Nuclear reaction state monitoring system based on anti-electron neutrino

Abstract

The invention provides a nuclear reaction state monitoring system based on anti-electron neutrino, and relates to the technical field of nuclear monitoring. The nuclear reaction state monitoring device comprises a shell and two central detectors; the two center detectors are arranged in the shell, are arranged in parallel in the length direction of the shell and are spaced by a first set length; the center detector sequentially comprises an organic glass layer, a stainless steel layer, a polyethylene shielding layer, a lead shielding layer and a plastic scintillator layer from inside to outside. The organic glass layer is filled with a gadolinium-containing liquid scintillator; the organic glass layer and the stainless steel layer are spaced by a second set length to form a detection area; the detection area is filled with mineral oil; a plurality of photomultipliers are arranged on the four inner walls of the stainless steel layer in an array mode. Modularization is adopted, a carrier or a lifting appliance can be conveniently used for moving, and meanwhile, if long-distance detection needs to be carried out, only a plurality of modules need to be networked.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear monitoring, and in particular to a nuclear reaction state monitoring system based on anti-electron neutrinos. Background Art

[0002] In recent years, the world's demand for low-carbon energy has been increasing. Civilian nuclear energy technology has been widely developed around the world. The traditional means of monitoring reactors by using neutron and gamma-ray detectors deployed inside the core has the following disadvantages: 1) The number of detectors deployed in the core is limited, resulting in a large monitoring blind area; 2) The flow of fissile materials (mainly Pu-239) in the civilian nuclear fuel cycle cannot be accurately tracked, posing a risk of nuclear fuel diversion; In addition, similar reactor anti-electron neutrino detectors currently have some limitations. For example, most anti-electron neutrino detectors are very large and fixed and cannot be moved. They serve a single purpose and are mainly built to achieve certain basic physics goals. Some other small detectors, although they can also be easily moved, have too small a target mass and limited detection distance, and they often need to be placed very close to the reactor. Summary of the invention

[0003] The purpose of the present invention is to provide a nuclear reaction state monitoring system based on anti-electron neutrinos, which is modular and can be easily moved using a carrier or a sling. At the same time, if long-distance detection is required, it is only necessary to network multiple modules.

[0004] A nuclear reaction state monitoring system based on anti-electron neutrinos, comprising: a plurality of nuclear reaction state monitoring devices; The nuclear reaction state monitoring device comprises a housing and two central detectors; The two central detectors are both arranged in the shell and are arranged in parallel along the length direction of the shell and are spaced apart by a first set length; an operating room is arranged at one end of the shell; The central detector is in the shape of a cuboid, and comprises, from the inside to the outside, an organic glass layer, a stainless steel layer, a polyethylene shielding layer, a lead shielding layer and a plastic scintillator layer; The organic glass layer is filled with gadolinium-containing liquid scintillator; a second set length is spaced between the organic glass layer and the stainless steel layer to form a detection area; The detection area is filled with mineral oil; and a plurality of photomultiplier tubes are arranged in an array on the four inner walls of the stainless steel layer.

[0005] Optionally, the number of the nuclear reaction state monitoring devices is 2; The two nuclear reaction state monitoring devices are arranged in parallel relative to the nuclear reaction area.

[0006] Optionally, the number of the nuclear reaction state monitoring device is 1; The operating room of the nuclear reaction state monitoring device is arranged facing the nuclear reaction area.

[0007] Optionally, a plurality of the nuclear reaction state monitoring devices are stacked in an array.

[0008] Optionally, the mass fraction of gadolinium in the gadolinium-containing liquid scintillator is 0.1%.

[0009] Optionally, the second set length includes a first sub-set length, a second sub-set length and a third sub-set length; The organic glass layer and the stainless steel layer are spaced apart by the first sub-set length along the length direction, the organic glass layer and the stainless steel layer are spaced apart by the second sub-set length along the width direction, and the organic glass layer and the stainless steel layer are spaced apart by the third sub-set length along the height direction.

