Small gamma-ray flaw detection device with shielding function and flaw detection method

Abstract

The invention provides a small gamma ray flaw detection device with a shielding function and a flaw detection method.The device comprises a fixing ring, an upper shielding shell, a lower shielding shell, a gamma source machine fixing bin and a gamma source machine, the fixing ring is arranged on a pipeline, and a sliding groove is formed in the lower end of the fixing ring; the upper shielding shell and the lower shielding shell are lapped on the sliding grooves of the fixing ring and can rotate along the sliding grooves of the fixing ring; the gamma source machine fixing bin is arranged on the upper shielding shell, and a gamma source machine is placed in the gamma source machine fixing bin. The device is convenient to disassemble and assemble, the inspection work efficiency is obviously improved, the gamma source machine is tightly connected with the inspected pipeline and the flaw detection device, the space needed by inspection is small, and rapid positioning and all-directional inspection can be achieved by simply rotating the device.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear power non-destructive testing, and particularly to a small γ-ray flaw detector with a shielding function and a flaw detection method. Background Art

[0002] When a CANDU-type heavy water reactor unit operates for about 30 years, all the pressure tubes in the reactor core need to be replaced, and at the same time, the main heat transfer branch pipes (referred to as Feeder pipes for short) connected to the inlets and outlets of the pressure tubes and their connecting components need to be replaced. According to relevant regulations and standards, after the Feeder pipes are replaced, more than 1,000 welds of different specifications need to be subjected to radiographic inspection. γ-ray flaw detection uses γ-rays emitted by radioactive nuclides for inspection, and γ-rays have the characteristics of high energy and strong penetration ability.

[0003] In the prior art, the space where the Feeder pipes are located is narrow, and the distance between two adjacent Feeder pipes is less than 20 cm. In addition, the γ-ray source device is very heavy, and the equipment handling takes a long time, resulting in low work efficiency; in addition, when performing γ-ray flaw detection in an open environment, a large-scale isolation and warning area needs to be established, resulting in the inability to implement other projects simultaneously, thus greatly increasing the construction period of the pressure tube full-core replacement project. Summary of the Invention

[0004] The present invention provides a small γ-ray flaw detector with a shielding function and a flaw detection method, which are used to solve the problems that the γ-ray source flaw detection equipment in the prior art is not suitable for narrow spaces and there is ray radiation during the flaw detection process.

[0005] The technical solution of the present invention is as follows:

[0006] The present invention provides a small γ-ray flaw detector with a shielding function, which includes a fixing ring, an upper shielding shell, a lower shielding shell, a γ-source machine fixing bin and a γ-source machine. The fixing ring is arranged on the pipeline, and a sliding groove is provided at the lower end of the fixing ring; the upper shielding shell and the lower shielding shell are lapped on the sliding groove of the fixing ring, and the upper shielding shell and the lower shielding shell can rotate along the sliding groove of the fixing ring; the γ-source machine fixing bin is arranged on the upper shielding shell, and the γ-source machine is placed in the γ-source machine fixing bin.

[0007] In some embodiments, positioning holes are provided on the fixing ring, and angle positioning holes are provided at the positions where the upper shielding shell laps with the sliding groove of the fixing ring. A device positioning pin is connected inside the positioning holes, and the device positioning pin is used to fix the fixing ring on the pipeline; a rotation positioning pin is provided in the angle positioning holes, and the rotation positioning pin passes through the upper shielding shell, and the rotation positioning pin is used to limit the position of the upper shielding shell on the fixing ring.

[0008] In some embodiments, both the upper shielding housing and the lower shielding housing are hollow semi-cylindrical structures; one end of the upper shielding housing and the lower shielding housing is hinged by a hinge, and the other end is connected by a buckle and locked with a pin shaft; the inner walls of the upper shielding housing and the lower shielding housing are provided with lead shielding, and the lead shielding is used to shield the rays of the γ-ray source machine.

[0009] In some embodiments, a shielding ring is provided at one end of the upper shielding housing and the lower shielding housing that is not connected to the fixing ring, and the shielding ring is used to shield the scattered rays inside the device; the shielding ring is fixed on the pipeline.

