A fuel element grid strip stiffness detection clamping tool and use method

Abstract

The present invention belongs to the technical field of nuclear fuel element manufacturing, and specifically relates to a fuel element grid strip stiffness detection clamping tool and a method of use. The present invention produces a detection fixture and a pressure head for two grid strips, and the clamping of the strip by the fixture fully meets the technical requirements. The double movable pressure head design of the present invention ensures full contact between the pressure head and the rigid convex, and fully realizes the simultaneous detection of the double rigid convex. The detection method of the present invention is accurate and reliable, and realizes the measurement of the strip clamping unit spring / rigid convex load-deformation curve.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear fuel element manufacturing, and in particular relates to a fuel element grid strip stiffness detection clamping tool and a use method thereof. Background Art

[0002] CF4 fuel elements are an important research field for nuclear fuel elements. Physical properties are one of their important characteristics. Studying the physical properties of its grid is of great significance to exploring nuclear power accident-resistant fuel. The physical and mechanical properties of the CF4 grid are characterized by measuring stiffness.

[0003] Therefore, the stiffness test of CF4 grid is very important. There is no relevant test before, so we need to design and manufacture a probe device that meets the stiffness test of CF4 grid, so as to establish a method for stiffness test of CF4 grid.

[0004] At present, there is no standard equipment and supporting fixtures for CF4 strip stiffness testing in China. Therefore, we use the existing tension and compression testing machine as the testing equipment, design and manufacture the clamping fixture that meets the test requirements, and apply it to the strip stiffness test. Summary of the invention

[0005] In view of the above shortcomings, the object of the present invention is to provide a fuel element grid strip stiffness detection clamping tool and a use method.

[0006] The technical solution of the present invention is as follows:

[0007] A fuel element grid strip stiffness detection clamping tool comprises a bottom plate, a lower clamping plate and an upper clamping plate, a sample is fixed between the upper clamping plate and the lower clamping plate, the bottom plate is placed on a test piece platform for testing, the lower clamping plate is installed above the bottom plate, the upper clamping plate is installed above the lower clamping plate, a detection through hole is arranged on the upper clamping plate, a spring pressure head or a rigid convex pressure head can be installed at the test position of the detection equipment for separate testing; the spring pressure head passes through the detection through hole of the upper clamping plate during the test and contacts with the sample; the rigid convex pressure head passes through the detection through hole of the upper clamping plate during the test and contacts with the sample.

[0008] The lower surface of the base plate ensures that the fixture is in stable contact with the testing machine platform. Five Φ6 positioning block holes are set on both sides of the base plate. Each positioning block hole on both sides is provided with a side fastening screw hole toward its outside, and a Φ12 circular through hole is set at both ends of the base plate.

[0009] The bottom plate is made of 1Cr18Ni9 and is in the shape of a flat plate with a length of 100mm to 105mm, a width of 45mm to 50mm, and a height of 11mm to 15mm.

[0010] The upper clamping plate is made of 1Cr18Ni9 and is an I-shaped flat plate as a whole, divided into a middle horizontal plate and vertical plates at both ends. The upper clamping plate has an overall length of 100mm to 105mm, a width of 85mm to 90mm, and a height of 15mm to 16mm.

[0011] Five protrusions parallel to the vertical plate are evenly arranged on the middle plate, and each protrusion is provided with three detection through holes, which are used to pass a spring pressure head or a rigid convex pressure head during detection; a fixed pressure block groove is formed between the protrusion bar and the vertical plate or between two adjacent protrusion bars, with a total of 6 fixed pressure block grooves, and a pressure block fastening screw hole is provided at the upper and lower parts of each fixed pressure block groove, with a total of 12 pressure block fastening screw holes, which are used for positioning and fastening the 6 fixed pressure blocks to the sample; a Φ6 lower clamping plate connecting hole is provided at the upper and lower ends of the vertical plate of the upper clamping plate, which is used to connect and fix the upper clamping plate to the lower clamping plate.

[0012] The lower clamping plate is made of 1Cr18Ni9 and is in the shape of a flat plate as a whole, with a length of 100mm to 105mm, a width of 85mm to 90mm, and a height of 5mm to 8mm.

[0013] Five simulated fuel rod slots are arranged in the middle of the lower clamping plate for simulating the installation and positioning of the fuel rods, with a length of 40 mm to 41 mm and a width of 5 mm to 6 mm.