[0010] Optionally, the first sub-setting length is 40 cm; the second sub-setting length is 40 cm; and the third sub-setting length is 5 cm.

[0011] Optionally, an isolation plate is provided between the two central detectors.

[0012] Optionally, the polyethylene shielding layer contains boron, and the mass fraction of boron in the polyethylene shielding layer is 24.8%-25.2%.

[0013] Optionally, the organic glass layer and the stainless steel layer are fixed by a fixing bracket.

[0014] The effects of the present invention are as follows: The nuclear reaction state monitoring system based on anti-electron neutrinos of the present invention is modularized and can be easily moved using a carrier or a sling. If long-distance detection is required, it is only necessary to network multiple modules. By networking modular detectors, the detection quality can be effectively improved and the detection radius can be increased. Not only can the monitoring of artificial nuclear devices be strengthened, but also the detection of natural anti-electron neutrinos can be realized.

[0015] The anti-electron neutrino-based nuclear reaction state monitoring system of the present invention can not only realize the monitoring of land reactors, but also can be used for shipboard sea trials to perform long-distance real-time monitoring of underwater reactors. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the nuclear reaction state monitoring device of the present invention; Figure 2 It is a schematic diagram of the structure of the central detector of the present invention; Figure 3 It is a schematic diagram of a stacked arrangement of a plurality of nuclear reaction state monitoring devices in an array according to the present invention; Figure 4 It is a schematic diagram of two nuclear reaction state monitoring devices of the present invention being arranged in parallel relative to the nuclear reaction area; Figure 5 The present invention is a schematic diagram of an operating room of a nuclear reaction state monitoring device arranged facing a nuclear reaction area.

[0017] In the figure: 1. Nuclear reaction status monitoring device; 2. Nuclear reaction area; 11. Shell; 12. Central detector; 13. Operating room; 121. Organic glass layer; 122. Stainless steel layer; 123. Polyethylene shielding layer; 124. Lead shielding layer; 125. Plastic scintillator layer; 126. Gadolinium-containing liquid scintillator; 127. Mineral oil; 128. Photomultiplier tube. DETAILED DESCRIPTION

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0019] The utilization of modern nuclear energy mainly comes from the fission of heavy nuclei, which is usually achieved by reactor devices. When a fissile nuclide (such as uranium-235 or plutonium-239, also recorded as U-235 or Pu-239) is hit by a neutron and fissions, it will release multiple neutrons, which will hit other fissile nuclides again, triggering more fission reactions and releasing more neutrons. This process will continue, forming a continuous chain reaction, thereby continuously releasing energy. At the same time, in the fission process of fission nuclides, in addition to neutrons, a large number of fission fragments will be produced. These fragments are not stable and need to be stabilized through β decay. The β decay process is accompanied by the production of anti-electron neutrinos. After research, it was found that on average, about 6 anti-electron neutrinos are produced for each nuclear fission, and the number of anti-electron neutrinos is related to the number of fissions in the reactor. Therefore, by detecting the changes in the flux of anti-electron neutrinos produced by the reactor, the operating status of the reactor can be obtained.

[0020] The present invention provides a nuclear reaction state monitoring system based on anti-electron neutrinos, which comprises: a plurality of nuclear reaction state monitoring devices 1. The size of the nuclear reaction state monitoring device 1 is 13.58 m×2.34 m×2.71 m.

[0021] like Figure 1 As shown, the nuclear reaction state monitoring device 1 includes a housing 11 and two central detectors 12 .

[0022] The two central detectors 12 are both arranged in the housing 11 and are arranged in parallel along the length direction of the housing 11 and are separated by a first set length. An operation room 13 is arranged at one end of the housing 11. Preferably, an isolation plate is arranged between the two central detectors 12. The operation room 13 is used for installation and debugging of the data acquisition system.