[0010] In some embodiments, the γ-ray source machine fixing bin is a hollow cylindrical structure, and a protruding structure is provided at the bottom of the γ-ray source machine fixing bin, and the protruding structure is used for positioning the γ-ray source machine when it is placed in the γ-ray source machine fixing bin; fastening bolt holes are opened on both sides of the γ-ray source machine fixing bin, and fastening bolts are provided in the positioning bolt holes, and the positioning bolts are used to fix the γ-ray source machine.

[0011] In some embodiments, the γ-ray source machine is connected to a control cable, and the control cable is used to control the operation of the γ-ray source machine.

[0012] In some embodiments, a back shielding block is provided outside the lower shielding housing. One end of the back shielding block is installed on the lower shielding housing by a hinge, and the other end of the back shielding block is fixed on the lower shielding housing by a fixing pin. The back shielding block can be opened and closed; a radiation film of the γ-ray source machine is placed between the back shielding block and the lower shielding housing.

[0013] In some embodiments, an anti-falling chain is provided on the fixing pin connecting the back shielding block and the lower shielding housing; an anti-falling chain is provided on the fastening bolt on the γ-ray source machine fixing bin.

[0014] In some embodiments, bolt holes are provided at one end of the upper shielding housing and the lower shielding housing connected to the fixing ring, and positioning bolts are provided in the bolt holes. The positioning bolts are used to fix the positions of the upper shielding housing and the lower shielding housing on the fixing ring.

[0015] The present invention proposes a small-scale γ-ray flaw detection method with a shielding function, and the method includes:

[0016] Step 1: Install a fixing ring and a shielding ring at both ends of the pipeline weld;

[0017] Step 2: Install the upper shielding housing and the lower shielding housing at the sliding groove position of the fixing ring;

[0018] Step 3: Install the γ-ray source machine in the γ-ray source machine fixing bin outside the upper shielding housing;

[0019] Step 4: Place a radiation film between the lower shielding housing and the back shielding block, and close the back shielding block;

[0020] Step 5: Control the γ-ray source machine through the control cable to perform pipeline flaw detection.

[0021] Step 6: Rotate to change the positions of the upper shielding housing and the lower shielding housing, and control the γ-ray source machine through the control cable to perform pipeline flaw detection from different directions.

[0022] Implementing the present invention has the following beneficial effects:

[0023] The present invention proposes a small γ-ray flaw detection device with a shielding function. The device realizes the shielding of the rays passing through the film by installing a lead back shielding block on the back. The device realizes the shielding of the rays from the window of the γ-ray machine by using the upper shielding housing and the lower shielding housing with increased lead shielding inside. The device realizes the shielding of the rays at the edge of the pipeline by using a shielding ring. The device is convenient to disassemble and assemble, the inspection work efficiency is significantly improved, the connection between the γ-ray source machine and the pipeline to be inspected and the flaw detection device is tight, the space required for inspection is small, and the device can be quickly positioned and inspected in all directions by simply rotating the device. Description of the Drawings

[0024] Figure 1 It is a schematic diagram of a small γ-ray flaw detection device with a shielding function proposed by an embodiment of the present invention;

[0025] Description of the Drawings: 1. Pipeline; 2. Fixed ring; 3. Device positioning pin; 4. Upper shielding housing; 5. Lower shielding housing; 6. γ-ray source machine fixed bin; 7. γ-ray source machine; 8. Control cable; 9. Back shielding block; 10. Shielding ring; 11. Rotating positioning pin. Detailed Embodiments

[0026] The technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings and specific embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] As Figure 1 shown, the present invention proposes a small γ-ray flaw detection device with a shielding function. The device includes a fixed ring 2, a shielding ring 10, an upper shielding housing 4, a lower shielding housing 5, a γ-ray source machine fixed bin 6, a γ-ray source machine 7, a back shielding block 9, and a control cable 8.

[0028] The fixed ring 2 is fixed on one side of the pipeline 1 to be inspected. A sliding groove is provided at the lower end of the fixed ring 2, and a positioning hole is provided on the fixed ring 2. An angular positioning hole is provided at the position where the upper shielding housing 4 overlaps with the sliding groove of the fixed ring 2. A device positioning pin 3 is connected inside the positioning hole, and the device positioning pin 3 is used to fix the fixed ring 2 on the pipeline; a rotating positioning pin 11 is provided in the angular positioning hole, and the rotating positioning pin 11 passes through the upper shielding housing 4. The rotating positioning pin 11 is used to limit the position of the upper shielding housing 4 on the fixed ring. The device positioning pin 3 and the rotating positioning pin 11 rely on friction to fix the position of the entire device.

