and retracting the telescoping guide tube 320, and can also be raised and lowered by manipulating the pantograph 302. The grapple 304 rises and falls with the pantograph 302 and, as described in embodiments herein, is raised and lowered by being movable on legs 326. In some cases, the grapple 304 can extend into the core assembly within the core and can additionally incorporate a predetermined amount of overtravel. For example, the grapple 304 can be configured with a travel stroke that can extend a predetermined distance beyond the top of the core assembly when positioned within the core.

[0072] In some embodiments, the grapple 304 is operatively coupled to one or more sensors. The one or more sensors may include a position sensor, a force sensor, an acceleration sensor, a visual sensor, or some other type of sensor. According to some embodiments, the force sensor is configured to generate a force signal associated with the grapple's contact with the core assembly. The force signal may be a compressive force when the grapple extends vertically to engage the core assembly, or may further be a side load and / or torque force applied to the grapple 304. The force sensor may be any suitable transducer that converts an input mechanical load (e.g., weight, tension, compression, or pressure) into an output electrical signal. Under the control of one or more processors, a fuel handling controller may receive the signal and determine the position, load, or force applied to the grapple 304. As discussed in further detail, this force may be used to engage the grapple with the core assembly or to move the grapple accordingly so that the load on the grapple is reduced.

[0073] 7A, 7B, and 7C, the grapple 304 is shown engaging with the core assembly. In some embodiments, the core assembly 210 may have a handling socket 702. The handling socket 702 includes a first bore 704 having a first diameter. The first bore 704 flares into a second bore 706 having a second diameter and a shoulder 708. The grapple 304 may have one or more fingers 710. The one or more fingers 710 are configured to selectively extend outward to interfere with the shoulder 708 and prevent unintentional removal of the grapple from within the handling socket 702 of the core assembly 210. FIG. 7A shows the fingers 710 retracted when the grapple 304 is inserted into the handling socket 702. According to some embodiments, as shown in Figure 7B, a camshaft 712 can be extended through the grapple 304 such that the fingers 710 are extended outward into the second bore 706. As shown in Figure 7C, once the camshaft 712 operates to extend the fingers 710 outward, as the grapple moves upward and away from the core assembly 210, the fingers 710 interfere with the shoulder 708, thereby preventing the removal of the grapple 304 from the core assembly 210.

[0074] 7A, 7B, and 7C show exemplary embodiments of a grapple that engages a core assembly, it should be understood that there are numerous configurations that could be implemented to provide the same functionality. For example, the grapple may include fingers that retract to grip the core assembly from outside the core assembly. The fingers may be biased to a retracted or extended position, and a camshaft may urge the fingers to an unbiased position so that the core assembly is gripped. As such, the illustrated embodiment is provided by way of example and should not be construed as limiting.

[0075] FIG. 8 illustrates an exemplary grapple assembly 304 for the IVTM 116, according to some embodiments, showing a typical gear train. As described herein, the IVTM is configured with multiple motions and degrees of freedom. One or more linkages are provided to achieve motion to enable the grapple 304 to reach the core socket location. This can result in translation, rotation, and combinations of motions. The linkage may be provided as a gear train and may include one or more gears, splines, rollers, nuts, power screws, lead screws, or other components. In some cases, the linkage converts rotational motion to linear motion, or vice versa. According to some embodiments, the grapple is configured to rotate via a grapple rotation gear train 802. The grapple rotation gear train 802 may receive a motor input through which input torque from the motor input may be increased, for example, by reduction gears within the grapple rotation gear train 802. Similarly, the grapple fingers may be operated by a grapple finger actuation gear train 804. In some cases, the grapple finger actuation gear train 804 and associated power transmission components convert rotational input into linear motion, for example, to linearly drive the camshaft 712 as described with respect to any of the embodiments described herein. Other power transmission components may include one or more sliding splines 810 and / or a ball nut 808.

[0076] One or more alignment rollers 806 may provide alignment between the various components. One or more ball nuts 808 may be provided to smoothly operate the ball nuts along the threaded shaft, converting rotational motion to linear motion. One or more sliding splines 810 may additionally be provided to provide motion input for operating the grapple. According to some embodiments, the gear train and power transmission components are configured to withstand the continuous environment of the nuclear reactor during power operation. In other words, in some embodiments, the IVTM, specifically the pantograph and grapple, are configured to be permanently installed within the reactor and remain in place during power operation, although they may be removed for maintenance. In these cases, the IVTM components are qualified at high temperatures to sustain neutron radioactivity and, in embodiments utilizing a sodium pool reactor, remain at least partially immersed in the primary sodium coolant. The components are formed from materials and / or have coatings configured to maintain reliability during power operation for extended periods of time (e.g., up to 18, 36, 60, 120, or more months).

