Method for configuring a pressurized water reactor with uranium-plutonium mixed fuel and stable plutonium isotope feedstock

Abstract

The present application relates to a kind of method and raw material of stable plutonium isotope raw material of configuration pressurized water reactor uranium-plutonium mixed fuel, which comprises the following steps: (1) equivalent 239 Pu ratio factor calculation;(2) raw material preparation: the raw material is divided into equivalent 239 Pu mass content less than target equivalent 239 Pu mass content P of raw material I, greater than target equivalent 239 Pu mass content P of raw material II two parts, respectively, carry out plutonium quality calculation and sorting;(3) first raw material selection and mixing: from raw material I and raw material II, the lowest and highest of plutonium quality, or close to average value preset number of raw material is selected respectively into A large tank, B large tank and fills up, respectively, from A large tank take out raw material, B large tank take out raw material and fill into product tank, so that the equivalent 239 Pu mass content is equal to target equivalent 239 Pu mass content P, obtain pressurized water reactor uranium-plutonium mixed fuel stable plutonium isotope raw material.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of manufacturing uranium-plutonium mixed fuel for pressurized water reactors, and particularly relates to a method for configuring stable plutonium isotope raw materials for uranium-plutonium mixed fuel for pressurized water reactors. BACKGROUND

[0002] China adopts a closed nuclear fuel cycle strategy, and through recycling of uranium-plutonium and minor actinides, uranium resources can be fully utilized, the amount of high-level waste can be reduced, the long-term radioactive hazard of nuclear waste can be reduced, and the sustainable development of nuclear energy can be ensured. The use of uranium-plutonium mixed fuel (MOX fuel) in pressurized water reactors is an important part of the closed nuclear fuel cycle and is also required by users of the third generation of pressurized water reactors.

[0003] According to the current procurement experience of UO2 fuel for pressurized water reactors, the nuclear power plant determines the type and quantity of new fuel assemblies used in subsequent cycle refueling through a fuel management report, so as to purchase corresponding fuel assemblies in advance from a fuel manufacturing plant. Similarly, for MOX fuel, the nuclear power plant needs to provide relevant parameters to the MOX fuel manufacturing plant, including the content of PuO2 in the MOX fuel, the isotope composition of Pu, the number of assemblies, etc.

[0004] The PuO2 raw material of the MOX fuel manufacturing plant is provided by a spent fuel reprocessing plant. The PuO2 raw material powder is basically stored and transported in the form of cups (kilogram level), and the isotope composition of the PuO2 powder in each cup may not be the same. Therefore, configuring MOX fuel with stable plutonium isotope composition and meeting the requirements of nuclear power plants is a technical difficulty in the process of manufacturing MOX fuel. SUMMARY

[0005] To solve the technical difficulties in the process of manufacturing MOX fuel, the purpose of the present application is to provide a method for configuring uranium-plutonium mixed fuel for pressurized water reactors and a spent fuel assembly. Through the method, the management of plutonium isotope composition can be realized, and uranium-plutonium mixed fuel for pressurized water reactors can be configured. 239 The method for configuring stable plutonium isotope raw materials for uranium-plutonium mixed fuel for pressurized water reactors comprises the following steps: 239 The quantity of Pu is as close as possible to the target value, so that all the raw materials in the library can be utilized as much as possible.

[0006] To achieve the above purpose, the method for configuring stable plutonium isotope raw materials for uranium-plutonium mixed fuel for pressurized water reactors comprises the following steps:

[0007] Step (1), equivalent 239 Pu ratio factor calculation, determine a set of reference plutonium isotope composition and target plutonium mass content, and calculate the equivalent 239 Pu ratio factor;

[0008] Step (2), raw material preparation, including the following steps:

[0009] A, the equivalent of all raw materials in the product library is calculated 239 Pu mass content is calculated and sorted, wherein the equivalent 239 Pu mass content = 239 Pu mass content + 241 Pu mass content × equivalent 239 Pu proportion factor, the user specifies the equivalent of uranium-plutonium mixed fuel 239 Pu mass content is the target equivalent 239 Pu mass content P, the raw materials are divided into two parts, the equivalent 239 Pu mass content is less than the target equivalent 239 Pu mass content P of raw material I, greater than the target equivalent 239 Pu mass content P of raw material II two parts;