[0014] Each simulated fuel rod slot is provided with clamping bars on both sides, 6 in total, with a length of 2.4mm-2.5mm, a width of 1.6mm-1.7mm, and a height of 2mm. The clamping bars are divided into non-assembly slot clamping bars 13 and assembly slot clamping bars. The assembly slot clamping bars are distributed on the outer sides of the simulated fuel rod slots at the left and right ends, 2 in total, and the length of the non-assembly slot clamping bars is half of the assembly slot clamping bars. The non-assembly slot clamping bars are distributed in the upper half between every two simulated fuel rod slots, 4 in total.

[0015] Two positioning blocks are provided at the left and right ends of the lower clamping plate to simulate the top of the fuel rod slot. The dimensions are 4.5mm-5mm in length, 2.5mm-3mm in width, and 2mm in height. With the cooperation of 6 clamping strips, the sample can be clamped. A Φ6 upper clamping plate connecting hole is set at the four corners of the lower clamping plate for connection and fixation with the upper clamping plate. Two M6 bottom plate connecting holes are set horizontally on the left and right sides of the lower clamping plate for connection and fixation of the lower clamping plate to the bottom plate.

[0016] A method for using a fuel element grid strip stiffness detection clamping tool, step 1: install the strip to be tested and the pressure block, the installation position of the pressure block should correspond to the clamping position on the bottom plate, first match an intermediate positioning clamping block with the strip, and install them into the middle hole of the upper and lower clamping plates together, so that the strip contacts the longitudinal positioning block on the lower clamping plate, adjust the clamping block to be flush with the end of the groove of the upper pressure plate, rotate the clamping screw to fix the strip and the clamping block, and then install the other 5 pressure blocks in this way, and apply a certain torque to the clamping screw in sequence to complete the clamping and fixing of the strip;

[0017] Step 2: When measuring the spring, first apply compression displacement to the nominal compression displacement point, use the fixed deflection test method, record the load value under the compression displacement, record the spring free height value, and restore to the free state; then apply compression displacement to the maximum compression displacement point, that is, take the spring free height position as the base point, use the fixed displacement test method, record the load value under the compression displacement, and restore to the free state again;

[0018] Step 3: After the test is completed, remove the grid strip from the test device.

[0019] The beneficial effects of the present invention are:

[0020] 1) Inspection fixtures and pressure heads for two types of grid strips were manufactured, and the clamping of the strips by the fixtures fully met the technical requirements.

[0021] 2) The double movable indenter design ensures full contact between the indenter and the rigid convex, and fully realizes the simultaneous detection of the double rigid convex.

[0022] 3) The detection method is accurate and reliable, and realizes the measurement of the spring / rigid convex load-deformation curve of the strip clamping unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the bottom plate structure of the present invention;

[0024] Figure 2 It is a schematic diagram of the structure of the upper clamping plate of the present invention;

[0025] Figure 3 It is a schematic diagram of the structure of the lower clamping plate of the present invention;

[0026] In the figure: 4: positioning block hole; 5: side fastening screw hole; 6: lower clamping plate connection hole; 7: detection through hole; 8: fixed pressure block groove; 9: pressure block fastening screw hole; 10: lower clamping plate connection hole; 11: simulated fuel rod groove; 12: assembly groove clamping strip; 13: non-assembly groove clamping strip; 14: positioning block; 15: upper clamping plate connection hole; 16: bottom plate connection hole. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] A fuel element grid strip stiffness detection clamping tool comprises a bottom plate, a lower clamping plate and an upper clamping plate.

[0029] A fuel element grid strip stiffness detection clamping tool, made of Cr18Ni9, assembled from a bottom plate, a lower clamping plate, and an upper clamping plate, with a length of 100mm to 105mm, a width of 85mm to 90mm, and a height of 48mm to 50mm. The sample is fixed between the upper clamping plate and the lower clamping plate, the bottom plate is placed on the test piece platform for testing, the lower clamping plate is installed above the bottom plate, the upper clamping plate is installed above the lower clamping plate, and a detection through hole is provided on the upper clamping plate. The test part of the detection equipment can be installed with a spring pressure head or a rigid convex pressure head for separate testing; the spring pressure head passes through the detection through hole of the upper clamping plate during the test and contacts the sample; the rigid convex pressure head passes through the detection through hole of the upper clamping plate during the test and contacts the sample.

[0030] The base plate is made of 1Cr18Ni9. Figure 1 As shown. The overall shape is a flat plate with a length of 100mm~105mm, a width of 45mm~50mm, and a height of 11mm~15mm. The lower surface of the base plate ensures that the fixture is in stable contact with the test machine platform. Five Φ6 positioning block holes 4 are set on the upper and lower sides of the base plate to achieve pre-support of the rigid convex and apply nominal displacement under the cooperation of simulated fuel rods of different height sizes. Each positioning block hole 4 on both sides is provided with a side fastening screw hole 5 toward its outer side for tightening the positioning block. A Φ12 circular through hole is set at both ends of the base plate for connection and fixation with the lower clamping plate.

