Primary circulation 18-month pressurized water reactor core of 4000 MW pressurized water reactor and loading method of primary circulation 18-month pressurized water reactor core

Abstract

The invention discloses a reactor core of a pressurized water reactor with power of 4000 MW for 18 months of first circulation and a loading method of the reactor core, the reactor core is composed of 177 groups of annular fuel assemblies, the enrichment degree of each annular fuel assembly is 4.1%, 4.25% or 4.45%, the annular fuel assembly with the highest enrichment degree of 4.45% is arranged in an outer area of the reactor core, and 88 groups of annular fuel assemblies with the enrichment degree of 4.25% are arranged in total; 4.25% of annular fuel assemblies with relatively low enrichment degree and 4.1% of annular fuel assemblies with low enrichment degree are arranged in the inner area of the reactor core according to a checkerboard format, 68 groups of annular fuel assemblies with the enrichment degree of 4.25% are arranged, and 21 groups of annular fuel assemblies with the enrichment degree of 4.1% are arranged. According to the invention, on the premise that the shape and size of the pressurized water reactor core composed of 177 groups of fuel assemblies are not changed, after the annular fuel assemblies are adopted, the power of the reactor core is improved by 25% and reaches 4000 MW compared with that of a pressurized water reactor core adopting rod-shaped fuel, and the first cycle life length reaches 18 months, so that the economical efficiency of the reactor core is obviously improved.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear engineering, and in particular relates to a pressurized water reactor core of a 4000MW pressurized water reactor with a first cycle of 18 months and a loading method thereof. Background Art

[0002] At present, the core of a pressurized water reactor consists of 177 fuel assemblies and uses 12-foot rod-shaped fuel assemblies. The reactor thermal output power is usually 3050-3180MW, the first cycle core life is 12-16 months, the core power is low, the core refueling cycle is short, and the economy is poor.

[0003] Compared with the above-mentioned rod-shaped fuel assemblies, annular fuel can cool the fuel cores in both the inner and outer channels, which can reduce the thickness of the fuel heat conduction, increase the heat transfer area of ​​the fuel, reduce the peak temperature of the core, and help improve the safety of the core. In addition, the use of annular fuel can increase the power density of the pressurized water reactor core by 20% to 50%, which is beneficial to the improvement of the economic efficiency of the nuclear power plant. However, with the increase of the nuclear power of the reactor, under the existing uranium loading conditions, the core refueling cycle will be shortened, and it may even be unable to meet the 12-month refueling requirement, which will lead to problems such as insufficient economy after operation. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a pressurized water reactor core with a first cycle of 18 months for a 4000MW pressurized water reactor and a loading method thereof in view of the above-mentioned deficiencies in the prior art, which can ensure that the pressurized water reactor core composed of 177 groups of fuel assemblies, without changing the core shape and size, after adopting annular fuel assemblies, the core power is increased by 25% to 4000MW compared with when rod-shaped fuel is used, and the first cycle life length reaches 18 months, thereby significantly improving the economic efficiency.

[0005] The technical solution of the present invention to solve the above technical problems is:

[0006] According to one aspect of the present invention, a method for loading the core of a 4000MW pressurized water reactor for the first 18-month cycle is provided, wherein the core is composed of 177 groups of annular fuel assemblies, and the enrichment of each annular fuel assembly is 4.1%, 4.25% or 4.45%, respectively, wherein:

[0007] The annular fuel assemblies with the highest enrichment of 4.45% are placed outside the core. There are 88 annular fuel assemblies with an enrichment of 4.25% in total.

[0008] The annular fuel assemblies with relatively low enrichment of 4.25% and the annular fuel assemblies with enrichment of 4.1% are arranged in a checkerboard pattern in the inner area of ​​the core, among which there are 68 groups of annular fuel assemblies with enrichment of 4.25% and 21 groups of annular fuel assemblies with enrichment of 4.1%.