[0010] B, the quality of plutonium of raw material I and raw material II is calculated and sorted respectively, wherein the quality of plutonium Q is 239 Pu and 241 The sum of the contents of Pu, respectively, the average value of the quality of plutonium Q I , the average value of the quality of plutonium Q II , Q I , Q II As a reference value when selecting raw materials;

[0011] Step (3), initial raw material selection and mixing, including the following steps:

[0012] A, from raw material I, select the lowest and highest quality of plutonium, or a preset number of single-cup raw materials close to the average value, and fill the A large tank, and select the lowest and highest quality of plutonium from raw material II, or a preset number of single-cup raw materials close to the average value, and fill the B large tank, so that the quality of the raw materials in the A large tank is close to the average value of the quality of plutonium Q I , the quality of the raw materials in the B large tank is close to the average value of the quality of plutonium Q II , wherein the mass of the raw material in the single cup is m, the capacity of the A large tank and the B large tank is n cups of raw material, and the total mass M of the A large tank and the B large tank is M = m*n;

[0013] B, respectively, the raw materials in the A large tank and the B large tank are taken out and filled into the product tank, so that the equivalent 239 Pu mass content is equal to the target equivalent 239 Pu mass content P, the total mass of the raw materials in the product tank is still M, and the stable plutonium isotope raw material of the pressurized water reactor uranium-plutonium mixed fuel is obtained.

[0014] Preferably, the equivalent239 The Pu ratio factor calculation specifically includes the following steps:

[0015] A. Determine the preset plutonium mass content of the uranium-plutonium mixed fuel assembly, which is generally proposed by the user;

[0016] B. Using the parameters of the fuel assembly and the core of the preset pressurized water reactor type, calculate the influence of the respective change of the plutonium odd-nucleus isotope mass content of the fuel assembly by the preset mass content on the effective multiplication factor k of the fuel assembly at the beginning of the life of the fuel assembly, to obtain the influence value of Pu on k at the beginning of the life of the fuel assembly, and the influence value of Pu on k at the beginning of the life of the fuel assembly, and according to the ratio of the two, equivalent Pu to Pu, to obtain the equivalent Pu ratio factor. eff 239 241 eff 241 239 239

[0017] Preferably, in step B of step (1), the respective change of the plutonium odd-nucleus isotope content of the fuel assembly by the preset mass content is 0.5-5%, -0.5--5%.

[0018] Preferably, the specific method of step B in step (1) is as follows:

[0019] Using the parameters of the fuel assembly and the core of the preset pressurized water reactor type, calculate the influence of the respective change of the plutonium odd-nucleus isotope content of the fuel assembly by the preset mass content on the effective multiplication factor k of the fuel assembly, and calculate eff 239 241 239 eff 241 eff 239 241 239 241 eff 241 239 ​​​​​​​​​​​​​​​​​​​​Pu, get equivalent 239 Pu ratio factor, i.e. equivalent 239 Pu ratio factor = 241 Pu's impact on k of fuel assembly at the beginning of life eff numerical value 239 Pu's impact on k of fuel assembly at the beginning of life eff numerical value.

[0020] Preferably, the specific method of step A in step (3) is as follows:

[0021] Select [n / 2] cups of raw materials with the smallest quality of plutonium in order from small to large from raw materials I, wherein [*] is a rounding down operator, and then select [n / 2] cups of raw materials with the largest quality of plutonium in order from large to small from raw materials I, if n is odd, then select 1 cup of raw materials closest to Q I , a total of n cups of raw materials, and get the isotopic mass content after mixing and equivalent 239 Pu mass content LP1 by mass average calculation, and load into A large tank for uniform mixing (the capacity of A large tank is n cups of raw materials, and the total mass M is M = m*n); select [n / 2] cups of raw materials with the smallest quality of plutonium in order from small to large from raw materials II, and then select [n / 2] cups of raw materials with the largest quality of plutonium in order from large to small from raw materials II, if n is odd, then select 1 cup of raw materials closest to Q II , a total of n cups of raw materials, and get the isotopic mass content after mixing and equivalent 239 Pu mass content HP1 by mass average calculation, and load into B large tank for uniform mixing.

[0022] Preferably, in step A in step (3), LP1 239 Pu mass content LP1 in A large tank or the equivalent 239 Pu mass content HP1 in B large tank is very close to the target equivalent 239 Pu mass content P, i.e. (P-LP1) / (HP1-LP1) < 1 / n or (HP1-P) / (HP1-LP1) < 1 / n, raw material selection needs to be re-performed.