[0077] In some embodiments, the drive assembly 306 for the IVTM is located on a first side of the reactor head 102, while the pantograph 302 and grapple 304 are located on a second, opposite side of the reactor head. For example, a ball screw that may control the telescoping tube actuation and / or the IVTM hold-down foot may be located above the reactor head. Therefore, the ball screw may not be immersed in the primary coolant sodium pool. Similarly, a second ball screw that may control the horizontal movement of the pantograph may also be located above the reactor vessel head. Meanwhile, the pantograph is located below the reactor vessel head and immersed in the primary coolant sodium pool. According to some embodiments, locating at least some of the IVTM driveline components above the reactor head places them in the head access area rather than immersed in the primary coolant sodium pool. This may increase the reliability of the IVTM, reduce potential failure modes, and improve recovery measures. Additionally, locating the ball screw above the reactor head rather than below it provides a straight-pull or “rising stem” type actuator and linear motion shaft seal, as opposed to a rotary shaft seal at the shaft's penetration through the rotating plug assembly. The actuators for the guide tube, pantograph, and grapple may be of any suitable configuration, including straight-pull actuators, rotary actuators, ball screw actuators, sliding actuators, linear shafts, and ball nut actuators. In some cases, the actuators for the guide tube, pantograph, and / or grapple may be located above the vessel head in the head access area, and repairs to these components may be routine without requiring removal of the entire IVTM or disruption of the primary pressure boundary. In some cases, the IVTM extends through the rotating plug 202 and forms a seal with the rotating plug 202 with a sliding shaft seal.In some embodiments, the IVTM 116 is secured to the rotating plug 202 through bolts, welds, flanges, seals, or other suitable structures.

[0078] According to some embodiments, the IVTM 116 is configured to remain within the reactor vessel at all times, even during power operation, and therefore may be formed from materials that can withstand the reactor core environment (e.g., sodium coolant, cover gas, operating temperatures, and neutron radioactivity).

[0079] 9 and 10 illustrate a deformed core assembly 210. In some cases, the core assembly deforms through thermomechanical stress and parameter-related change mechanisms. As shown in FIG. 10, the core assembly undergoes deformation in a first bending mode, which may result in bowing. In some cases, core components may also undergo bending in higher bending modes. While core assembly deformation may be reduced through improving the core assembly's stiffness and resistance to creep and swelling, bowing still needs to be considered.

[0080] The deformed core assembly 210 may have a bow value 902 related to bending stresses in the core assembly 210. The bow value 902 may be related to the load applied to the grapple 304 during insertion or extraction of the core assembly 210. When the core assembly 210 is inserted or extracted, the upper end 1002 may experience an offset 1004 from the core component position within the core. The offset 1004 may be determined between the position of the core assembly upper end 1002 and a line 1006 into a socket position 1008 within the core.

[0081] Further, referring to FIG. 11 , in some embodiments, the grapple 304 is configured to handle core components 210 undergoing primary, secondary, and / or tertiary bending modes (e.g., C-shaped, S-shaped, or W-shaped). As described above, the grapple 304 may be in communication with one or more sensors 1102. The sensors 1102 may be load sensors configured to detect a load on the grapple 304. The load may be torque, a lateral load, a compressive load, a tensile load, or the like. In some examples, the grapple 304 may be a floating grapple 304 that can move laterally (e.g., in a horizontal plane) to reduce the load imparted to the grapple 304 by the core assemblies 210. Thus, the grapple 304 may move in the direction indicated by arrow 1104 to account for deformations of individual core assemblies 210. In some embodiments, the sensors may send signals to a grapple controller. The grapple controller determines the direction and magnitude of the load and then initiates movement of the grapple 304 to reduce or eliminate the load on the grapple 304. In some cases, the grapple is under the control of a fuel handling monitoring and control system. The fuel handling monitoring and control system may be configured to monitor and control subsystems and subcomponents of the fuel handling system. The fuel handling monitoring and control system may be in communication with a plant monitoring and control system. The plant monitoring and control system is configured to communicate with all systems within the reactor through one or more subcontrol systems. The grapple 304 may be moved by actuating one or more of the pantograph arm, grapple rotation, IVTM rotation, or rotating plug rotation. In this manner, the grapple 304 can be moved to reduce additional stresses imparted to the core assembly 210 during insertion or extraction, thereby reducing stress on surrounding core assemblies and reducing contact between adjacent core assemblies.

[0082] According to some embodiments, the grapple 304 may additionally or alternatively be compliant so that the nose 1106 of the grapple 304 can pivot to align with the handling socket of the core assembly 210. In some cases, the nose 1106 may include a spherical bearing (e.g., a ball-and-socket coupling) so that the nose can pivot about the coupling. Of course, any suitable type of coupling that provides some compliance and freedom of movement for the nose may be used. In some cases, the grapple 304 has angular compliance. In some cases, the angular compliance may be on the order of 0.24°, or 0.37°, or 0.5°, or 0.625°, or 0.75°, or 1°, or more. In some cases, providing an angular offset for the grapple 304 allows the extraction load to be more evenly distributed among the grapple fingers.