[0031] The upper clamping plate is made of 1Cr18Ni9. Figure 2As shown. The whole is an I-shaped flat plate, which is divided into a middle horizontal plate and vertical plates at both ends. The overall length of the upper clamping plate is 100mm~105mm, the width is 85mm~90mm, and the height is 15mm~16mm. Five protrusions parallel to the vertical plate are evenly arranged on the middle plate, and each protrusion is provided with three detection through holes 7, which are used to pass the spring pressure head or rigid convex pressure head during detection; a fixed pressure block groove 8 is formed between the protrusion bar and the vertical plate or between two adjacent protrusion bars, a total of 6 fixed pressure block grooves 8, and a pressure block fastening screw hole 9 is provided at the upper and lower parts of each fixed pressure block groove 8, a total of 12 pressure block fastening screw holes 9, which are used for positioning and fastening the 6 fixed pressure blocks and the sample. A Φ6 lower clamping plate connecting hole 10 is provided at the upper and lower ends of the vertical plate of the upper clamping plate, which is used to connect and fix the upper clamping plate with the lower clamping plate.

[0032] The lower clamping plate is made of 1Cr18Ni9. Figure 3 As shown. The overall shape is a flat plate, with a length of 100mm to 105mm, a width of 85mm to 90mm, and a height of 5mm to 8mm. Five simulated fuel rod slots 11 are arranged in the middle of the lower clamping plate for simulating the installation and positioning of the fuel rods, with a length of 40mm to 41mm and a width of 5mm to 6mm. There are clamping bars on both sides of each simulated fuel rod slot 11, totaling 6, with a length of 2.4mm to 2.5mm, a width of 1.6mm to 1.7mm, and a height of 2mm. The clamping bars are divided into non-assembly slot clamping bars 13 and assembly bar clamping bars 12. The assembly slot clamping bars 12 are distributed on the outside of the simulated fuel rod slots 11 at the left and right ends, with a total of 2 bars. The length of the non-assembly slot clamping bars 13 is half of the length of the assembly slot clamping bars 12. The non-assembly slot clamping bars 13 are distributed in the upper half between every two simulated fuel rod slots 11, with a total of 4 bars.

[0033] Two positioning blocks are provided at the left and right ends of the lower clamping plate, simulating the upper part of the fuel rod slot 11, with the dimensions of 4.5mm-5mm in length, 2.5mm-3mm in width, and 2mm in height. With the cooperation of 6 clamping strips, the sample can be clamped. A Φ6 upper clamping plate connection hole 15 is provided at each of the four corners of the lower clamping plate for connection and fixation with the upper clamping plate. Two M6 bottom plate connection holes are provided horizontally on the left and right sides of the lower clamping plate for connection and fixation between the lower clamping plate and the bottom plate.

[0034] A fuel element grid strip stiffness detection clamping tool and a method for using the tool, the method comprising the following steps:

[0035] Step 1: Install the strip and pressure block to be inspected. The installation position of the pressure block should correspond to the clamping position on the bottom plate. First, match a middle positioning clamp block with the strip and install them into the middle hole of the upper and lower clamping plates together, so that the strip contacts the longitudinal positioning block on the lower clamping plate, adjust the clamp block to be flush with the end of the groove of the upper pressure plate, rotate the clamping screw to fix the strip and the clamp block, and then install the other 5 pressure blocks in this way. Apply a certain torque to the clamping screws in sequence to complete the clamping and fixation of the strip.

[0036] Step 2: When measuring the spring, first apply compression displacement to the nominal compression displacement point, use the fixed deflection (deformation) test method, record the load value under the compression displacement, record the spring free height value, and restore to the free state; then apply compression displacement to the maximum compression displacement point (with the spring free height position as the base point), use the fixed displacement test method, record the load value under the compression displacement, and restore to the free state again.

[0037] Step 3: After the test is completed, remove the grid strip from the test device.

[0038] In the drawings of the embodiments disclosed in the present invention, only the methods related to the embodiments disclosed in the present invention are involved, and other methods can refer to the general design. In the case of no conflict, the same embodiment and different embodiments of the present invention can be combined with each other;

