CN112764078B

CN112764078B - Nuclear material measuring device

Info

Publication number: CN112764078B
Application number: CN202011527647.1A
Authority: CN
Inventors: 祝利群; 柏磊; 许小明; 李新军; 邵婕文; 程毅梅; 靳占勇
Original assignee: China Institute of Atomic of Energy
Current assignee: China Institute of Atomic of Energy
Priority date: 2020-12-22
Filing date: 2020-12-22
Publication date: 2022-08-09
Anticipated expiration: 2040-12-22
Also published as: CN112764078A

Abstract

The invention relates to a nuclear material measuring device, which comprises a material channel, a neutron measuring structure and an isotope detection structure; the material channel extends into the neutron measurement structure so that the material channel can perform neutron measurement on nuclear materials in the material channel; the neutron measurement structure is provided with a detection slit matched with the isotope detection structure so that the isotope detection structure can carry out isotope measurement on the nuclear material. The invention has the following beneficial effects: the invention realizes the comprehensive measurement automation including neutron measurement and isotope measurement (gamma measurement) by arranging the detection slit on the neutron measurement structure, avoids the radiation hazard of operators and ensures the safety of the operators. The nuclear material radiation shielding device can measure nuclear materials distributed at different positions in the shelf, and can well shield nuclear radiation of the materials, so that the radiation level of a measuring environment is kept at a lower level.

Description

Nuclear material measuring device

Technical Field

The invention belongs to the field of nuclear industry, and particularly relates to a barrel material measuring device.

Background

For nuclear materials, in particular plutonium-containing materials, the object of the measurement is generally to obtain isotopic information and plutonium-containing qualities of the nuclear material.

In the prior art, well-type neutron measurement and measurement equipment is generally adopted to measure the quality of plutonium, and then a high-purity germanium detector is used to measure isotope information of materials.

In real operation, the measurement of a plurality of nuclear materials placed in a sample shelf has great difficulty. Nuclear materials used in the nuclear industry carry hazardous radioactivity. The radiation generated by these nuclear materials is extremely harmful to the human body, so the safety of operators must be ensured in the process of transporting the nuclear materials. And the gamma measurement is carried out by the high-purity germanium detector by adopting an open type measurement method, and an operator needs to move the detector to align to measurement samples with different heights in a shelf during measurement, so that the radiation safety problem exists.

And at present, no suitable device is available for carrying out isotope and total plutonium mass comprehensive measurement and analysis on a plurality of nuclear materials with incompletely identical isotopes placed in a shelf.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a nuclear material measuring device.

The technical scheme of the invention is as follows:

a nuclear material measuring device comprises a material channel, a neutron measuring structure and an isotope detection structure; the material channel extends into the neutron measurement structure so that the material channel can perform neutron measurement on nuclear materials in the material channel; the neutron measurement structure is provided with a detection slit matched with the isotope detection structure so that the isotope detection structure can carry out isotope measurement on the nuclear material.

Further, in the nuclear material measuring device, the neutron measuring structure comprises a lead shielding layer, an inner polyethylene moderating body, a graphite reflecting layer, an outer polyethylene shielding body and a measuring assembly; the material channel extends into the lead shielding layer to form a measuring cavity; an inner polyethylene slowing-down body, a graphite reflecting layer and an outer polyethylene shielding body are sequentially coated outside the lead shielding layer; a neutron detector of the measuring assembly is embedded in the inner polyethylene moderating body; the detection slit penetrates through the lead shielding layer, the inner polyethylene slowing body, the graphite reflecting layer and the outer polyethylene shielding body.

Further, in the nuclear material measuring device, the inner polyethylene moderating body, the graphite reflecting layer and/or the outer polyethylene shielding body are formed by stacking a plurality of plates made of corresponding materials, and are fixedly connected with the base of the neutron measuring structure through fastening screws.

Further, in the nuclear material measuring device, the material channel includes a pre-buried pipeline, an intermediate pipeline and a measuring pipeline; the embedded pipeline is embedded in the top of the measuring chamber, and the middle pipeline is connected with the embedded pipeline and the measuring pipeline; the lower end of the measuring pipeline is positioned on a base of the neutron measuring structure.

Further, in the nuclear material measuring device, a step used for being matched with the nuclear material shelf is arranged between the measuring pipeline and the middle pipeline.

Further, in the above nuclear material measuring device, the isotope detection structure includes a vertically moving part and a detector platform; the isotope detector is arranged on the detector platform, and the detector platform can drive the isotope detector to vertically move along the vertical moving part so that the probe of the isotope detector is aligned with the nuclear material in the detection slit.