[0083] In some cases, the grapple 304 is configured to allow the grapple 304 to "float" laterally to follow the distorted core component into or out of the core when the distorted core component is being extracted or inserted. This may be accomplished by utilizing the drive mechanism and electronics of the IVTM to measure driveline torque and then react to that torque by moving the grapple to substantially follow the shape of the core assembly and limit the forces on the core component and IVTM. In some cases, this may also be provided by disengaging the pantograph driveline, allowing the pantograph, and therefore the grapple, to move freely in a horizontal plane in response to loads applied externally by the distorted core component.

[0084] Additionally, having the grapple floating on the IVTM driveline provides the advantage of a more linear insertion into the core component handling socket during core component socket insertion.

[0085] Referring to FIG. 12, a process 1200 for extracting a deformed core assembly is shown. In block 1202, an IVTM is positioned above the desired core assembly and may include floating the IVTM driveline to provide compliance and freedom of movement in response to external forces or loads. In block 1204, the grapple is lowered to a predetermined distance above the core assembly handling socket or to a distance where the grapple nose begins to insert into the handling socket. Additionally, preset limits for side load or axial load can be established, and the grapple may be lowered until either full insertion is achieved or these loads are determined (measured), at which point the process can proceed. In block 1206, the brake for the pantograph arm can be engaged and the IVTM rotation drive motor can be disengaged. This allows the IVTM to rotate freely in response to any side loads applied to the grapple 304. In block 1208, the grapple may be driven into the handling socket until it reaches either a predetermined load or position encoder position. During this insertion process, the pantograph arm may extend and / or the IVTM rotary drive encoder may be monitored for deviation from the position when the brake was disengaged. If a load or position value above a threshold is determined (measured) by the encoder (which may indicate movement outside of expected parameters or outside the movement envelope), the brake may be re-engaged and movement halted. Recovery movement could then proceed to assess and correct the situation.

[0086] The grapple fingers may be extended and the core component extraction process may proceed at block 1210. The grapple fingers may be extended through any suitable mechanism (e.g., by inserting a camshaft through a cam to extend the fingers).

[0087] The IVTM driveline may remain floating until the core assembly is removed a distance sufficient to remove it from the core socket in block 1212. The predetermined distance may correlate to the lower load pad of the removed core assembly passing without touching the upper load pad of the adjacent core assembly.

[0088] Once extracted to a predetermined height, the drive brake may be re-engaged and the extraction process may proceed without further grapple compliance, at block 1214. The predetermined height may correspond to a portion of the extraction stroke (e.g., 75%, 80%, 85%, 90%, 95%, or more of the extraction stroke).

[0089] The core assembly insertion process may follow a very similar process, but reversed to account for deformation of the core assembly. In some cases, horizontal compliance may be achieved using a rack and pinion plate, floating (e.g., disengaging) the IVTM drive motor, or some other compliant structure.

[0090] 13 illustrates another process 1300 for extracting a deformed core assembly, according to some embodiments. At block 1302, an IVTM is positioned above the desired core assembly.

[0091] The grapple is lowered a predetermined distance above the core assembly handling socket at block 1304. In some embodiments, the grapple nose can be pivoted into alignment with the core assembly handling socket as described herein, for example, by a spherical joint that allows the grapple nose to pivot up to about 1° or more.

[0092] In block 1306, the grapple is driven into the handling socket. During this process, the grapple nose may pivot freely to align the grapple nose with the handling socket. Alignment of the grapple nose with the core assembly handling socket may be achieved through position sensors, and movement may be controlled by an IVTM controller. The movement may include rotating the rotating plug, rotating the IVTM, moving the grapple on its legs, and / or extending the pantograph arm. In some cases, one or more sensors sense compressive and side loads on the grapple. In some cases, an IVTM driveline is engaged, and the grapple is moved to reduce the side load on the grapple. For example, if the core assembly may be in a deformed state such that its upper end is not in an expected position, a sensor may sense a side load being applied to the grapple due to the core assembly handling socket being out of position as the grapple nose attempts to enter the core assembly handling socket. The sensor may transmit a signal related to the displacement of the core assembly handling socket, and the IVTM driveline may reposition the grapple nose so that it is better aligned with the core assembly handling socket, thereby reducing the sensed side load on the grapple nose.

[0093] At block 1308, the grapple fingers are extended. In some cases, the grapple may have two, three, four, five, or more grapple fingers that can be extended to engage a portion of the core assembly handling socket. In some embodiments, the grapple is configured with three fingers for extending into and engaging the core assembly handling socket.