[0009] Optionally, a portion of the annular fuel assemblies are provided with burnable poison rods, and the number of burnable poison rods in each annular fuel assembly is 4, 8 or 12.

[0010] Optionally, the burnable poison rod is a gadolinium-loaded fuel rod, and the weight percentage of Gd2O3 in the gadolinium-loaded fuel rod is 8.0%.

[0011] Optionally, the gadolinium-loaded fuel rods 235 U enrichment is 2.5%.

[0012] Optionally, there are 40 groups of annular fuel assemblies with an enrichment of 4.45% and no burnable poison rods; 16 groups of annular fuel assemblies with an enrichment of 4.45% and containing 4 burnable poison rods; 20 groups of annular fuel assemblies with an enrichment of 4.45% and containing 8 burnable poison rods; and 12 groups of annular fuel assemblies with an enrichment of 4.45% and containing 12 burnable poison rods.

[0013] Optionally, there are 4 groups of annular fuel assemblies with an enrichment of 4.25% and no burnable poison rods; there are 24 groups of annular fuel assemblies with an enrichment of 4.25% and containing 4 burnable poison rods; there are 40 groups of annular fuel assemblies with an enrichment of 4.25% and containing 12 burnable poison rods.

[0014] Optionally, there are 12 groups of annular fuel assemblies with an enrichment of 4.1% and containing 8 burnable poison rods; there are 9 groups of annular fuel assemblies with an enrichment of 4.1% and containing 12 burnable poison rods.

[0015] According to another aspect of the present invention, a pressurized water reactor core of a 4000MW pressurized water reactor with a first cycle of 18 months is provided, which is loaded by using the method described above.

[0016] Beneficial effects:

[0017] Compared with the prior art, the 18-month first cycle pressurized water reactor core and loading method of the 4000MW pressurized water reactor of the present invention can ensure that the core of the pressurized water reactor composed of 177 fuel assemblies can increase the core power by 25% to 4000MW after adopting annular fuel assemblies, and the first cycle life reaches 18 months, without changing the core size. The annular fuel can cool the fuel core blocks in the inner and outer channels at the same time, which can reduce the fuel heat conduction thickness, increase the fuel heat transfer area, reduce the core block peak temperature, and significantly improve the core safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic structural diagram of a pressurized water reactor core of a 4000MW pressurized water reactor in the first cycle of 18 months according to an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0020] In the description of the present invention, it should be noted that the term "upper" and the like to indicate orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience and simplification of description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0021] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0022] In view of the fact that the output thermal power of a pressurized water reactor core composed of 177 groups of fuel assemblies in the prior art is only 3050-3180MW, the first cycle core life length is 12-16 months, and there are problems such as low core power, short core refueling cycle, poor economy, etc., the present invention discloses a pressurized water reactor core loading method for the first cycle of 18 months of a 4000MW pressurized water reactor, the core is composed of 177 groups of annular fuel assemblies, and the enrichment of each annular fuel assembly is 4.1%, 4.25% or 4.45%, respectively, wherein:

[0023] The annular fuel assemblies with the highest enrichment of 4.45% are placed outside the core. There are 88 annular fuel assemblies with an enrichment of 4.25% in total.

[0024] The annular fuel assemblies with relatively low enrichment of 4.25% and the annular fuel assemblies with enrichment of 4.1% are arranged in a checkerboard pattern in the inner area of ​​the core, among which there are 68 groups of annular fuel assemblies with enrichment of 4.25% and 21 groups of annular fuel assemblies with enrichment of 4.1%.

[0025] Correspondingly, the present invention also discloses a pressurized water reactor core of a 4000MW pressurized water reactor with a first cycle of 18 months, which is loaded by using the method described above.

[0026] Compared with the prior art, the present invention can ensure that the core power of a pressurized water reactor composed of 177 fuel assemblies is increased by 25% to 4000MW after adopting annular fuel assemblies without changing the core shape and size, and the first cycle life reaches 18 months, thereby significantly improving the core economy.

