A detachable annular fuel test assembly

Abstract

The present invention relates to the field of reactor engineering technology, and specifically discloses a detachable annular fuel test assembly, wherein an upper tube seat and a guide tube connecting tube, a guide tube and a guide tube connecting tube, an internal annular fuel simulation rod and a lower tube seat, a guide tube and a lower tube seat, a lower tube seat and a lower tube seat support leg are all fixedly connected by screws, and has a detachable function. Some components can be replaced according to relevant test requirements without replacing new components, thereby reducing test and manufacturing costs.

Description

Technical Field

[0001] The invention belongs to the technical field of reactor engineering, and in particular relates to a detachable annular fuel test assembly. Background Art

[0002] Fuel assembly is one of the most important components in the core. Its performance directly affects the economy and sustainable development goals of nuclear power plants and indirectly affects safety goals.

[0003] The benefit of annular fuel over conventional solid cylindrical fuel is that at very high linear power density, the temperature at the center of the fuel remains low, less energy is stored in the fuel, less fission gas is released, and better fuel performance can be expected under normal operation and transient conditions.

[0004] In order to ensure the safe use of annular fuel assemblies in reactors, a large number of performance tests are required to verify their safety and reliability after the structural design is completed. Among them, the data on the comprehensive performance of annular fuel obtained through various in-pile and out-of-pile tests of test assemblies can provide real and reliable test data for the performance safety analysis and engineering application of annular fuel. Therefore, it is very necessary and of great significance to carry out various test work using test assemblies, which can promote the development of nuclear power in a safer and more economical direction.

[0005] The existing annular fuel assembly consists of an upper tube seat, a compression spring, a fuel rod, a spacer grid, a guide tube, an instrument tube, a lower tube seat, and a foreign body protection net. The components are connected and fixed by welding. If this type of assembly is used to conduct tests with different test parameters under the same test conditions, such as tests with different spacer grid drag coefficients, the test object needs to be replaced with a new whole assembly after each test, resulting in a waste of test resources and research and development funds. In addition, using different assemblies to conduct tests under the same test conditions may result in additional test errors.

[0006] Therefore, it is necessary to design an annular test assembly with disassembly function. Summary of the invention

[0007] The object of the present invention is to provide a detachable annular fuel test assembly, which is convenient for disassembly and assembly when conducting a hydraulic simulation test.

[0008] The technical solution of the present invention is as follows:

[0009] A detachable annular fuel test assembly comprises an upper tube seat, an annular fuel simulation rod, a positioning grid, a guide tube, an instrument tube, and a lower tube seat;

[0010] The annular fuel simulation rod comprises an upper end plug, a lower end plug, an inner cladding, and an outer cladding; the inner cladding and the outer cladding are coaxially nested, an upper end plug is provided above the inner cladding and the outer cladding, and a lower end plug is provided below;

[0011] The upper end of the guide tube is clamped on the upper tube seat through a connecting mechanism for transverse positioning, and the lower end is fixed to the lower tube seat through a skeleton shoulder screw;

[0012] The upper end of the instrument tube extends into the limiting hole at the center of the upper tube seat for lateral positioning;

[0013] There are multiple positioning grids, which are arranged in sequence along the axial direction of the annular fuel simulation rod, and the two are fixed by positioning grid positioning pins;

[0014] The annular fuel simulation rod, guide tube and instrument tube are inserted into the positioning grid, wherein the instrument tube is located at the center;

[0015] The bottom end of the annular fuel simulation rod is inserted into and fixed in the lower tube seat, and when the annular fuel simulation rod generates irradiation growth, it expands upward.

[0016] A threaded hole is opened on the side wall of the lower tube seat, and the lower tube seat side plate positioning pin is screwed into the lower tube seat, and the top end of the lower tube seat side plate positioning pin is pressed against a circle of annular fuel simulation rods located on the outer edge, so as to axially position the circle of annular fuel simulation rods located on the outer edge.

[0017] An annular V-groove is processed on the lower end plug of the annular fuel simulation rod located at the outer edge, and the top end of the positioning pin of the lower tube seat side plate is pushed into the annular V-groove of the lower end plug of the annular fuel simulation rod for axial positioning.

[0018] The bottom end of the annular fuel simulation rod located in the middle is fixedly connected to the lower pipe seat through a fuel rod locking nut.

[0019] The positioning pins of the positioning grid are arranged at the four corners of the positioning grid and penetrate the annular fuel simulation rods located at the four corners, so as to fix the positioning grid and the annular fuel simulation rods.

[0020] An external thread is processed on the upper end of the guide tube and connected with the lower end of the guide tube connecting sleeve through a thread; the upper end of the guide tube connecting sleeve is clamped on the upper tube seat through a thread.

