A device and method for loading and unloading fuel balls of a high-temperature gas-cooled reactor

Abstract

The present invention discloses a device and method for loading and unloading fuel balls of a high-temperature gas-cooled reactor. The bottom outlet of the reactor pressure vessel is connected to the inlet of a charging control valve group, the outlet of the charging control valve group is connected to the inlet of a burnup measuring device, the outlet of the burnup measuring device is connected to the inlet of a discharge control valve group, the first outlet of the discharge control valve group is connected to the inlet of a fuel storage system and the inlet of a rotatable charging device, the second outlet of the discharge control valve group is connected to the inlet of the fuel storage system, the outlet of the rotatable charging device is connected to the inlet of the reactor pressure vessel, the outlet of the fuel storage system and the outlet of a new fuel tank are respectively connected to the inlet of the charging control valve group. The device and method can flatten the neutron flux distribution in the core and improve the safety and economy of the reactor.

Description

Technical Field

[0001] The invention belongs to the field of nuclear reactor fuel loading and unloading, and relates to a device and method for loading and unloading high-temperature gas-cooled reactor fuel balls. Background Art

[0002] The fuel spheres of a pebble-bed high-temperature gas-cooled reactor (HTGR) must circulate inside and outside the reactor multiple times during normal operation. The current fuel loading and unloading system divides fuel into two categories: spent fuel spheres and recycled fuel spheres, without distinguishing between fuels with different burnup depths. During the loading process, the recyclable fuel spheres and newly loaded fuel spheres are directly transferred back to the core, where they fall randomly into the pebble bed.

[0003] As long as the burnup depth of recycled fuel spheres is less than 80,000MW / tU, they are recirculated into the reactor core. After passing through the fuel loading and unloading system, new fuel spheres with a burnup of 0MW / tU and recycled fuel spheres with a burnup of 80,000MW / tU randomly fall into the core from the reactor loading port. This indiscriminate and random falling behavior inevitably leads to an asymmetric radial power distribution in the core during daily operation, and in severe cases, can even cause severe radial power skew. Furthermore, the core's axial power distribution also exhibits significant randomness. How to flatten the core's neutron flux distribution and improve the reactor's safety and economic efficiency has become a difficult problem for the industry. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a loading and unloading device and method for high-temperature gas-cooled reactor fuel balls, which can flatten the core neutron flux distribution and improve the safety and economy of the reactor.

[0005] To achieve the above-mentioned object, the loading and unloading device for high-temperature gas-cooled reactor fuel pellets of the present invention includes a reactor pressure vessel, a loading control valve group, a burnup measurement device, a unloading control valve group, a fuel storage system, a rotatable loading device, a new fuel tank, a loading and unloading control system, and a core measurement system for measuring the core neutron flux distribution diagram in the reactor pressure vessel;

[0006] The bottom outlet of the reactor pressure vessel is connected to the inlet of the charging control valve group, the outlet of the charging control valve group is connected to the inlet of the burnup measuring device, the outlet of the burnup measuring device is connected to the inlet of the unloading control valve group, the first outlet of the unloading control valve group is connected to the inlet of the fuel storage system and the inlet of the rotatable charging device, the second outlet of the unloading control valve group is connected to the inlet of the fuel storage system, the outlet of the rotatable charging device is connected to the inlet of the reactor pressure vessel, and the outlet of the fuel storage system and the outlet of the new fuel tank are respectively connected to the inlet of the charging control valve group;

[0007] The input end of the loading and unloading control system is connected to the output end of the core measurement system and the output end of the burnup measurement device, and the output end of the loading and unloading control system is connected to the control end of the unloading control valve group and the control end of the loading control valve group.

[0008] The fuel storage system includes several inlet storage tanks and spent fuel tanks, wherein the inlet of the inlet storage tank and the inlet of the spent fuel tank are respectively connected to the unloading control valve group, and the outlet of the inlet storage tank and the outlet of the new fuel tank are respectively connected to the inlet of the loading control valve group.

[0009] The number of inlet storage tanks is three.

[0010] The rotatable loading device includes a rotatable loading tube and a rotatable magnetic field generating device, wherein the rotatable loading tube is provided with a permanent magnet. The rotatable loading tube passes through the rotatable magnetic field generating device and is inserted into the reactor pressure vessel. The control end of the rotatable magnetic field generating device is connected to the loading and unloading control system.