[0029] The upper shielding housing 4 and the lower shielding housing 5 overlap on the sliding groove of the fixed ring 2, and the upper shielding housing 4 and the lower shielding housing 5 can rotate 360° on the sliding groove. Both the upper shielding housing 4 and the lower shielding housing 5 are hollow semi-cylindrical structures; one end of the upper shielding housing 4 and the lower shielding housing 5 is hinged in a hinge manner, and the other end is connected by a buckle and locked with a pin shaft. Lead shielding is provided on the inner walls of the upper shielding housing 4 and the lower shielding housing 5. The lead shielding is used to shield the rays of the γ-ray machine 7. The fixed ring 2 and the shielding housing can shield the scattered rays emitted from the inside of the pipeline 1 on one side of the pipeline 1. Bolt holes are provided at the ends of the upper shielding housing 4 and the lower shielding housing 5 connected to the fixed ring 2, and positioning bolts are provided in the bolt holes. The positioning bolts are used to fix the positions of the upper shielding housing 4 and the lower shielding housing 5 on the fixed ring 2. When the positioning bolts are loosened, the shielding housing can rotate freely on the fixed ring 2. By fixing the positioning bolts, the fixing bolts fix the two shielding housings through friction.

[0030] The shielding ring 10 is provided at one end of the upper shielding housing 4 and the lower shielding housing 5 that is not connected to the fixed ring 2. The shielding ring 10 is fixed on the other side of the pipeline 1 to be inspected, and a shielding device is provided thereon, which has a shielding function. The shielding ring 10 is mainly used to shield the scattered rays emitted from the inside of the pipeline 1 on the other side of the pipeline 1. The shielding ring 10 prevents the shielding device from directly contacting the pipeline 1, thereby causing damage to the surface of the pipeline 1.

[0031] The γ - source machine fixed bin 6 is set on the upper shielding housing 4, and the γ - source machine 7 is placed inside the γ - source machine fixed bin 6. The γ - source machine fixed bin 6 is of a hollow cylindrical structure. There is a protruding structure at the bottom of the γ - source machine fixed bin 6, and this protruding structure is used for positioning the γ - source machine 7 when it is placed into the γ - source machine fixed bin 6. When the γ - source machine 7 is placed into the γ - source machine fixed bin 6, the bottom of the γ - source machine 7 is stuck on the protruding structure at the bottom of the γ - source machine fixed bin 6, thus realizing the positioning function. There are fastening bolt holes on both sides of the γ - source machine fixed bin 6, and fastening bolts are arranged in the positioning bolt holes. The fastening bolts are used to fix the γ - source machine 7. When the γ - source machine 7 is placed into the γ - source machine fixed bin 6, the fastening bolts are screwed into the fastening bolt holes, and the fastening bolts press against the γ - source machine 7, thus fastening the γ - source machine 7. When the γ - source machine 7 is placed into the γ - source machine fixed bin 6, the protruding structure positions it, ensuring that the γ - source machine 7 fits with the fixed bin and realizing the rapid alignment of the γ - source machine 7. At this time, the fastening bolts are locked, and the γ - source machine 7 is fixed by friction to prevent the γ - source machine 7 from falling due to gravity. There is an anti - falling ring on the fastening bolts to prevent loosening and falling.

[0032] The γ - source machine 7 is connected to the control cable 8, and the control cable 8 controls the pushing of the γ - source of the source machine 7 to the exposure window and the retraction of the γ - source back into the γ - source machine 7, and the control cable 8 completes the control of the γ - source machine 7.