[0027] Example 1

[0028] This embodiment discloses a method for loading the core of a 4000MW pressurized water reactor for the first 18-month cycle. The core consists of 177 groups of annular fuel assemblies, and the enrichment of each annular fuel assembly is 4.1%, 4.25% or 4.45%, respectively.

[0029] The annular fuel assemblies with the highest enrichment of 4.45% are placed outside the core. There are 88 annular fuel assemblies with an enrichment of 4.25% in total.

[0030] The annular fuel assemblies with relatively low enrichment of 4.25% and the annular fuel assemblies with enrichment of 4.1% are arranged in a checkerboard pattern in the inner area of ​​the core, among which there are 68 groups of annular fuel assemblies with enrichment of 4.25% and 21 groups of annular fuel assemblies with enrichment of 4.1%.

[0031] Specifically, the height of the core active section is 365.76 cm, and the size of the annular fuel assembly is 12 feet. The annular fuel assembly includes a number of fuel rods, guide tubes and instrument tubes. In this embodiment, the annular fuel assembly includes 160 fuel rods, 8 guide tubes and 1 instrument tube. The fuel rods in each annular fuel assembly are arranged in a 13×13 manner.

[0032] In some embodiments, a portion of the annular fuel assemblies are provided with burnable poison rods, and the number of burnable poison rods in each annular fuel assembly is 4, 8, or 12.

[0033] In some more specific embodiments, as shown in Table 1, there are 40 groups of annular fuel assemblies with an enrichment of 4.45% and no burnable poison rods; there are 16 groups of annular fuel assemblies with an enrichment of 4.45% and containing 4 burnable poison rods; there are 20 groups of annular fuel assemblies with an enrichment of 4.45% and containing 8 burnable poison rods; there are 12 groups of annular fuel assemblies with an enrichment of 4.45% and containing 12 burnable poison rods.

[0034] There are 4 groups of annular fuel assemblies with an enrichment of 4.25% and no burnable poison rods; there are 24 groups of annular fuel assemblies with an enrichment of 4.25% and containing 4 burnable poison rods; there are 40 groups of annular fuel assemblies with an enrichment of 4.25% and containing 12 burnable poison rods.

[0035] There are 12 groups of annular fuel assemblies with an enrichment of 4.1% and containing 8 burnable poison rods; there are 9 groups of annular fuel assemblies with an enrichment of 4.1% and containing 12 burnable poison rods.

[0036] Table 1

[0037]

[0038] In some embodiments, the burnable poison rod is a gadolinium-loaded fuel rod, and the weight percentage of Gd2O3 in the gadolinium-loaded fuel rod is 8.0%. This can achieve the best power flattening effect of the core, which is beneficial to the safety of the core. In addition, the release of burnable poison at this ratio throughout the entire life cycle can best match the changes in core reactivity and better control the reactivity.

[0039] In some embodiments, the gadolinium-loaded fuel rod 235 The U enrichment is 2.5%, which can achieve the best power flattening effect of the core, which is beneficial to the safety of the core. The release of combustible poisons at this ratio throughout the entire life cycle can best match the changes in core reactivity and better control reactivity.

[0040] This embodiment also discloses a pressurized water reactor core of a 4000MW pressurized water reactor with a first cycle of 18 months obtained by the above method. The specific structure of the core is as described in the above method and will not be repeated here.

[0041] Compared with the prior art, the core loading method of the 4000MW PWR of this embodiment can ensure that the core of the PWR composed of 177 fuel assemblies is increased by 25% to 4000MW after adopting the annular fuel assembly without changing the core size, and the life span of the first cycle reaches 18 months, thereby significantly improving the core economy. In addition, the annular fuel can cool the fuel core blocks in the inner and outer channels at the same time, which can reduce the heat conduction thickness of the fuel, increase the heat transfer area of ​​the fuel, reduce the peak temperature of the core blocks, and thus significantly improve the core safety.