[0021] The axial positioning of the lower end of the guide tube is achieved by screwing the skeleton shoulder screw into the boss thread inside the lower tube seat and extending it into the lower end of the guide tube.

[0022] A lower tube seat support leg is provided below the lower tube seat, and the two are connected by a lower tube seat support leg positioning pin, which is convenient for disassembly and does not affect the nut assembly of the annular fuel simulation rod and the lower tube seat.

[0023] A compression spring is arranged on the upper part of the upper tube seat, which cooperates with the upper grid plate of the core to realize the compression of the annular fuel test assembly in the core and prevent the annular fuel test assembly from moving in the core.

[0024] It is suitable for hydraulic simulation tests on pressurized water reactors, fast reactors, low-temperature heating reactors, space reactors, boiling water reactors, micro reactors, zero-power reactors, heavy water reactors, power reactors, and marine power reactors.

[0025] The remarkable effects of the present invention are:

[0026] (1) In the detachable fuel assembly of the present invention, the upper tube seat and the guide tube connecting tube, the guide tubes and the guide tube connecting tubes, the inner annular fuel simulation rod and the lower tube seat are fixed by threaded connection;

[0027] The compression spring and the upper tube seat, and the guide tube and the lower tube seat are fixed by screw connection;

[0028] The positioning grid is connected to the outermost annular fuel simulation rod, the lower tube seat and the lower tube seat support leg through pins;

[0029] The assembly method between the components in the assembly has a detachable function, and some components can be replaced according to the relevant needs of the test without replacing new components, which reduces the test and manufacturing costs.

[0030] (2) The present invention simplifies the assembly process and assembly procedures of the fuel assembly, and there is no need to consider the welding process of the assembly and the steps of removing the weld inspection, which can save the assembly manufacturing and inspection cycle.

[0031] (3) The detachable design of the fuel assembly of the present invention can replace only the required research components according to the needs of the hydraulic test, while ensuring that the hydraulic characteristics of the remaining components remain unchanged, thereby controlling the influence of the remaining components other than the required research components on the test error and improving the measurement accuracy of the assembly in the hydraulic test. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the overall structure of the component;

[0033] Figure 2 Schematic diagram of the upper tube seat;

[0034] Figure 3 Assemble the cutaway view of the spacer grid locating pins;

[0035] Figure 4 This is a schematic diagram of the assembly of the positioning pins of the positioning grid;

[0036] Figure 5 It is a schematic diagram of the lower pipe seat;

[0037] Figure 6 This is the matching diagram of the lower tube seat and the side plate positioning pins;

[0038] Figure 7 This is a cross-sectional view of the lower tube seat.

[0039] In the figure: 1. Upper tube seat; 2. Annular fuel simulation rod; 3. Positioning grid; 4. Guide tube; 5. Instrument tube; 6. Lower tube seat; 7. Fuel rod locking nut; 8. Lower tube seat leg positioning pin; 9. Lower tube seat side plate positioning pin; 10. Positioning grid positioning pin; 11. Lower tube seat leg; 12. Frame shoulder screw. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] like Figure 1 The detachable annular fuel test assembly shown is suitable for hydraulic simulation test, and comprises an upper pipe seat 1, an annular fuel simulation rod 2, a positioning grid 3, a guide tube 4, an instrument tube 5, and a lower pipe seat 6.

[0042] A compression spring is provided on the upper portion of the upper tube seat 1, which cooperates with the upper grid plate of the core to achieve compression of the annular fuel test assembly in the core and prevent the annular fuel test assembly from moving in the core.

[0043] The annular fuel simulation rod 2 comprises an upper end plug, a lower end plug, an inner cladding and an outer cladding. The inner cladding and the outer cladding are coaxially nested, and an upper end plug is arranged above the inner cladding and the outer cladding, and a lower end plug is arranged below the inner cladding and the outer cladding.

[0044] like Figure 2 As shown, an external thread is processed on the upper end of the guide tube 4, and is connected to the lower end of the guide tube connecting sleeve through a thread.

[0045] The upper end of the guide tube connecting sleeve is clamped on the upper tube seat 1 through a thread.

[0046] The upper end of the instrument tube 5 extends into the limiting hole at the center of the upper tube seat 1 for transverse positioning.

[0047] There are multiple spacer grids 3, which are arranged in sequence along the axial direction of the annular fuel dummy rod 2. The annular fuel dummy rod 2, the guide tube 4 and the instrument tube 5 are inserted into the spacer grids 3, wherein the instrument tube 5 is located at the center.

[0048] like Figure 3 , Figure 4 As shown, spacer grid positioning pins 10 are respectively provided at the four corners of the spacer grid 3 and penetrate the annular fuel dummy rods 2 located at the four corners for fixing the spacer grid 3 and the annular fuel dummy rods 2 .