[0023] like Figure 2 As shown, the central detector 12 is in the shape of a cuboid, and includes, from the inside to the outside, a plexiglass layer 121 , a stainless steel layer 122 , a polyethylene shielding layer 123 , a lead shielding layer 124 and a plastic scintillator layer 125 .

[0024] The organic glass layer 121 is filled with a gadolinium-containing liquid scintillator 126; the organic glass layer 121 and the stainless steel layer 122 are separated by a second set length to form a detection area. Preferably, the mass fraction of gadolinium in the gadolinium-containing liquid scintillator 126 is 0.1%. The second set length includes a first sub-set length, a second sub-set length and a third sub-set length. The organic glass layer 121 and the stainless steel layer 122 are separated by the first sub-set length in the length direction, the organic glass layer 121 and the stainless steel layer 122 are separated by the second sub-set length in the width direction, and the organic glass layer 121 and the stainless steel layer 122 are separated by the third sub-set length in the height direction. Specifically, the first sub-set length is 40 cm; the second sub-set length is 40 cm; and the third sub-set length is 5 cm.

[0025] The gadolinium-containing liquid scintillator 126 is used as a detection medium to identify anti-β decay. The stainless steel layer 122 provides shielding for the gadolinium-containing liquid scintillator 126 from external natural radioactivity. The polyethylene shielding layer 123 is used to shield neutrons generated by external structures. The lead shielding layer 124 is used to absorb high-energy gamma rays and other ionizing radiation. The plastic scintillator layer 125 is used as an anti-coincidence detector for cosmic ray muons and also as an outer shielding structure of the central detector 12.

[0026] Specifically, the organic glass layer 121 and the stainless steel layer 122 are fixed by a fixing bracket.

[0027] The polyethylene shielding layer 123 contains boron, and the mass fraction of boron in the polyethylene shielding layer 123 is 24.8%-25.2%, preferably 25%.

[0028] The detection area is filled with mineral oil 127 ; and a plurality of photomultiplier tubes 128 are arranged in an array on the four inner walls of the stainless steel layer 122 .

[0029] Mineral oil 127 acts as a buffer layer between the gadolinium-containing liquid scintillator 126 and the external structure, shielding the photomultiplier tube 128 and other external structures from natural radioactive interference.

[0030] There are 15 rows of photomultiplier tubes 128 arranged on the side wall along the length direction of the stainless steel layer 122, with 5 photomultiplier tubes 128 in each row, and there are 3 rows of photomultiplier tubes 128 arranged on the side wall along the width direction of the stainless steel layer 122, with 5 photomultiplier tubes 128 in each row.

[0031] Optionally, the number of the nuclear reaction state monitoring devices 1 is 2.

[0032] like Figure 4 As shown, the two nuclear reaction state monitoring devices 1 are arranged in parallel relative to the nuclear reaction region 2 .

[0033] Optionally, the number of the nuclear reaction state monitoring device 1 is 1.

[0034] like Figure 5 As shown, the operating room 13 of the nuclear reaction state monitoring device 1 is arranged facing the nuclear reaction area 2. Relative measurement can be achieved through two different central detectors 12 in the same nuclear reaction state monitoring device 1 or through two different nuclear reaction state monitoring devices 1. This arrangement can greatly reduce the dependence on the reactor neutrino model, and the accuracy of the reactor neutrino model can be verified while monitoring the reactor operating status.

[0035] Alternatively, if Figure 3 As shown, a plurality of the nuclear reaction state monitoring devices 1 are stacked in an array. Such a networking method can quickly and effectively increase the target mass of the nuclear reaction state monitoring device 1, and can greatly increase the detection distance. This stacking networking method can not only realize the monitoring of land reactors, but also can be used for shipboard sea trials to perform long-distance real-time monitoring of underwater reactors.