[0042] Example 2

[0043] This embodiment discloses a method for loading the core of a 4000MW pressurized water reactor for the first 18-month cycle, which is basically the same as the method described in Example 1, except that:

[0044] like Figure 1 As shown, the horizontal coordinates are arranged from right to left by AR, and the vertical coordinates are arranged from top to bottom by 1-15. The method includes:

[0045] Twelve groups of annular fuel assemblies with an enrichment of 4.1% and containing eight gadolinium-loaded poison rods are arranged at positions H4, J5, G5, L7, E7, M8, D8, L9, E9, J11, G11, and H12 of the core;

[0046] Nine groups of annular fuel assemblies with an enrichment of 4.1% and 12 gadolinium-loaded poison rods are arranged at positions H6, J7, G7, K8, H8, F8, J9, G9 and H10 of the core;

[0047] Arrange 24 groups of annular fuel assemblies with an enrichment of 4.25% and containing 4 gadolinium-loaded poison rods at positions H5, L8, E8, H11, J3, G3, K4, F4, L5, E5, M6, K6, F6, D6, N7, C7, N9, C9, M10, K10, F10, D10, L11, E11, K12, F12, J13, and G13 of the core;

[0048] 40 annular fuel assemblies with an enrichment of 4.25% and containing 12 gadolinium-loaded poison rods are arranged at positions H3, L4, J4, G4, E4, M5, K5, F5, D5, L6, J6, G6, E6, M7, K7, H7, F7, D7, N8, J8, G8, C8, M9, K9, H9, F9, D9, L10, J10, G10, E10, M11, K11, F11, D11, L12, J12, G12, E12, and H13 of the core;

[0049] Arrange 40 groups of annular fuel assemblies with an enrichment of 4.45% and without gadolinium-containing poison rods at positions K1, J1, H1, G1, F1, M2, L2, E2, D2, N3, C3, P4, B4, P5, B5, R6, A6, R7, A7, R8, A8, R9, A9, R10, A10, P11, B11, P12, B12, N13, C13, M14, L14, E14, D14, K15, J15, H15, G15, and F15 of the core;

[0050] Arrange 16 groups of annular fuel assemblies with an enrichment of 4.45% and containing 4 gadolinium-loaded poison rods at positions K2, F2, M3, D3, N4, C4, P6, B6, P10, B10, N12, C12, M13, D13, K14 and F14 of the core;

[0051] Arrange 20 groups of annular fuel assemblies with an enrichment of 4.45% and containing 8 gadolinium-loaded poison rods at positions J2, H2, G2, L3, E3, N5, C5, P7, B7, P8, B8, P9, B9, N11, C11, L13, E13, J14, H14 and G14 of the core;

[0052] Twelve groups of annular fuel assemblies with an enrichment of 4.45% and containing 12 gadolinium-loaded poison rods are arranged at positions K3, F3, M4, D4, N6, C6, N10, C10, M12, D12, K13 and F13 of the core.

[0053] It should be noted that Figure 1 A combination of letters and numbers is used to indicate the position of the fuel assembly in the core. For example, H4 indicates that the position of the fuel assembly in the core is H4.

[0054] This embodiment also discloses a pressurized water reactor core of a 4000MW pressurized water reactor with a first cycle of 18 months obtained by the above method. The specific structure of the core is as described in the above method and will not be repeated here.

[0055] After calculation, the main parameters of the first cycle of the pressurized water reactor core of this embodiment are as shown in Table 2.

