Gamma ray collimation device and method

Abstract

The invention discloses a gamma ray collimation device and method, and relates to the technical field of reactor engineering. Comprising a displacement unit, the displacement unit comprises an operation table, two bases arranged on the operation table, two fixing plates arranged on the bases and a sliding bracket, and the sliding bracket is connected between the two fixing plates in a sliding mode; and the monitoring unit comprises a shielding chamber and a rear collimator. According to the gamma ray collimation device, the rotary manual roller is arranged to drive the sliding bracket to do horizontal linear motion, the radioactive source, the collimator and the detector can be axially and symmetrically arranged, the radioactive source, the collimator and the detector are fixed to the sliding bracket so that collimation adjustment can be conveniently carried out during measurement, the gamma ray collimation device can collimate divergent gamma rays into single-energy narrow-beam rays, and the single-energy narrow-beam rays can be used for measuring the single-energy narrow-beam rays. The measurement precision is improved. The device is simple in structure, different gamma radioactive sources and detectors can be replaced conveniently, and the device adapts to different measurement scenes.

Description

Technical Field

[0001] The present invention relates to the technical field of reactor engineering, and in particular to a gamma ray collimation device and method. Background Art

[0002] The fuel element of the pebble bed high temperature gas-cooled reactor is a sphere consisting of a fuel area with a diameter of about 50 mm and a fuel-free area with a thickness of about 5 mm, which is composed of coated fuel particles dispersed in a graphite matrix. In the helium operating atmosphere of the pebble bed reactor, the friction coefficient and wear rate between the graphite spheres will increase greatly, thus generating graphite dust.

[0003] The presence and deposition of graphite dust in the reactor will lead to increased radioactivity in the primary circuit, blockage of the fuel ball circulation, uncertainty of the fuel residence time in the reactor, and other issues. Therefore, it is necessary to monitor the graphite dust deposition rate at key components in the reactor. Gamma ray attenuation technology is an effective method to measure the graphite dust deposition rate of pebble bed high temperature gas-cooled reactors. By using the different attenuation coefficients of gamma rays in the pipe wall, graphite and helium, the accurate graphite dust deposition rate in the pipeline can be obtained. Summary of the invention

[0004] In view of the above problems existing in the existing gamma-ray collimation device, the present invention is proposed.

[0005] Therefore, the present invention provides a gamma ray collimation device, the purpose of which is to solve the problem that the existence and deposition of graphite dust in the reactor will lead to increased radioactivity in the first loop, blockage of fuel ball circulation, and uncertainty of the residence time of the fuel in the reactor.

[0006] To solve the above technical problems, the present invention provides the following technical solutions: a gamma-ray collimation device, comprising a displacement unit, including an operating table, two groups of bases arranged on the operating table, two groups of fixed plates and a sliding bracket arranged on the base, and the sliding bracket is slidably connected between the two groups of fixed plates; a monitoring unit, comprising a shielding room and a rear collimator, and the shielding room and the rear collimator are respectively arranged on the sliding bracket.

[0007] As a preferred solution of the gamma ray collimation device described in the present invention, the fixed plate includes a connecting shaft, the connecting shaft passes through the center of the fixed plate on one side, a handle is provided at one end of the connecting shaft, and a manual roller is provided at the other end; the two groups of fixed plates are mirror-imaged with the central axis of the base.

[0008] As a preferred solution of the gamma ray collimation device of the present invention, the other end of the manual roller is provided with a rotating shaft, which is rotatably connected to the inner side of the fixing plate on the other side.

[0009] As a preferred solution of the gamma ray collimation device described in the present invention, two groups of fixed rollers are rotatably connected between the two groups of fixed plates through a rotating shaft, the two groups of fixed rollers are mirror-set with the manual roller as the central axis, the diameters of the two groups of fixed rollers and the manual roller are equal, and there is a certain distance between the outer walls of the two groups of fixed rollers and the manual roller.

[0010] As a preferred solution of the gamma ray collimation device of the present invention, wherein: the sliding bracket comprises a sawtooth groove, the sawtooth groove is arranged at the bottom of the sliding bracket and the outer wall of the manual roller, and the sliding groove is arranged on the inner side of the two sets of fixed plates;

[0011] The sliding bracket is limited in two groups of sliding grooves, and the manual roller and the sliding bracket are matched.

[0012] As a preferred solution of the gamma ray collimation device of the present invention, the shielding room includes a lead tank, a stainless steel sleeve arranged outside the lead tank, and a sealing cover arranged on the lead tank.