[0094] In block 1310, the core assembly is extracted from its socket location within the core, and the grapple extraction path is adjusted based on the deformation of the core assembly. One or more sensors may monitor the load on the grapple. If the grapple experiences a side load, for example, from a bowed core assembly, the IVTM driveline may reposition the grapple to accommodate the deformed core assembly and reduce the load on the grapple. This reduces the load that the deformed core assembly imposes on adjacent core assemblies during its extraction. In some cases, the grapple may be moved in a circuitous or arcuate path while extracting the deformed core assembly and is not limited to a straight extraction path.

[0095] According to some embodiments, each core component is identified, which may be by a unique identifier that allows the IVTM to distinguish between each core component. As used herein, core component identification (CCID) is the process of verifying the identity and functionality of a component by an intracore transfer vehicle. CCID may be used to provide an additional safeguard and backup to computer tracking of core components, preventing costly delays and damage due to mishandling of core components.

[0096] See Figures 14A and 14B. In some embodiments, each core component is formed with a series of one or more notches 1402 around the circumference of the core component (e.g., notches around handling sockets). Mechanical pawls 1404 may be biased to rise (lift) and drop into the notches as the core component rotates. The described pawl and notch system is a mechanical system that can be configured to function as a CCID in many types of nuclear reactors, including those that utilize pools of metal coolant, where optical sensors may be less effective.

[0097] In a mechanical CCID system, the movement of a mechanical element (e.g., claw 1404) can be transferred to a sensor. The sensor can be mounted above the reactor vessel. The movement of the mechanical element 1404 can be produced by a Braille-like pattern on the core component handling socket. The Braille-like pattern can be used to represent the component's serial number. The pattern read by the mechanical element 1404 is a surface feature. The surface feature can be a series of bumps, grooves, indentations, lands, protrusions, notches, or other physical characteristics that can cause movement of the mechanical element 1404. In some cases, the mechanical element is a claw 1404 biased toward the core component, and the surface feature of the handling socket 702 can cause movement of the claw 1404 when the core component is rotated. For example, if the claws 1404 are biased toward a core component, the core component may be rotated about its axis, causing the claws to move toward or away from the center of the core component. These movements of the claws 1404 may be measured by sensors and used to identify information about the particular core component being handled by the grapple 304.

[0098] The combination of multiple notches may be configured to include depth, length, sidewall draft, or other physical attributes that may be meaningful to the path of the pawl 1404. The combination of multiple notches may be used to provide a unique identification of the core component, the type of core component, and the angular orientation of the core component. In some cases, a single notch may provide angle index information corresponding to the rotation angle of the core component.

[0099] In use, once the grapple 304 retrieves the core component, the grapple 304 may position the core component so that the mechanical identification markings are adjacent to the claws 1404. The grapple may then rotate the core component 210 about its longitudinal axis approximately 180 degrees, or approximately 270 degrees, or approximately 360 degrees, or approximately 540 degrees, or more. During rotation, the identification markings cause the claws 1404 to move, and a signal indicative of the claw movement is sent to a control computer. The control computer may be configured to interpret the claw movement into data related to the core component. For example, time versus notch detection data acquisition may be generated from state changes of the CCID control shaft sensors. In some embodiments, an identification code may be created in each core component using any suitable number and position of notches. In some embodiments, 18 or more positions around the circumference of the core component handling socket may be used as notch locations. These locations may be regularly spaced, for example, at approximately 20-degree intervals. As an example, if there are 18 equally spaced notches (or information bits), with 2-bit intervals devoted to orientation bits, and assuming the ID notches are the same size and length, the ID code may therefore be 16 bits, or one of over 65,535 unique identification codes. Of course, more or fewer informational surface features may be used to provide information about the core component. As described elsewhere, the surface features may be notches, or additionally or alternatively, bumps, protrusions, grooves, bosses, valleys, lands, dimples, pockets, ridges, or any other surface feature that may be used as informational data related to the core component.

[0100] The database may contain data related to one or more core components. Movements of the claw may be matched with entries in the database to determine the identity of the core component and other data, including, but not limited to, the core component type, time in service, remaining useful life, previous location within the core, deformation information, burnup, elongation, temperature, etc. Core component data may be updated to the database with each manipulation of the core component by the grapple.

[0101] According to some embodiments, the claw 1404 includes a claw arm 1406. The claw arm 1406 may be pivotally mounted in any suitable location (e.g., on the guide tube 320). The claw arm 1406 may be mounted perpendicular to the guide tube so as to interact with the core component handling socket once it is grappled and raised along the grapple stroke. This may be the top of the grapple stroke. In some cases, the pantograph is fully retracted and the grapple is moved to the top of the grapple stroke to place the claw in contact with the core component. In some cases, the claw arm may be rotated out of the way to allow the legs of the pantograph to extend and retract.