[0033] The back shielding block 9 is arranged outside the lower shielding housing 5. One end of the back shielding block 9 is installed on the lower shielding housing 5 in a hinge - like manner, and the other end of the back shielding block 9 is fixed to the lower shielding housing 5 through a fixing pin. The back shielding block 9 can be opened and closed. Between the back shielding block 9 and the lower shielding housing 5 is used to place the ray film of the γ - source machine 7. The back shielding block 9 is used to shield the rays after the γ - source machine 7 passes through the film. The opening - and - closing design of the back shielding block 9 facilitates the disassembly of components during flaw detection work. The fixing pin and anti - falling chain designed on the back shielding block 9 are used to prevent loosening and falling on - site.

[0034] The present invention proposes a small - sized γ - ray flaw detection method with a shielding function, and this method includes:

[0035] Step 1: Install the fixing ring 2 and the shielding ring 10 at both ends of the weld of the pipeline 1; the fixing ring 2 is fixed on the pipeline 1 through the device positioning pin 3.

[0036] Step 2: Install the upper shielding housing 4 and the lower shielding housing 5 at the sliding groove position of the fixing ring 2, and fix the positions of the upper shielding housing 4 and the lower shielding housing 5 on the fixing ring 2 through the rotating positioning pin 11.

[0037] Step 3: Install the γ - source machine 7 in the γ - source machine fixed bin 6 on the outer side of the upper shielding housing 4, and lock the fastening bolts of the γ - source machine fixed bin 6 to fix the γ - source machine 7.

[0038] Step 4: Place the radiographic film between the lower shielding housing 5 and the back shielding block 9, and close the back shielding block 9 with the fixing pins.

[0039] Step 5: Control the γ-ray source machine 7 through the control cable 8 to perform flaw detection on the pipeline 1.

[0040] Step 6: Remove the rotary positioning pin 11, rotate to change the positions of the upper shielding housing 4 and the lower shielding housing 5, insert the rotary positioning pin 11 again, and control the γ-ray source machine 7 through the control cable 8 to perform flaw detection on the pipeline 1 from different orientations.

[0041] In the prior art, conventional γ-ray flaw detection requires isolating the entire floor or the entire workshop. However, when using the ray flaw detection device of the present invention, the shielding effect is good, and ray flaw detection operations can be carried out in a small-ray flaw detection isolation area within a single floor. At the same time, the ray flaw detection device of the present invention is convenient for disassembly and assembly, the inspection work efficiency is significantly improved, the γ-ray machine is closely connected to the pipeline 1 to be inspected and the flaw detection device, and the space required for inspection is small; rapid positioning and omnidirectional inspection can be achieved by simply rotating the ray flaw detection device.

[0042] Through application in a nuclear power plant, it is found that when using the above-mentioned small γ-ray flaw detection device with a shielding function (Se75 radiation source, 20Ci), when the outer diameter of the pipeline to be inspected is 48 mm to 101 mm and the wall thickness of the pipeline 1 is less than or equal to 10 mm, the inspection effect can reach the same level as that of conventional γ-ray flaw detection, meeting the requirements of relevant regulations and standards. The maximum dose rate in direct contact with the surface of the device proposed by the present invention is 1.028 mSv / h, the dose rate at a distance of 2 meters is 2.24 μSv / h, and the dose rate at a distance of 5 meters is 0.12 μSv / h. Therefore, using this ray flaw detection device can greatly reduce the scope of the γ-ray flaw detection site isolation area, and other professionals can work simultaneously 2 m away during ray flaw detection.

[0043] The above embodiments only represent several implementation manners of the present invention, and the description is relatively specific and detailed, but it should not be construed as a limitation to the scope of the invention patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent of the present invention should be subject to the appended claims.

Claims

1. A small γ-ray flaw detection device with a shielding function, characterized in that, The device includes a fixing ring (2), an upper shielding housing (4), a lower shielding housing (5), a gamma source machine fixing bin (6) and a gamma source machine (7). The fixing ring (2) is arranged on the pipeline (1), and a sliding groove is provided at the lower end of the fixing ring (2); the upper shielding housing (4) and the lower shielding housing (5) are lapped on the sliding groove of the fixing ring (2), and the upper shielding housing (4) and the lower shielding housing (5) can rotate along the sliding groove of the fixing ring (2); the gamma source machine fixing bin (6) is arranged on the upper shielding housing (4), and the gamma source machine (7) is placed in the gamma source machine fixing bin (6).