[0013] As a preferred solution of the gamma-ray collimation device of the present invention, the lead tank is generally in a cubic structure, and the interior is a hollow structure as a central source chamber.

[0014] As a preferred solution of the gamma ray collimation device of the present invention, a front collimation hole is provided on one side of the stainless steel sleeve, the front collimation hole passes through the lead tank and is connected to the central source chamber, and a hole plug is provided in the front collimation hole.

[0015] As a preferred solution of the gamma-ray collimation device of the present invention, the rear collimator has a cylindrical structure, and a rear collimation hole is provided at the center of one end thereof.

[0016] The beneficial effects of the present invention are as follows: by setting a rotating manual roller to drive the sliding bracket to make horizontal linear motion, it is convenient to configure the radiation source, collimator and detector positions axially symmetrically, and all three are fixed on the sliding bracket to facilitate collimation adjustment during measurement.

[0017] Another object of the present invention is a gamma ray collimation method, which aims to measure the graphite dust deposition rate in a pebble bed high temperature gas-cooled reactor using gamma ray attenuation technology.

[0018] In order to solve the above technical problems, the present invention provides the following technical solutions: placing a gamma radiation source in a shielded room and opening the hole plug; placing a rear collimator in front of the detector; keeping the gamma source, the collimator, and the detector perpendicular to the cross section of the pipeline to be tested, and adjusting the sliding bracket until the detector receives the collimated ray signal.

[0019] The beneficial effects of the present invention are as follows: the gamma ray collimation device can collimate the divergent gamma rays into monoenergetic narrow beam rays, thereby improving the measurement accuracy; the device has a simple structure, is easy to replace different gamma radiation sources and detectors, and is adaptable to different measurement scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 It is a schematic diagram of the overall structure of the gamma-ray collimation device of the present invention.

[0022] Figure 2 It is a schematic diagram of the partial structure of the gamma-ray collimation device of the present invention.

[0023] Figure 3 It is a partial structural plan view of the gamma-ray collimation device of the present invention.

[0024] Figure 4 It is a schematic diagram of the partial structure of the gamma-ray collimation device of the present invention. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0026] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0027] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it an embodiment that is mutually exclusive with other embodiments, either individually or selectively.

[0028] Secondly, the present invention is described in detail with reference to the schematic diagram. When describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0029] Example 1, reference Figure 1 - Figure 3 , which is the first embodiment of the present invention, provides a gamma ray collimation device, including two sets of bases 102, the two sets of bases 102 are mirror-imaged at the position of the central axis of the operating table 101, and two fixed plates 103 are arranged on the two sets of bases 102. The central position of the fixed plate 103 on one side is rotatably connected with a connecting shaft 103a, and the fixed plate 103 is connected to a manual roller 103c and a handle 103b through the connecting shaft 103a, so that the manual roller 103c can be rotated and adjusted, and the handle 103b is convenient for the operator. The operator rotates the manual roller 103c, and two groups of fixed rollers 103d are rotatably connected between the fixed plates 103 through the rotating shaft. The two groups of fixed rollers 103d are mirror-imaged with the manual roller 103c as the central axis. The diameters of the two groups of fixed rollers 103d and the manual roller 103c are equal, and there is a certain distance between the outer walls of the two groups of fixed rollers 103d and the manual roller 103c. When the manual roller 103c is driven to roll by rotating the handle 103b, it will not contact the fixed roller 103d, thereby avoiding the occurrence of jamming.

[0030] Furthermore, a slide groove 104b is opened at the same position on the inner side of the two sets of fixed plates 103, and the slide groove 104b is opened above the manual roller 103c, and they are slidably connected with the sliding bracket 104. The slide groove 104b limits the moving range of the sliding bracket 104, and only allows the sliding bracket 104 to perform horizontal linear motion, and the bottom of the sliding bracket 104.

[0031] Among them, a sawtooth groove 104a is provided on the bottom surface of the sliding bracket 104 and the outer wall of the manual roller 103c. The sawtooth groove 104a is triangular in shape. When the sliding bracket 104 is slidably connected in the sliding groove 104b, the bottom of the sliding bracket 104 will contact with the fixed roller 103d. The fixed roller 103d can effectively reduce the friction force and improve the movement efficiency. At the same time, it provides the necessary support force to ensure stability and help reduce the wear of the sliding bracket 104 during the movement. The bottom of the sliding bracket 104 will mesh with the sawtooth groove 104a at the bottom of the manual roller 103c to achieve precise movement of the sliding bracket 104.

