A wide range neutron criticality detector

Abstract

The present invention provides a wide-range neutron criticality detector, comprising a cylinder, a bottom plate is arranged at the bottom of the cylinder, a shielding plate is arranged on the bottom plate, a He‑3 proportional counter tube is arranged on one side of the shielding plate, a detector circuit board and a first GM detector and a second GM detector are arranged on the other side of the shielding plate, the He‑3 proportional counter tube, the first GM detector and the second GM detector are all connected to the detector circuit board, so that the alarm threshold is continuously adjustable in the entire range, and the nuclear criticality response time of the detector is (millisecond level).

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear radiation detection, and in particular relates to a wide-range neutron criticality detector. Background Art

[0002] There is a potential risk of nuclear criticality accidents when handling, applying, storing and transporting fissile materials. Although the probability of an accident is very small, once it occurs, the harm caused is huge. The neutron criticality monitoring alarm system can give an alarm before a criticality accident occurs, record the radiation and change process at the accident site, and analyze the criticality accident process.

[0003] Since nuclear criticality accidents last very short (milliseconds) and generate extremely large radiation fields, various factors combined together cause ordinary regional radiation detectors to fail. Therefore, the nuclear criticality alarm system must consider the detector's response time, measurement range and other extreme conditions.

[0004] Currently, when measuring neutron radiation, the He-3 proportional counter tube and the gamma rays in the measurement environment will have an impact, making the neutron measurement results inaccurate, affecting the response of the alarm system and making the alarm threshold discontinuous. Summary of the invention

[0005] The present invention solves the technical problem of inaccurate neutron measurement results by providing a wide-range neutron criticality detector in view of the above-mentioned deficiencies in the prior art, so that the alarm threshold is continuously adjustable over the entire range and the nuclear criticality response time of the detector is (millisecond level).

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a wide-range neutron critical detector, including a cylinder, a bottom plate is arranged at the bottom of the cylinder, a shielding plate is arranged on the bottom plate, a He-3 proportional counter tube is arranged on one side of the shielding plate, and a detector circuit board and a first GM detector and a second GM detector are arranged on the other side of the shielding plate. The He-3 proportional counter tube, the first GM detector and the second GM detector are all connected to the detector circuit board. The detection range of the first GM detector is 0.5mGy / h~10Gy / h, and the detection range of the second GM detector is 0.1μGy / h~0.5mGy / h.

[0007] The detection range of the He-3 proportional counter tube is 10 μGy / h to 1 Gy / h.

[0008] A single chip microcomputer is arranged on the detector circuit board.

[0009] The first GM detector and the second GM detector are used to measure interference generated by gamma rays.

[0010] After the output pulse of the He-3 proportional counter tube is converted into a dose rate and the interference caused by the gamma ray is deducted, the alarm signal is transmitted to the alarm logic unit of the single chip microcomputer after threshold screening.

[0011] The single chip microcomputer is also provided with an RS485 port.

[0012] One end of the He-3 proportional counter tube is also provided with a He-3 tube fixing seat and a He-3 tube pressing block.

[0013] The cylinder is a shielding sleeve.

[0014] The front end of the cylinder is also provided with a front end fixing plate and a sealing ring.

[0015] The front end fixing plate is also provided with an aviation socket and an aviation plug matching the aviation socket.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] The He-3 proportional counter tube detector of the present invention is responsible for regional neutron radiation measurement, and two GM tubes are responsible for auxiliary measurement of regional γ, eliminating the influence of γ rays in the He-3 proportional counter tube, so that the neutron measurement result is more accurate.

[0018] When the detector is working, the output pulse of the He-3 proportional counter tube is converted into a dose rate, and after deducting the interference caused by the gamma rays, the alarm signal is transmitted to the alarm logic unit of the host after threshold screening, so that the alarm threshold can be continuously adjusted over the entire range, and the nuclear critical response time of the detector is (millisecond level).

[0019] Another advantage of the present invention is that the detection range of the first GM detector is 0.5mGy / h to 10Gy / h, and the detection range of the second GM detector is 0.1μGy / h to 0.5mGy / h, respectively measuring low and high ranges, thereby realizing detection and alarm in a wider range.

[0020] The He-3 proportional counter tube of the present invention is integrated with the processing circuit to record the pulses during critical events. When the dose rate reaches the alarm threshold, an alarm signal is issued. The alarm signal and the dose rate can be transmitted over a long distance via RS485. The transmission distance is 1000m and there is no external interference and signal attenuation during the transmission process, thereby avoiding false alarms caused by inaccurate measurement data and ensuring normal production and personnel safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the three-dimensional structure of the neutron criticality detector of the present invention;

[0022] Figure 2 for Figure 1 Side view of

[0023] Figure 3 This is the schematic diagram of the neutron criticality detector;

[0024] Figure 4 This is the neutron criticality detector alarm logic block diagram;

[0025] Figure markings: cylinder-1, base plate-2, shielding plate 3, He-3 proportional counter tube 4, circuit board 5, first GM detector 6, second GM detector 7, He-3 tube fixing seat 8, He-3 tube pressing block for fixing 9, front end fixing plate 10, sealing ring 11, aviation socket 12, aviation plug 13. DETAILED DESCRIPTION

[0026] The following will be combined with the accompanying drawings in the present invention to clearly and completely describe the technical solutions in the invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of the present invention.