Further, in the nuclear material measuring device, the neutron measuring structure and the isotope detection structure are both arranged in the measuring chamber, and the material channel penetrates through the chamber wall of the measuring chamber to extend into the neutron measuring structure.

The invention has the following beneficial effects:

1. the invention realizes the comprehensive measurement automation including neutron measurement and isotope measurement (gamma measurement) by arranging the detection slit on the neutron measurement structure, avoids the radiation hazard of operators and ensures the safety of the operators.

2. The nuclear material radiation shielding device can measure nuclear materials distributed at different positions in the shelf, and can well shield nuclear radiation of the materials, so that the radiation level of a measuring environment is kept at a lower level.

3. An independent measuring chamber is adopted, the measuring chamber is of a concrete structure, and an operator operates the measuring chamber outdoors, so that the risk of nuclear radiation on the operator is reduced better;

4. the measuring cavity of the neutron measuring structure is wrapped by multiple layers of shielding materials, so that neutrons of a measured material can be effectively captured by the neutron measuring tube under the conditions of reducing the environmental background during measurement and ensuring the nuclear radiation dose around the measuring equipment to be within a safe range, and the detection efficiency is ensured;

5. the neutron detector is embedded into the polyethylene moderating body on the inner layer, and neutron data of the nuclear material can be better detected.

6. The isotope detector can vertically move, can better scan nuclear materials in the hanging cup shelf, and can perform positioning automatic measurement on shelf materials with different specifications.

Drawings

Fig. 1 is a schematic structural view of a nuclear material measuring apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a neutron measurement structure according to one embodiment of the invention.

Fig. 3 is a top view of fig. 2.

Fig. 4 is a schematic structural diagram of a material passage according to an embodiment of the present invention.

Fig. 5 is a schematic structural view of an isotope detection configuration in accordance with an embodiment of the present invention.

In the above drawings, 1, a measuring chamber; 2. a neutron measurement structure; 3. a material channel; 4. an isotope detection structure; 5. a control system; 21. a base; 22. a lead shielding layer; 23. an inner polyethylene moderator; 24. a graphite reflective layer; 25. an outer polyethylene shield; 26. a set-top box; 27. a screw; 28. a neutron detector; 29. a screw; 31. pre-burying a pipeline; 32. an intermediate pipeline; 33. measuring a pipeline; 34. a shelf; 41. a vertical moving member; 42. an isotope detector.

Detailed Description

The invention is described in detail below with reference to the figures and examples.

As shown in fig. 1, the present invention provides a nuclear material measuring device, which includes a material passage 3, a neutron measuring structure 2, and an isotope detection structure 4; the material channel 3 extends into the neutron measurement structure 2 so that the neutron measurement structure can perform neutron measurement on nuclear materials in the material channel 3; the neutron measurement structure 2 is provided with a detection slit matched with the isotope detection structure 4, so that the isotope detection structure 4 can perform isotope measurement on the nuclear material.

The invention realizes the comprehensive measurement automation including neutron measurement and isotope measurement (gamma measurement) by arranging the detection slit on the neutron measurement structure 2, avoids the radiation hazard of operators and ensures the safety of the operators.

As shown in fig. 2 and 3, the neutron measurement structure 2 includes a lead shielding layer 22, an inner polyethylene moderator 23, a graphite reflective layer 24, an outer polyethylene shield 25, and a measurement assembly; the material channel 3 extends into the lead shielding layer 22 to form a measuring cavity; the outer side of the lead shielding layer 22 is sequentially coated with an inner polyethylene slowing-down body 23, a graphite reflecting layer 24 and an outer polyethylene shielding body 25; the neutron detector 28 (neutron measurement tube) of the measurement assembly is embedded in the inner polyethylene moderator 23; the probe slit passes through the lead shield 22, the inner polyethylene moderator 23, the graphite reflective layer 24, and the outer polyethylene shield 25. The set-top box 26 of the measurement assembly is arranged on top of the neutron measurement structure 2. The lead shielding layer 22 is capable of shielding gamma rays. The inner polyethylene moderating layer mainly functions as neutron moderation to ensure that the measuring tube can detect neutrons. Graphite reflection stratum 24 is mainly as being neutron reflection, guarantees that the neutron that the scattering goes out can be reflected back and get into neutron survey buret and be detected, improves detection efficiency.

The inner polyethylene moderator 23, the graphite reflective layer 24 and/or the outer polyethylene shield 25 are formed by stacking a plurality of plates made of corresponding materials, and are fixedly connected with the base 21 of the neutron measurement structure 2 through fastening screws (27, 29).