[0011] The number of the charging control valves in the charging control valve group is four, wherein one charging control valve corresponds to one import storage tank or one new fuel tank.

[0012] There are four unloading control valves in the unloading control valve group, wherein one unloading control valve corresponds to one inlet storage tank or one spent fuel tank.

[0013] The first import storage tank is filled with fuel balls with a burnup of less than 20,000MWd / tU, the second import storage tank is filled with fuel balls with a burnup of 20,000-50,000MWd / tU, the third import storage tank is filled with fuel balls with a burnup of 50,000-80,000MWd / tU, and the spent fuel tank is filled with fuel balls with a burnup of more than 80,000MWd / tU.

[0014] The rotatable charging device is equipped with four magnetic field coils evenly distributed along the circumference.

[0015] A method for loading and unloading high-temperature gas-cooled reactor fuel pellets comprises the following steps:

[0016] The loading and unloading control system measures the distribution diagram of the core neutron flux through the core measurement system, and at the same time controls the rotatable loading device to drop the high-burnup fuel balls into the area of ​​the reactor pressure vessel where the neutron flux peak is located, and drops the low-burnup fuel balls or new fuel balls into the area of ​​the reactor pressure vessel where the neutron flux valley is located.

[0017] The present invention has the following beneficial effects:

[0018] During specific operation of the high-temperature gas-cooled reactor fuel ball loading and unloading device and method described in the present invention, the loading and unloading control system measures the distribution diagram of the core neutron flux through the core measurement system, and at the same time controls the rotatable loading device to drop high-burnup fuel balls into the area where the neutron flux peak is located, and drops low-burnup fuel balls or new fuel balls into the area where the neutron flux valley is located, so as to achieve the purpose of evenly distributing the fuel balls and flattening the neutron flux distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the present invention;

[0020] Figure 2 It is a schematic structural diagram of the rotatable charging device 9 in the present invention.

[0021] Among them, 1 is the reactor pressure vessel, 2 is the fuel storage system, 3 is the fuel consumption measuring device, 4 is the unloading control valve group, 5 is the loading control valve group, 6 is the loading and unloading control system, 7 is the core radial power distribution curve under random state, 8 is the core radial power distribution curve after control 8, 9 is the rotatable loading device, 10 is the rotatable magnetic field generating device, 11 is the rotatable loading tube, 12 is the permanent magnet, and 13 is the core measurement system. DETAILED DESCRIPTION

[0022] The present invention is described in further detail below with reference to the accompanying drawings:

[0023] refer to Figure 1 The loading and unloading device for high-temperature gas-cooled reactor fuel balls of the present invention comprises a reactor pressure vessel 1, a loading control valve group 5, a burnup measuring device 3, a unloading control valve group 4, a fuel storage system 2, a rotatable loading device 9, a new fuel tank 23, a loading and unloading control system 6, and a core measurement system 13 for measuring the core neutron flux distribution diagram in the reactor pressure vessel 1; the bottom outlet of the reactor pressure vessel 1 is connected to the inlet of the loading control valve group 5, the outlet of the loading control valve group 5 is connected to the inlet of the burnup measuring device 3, the outlet of the burnup measuring device 3 is connected to the inlet of the unloading control valve group 4, and the unloading control valve group The first outlet of the unloading control valve group 4 is connected to the inlet of the fuel storage system 2 and the inlet of the rotatable charging device 9. The second outlet of the unloading control valve group 4 is connected to the inlet of the fuel storage system 2. The outlet of the rotatable charging device 9 is connected to the inlet of the reactor pressure vessel 1. The outlet of the fuel storage system 2 and the outlet of the new fuel tank 23 are respectively connected to the inlet of the charging control valve group 5. The input end of the loading and unloading control system 6 is connected to the output end of the core measurement system 13 and the output end of the burnup measurement device 3. The output end of the loading and unloading control system 6 is connected to the control end of the unloading control valve group 4 and the control end of the charging control valve group 5.

[0024] The fuel storage system 2 includes several inlet storage tanks 21 and spent fuel tanks 22, wherein the inlet of the inlet storage tank 21 and the inlet of the spent fuel tank 22 are respectively connected to the unloading control valve group 4, and the outlet of the inlet storage tank 21 and the outlet of the new fuel tank 23 are respectively connected to the inlet of the loading control valve group 5.