[0056] Table 2

[0057] Parameter name First cycle Cycle length (MWd / tU) 27256 Cycle length (EFPD) 480 Maximum nuclear enthalpy rise factor 1.410 Maximum hot spot factor 2.464 Critical boron concentration (ppm) 2077 Moderator temperature coefficient (pcm / ℃) -0.484 Maximum fuel consumption of components (MWd / tU) 33178

[0058] At present, there is no clear safety criterion for the core parameters of a pressurized water reactor using an annular fuel assembly. Referring to the existing design criteria for the pressurized water reactor core of the 177 assembly, the core design criteria in this embodiment are as follows:

[0059] 1) Core fuel assembly 235 U enrichment ≤4.95%;

[0060] 2) The maximum nuclear enthalpy rise factor of the core is ≤1.48 and the maximum hot spot factor is ≤2.50 as the design criteria;

[0061] 3) Core moderator temperature coefficient ≤ 0pcm / ℃;

[0062] 4) The maximum fuel consumption value of the component is ≤52000MWd / tU.

[0063] According to the calculation results of the main core parameters in Table 2, it can be determined that the core parameters meet the design criteria requirements.

[0064] Furthermore, a core loading method for a 4000MW PWR with a first cycle of 18 months can be determined. Without changing the core size, annular fuel can be applied to a PWR core with 177 components. The core power is increased by 25% compared with the use of rod-shaped fuel, and the first cycle life reaches 18 months.

[0065] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for loading the core of a 4000MW pressurized water reactor for the first 18-month cycle, characterized in that: The core consists of 177 annular fuel assemblies, each with an enrichment of 4.1%, 4.25% or 4.45%, including: The annular fuel assemblies with the highest enrichment of 4.45% are placed outside the core. There are 88 annular fuel assemblies with an enrichment of 4.25% in total. The annular fuel assemblies with relatively low enrichment of 4.25% and the annular fuel assemblies with enrichment of 4.1% are arranged in a checkerboard pattern in the inner area of ​​the core, among which there are 68 groups of annular fuel assemblies with enrichment of 4.25% and 21 groups of annular fuel assemblies with enrichment of 4.1%.

2. The method for loading the core of a 4000MW pressurized water reactor for the first 18 months of the cycle according to claim 1, characterized in that: A portion of the annular fuel assemblies are provided with burnable poison rods, and the number of the burnable poison rods in each annular fuel assembly is 4, 8 or 12.

3. The method for loading the core of a 4000MW pressurized water reactor for the first 18 months of the cycle according to claim 2, characterized in that: The burnable poison rod adopts a gadolinium-loaded fuel rod, and the weight percentage of Gd2O3 in the gadolinium-loaded fuel rod is 8.0%.

4. The method for loading the core of a 4000MW pressurized water reactor for the first 18 months of the cycle according to claim 3, characterized in that: Gadolinium-loaded fuel rods 235 U enrichment is 2.5%.

5. The method for loading the core of a 4000MW pressurized water reactor for the first 18-month cycle according to claim 2, characterized in that: There are 40 groups of annular fuel assemblies with an enrichment of 4.45% and without burnable poison rods; There are 16 groups of annular fuel assemblies with an enrichment of 4.45% and 4 burnable poison rods; There are 20 groups of annular fuel assemblies with an enrichment of 4.45% and 8 burnable poison rods; There are 12 groups of annular fuel assemblies with an enrichment of 4.45% and 12 burnable poison rods.

6. The method for loading the core of a 4000MW pressurized water reactor for the first 18 months of the cycle according to claim 2, characterized in that: There are 4 groups of annular fuel assemblies with an enrichment of 4.25% and no burnable poison rods; There are 24 groups of annular fuel assemblies with an enrichment of 4.25% and 4 burnable poison rods; There are 40 groups of annular fuel assemblies with an enrichment of 4.25% and 12 burnable poison rods.

7. The method for loading the core of a 4000MW pressurized water reactor for the first 18-month cycle according to claim 2, characterized in that: There are 12 groups of annular fuel assemblies with an enrichment of 4.1% and 8 burnable poison rods; There are 9 groups of annular fuel assemblies with an enrichment degree of 4.1% and 12 burnable poison rods.

8. A 4000MW PWR core with a first cycle of 18 months, characterized in that: The method according to any one of claims 1 to 7 is used for loading.

Images