The measurement cavity of the neutron measurement structure 2 is wrapped by multiple layers of shielding materials, the environment background is reduced in measurement, and the neutron of a measured material can be effectively captured by the neutron measurement tube under the condition that the nuclear radiation dose around the measurement device is within a safety range, so that the detection efficiency is guaranteed.

As shown in fig. 4, the material passage 3 includes an embedded pipeline 31, an intermediate pipeline 32 and a measuring pipeline 33; the embedded pipeline 31 is embedded at the top of the measuring chamber 1, and the intermediate pipeline 32 is connected with the embedded pipeline 31 and the measuring pipeline 33; the lower end of the measurement pipe 33 is positioned on the base 21 of the neutron measurement structure 2. A step for matching with the nuclear material shelf 34 is arranged between the measuring pipe 33 and the middle pipe 32. According to different specifications of the cup racks, the cup racks in the material channel 3 can be selectively placed on the base 21 or hung on the steps.

As shown in fig. 5, the isotope detection structure 4 includes a vertically moving part 41 and a detector platform; the isotope detector 42 is mounted on the detector platform, and the detector platform can drive the isotope detector 42 to vertically move along the vertical moving component 41 so as to make the probe of the isotope detector 42 align with the nuclear material in the detection slit.

When the nuclear material measuring device is used, an operator controls the nuclear material measuring device through the control system 5, and the suspension cup shelf filled with the nuclear material enters the measuring pipeline 33 through the embedded pipeline 31 and the middle pipeline 32 of the material channel 3. Then starting a measuring system, and enabling a detecting instrument to enter a specified position to scan the nuclear materials to obtain gamma ray data of the nuclear materials; meanwhile, a measuring pipe in the polyethylene moderating layer of the inner layer obtains neutron data, and material parameters are obtained through nuclear data processing software.

In this embodiment, the neutron measurement structure 2 and the isotope detection structure 4 are both disposed in the measurement chamber 1, and the material passage 3 passes through a chamber wall of the measurement chamber 1 (in this embodiment, a top of the measurement chamber 1) to extend into the neutron measurement structure 2. The measuring chamber 1 is an independent measuring chamber with a concrete structure, and an operator operates outdoors, so that the risk of nuclear radiation on the operator is reduced better; the isotope detector 42 can move vertically, can better scan nuclear materials in the hanging cup shelf, and can perform positioning automatic measurement on shelf materials with different specifications.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include such modifications and variations.

Claims

1. A nuclear material measuring device is characterized by comprising a material channel, a neutron measuring structure and an isotope detection structure; the material channel extends into the neutron measurement structure so that the material channel can perform neutron measurement on nuclear materials in the material channel; the neutron measurement structure is provided with a detection slit matched with the isotope detection structure so that the isotope detection structure can carry out isotope measurement on the nuclear material, and the neutron measurement structure comprises a lead shielding layer, an inner polyethylene slowing body, a graphite reflecting layer, an outer polyethylene shielding body and a measurement component; the material channel extends into the lead shielding layer to form a measuring cavity; an inner polyethylene slowing-down body, a graphite reflecting layer and an outer polyethylene shielding body are sequentially coated outside the lead shielding layer; a neutron detector of the measuring assembly is embedded in the inner polyethylene moderating body; the detection slit penetrates through the lead shielding layer, the inner polyethylene slowing body, the graphite reflecting layer and the outer polyethylene shielding body, and the material channel comprises a pre-buried pipeline, an intermediate pipeline and a measuring pipeline; the embedded pipeline is embedded in the top of the measuring chamber, and the middle pipeline is connected with the embedded pipeline and the measuring pipeline; the lower end of the measuring pipeline is positioned on a base of the neutron measuring structure.

2. The nuclear material measuring device of claim 1, wherein the inner polyethylene moderator body, the graphite reflector layer, and/or the outer polyethylene shield body are formed by stacking a plurality of plates made of corresponding materials, and are fixedly connected to the base of the neutron measuring structure through fastening screws.

3. The nuclear material measuring device of claim 1, wherein a step for engaging with a nuclear material shelf is provided between the measuring pipe and the intermediate pipe.

4. The nuclear material measuring device of claim 1, wherein the isotope detection structure includes a vertically moving component and a detector platform; the isotope detector is arranged on the detector platform, and the detector platform can drive the isotope detector to vertically move along the vertical moving part so that the probe of the isotope detector is aligned with the nuclear material in the detection slit.

5. The nuclear material measuring device of any one of claims 1 to 4, wherein the neutron measuring structure and the isotope detection structure are both disposed within a measuring chamber, and the material passage passes through a chamber wall of the measuring chamber to extend into the neutron measuring structure.