[0102] According to some embodiments, in use, claw arm 1406 can first be rotated out of the way, pantograph 302 can be extended to the target core component, grapple 304 can engage the target core component, and grapple 304 can remove the core component from the core. Telescoping guide tube 320 can be actuated to raise pantograph 302 so that it can retract into main guide tube 320. Pantograph 302 can then fully retract, allowing the core component to reach inward toward claw 1404. Claw arm 1406 can then be actuated and rotated into a position that causes claw 1404 to engage with a handling socket on the core component.

[0103] The grapple head driver can rotate the core component, causing the claws 1404 to read a notch on the handling socket. The claws 1404 rise along the outer diameter of the handling socket, and when they encounter a special alignment notch, the claw arms rotate inward and the claws 1404 drop into the notch; this angular movement of the claws 1404 is sensed by an encoder. Similarly, the claws 1404 undergo further movement and encounter additional surface features, which may indicate the core component's serial number. The claw arms 1406 can then be rotated out of the way, and the handling process can proceed.

[0104] In some examples, the claw arm 1406 may be positioned in other locations (e.g., on the grapple itself). This may alleviate the need to fully move the grapple or retract the pantograph to perform core component identification. For example, the claw arm 1404 may be attached to the side or top of the grapple. As described elsewhere herein, a driveline may be configured to pivot the claw arm downward until the claw 1404 contacts the core component and identification is performed. Similarly, the claw arm 1406 may be positioned on a pantograph leg. This may allow identification whether the pantograph is in an extended or retracted state. This embodiment is shown in FIGS. 15A and 15B, where the claw arm 1406 is positioned on the pantograph leg 326.

[0105] Some embodiments may incorporate an ultrasonic identification system. In such an ultrasonic identification system, ultrasonic waves are emitted to serial numbers etched or embossed on core components, and the ultrasonic waves are picked up by a receiver. The receiver may provide raw data to a computer algorithm, which interprets the serial numbers. The ultrasonic CCID may be implemented in combination with or in place of a mechanical CCID system. In some cases, the mechanical CCID may provide core component identification functionality, and the ultrasonic system may be used for various inspection techniques, such as in-service inspection. In-service inspection may be used to inspect safety-related structures, identify or locate obstacles that could cause collisions in fuel handling equipment, and detect other defects. Of course, the ultrasonic system may also serve as a backup CCID to the mechanical CCID in case the mechanical CCID fails.

[0106] The systems and components described herein may be under the control of one or more computer systems configured with instructions to receive data, interpret data, send control instructions, and provide feedback.

[0107] In some cases, the subcomponents of the fuel handling system are semi-autonomous machines that can perform their specific functions locally automatically or locally manually without interfacing with other systems. In those cases, a fuel handling supervisory control system (FHC) may collect condition and status information for those machines for presentation to a fuel handling operator for monitoring. Furthermore, each of these subcomponents may be provided with means for directing control of the operation of that machine.

[0108] In some cases, multiple subcomponents of the fuel handling system are monitored and directly controlled from the FHC system. In these cases, the FHC may provide the necessary input / output (I / O) hardware and software to directly receive the parameters necessary to direct the monitoring and control of the subcomponent's functions.

[0109] The FHC may also be responsible for collecting and distributing all information between systems, subsystems, and components (SSCs) that support the operation of the FH. Some representative examples include interface parameters that support the functions of the FH SSCs, neutron monitoring, argon gas and radioactive waste systems, and the physical location and component status of autonomous FH vehicles as they interact with other FH vehicles.

[0110] In some embodiments, a data acquisition and control (DAC) system allows the fuel handling system to communicate with the FHC system. This may be bidirectional, for example, to transmit status and position data and receive command instructions. In some embodiments, the equipment may support multiple types of inputs and outputs, including analog inputs, bistable inputs, analog outputs, and bistable outputs, among others. Analog inputs are electronic signals generated directly from sensors and transmitters installed within the plant equipment. In some cases, these signals may include thermocouples (T / C) and resistance thermal detectors (RTDs)—temperature elements installed within the plant equipment with cold junction compensation and lead length compensation applied. A linear voltage signal may be provided by a process transmitter. The process transmitter may be installed within the plant equipment or may be tube-connected to the plant equipment. The transmitter may function to cover the process parameter to a measurable linear signal representing a calibration range of 0 to 100% of the process.

[0111] Any of the inputs and outputs described herein may be used to affect the control and / or operation of the fuel handling systems, as well as the pantographs and grapples described herein.