[0036] In addition, the outer nuclear reaction state monitoring device 1 can also serve as a shield and anti-coincidence system for the inner nuclear reaction state monitoring device 1. This method can effectively reduce the background noise of the inner nuclear reaction state monitoring device 1, improve the signal-to-noise ratio, and increase the detection accuracy of the inner nuclear reaction state monitoring device 1 for anti-electron neutrinos.

[0037] After stacking, the target mass has a larger volume and can be used to detect natural anti-electron neutrinos, such as anti-electron neutrinos in atmospheric neutrinos, solar neutrinos and supernova neutrinos.

[0038] Preferably, a plurality of nuclear reaction state monitoring devices 1 are deployed around the nuclear reaction region 2 to detect neutrinos at different angles, and the detection accuracy is increased through mutual verification.

[0039] Each central detector 12 obtains a number of anti-electron neutrinos, and the final number of anti-electron neutrinos can be obtained by adding them up according to the actual number of nuclear reaction state monitoring devices 1 and the networking method.

[0040] The embodiments described above are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A nuclear reaction state monitoring system based on anti-electron neutrinos, characterized in that: It includes: Several nuclear reaction status monitoring devices; The nuclear reaction state monitoring device comprises a housing and two central detectors; The two central detectors are both arranged in the shell and are arranged in parallel along the length direction of the shell and are spaced apart by a first set length; an operating room is arranged at one end of the shell; The central detector is in the shape of a cuboid, and comprises, from the inside to the outside, an organic glass layer, a stainless steel layer, a polyethylene shielding layer, a lead shielding layer and a plastic scintillator layer; The organic glass layer is filled with gadolinium-containing liquid scintillator; a second set length is spaced between the organic glass layer and the stainless steel layer to form a detection area; The detection area is filled with mineral oil; and a plurality of photomultiplier tubes are arranged in an array on the four inner walls of the stainless steel layer.

2. The anti-electron neutrino-based nuclear reaction state monitoring system according to claim 1, characterized in that: The number of the nuclear reaction state monitoring devices is 2; The nuclear reaction state monitoring device is arranged in parallel with the nuclear reaction area.

3. The anti-electron neutrino-based nuclear reaction state monitoring system according to claim 1, characterized in that: The number of the nuclear reaction state monitoring device is 1; The operating room of the nuclear reaction state monitoring device is arranged facing the nuclear reaction area.

4. The anti-electron neutrino-based nuclear reaction state monitoring system according to claim 1, characterized in that: A plurality of the nuclear reaction state monitoring devices are stacked in an array.

5. The anti-electron neutrino-based nuclear reaction state monitoring system according to claim 1, characterized in that: The mass fraction of gadolinium in the gadolinium-containing liquid scintillator is 0.1%.

6. The anti-electron neutrino-based nuclear reaction state monitoring system according to claim 1, characterized in that: The second set length includes a first sub-set length, a second sub-set length and a third sub-set length; The organic glass layer and the stainless steel layer are spaced apart by the first sub-set length along the length direction, the organic glass layer and the stainless steel layer are spaced apart by the second sub-set length along the width direction, and the organic glass layer and the stainless steel layer are spaced apart by the third sub-set length along the height direction.

7. The anti-electron neutrino-based nuclear reaction state monitoring system according to claim 6, characterized in that: The first sub-piece is set to have a length of 40 cm; the second sub-piece is set to have a length of 40 cm; and the third sub-piece is set to have a length of 5 cm.

8. The anti-electron neutrino-based nuclear reaction state monitoring system according to claim 1, characterized in that: An isolation plate is provided between the two central detectors.

9. The anti-electron neutrino-based nuclear reaction state monitoring system according to claim 1, characterized in that: The polyethylene shielding layer contains boron, and the mass fraction of boron in the polyethylene shielding layer is 24.8%-25.2%.

10. The anti-electron neutrino-based nuclear reaction state monitoring system according to claim 1, characterized in that: The organic glass layer and the stainless steel layer are fixed by a fixing bracket.

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