[0032] Furthermore, the shielding room 201 and the rear collimator 202 are placed on the sliding brackets 104 on both sides, and the positions of the shielding room 201 and the rear collimator 202 are adjusted by continuously rotating the handles 103b on the bases 102 on both sides, so as to achieve axial symmetry among the radiation source, the collimator and the detector, thereby achieving the effect of the experimental purpose.

[0033] Example 2, reference Figure 1 and Figure 4, which is the second embodiment of the present invention. This embodiment is different from the first embodiment in that it includes a lead tank 201a, which is made of lead material and can absorb gamma photons to reduce radiation leakage. The presence of the lead layer greatly reduces the penetration ability of gamma rays, protecting operators and the surrounding environment from radiation hazards. The central position of the lead tank presents a hollow structure as a central source chamber 201d, which is used to place the radiation source to ensure that the radiation source can be safely placed and taken out.

[0034] Furthermore, a stainless steel sleeve 201b is sleeved on the outside of the lead tank 201a, and the stainless steel sleeve 201b encloses the main body of the lead tank 201a to prevent the operator from directly contacting the toxic metallic lead. The stainless steel sleeve 201b is made of stainless steel and has good corrosion resistance and mechanical strength. The stainless steel sleeve 201b not only provides additional protection, but also makes the entire device more sturdy and durable. An upper cover is provided on the lead tank 201a for the introduction and export of the radiation source.

[0035] Among them, the front collimation hole 201e passes through the lead tank 201a and is connected to the central source chamber 201d, which is used to control the direction of the gamma rays. The size design of the collimation hole is the same as that of the rear collimator 202, ensuring that the rays can pass through accurately while avoiding unnecessary radiation leakage. The hole plug 201f closes the front collimation hole 201e when the device is not in use to prevent radiation leakage.

[0036] Furthermore, a rear collimator 202 is placed in front of the detector to further control the direction of the gamma rays. The main body of the rear collimator 202 is lead and the outer layer is encapsulated with stainless steel. The collimation hole of the rear collimator 202 is the same as the front collimation hole 201e, ensuring that the rays can accurately reach the detector while providing additional radiation shielding.

[0037] The remaining structures are the same as those of Example 1.

[0038] Example 3, reference Figure 1 - Figure 4 , which is the third embodiment of the present invention, and this embodiment is different from the second embodiment in that: the gamma ray source is placed in the central source chamber 201d of the shielding chamber 201, and the source chamber is ensured to be well sealed to prevent radiation leakage. The shielding chamber 201 is sealed with an upper cover to ensure the shielding effect, and the shielding chamber 201 is fixed on the sliding bracket 104 to facilitate subsequent position adjustment.

[0039] The hole plug 201f is removed from the collimation hole of the shielding room 201 to expose the front collimation hole 201e. Make sure that the collimation hole is aligned with the radiation source so that the gamma ray can be emitted through the front collimation hole 201e.

[0040] Place the rear collimator 202 on another sliding bracket 104 and align the collimation hole with the detector. Adjust the position of the sliding bracket 104 to ensure that the rear collimation hole 202a of the rear collimator 202 is parallel to the detection surface of the detector.

[0041] Use the slide to adjust the positions of the gamma source, the front collimator, the rear collimator 202 and the detector to ensure that they are perpendicular to the cross section of the pipe to be tested. Adjust the position of the device until the detector can receive the gamma ray signal after being collimated by the front collimator and the rear collimator 202.

[0042] The gamma ray source is started, and the gamma ray is directed toward the detector through the front collimator and the rear collimator 202. The intensity of the gamma ray is measured using the detector, and the measurement data is recorded.

[0043] When the gamma ray attenuation degrees (IS, Ig, Iα) are measured when the pipeline is full of graphite, full of helium, and a certain graphite dust deposition state, the corresponding graphite dust deposition rate α can be obtained by substituting into formula (1):

[0044] Conduct statistical analysis on the measurement data to evaluate the accuracy and reliability of the measurement results. Analyze the trend of graphite dust deposition rate over time and evaluate the deposition of graphite dust in the pile.

[0045] During the operation, wear personal protective equipment, such as protective clothing, protective glasses and protective gloves, avoid direct contact with the gamma ray source, and ensure a safe distance. After the operation, turn off the gamma ray source and restore the device to its initial state.