[0112] As described above, databases may be used to store historical data related to the fuel handling system and each core component that enters and exits the reactor. For example, a fuel handling machine operating zone configuration database may store information related to the volume envelope within which the fuel handling system may be moved within an approved load path without colliding with fixed building equipment or other movable fuel handling equipment. In some embodiments, the FHC may maintain a configuration database identifying the load path with its X-axis, Y-axis, and Z-axis position configuration and the location of all static equipment for use in controlling the movement of the FH machine. Because static operating zones may change over the life of the plant, the FHC may maintain this information in a configurable database that can be modified over time. Mobile machine interferences may also be established in this database, and the FHC can monitor current positions to update a dynamic operating map of multiple mobile machines that may interact within the same plane and path.

[0113] Additionally, a core component inventory and tracking database may include data related to individual core components. In some cases, the FHC may be responsible for handling all core components from the time they are delivered into the Core Component Conditioning System until they are stored in an Interim Storage facility. A nuclear operating plant may be responsible for maintaining an inventory of all radioactive materials from the time they are received until they are shipped off-site. Additionally, the reactor core configuration may be maintained as designed for each fuel cycle. For light water reactors, this process is easily maintained visually and therefore can be tracked manually throughout the plant's life. However, in sodium-cooled fast reactors, visual identification and location of all fuel transfer machines or the reactor vessel is not possible. Therefore, the FHC may be configured to produce the information necessary to support regulatory requirements. Therefore, according to some embodiments, the FHC may maintain a Core Component Inventory and Tracking database that may be both manually and / or automatically updated through any suitable human-machine interface and machine-handled core component movements.

[0114] The database may include a configuration data set that may identify each core component of the reactor. The configuration data set includes each core component's type, its unique core component identification code, and any other information about the component that may need to be maintained to support the required inventory records. This information may initially be loaded manually by a plant operator. If some of the information required for inventory control (e.g., fuel monitoring parameters to identify isotope concentrations) requires dynamic updates, this can be updated dynamically through interactions with other plant monitoring processors connected to the FHC and then verified by operations for official record maintenance.

[0115] The database may also be used to maintain the current location within the plant of all of the fuel handling machine subsystems, their temporary coupling with Core Component Transfer Adapters, and their movements and locations during the life of the plant.

[0116] The database may also be a repository for planned core component movement sequences. When it comes time to execute a move, the sequences can be retrieved and utilized through a combination of operator-automated move sequences executed by a machine and verified by an operator, or for manual direction of the move by an operator, depending on how the process for fuel movement unfolds.

[0117] In some embodiments, the database may include one or more of the following: intra-furnace transfer machine (IVTM) operational support data; which components were moved; where the components were moved to; the grapple height left at the time of the move; the grapple height found at the time of the pick-up; when the move occurred; the location from which the move was made; the location to which the move was made; the forces applied by the drive unit during the entire move; and the forces sensed on the non-driven IVTM components during the entire move.

[0118] The general nature of the embodiments of the present disclosure will be sufficiently apparent from the foregoing description of such specific embodiments that others may readily modify and / or adapt the specific embodiments for various applications without undue experimentation by applying the knowledge of those skilled in the art without departing from the general concepts of the embodiments of the present disclosure. Such adaptations and modifications are therefore intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. The phraseology or terminology used herein is intended to be illustrative, not limiting, as the term or terminology would be interpreted by one of ordinary skill in the art in light of the teaching and guidance presented herein.

[0119] The breadth and scope of embodiments of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

[0120] Unless otherwise specified or understood differently within the context in which they are used, conditional words such as "can," "could," "might," or "may," among others, are generally intended to convey that particular implementations may include particular features, elements, and / or operations, while other implementations do not include particular features, elements, and / or operations. As such, such conditional words generally do not intend that features, elements, and / or operations are in any way required in one or more implementations, or that logic for determining whether these features, elements, and / or operations are included in any particular implementation, or whether these features, elements, and / or operations should be performed in any particular implementation, with or without user input or prompting, is necessarily included in one or more implementations.

[0121] Throughout this specification, the term "substantially" with respect to a given parameter, property, or condition may mean and include the extent to which one of ordinary skill in the art would understand that the given parameter, property, or condition is met with slight variations, such as within acceptable manufacturing tolerances. As an example, depending on the particular parameter, property, or condition that is substantially met, the parameter, property, or condition may be at least about 90% met, at least about 95% met, or at least about 99% met.

[0122] As used herein, the terms "about" and "approximately" may, in some embodiments, indicate a variability of up to ±5% of the associated numerical value, for example, a variability of up to ±2%, or a variability of up to ±1%.

[0123] Those skilled in the art will recognize that any process or method disclosed herein can be varied in many ways. The process parameters and order of steps described and / or illustrated herein are given by way of example only and can be varied as desired. For example, although the steps illustrated and / or described herein may be shown or discussed in a particular order, these steps do not necessarily have to be performed in the order illustrated or discussed.