[0025] There are three import storage tanks 21; there are four loading control valves in the loading control valve group 5, wherein one loading control valve corresponds to one import storage tank 21 or one new fuel tank 23; there are four unloading control valves in the unloading control valve group 4, wherein one unloading control valve corresponds to one import storage tank 21 or one spent fuel tank 22.

[0026] refer to Figure 2 The rotatable charging device 9 includes a rotatable charging tube 11 and a rotatable magnetic field generating device 10, wherein a permanent magnet 12 is provided on the rotatable charging tube 11. The rotatable charging tube 11 passes through the rotatable magnetic field generating device 10 and is inserted into the reactor pressure vessel 1. The control end of the rotatable magnetic field generating device 10 is connected to the loading and unloading control system 6. The rotatable charging device 9 is equipped with four magnetic field coils evenly distributed along the circumference.

[0027] The first inlet storage tank 21 is filled with fuel balls with a burnup of less than 20,000 MWd / tU, the second inlet storage tank 21 is filled with fuel balls with a burnup of 20,000-50,000 MWd / tU, the third inlet storage tank 21 is filled with fuel balls with a burnup of 50,000-80,000 MWd / tU, and the spent fuel tank 22 is filled with fuel balls with a burnup of more than 80,000 MWd / tU.

[0028] The method for loading and unloading high-temperature gas-cooled reactor fuel balls of the present invention comprises the following steps:

[0029] The loading and unloading control system 6 measures the distribution diagram 7 of the core neutron flux through the core measurement system 13, and gives priority to sending the recycled fuel balls back to the core immediately. By controlling the rotatable loading device 9, the high-burnup fuel balls are dropped into the area where the neutron flux peak is located, and the low-burnup fuel balls or new fuel balls are dropped into the area where the neutron flux valley is located. The rotatable loading device 9 can control the magnetic field to be stable at any angle in the 360° direction, so that the fuel balls can be dropped into any corresponding ball landing area in the core, thereby achieving the effect of evenly distributing the fuel balls and flattening the neutron flux.

[0030] When the fuel spheres are not immediately loaded into the core and need to be temporarily stored or stored as spent fuel, the loading and unloading control system 6 adjusts the unloading control valve group 4 to respectively introduce the fuel spheres with a burnup of less than 20,000 MWd / tU, the fuel spheres with a burnup of 20,000-50,000 MWd / tU, and the fuel spheres with a burnup of 50,000-80,000 MWd / tU into the first introduction storage tank 21, the second introduction storage tank 21, the third introduction storage tank 21, and the spent fuel tank 22. When it is necessary to select fuel balls with a specific burnup depth or new fuel balls, the loading and unloading control system 6 controls the loading control valve group 5 to respectively import fuel balls with a burnup of less than 20,000 MWd / tU, fuel balls with a burnup of 20,000-50,000 MWd / tU, fuel balls with a burnup of 50,000-80,000 MWd / tU, and new fuel balls into the system from the first import storage tank 21, the second import storage tank 21, the third import storage tank 21, and the new fuel tank 23. By temporarily storing and recycling the fuel balls according to their burnup, the core axial power can be distributed as required.

[0031] The rotatable charging device 9 includes a rotatable charging tube 11 with a permanent magnet 12 and a rotatable magnetic field generating device 10. The direction of the magnetic field generated by the rotatable magnetic field generating device 10 is adjusted to drive the rotatable charging tube 11 to rotate, thereby achieving loading at different positions. Specifically, a magnetic field coil is arranged at 0°, 90°, 180°, and 270° directions of the rotatable charging device 9, wherein 0° and 180° form a pair, and 90° and 270° form a pair. The magnitude and direction of the current in the magnetic field coil are controlled by the loading and unloading control system 6, for example Figure 2 When a magnetic field in the direction of 135° needs to be generated, a positive current is passed at 0° and 90°, and a negative current is passed at 180° and 270°, so that the magnetic fields of the two pairs of poles are superimposed to generate a synthetic magnetic field in the direction of 135°. If magnetic fields at other angles are required, the current direction and magnitude of each magnetic field coil can be changed to make the superimposed magnetic field rotate in the required direction. The permanent magnet 12 is acted upon by the magnetic field force, driving the rotatable loading tube 11 to rotate arbitrarily within 360°.