[0049] like Figures 5 to 7As shown, the bottom end of the annular fuel dummy rod 2 is inserted and fixed in the lower tube seat 6, wherein the bottom end of the annular fuel dummy rod 2 located in the middle is fixedly connected to the lower tube seat 6 through the fuel rod locking nut 7; an annular V groove is processed on the lower end plug of the annular fuel dummy rod 2 located at the outer edge, and the lower tube seat side plate positioning pin 9 is screwed into the lower tube seat 6 by opening a threaded hole on the side wall of the lower tube seat 6, and the top end of the lower tube seat side plate positioning pin 9 is pushed into the annular V groove of the lower end plug of the annular fuel dummy rod 2 for axial positioning, so as to fix the annular fuel dummy rod 2 located at the outer edge. When the annular fuel dummy rod 2 grows by irradiation, it expands upward.

[0050] The lower end of the guide tube 4 is fixed to the lower tube seat 6 by a skeleton shoulder screw 12 , and the axial positioning of the lower end of the guide tube 4 is achieved by screwing the skeleton shoulder screw 12 into the boss thread inside the lower tube seat 6 and extending it into the lower end of the guide tube 4 .

[0051] A lower tube seat leg 11 is provided below the lower tube seat 6 , and the two are connected via a lower tube seat leg positioning pin 8 , which is convenient for disassembly and does not affect the nut assembly of the annular fuel simulation rod 2 and the lower tube seat 6 .

Claims

1. A detachable annular fuel test assembly, characterized in that: It comprises an upper tube seat (1), an annular fuel simulation rod (2), a positioning grid (3), a guide tube (4), an instrument tube (5), and a lower tube seat (6); The annular fuel simulation rod (2) comprises an upper end plug, a lower end plug, an inner cladding, and an outer cladding; the inner cladding and the outer cladding are coaxially nested, an upper end plug is provided above the inner cladding and the outer cladding, and a lower end plug is provided below the inner cladding and the outer cladding; The upper end of the guide tube (4) is clamped on the upper tube seat (1) through a connecting mechanism for transverse positioning, and the lower end is fixed to the lower tube seat (6) through a skeleton shoulder screw (12); The upper end of the instrument tube (5) extends into a limiting hole at the center of the upper tube seat (1) for lateral positioning; There are a plurality of positioning grids (3), which are arranged in sequence along the axial direction of the annular fuel simulation rod (2), and the two are fixed by positioning grid positioning pins (10); The annular fuel simulation rod (2), guide tube (4) and instrument tube (5) are inserted into the positioning grid (3), wherein the instrument tube (5) is located at the center; The bottom end of the annular fuel simulation rod (2) is inserted into and fixed in the lower tube seat (6), and when the annular fuel simulation rod (2) grows due to irradiation, it expands upward; A threaded hole is formed on the side wall of the lower tube seat (6), and the lower tube seat side plate positioning pin (9) is screwed into the lower tube seat (6), and the top end of the lower tube seat side plate positioning pin (9) is pressed against a ring of fuel simulation rods (2) located at the outer edge, so as to axially position the ring of fuel simulation rods (2) located at the outer edge; The bottom end of the annular fuel simulation rod (2) located in the middle is fixedly connected to the lower pipe seat (6) via a fuel rod locking nut (7); The positioning grid positioning pins (10) are arranged at the four corners of the positioning grid (3) and penetrate the annular fuel simulation rods (2) located at the four corners, and are used to fix the positioning grid (3) and the annular fuel simulation rods (2); A lower tube seat support leg (11) is provided below the lower tube seat (6), and the two are connected via a lower tube seat support leg positioning pin (8).

2. A detachable annular fuel test assembly as claimed in claim 1, characterized in that: An external thread is processed on the upper end of the guide tube (4) and is connected to the lower end of the guide tube connecting sleeve via a thread; the upper end of the guide tube connecting sleeve is clamped on the upper tube seat (1) via a thread.

3. A detachable annular fuel test assembly as claimed in claim 2, characterized in that: The axial positioning of the lower end of the guide tube (4) is achieved by screwing the skeleton shoulder screw (12) into the boss thread inside the lower tube seat (6) and extending it into the lower end of the guide tube (4).

4. A detachable annular fuel test assembly as claimed in claim 3, characterized in that: A compression spring is arranged on the upper part of the upper tube seat (1), which cooperates with the upper grid plate of the core to realize compression of the annular fuel test assembly in the core and prevent the annular fuel test assembly from moving in the core.

5. A detachable annular fuel test assembly according to any one of claims 1 to 4, characterized in that: It is suitable for hydraulic simulation tests on pressurized water reactors, fast reactors, low-temperature heating reactors, space reactors, boiling water reactors, micro reactors, zero-power reactors, heavy water reactors, power reactors, and marine power reactors.

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