[0046] The remaining structure is the same as that of Example 2.

[0047] Importantly, it should be noted that the construction and arrangement of the present application shown in a plurality of different exemplary embodiments are only exemplary. Although only a few embodiments are described in detail in this disclosure, it should be readily understood by those who refer to this disclosure that many modifications are possible (e.g., the size, scale, structure, shape and proportion of various elements, and parameter values ​​such as temperature, pressure, etc., installation arrangements, use of materials, color, directional changes, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in the application. For example, the element shown as integrally formed can be composed of multiple parts or elements, the position of the element can be inverted or otherwise changed, and the nature or number or position of the discrete element can be changed or changed. Therefore, all such modifications are intended to be included in the scope of the present invention. The order or sequence of any process or method steps can be changed or reordered according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure of performing the function described herein, and is not only structurally equivalent but also equivalent structure. Without departing from the scope of the present invention, other replacements, modifications, changes and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments. Therefore, the invention is not limited to a specific embodiment, but extends to numerous modifications still falling within the scope of the appended claims.

[0048] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment (ie, those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention) may not be described.

[0049] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A gamma ray collimation device, characterized in that: include, The displacement unit (100) comprises an operating table (101), two groups of bases (102) arranged on the operating table (101), two groups of fixed plates (103) and a sliding bracket (104) arranged on the base (102), and the sliding bracket (104) is slidably connected between the two groups of fixed plates (103); The monitoring unit (200) comprises a shielding room (201) and a rear collimator (202); the shielding room (201) and the rear collimator (202) are respectively arranged on a sliding bracket (104).

2. The gamma-ray collimation device according to claim 1, characterized in that: The fixing plate (103) comprises a connecting shaft (103a), the connecting shaft (103a) passes through the center of the fixing plate (103) located on one side, one end of the connecting shaft (103a) is provided with a handle (103b), and the other end is provided with a manual roller (103c); The two groups of fixing plates (103) are arranged in a mirror image with respect to the central axis of the base (102).

3. The gamma-ray collimation device according to claim 2, characterized in that: The other end of the manual roller (103c) is provided with a rotating shaft, which is rotatably connected to the inner side of the fixing plate (103) on the other side.

4. The gamma-ray collimation device according to any one of claims 1 to 3, characterized in that: Two groups of fixed rollers (103d) are rotatably connected between the two groups of fixed plates (103) via a rotating shaft; the two groups of fixed rollers (103d) are mirror-imaged with the manual roller (103c) as the central axis; the diameters of the two groups of fixed rollers (103d) and the manual roller (103c) are equal; and a certain distance exists between the outer walls of the two groups of fixed rollers (103d) and the manual roller (103c).

5. The gamma ray collimation device according to claim 4, characterized in that: The sliding bracket (104) comprises a sawtooth groove (104a), the sawtooth groove (104a) is arranged at the bottom of the sliding bracket (104) and the outer wall of the manual roller (103c), and a sliding groove (104b) is arranged on the inner side of the two sets of fixed plates (103); The sliding bracket (104) is limited in two groups of sliding grooves (104b), and the manual roller (103c) and the sliding bracket (104) are matched.

6. The gamma-ray collimation device according to claim 5, characterized in that: The shielding room (201) comprises a lead tank (201a), a stainless steel sleeve (201b) arranged outside the lead tank (201a), and a sealing cover (201c) arranged on the lead tank (201a).

7. The gamma-ray collimation device according to claim 6, characterized in that: The lead tank (201a) generally presents a cubic structure, and the interior presents a hollow structure as a central source chamber (201d).

8. The gamma-ray collimation device according to claim 7, characterized in that: A front collimation hole (201e) is provided on one side of the stainless steel sleeve (201b); the front collimation hole (201e) passes through the lead tank (201a) and is connected to the central source chamber (201d); and a hole plug (201f) is provided in the front collimation hole (201e).

9. The gamma-ray collimation device according to claim 8, characterized in that: The rear collimator (202) presents a cylindrical structure, and a rear collimator hole (202a) is provided at the center of one end thereof.

10. A gamma ray collimation method, characterized in that: include Place a gamma radiation source in a shielded room (201) and open the hole plug (201f); placing a rear collimator (202) in front of the detector; The gamma source, the collimator and the detector are kept perpendicular to the cross section of the pipeline to be tested, and the sliding bracket (104) is adjusted until the detector receives the collimated ray signal.

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