Claims

1. A loading and unloading device for high temperature gas-cooled reactor fuel balls, characterized in that: The invention comprises a reactor pressure vessel (1), a loading control valve group (5), a burnup measuring device (3), a discharge control valve group (4), a fuel storage system (2), a rotatable loading device (9), a new fuel tank (23), a loading and unloading control system (6), and a core measurement system (13) for measuring a core neutron flux distribution diagram in the reactor pressure vessel (1); The bottom outlet of the reactor pressure vessel (1) is connected to the inlet of the charging control valve group (5), the outlet of the charging control valve group (5) is connected to the inlet of the burnup measuring device (3), the outlet of the burnup measuring device (3) is connected to the inlet of the unloading control valve group (4), the first outlet of the unloading control valve group (4) is connected to the inlet of the rotatable charging device (9), the second outlet of the unloading control valve group (4) is connected to the inlet of the fuel storage system (2), the outlet of the rotatable charging device (9) is connected to the inlet of the reactor pressure vessel (1), and the outlet of the fuel storage system (2) and the outlet of the new fuel tank (23) are respectively connected to the inlet of the charging control valve group (5); The input end of the loading and unloading control system (6) is connected to the output end of the core measurement system (13) and the output end of the burnup measurement device (3), and the output end of the loading and unloading control system (6) is connected to the control end of the unloading control valve group (4) and the control end of the loading control valve group (5); The rotatable charging device (9) comprises a rotatable charging tube (11) and a rotatable magnetic field generating device (10), wherein a permanent magnet (12) is provided on the rotatable charging tube (11), and the rotatable charging tube (11) passes through the rotatable magnetic field generating device (10) and is inserted into the reactor pressure vessel (1), and the control end of the rotatable magnetic field generating device (10) is connected to the loading and unloading control system (6).

2. The high temperature gas-cooled reactor fuel ball loading and unloading device according to claim 1, characterized in that: The fuel storage system (2) comprises a plurality of inlet storage tanks (21) and spent fuel tanks (22), wherein the inlet of the inlet storage tank (21) and the inlet of the spent fuel tank (22) are respectively connected to the unloading control valve group (4), and the outlet of the inlet storage tank (21) and the outlet of the new fuel tank (23) are respectively connected to the inlet of the loading control valve group (5).

3. The high temperature gas-cooled reactor fuel ball loading and unloading device according to claim 1, characterized in that: The number of the inlet storage tanks (21) is three.

4. The device for loading and unloading fuel balls for a high temperature gas-cooled reactor according to claim 3, characterized in that: The number of the charging control valves in the charging control valve group (5) is four, wherein one charging control valve corresponds to one import storage tank (21) or one new fuel tank (23).

5. The device for loading and unloading fuel balls for a high temperature gas-cooled reactor according to claim 3, characterized in that: The number of the unloading control valves in the unloading control valve group (4) is four, wherein one unloading control valve corresponds to one inlet storage tank (21) or one spent fuel tank (22).

6. The high temperature gas-cooled reactor fuel ball loading and unloading device according to claim 3, characterized in that: The first inlet storage tank (21) is filled with fuel balls with a burnup of less than 20,000 MWd / tU, the second inlet storage tank (21) is filled with fuel balls with a burnup of 20,000-50,000 MWd / tU, the third inlet storage tank (21) is filled with fuel balls with a burnup of 50,000-80,000 MWd / tU, and the spent fuel tank (22) is filled with fuel balls with a burnup of more than 80,000 MWd / tU.

7. The high temperature gas-cooled reactor fuel ball loading and unloading device according to claim 1, characterized in that: The rotatable charging device (9) is equipped with four magnetic field coils evenly distributed along the circumference.

8. A method for loading and unloading fuel balls of a high temperature gas-cooled reactor, characterized in that: The loading and unloading device for high temperature gas-cooled reactor fuel balls according to claim 1 comprises the following steps: The loading and unloading control system (6) measures the distribution diagram of the core neutron flux through the core measurement system (13), and at the same time controls the rotatable loading device (9) to drop the high-burnup fuel balls into the area where the neutron flux peak is located in the reactor pressure vessel (1), and drops the low-burnup fuel balls or new fuel balls into the area where the neutron flux valley is located in the reactor pressure vessel (1).

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