[0124] Additionally, the various exemplary methods described and / or illustrated herein may omit one or more of the steps described or illustrated herein or may include additional steps in addition to those disclosed. Furthermore, the steps of any method disclosed herein may be combined with any one or more steps of any other method disclosed herein.

[0125] Additionally, the various exemplary methods described and / or illustrated herein may omit one or more of the steps described or illustrated herein or may include additional steps in addition to those disclosed. Furthermore, the steps of any method disclosed herein may be combined with any one or more steps of any other method disclosed herein.

[0126] Of course, it is not possible to describe every conceivable combination of elements and / or methodologies for purposes of describing various features of the present disclosure. However, those skilled in the art will recognize that many more combinations and permutations of the disclosed features are possible. Accordingly, various modifications can be made to the present disclosure without departing from the scope or spirit of the disclosure. Moreover, other embodiments of the present disclosure will become apparent from consideration of the specification and accompanying drawings, as well as from the practice of the disclosed embodiments presented herein. The examples presented in the specification and accompanying drawings are to be considered in all respects as illustrative and not restrictive. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

[0127] Unless otherwise specified, the terms "a" or "an" as used herein shall be construed to mean "at least one of." Finally, for ease of use, the terms "including" and "having" (and their derivatives) as used herein are interchangeable with the term "comprising" and have the same meaning.

[0128] From the foregoing description and the accompanying drawings, it will be understood that, although specific implementations have been described herein for illustrative purposes, various modifications may be made without departing from the spirit and scope of the appended claims and the elements recited therein. In addition, while certain aspects are presented below in certain claim forms, the inventors contemplate various aspects in any available claim form. For example, while only some aspects may currently be described as embodied in a particular configuration, other aspects may similarly be embodied in such a manner. Various modifications and changes may be made as would be apparent to those skilled in the art having the benefit of this disclosure. All such modifications and changes are intended to be encompassed, and therefore the foregoing description should be considered in an illustrative, rather than a limiting, sense. [Brief explanation of the drawings]

[0129] [Figure 1] 1 illustrates various components of a nuclear reactor, according to some embodiments. [Figure 2] 1 illustrates an in-reactor fuel handling machine, according to some embodiments. [Figure 3] 1 illustrates an internal fuel transfer machine that may form a component of an internal fuel handling machine, according to some embodiments. [Figure 4A] FIG. 2 is a top view of an exemplary intrareactor fuel transfer machine, according to some embodiments. [Figure 4B] FIG. 4B is a side view of the intra-reactor fuel transfer machine of FIG. 4A, according to some embodiments. [Figure 5] FIG. 10 is a top view of a rotating plug assembly, an in-core storage system, a fuel elevator, and an in-core fuel transfer machine, according to some embodiments. [Figure 6] FIG. 10 is a side view of a pantograph grapple mechanism of an intra-reactor fuel transfer machine, according to some embodiments. [Figure 7A] 13 illustrates a grapple head with fingers retracted according to some embodiments. [Figure 7B]10 illustrates a grapple head with fingers extended within a handling socket of a core assembly according to some embodiments. [Figure 7C] 10 illustrates a grapple head with fingers engaged within a handling socket of a core assembly according to some embodiments. [Figure 8] 1 illustrates a grapple assembly, according to some embodiments. [Figure 9] 1 illustrates a deformed core assembly having a primary deformation according to some embodiments. [Figure 10] 10 illustrates a deformed core assembly being removed from a core socket according to some embodiments. [Figure 11] 1 illustrates a floating or compliant grapple configured to move in a horizontal plane, according to some embodiments. [Figure 12] FIG. 10 is a process flow diagram for extraction of a deformed core assembly according to some embodiments. [Figure 13] FIG. 10 is a process flow diagram for extraction of a deformed core assembly according to some embodiments. [Figure 14A] 1 illustrates a core component identification system including a claw attached to a guide tube, according to some embodiments. [Figure 14B] FIG. 10 is a top cross-sectional view illustrating surface features formed into a core component and tabs that engage the surface features to determine the unique identity of the core component, according to some embodiments. [Figure 15A] 1 illustrates a core component identification system including a claw attached to a pantograph, according to some embodiments. [Figure 15B] FIG. 10 is a top cross-sectional view illustrating surface features formed into a core component and tabs that engage the surface features to determine a unique identifier of the core component, according to some embodiments.