2. The small gamma-ray flaw detector with a shielding function according to claim 1, characterized in that, The fixing ring (2) is provided with positioning holes. The upper shielding housing (4) is provided with angular positioning holes at the position lapped with the sliding groove of the fixing ring (2). A device positioning pin (3) is connected inside the positioning holes. The device positioning pin (3) is used to fix the fixing ring (2) on the pipeline (1); a rotation positioning pin (11) is arranged in the angular positioning holes. The rotation positioning pin (11) passes through the upper shielding housing (4). The rotation positioning pin (11) is used to limit the position of the upper shielding housing (4) on the fixing ring (2).

3. The small-sized γ-ray flaw detector with a shielding function according to claim 2, characterized in that, Both the upper shielding housing (4) and the lower shielding housing (5) are hollow semi-cylindrical structures; one end of the upper shielding housing (4) and the lower shielding housing (5) is hinged in a hinge manner, and the other end is connected by a buckle and locked with a pin shaft; a lead shield is arranged inside the upper shielding housing (4) and the lower shielding housing (5). The lead shield is used to shield the rays of the gamma source machine (7).

4. A small γ-ray flaw detector with a shielding function according to claim 3, characterized in that, A shielding ring (10) is provided at one end of the upper shielding housing (4) and the lower shielding housing (5) that is not connected to the fixing ring (2). The shielding ring (10) is used to shield the scattered rays inside the device; the shielding ring (10) is fixed on the pipeline (1).

5. A small γ-ray flaw detector with a shielding function according to claim 4, characterized in that The gamma source machine fixing bin (6) is a hollow cylindrical structure. A protruding structure is provided at the bottom of the gamma source machine fixing bin (6). The protruding structure is used for positioning the gamma source machine (7) when it is placed in the gamma source machine fixing bin (6); fastening bolt holes are opened on both sides of the gamma source machine fixing bin (6). Fastening bolts are arranged in the positioning bolt holes. The positioning bolts are used to fix the gamma source machine (7).

6. A small γ-ray flaw detector with a shielding function according to claim 5, characterized in that, The gamma source machine (7) is connected to a control cable (8). The control cable (8) is used to control the operation of the gamma source machine (7).

7. A small γ-ray flaw detector with a shielding function according to claim 6, characterized in that, A back shielding block (9) is arranged outside the lower shielding housing (5). One end of the back shielding block (9) is installed on the lower shielding housing (5) in a hinge manner, and the other end of the back shielding block (9) is fixed on the lower shielding housing (5) by a fixing pin. The back shielding block (9) can be opened and closed; a radiation film of the gamma source machine (7) is placed between the back shielding block (9) and the lower shielding housing (5).

8. A small γ-ray flaw detector with a shielding function according to claim 6, characterized in that, An anti-drop chain is arranged on the fixing pin connecting the back shielding block (9) and the lower shielding housing (5); an anti-drop chain is arranged on the fastening bolt on the gamma source machine fixing bin (6).

9. A small γ-ray flaw detector with a shielding function according to claim 1, characterized in that, One end of the upper shielding housing (4) and the lower shielding housing (5) connected to the fixing ring (2) is provided with bolt holes, and positioning bolts are arranged in the bolt holes. The positioning bolts are used to fix the positions of the upper shielding housing (4) and the lower shielding housing (5) on the fixing ring (2).

10. A small γ-ray flaw detection method with a shielding function according to any one of claims 1-9, characterized in that, The method includes: Step 1: Install a fixing ring (2) and a shielding ring (10) at both ends of the weld of the pipeline (1); Step 2: Install an upper shielding housing (4) and a lower shielding housing (5) at the sliding groove position of the fixing ring (2); Step 3: Install a γ-ray source machine (7) in the γ-ray source machine fixing bin (6) outside the upper shielding housing (4); Step 4: Place a radiographic film between the lower shielding housing (5) and the back shielding block (9), and close the back shielding block (9); Step 5: Control the γ-ray source machine (7) to perform flaw detection on the pipeline (1) through the control cable (8); Step 6: Rotate to change the positions of the upper shielding housing (4) and the lower shielding housing (5), and control the γ-ray source machine (7) to perform flaw detection on the pipeline (1) from different orientations through the control cable (8).

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