[0027] like Figure 1 and Figure 2 As shown, the present invention provides a wide-range neutron critical detector, including a cylinder 1, a bottom plate 2 is arranged at the bottom of the cylinder, a shielding plate 3 is arranged on the bottom plate 2, a He-3 proportional counter tube 4 is arranged on one side of the shielding plate 3, and a detector circuit board 5 and a first GM detector 6 and a second GM detector 7 are arranged on the other side of the shielding plate 3. The He-3 proportional counter tube, the first GM detector and the second GM detector are all connected to the detector circuit board. The detection range of the first GM detector is 0.5mGy / h~10Gy / h, and the detection range of the second GM detector is 0.1μGy / h~0.5mGy / h. One end of the He-3 proportional counter tube is fixed with a He-3 tube fixing seat 8 and a He-3 tube pressing block 9. The cylinder 1 is a shielding sleeve. The front end of the cylinder is also provided with a front end fixing plate 10 and a sealing ring 11, so that the neutron critical detector is an integral structure with good seismic performance and strong radiation resistance. The front end fixing plate 10 is also provided with an aviation socket 12 and an aviation plug 13 matching the aviation socket.

[0028] like Figure 3As shown in the figure, the neutron critical detector is composed of a He-3 proportional counter tube detector and two GM tube detectors. The He-3 proportional counter tube detector is responsible for the regional neutron radiation measurement, and the two GM tubes are responsible for the auxiliary measurement of the regional γ. The influence of the γ rays in the He-3 proportional counter tube is deducted to make the neutron measurement result more accurate. Specifically, after the output pulse of the He-3 proportional counter tube is converted into a dose rate, the interference caused by the γ rays is deducted, and after the threshold is screened, the alarm signal is transmitted to the alarm logic unit of the host. The alarm logic Figure 4 As shown, the alarm threshold is continuously adjustable over the entire range, and the detector has a nuclear critical response time (millisecond level).

[0029] Among them, the detection range of the He-3 proportional counter tube is 10μGy / h~1Gy / h, the detection range of GM tube 1 is 0.1μGy / h~0.5mGy / h, and the detection range of GM tube 2 is 0.5mGy / h~10Gy / h, which measure the low and high ranges respectively, realizing detection and alarm over a wider range.

[0030] The He-3 proportional counter tube is integrated with the processing circuit to record the pulses during critical events. When the dose rate reaches the alarm threshold, an alarm signal is issued. The alarm signal and dose rate can be transmitted over long distances via RS485. The transmission distance is 1000m and there is no external interference or signal attenuation during the transmission process, thus avoiding false alarms caused by inaccurate measurement data and ensuring normal production and personnel safety.

Claims

1. A wide range neutron criticality detector, comprising a cylinder, characterized in that: A bottom plate is arranged at the bottom of the cylinder body, a shielding plate is arranged on the bottom plate, a He-3 proportional counter tube is arranged on one side of the shielding plate, a detector circuit board and a first GM detector and a second GM detector are arranged on the other side of the shielding plate, the He-3 proportional counter tube, the first GM detector and the second GM detector are all connected to the detector circuit board, the detection range of the first GM detector is 0.5mGy / h~10Gy / h, and the detection range of the second GM detector is 0.1μGy / h~0.5mGy / h.

2. A wide range neutron criticality detector according to claim 1, characterized in that: The detection range of the He-3 proportional counter tube is 10 μGy / h to 1 Gy / h.

3. A wide range neutron criticality detector according to claim 1, characterized in that: A single chip microcomputer is arranged on the detector circuit board.

4. A wide range neutron criticality detector according to claim 1, characterized in that: The first GM detector and the second GM detector are used to measure interference generated by gamma rays.

5. A wide range neutron criticality detector according to claim 4, characterized in that: After the output pulse of the He-3 proportional counter tube is converted into a dose rate and the interference caused by the gamma ray is deducted, the alarm signal is transmitted to the alarm logic unit of the single chip microcomputer after threshold screening.

6. A wide range neutron criticality detector according to claim 3, characterized in that: The single chip microcomputer is also provided with an RS485 port.

7. A wide range neutron criticality detector according to claim 1, characterized in that: One end of the He-3 proportional counter tube is also provided with a He-3 tube fixing seat and a He-3 tube pressing block.

8. The wide range neutron criticality detector according to claim 1, characterized in that: The cylinder is a shielding sleeve.

9. A wide range neutron criticality detector according to claim 8, characterized in that: The front end of the cylinder is also provided with a front end fixing plate and a sealing ring.

10. A wide range neutron criticality detector according to claim 9, characterized in that: The front end fixing plate is also provided with an aviation socket and an aviation plug matching the aviation socket.

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