Claims

1. An in-reactor fuel transfer machine, a drive assembly configured to be mounted above a reactor head of the nuclear reactor; a telescoping guide tube operatively coupled to the drive assembly, the telescoping guide tube extending through the reactor head; a pantograph mechanism coupled to the telescopic guide tube, an upper arm having a first upper arm end and a second upper arm end, the upper arm operatively coupled to the telescoping guide tube at the first upper arm end; a lower arm having a first lower arm end and a second lower arm end, the lower arm operatively coupled to the telescoping guide tube at the first lower arm end; a leg coupled to the second upper arm end and the second lower arm end, the leg defining a path; a grapple coupled to the leg, the grapple configured to move along the path; a pantograph mechanism including: an in-reactor fuel transfer machine including:

2. a pantograph driveline selectively engageable with the upper arm and the lower arm; The intra-reactor fuel transfer machine of claim 1 , wherein the drive assembly is configured to rotate the upper arm and the lower arm away from the telescoping guide tube.

3. the legs are configured to be moved away from the telescopic guide tube by actuation of the upper arm and the lower arm; The in-reactor fuel transfer machine of claim 2 , wherein the legs are further configured to maintain a parallel state with the telescoping guide tube during actuation of the upper arm and the lower arm.

4. 3. The in-reactor fuel transfer machine of claim 2, wherein the grapple is configured to float by disengaging the pantograph drive line and allowing the grapple to move in a horizontal plane in response to an external force applied to the grapple.

5. The in-reactor fuel transfer machine of claim 1 , wherein the grapple includes a plurality of fingers biased in a parallel orientation relative to the legs.

6. The in-reactor fuel transfer machine of claim 5 , wherein the grapple includes a shaft configured to be slidable so that the plurality of fingers spread outward.

7. the telescoping guide tube defines a longitudinal axis; The intra-reactor fuel transfer machine of claim 1 , further comprising a rotary motor configured to rotate the intra-reactor fuel transfer machine about the guide tube longitudinal axis.

8. The in-reactor fuel transfer machine of claim 1 , wherein the pantograph is configured to remain within the reactor vessel during power operation of the reactor.

9. 9. The in-core fuel transfer machine of claim 8, wherein the pantograph is permanently installed in a position that leaves the pantograph submerged in a pool of sodium.

10. The intracore fuel transfer machine of claim 1 , further comprising a force sensor coupled to the grapple, the force sensor configured to sense one or more forces applied to the grapple.

11. 11. The in-reactor fuel transfer machine of claim 10, further comprising an encoder coupled to the drive assembly and configured to operate the drive assembly to move the pantograph in response to one or more forces applied to the grapple.

12. The intra-reactor fuel transfer machine of claim 11 , wherein the encoder is configured to move the grapple to reduce a force applied to the grapple by a deformed core assembly.

13. 12. The in-core fuel transfer machine of claim 11, wherein the encoder is configured to move the grapple in a circuitous path while withdrawing a deformed core assembly from a core socket within the nuclear reactor core.

14. The in-reactor fuel transfer machine of claim 1 , wherein the grapple further comprises a ball joint configured to allow the grapple to pivot freely within predetermined angular limits.

15. The in-reactor fuel transfer machine according to claim 1 , further comprising a ball screw actuator for extending and retracting said telescopic guide tube.

16. the ball screw actuator is mounted above the reactor head; The ball screw actuator a sliding shaft that penetrates the reactor head at a penetration portion; a sliding shaft seal at the penetration; 16. The in-reactor fuel transfer machine of claim 15, comprising:

17. further comprising a mechanical core component identification system; the mechanical core component identification system includes a claw configured to be selectively biased toward the core component when the core component is held in the grapple; 2. The in-reactor fuel transfer machine of claim 1, wherein the claw is further configured to identify the core component by reading a series of notches formed in the core component as the core component is rotated by the grapple.

18. 1. A method for extracting a deformed core assembly from a nuclear reactor core, comprising: positioning a grapple of a pantograph type intracore fuel transfer machine above a selected core assembly; disengaging a pantograph driveline to allow said pantograph to float in a horizontal plane; driving the grapple into a handling socket of a selected core assembly; extending grapple fingers within the handling socket; removing the selected core assembly from the reactor core while the pantograph drive line is disengaged; engaging the pantograph drive line after a predetermined extraction distance to complete extraction of the selected core assembly; A method comprising:

19. 20. The method of extracting a deformed core assembly of claim 18, wherein extracting the selected core assembly from the nuclear reactor core includes moving the grapple along a circuitous path.

20. 20. The method of extracting a deformed core assembly of claim 18, further comprising determining a side load on the grapple from the deformed core assembly.

21. 21. The method of extracting a deformed core assembly of claim 20, further comprising: causing the grapple to move in a horizontal plane based at least in part on the side load.

22. engaging a claw with an outer periphery of the core assembly; rotating the core assembly; further comprising identifying the deformed core assembly by 20. The method of claim 18, wherein the claws follow a shape of a periphery of the core assembly and determine a unique identifier associated with the core assembly based at least in part on the shape of the periphery of the core assembly.

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