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A fuel element grid strip stiffness detection clamping tool, comprising a bottom plate, a lower clamping plate, and an upper clamping plate, characterized in that: The sample is fixed between the upper clamping plate and the lower clamping plate, the bottom plate is placed on the test piece platform for testing, the lower clamping plate is installed above the bottom plate, the upper clamping plate is installed above the lower clamping plate, and a detection through hole is set on the upper clamping plate. The test part of the detection equipment can be installed with a spring pressure head or a rigid convex pressure head for separate testing; the spring pressure head passes through the detection through hole of the upper clamping plate during the test and contacts the sample; the rigid convex pressure head passes through the detection through hole of the upper clamping plate during the test and contacts the sample; the lower surface of the bottom plate ensures that the fixture is in stable contact with the test machine platform, and 5 Φ6 positioning block holes are set on the upper and lower sides of the bottom plate, and each positioning block hole on both sides is set with a side fastening screw hole to its outside, and a Φ12 circular through hole is set at both ends of the bottom plate; the upper clamping plate is made of 1Cr 18 Ni9 is an I-shaped flat plate as a whole, which is divided into a middle horizontal plate and vertical plates at both ends. The overall length of the upper clamping plate is 100mm-105mm, the width is 85mm-90mm, and the height is 15mm-16mm; 5 protrusions parallel to the vertical plate are evenly arranged on the middle horizontal plate, and each protrusion is provided with 3 detection through holes, which are used to pass the spring pressure head or rigid convex pressure head during detection; a fixed pressure block groove is formed between the protrusion bar and the vertical plate or between two adjacent protrusion bars, with a total of 6 fixed pressure blocks. There are 12 fixed pressure block slots, with a pressure block fastening screw hole set at the upper and lower parts of each fixed pressure block slot, for positioning and fastening the 6 fixed pressure blocks to the sample; a Φ6 lower clamping plate connecting hole is set at both upper and lower ends of the vertical plate of the upper clamping plate, for connecting and fixing the upper clamping plate to the lower clamping plate; 5 simulated fuel rod slots are set in the middle part of the lower clamping plate for simulating the installation and positioning of the fuel rods, with a length of 40mm to 41mm and a width of 5mm to 6mm.

2. A fuel element grid strip stiffness detection clamping tool as claimed in claim 1, characterized in that: The base plate is made of 1Cr 18 Ni9 is in the shape of a flat plate as a whole, with a length of 100mm to 105mm, a width of 45mm to 50mm, and a height of 11mm to 15mm.

3. A fuel element grid strip stiffness detection clamping tool as claimed in claim 1, characterized in that: The lower clamping plate is made of 1Cr 18 Ni9 is in the shape of a flat plate as a whole, with a length of 100mm to 105mm, a width of 85mm to 90mm, and a height of 5mm to 8mm.

4. A fuel element grid strip stiffness detection clamping tool as claimed in claim 1, characterized in that: Each simulated fuel rod slot is provided with clamping bars on both sides, for a total of 6 bars. The length of the clamping bars is 2.4mm-2.5mm, the width is 1.6mm-1.7mm, and the height is 2mm. The clamping bars are divided into non-assembly slot clamping bars and assembly slot clamping bars. The assembly slot clamping bars are distributed on the outer sides of the simulated fuel rod slots at the left and right ends, for a total of 2 bars. The length of the non-assembly slot clamping bars is half of the assembly slot clamping bars. The non-assembly slot clamping bars are distributed in the upper part between every two simulated fuel rod slots, for a total of 4 bars.

5. A fuel element grid strip stiffness detection clamping tool as claimed in claim 4, characterized in that: Two positioning blocks are provided at the left and right ends of the lower clamping plate to simulate the top of the fuel rod slot. The dimensions are 4.5mm~5mm in length, 2.5mm~3mm in width, and 2mm in height. With the cooperation of 6 clamping strips, the sample can be clamped. A Φ6 upper clamping plate connecting hole is set at the four corners of the lower clamping plate for connection and fixation with the upper clamping plate. Two M6 bottom plate connecting holes are set horizontally on the left and right sides of the lower clamping plate for connection and fixation of the lower clamping plate with the bottom plate.

6. A method for using a fuel element grid strip stiffness detection clamping tool as claimed in claim 5, characterized in that: Step 1: Install the strip to be inspected and the pressure block. The installation position of the pressure block should correspond to the clamping position on the bottom plate. Ensure that the strip contacts the positioning block on the lower clamping plate. Adjust the positioning block to be flush with the end of the groove of the upper pressure plate. Turn the clamping screw to fix the strip and the lower clamping plate. Then install the other 5 pressure blocks in this way. Apply a certain torque to the clamping screws in sequence to complete the clamping and fixing of the strip. Step 2: When measuring the spring, first apply compression displacement to the nominal compression displacement point, use the fixed deflection test method, record the load value under the compression displacement, record the spring free height value, and restore to the free state; then apply compression displacement to the maximum compression displacement point, that is, take the spring free height position as the base point, use the fixed displacement test method, record the load value under the compression displacement, and restore to the free state again; Step 3: After the test is completed, remove the grid strip from the test device.

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