[0023] Preferably, in step B in step (3), the specific method of loading raw materials from A large tank and B large tank into product tank is as follows:

[0024] The mass LW of raw materials taken out from A large tank required for the target value of equivalent 239 Pu mass content can be obtained by solving the following binary linear equation set iAnd the mass HW of raw materials taken out from tank B i The system of equations is as follows:

[0025] LW i *LP i +HW i *HP i =P*M、

[0026] LW i +HW i =M,

[0027] Where i = 1, LP i The equivalent of removing raw materials from tank A 239 PU mass content, HP i Equivalent to removing raw materials from tank B 239 Pu quality content;

[0028] Based on the mass LW1 of raw material taken from tank A and the mass HW1 of raw material taken from tank B obtained above, the corresponding mass of raw material powder is loaded into product tank N1. The equivalent mass of raw material powder in product tank N1 is... 239 Pu mass content equals target equivalent 239 Pu mass content P.

[0029] Preferably, step (3) is followed by:

[0030] Step (4), subsequent raw material selection and mixing, includes the following steps:

[0031] A. From the remaining raw material I, select a predetermined number of single-cup raw materials with the lowest and highest quality plutonium, or those close to the average quality, and fill container A as close to full as possible. From the remaining raw material II, select a predetermined number of single-cup raw materials with the lowest and highest quality plutonium, or those close to the average quality, and fill container B as close to full as possible. This ensures that the quality of the raw materials in container A is close to the average quality Q of plutonium in raw material I. I The quality of the raw materials in tank B is close to the average quality Q of plutonium in raw material II. II .

[0032] B. Take raw materials from tank A and tank B respectively, and load them into the product tanks, so that the equivalent amount in the product tanks... 239 Pu mass content equals target equivalent 239 The mass content of Pu is P, and the total mass of raw materials in the product tank is still M, thus obtaining an equivalent mass. 239 Raw materials with consistent Pu content are used to manufacture uranium-plutonium mixed fuels.

[0033] Preferably, step (4) is followed by:

[0034] After step (5) continues, the subsequent raw material selection and mixing are repeated for a predetermined number of times of step (4) to obtain the equivalent 239 The raw materials with the same Pu mass content are used to manufacture the uranium-plutonium mixed fuel.

[0035] Preferably, the specific method of step A in step (4) is as follows:

[0036] The mass of the remaining powder in the A large tank is MA1-LW1, and the mass of the remaining powder in the B large tank is MB1-HW1, where MA1 is the total mass of the powder in the A large tank before reduction, MB1 is the total mass of the powder in the B large tank before reduction, LW1 is the mass of the raw material taken out from the A large tank, and HW1 is the mass of the raw material taken out from the B large tank. M-(MA1-LW1) and M-(MB1-HW1) are divided by m and rounded to a1 and b1, respectively. MA2=(MA1-LW1)+m*a1 and MB2=(MB1-HW1)+m*b1, where MA2 is the mass of the A large tank after refilling, and MB2 is the mass of the B large tank after refilling.

[0037] From the remaining raw material I, [a1 / 2] cups of raw material with the smallest plutonium quality are selected in order from small to large, where [ ] is a rounding-down operator. From the remaining raw material I, [a1 / 2] cups of raw material with the largest plutonium quality are selected in order from large to small. If a1 is odd, 1 cup of raw material closest to Q I is selected. A total of a1 cups of raw material are loaded into the A large tank. The equivalent 239 Pu mass content LP2 of the isotopic composition after refilling in the A large tank is calculated by mass average. From the remaining raw material II, [b1 / 2] cups of raw material with the smallest plutonium quality are selected in order from small to large. From the remaining raw material II, [b1 / 2] cups of raw material with the largest plutonium quality are selected in order from large to small. If b1 is odd, 1 cup of raw material closest to Q II is selected. A total of b1 cups of raw material are loaded into the B large tank. The equivalent 239 Pu mass content HP2 of the isotopic composition after refilling in the B large tank is calculated by mass average.

[0038]

[0039]

[0040] where P i is the equivalent 239 Pu mass content of each cup of raw material. When the equivalent 239 Pu mass content LP2 of the isotopic composition after refilling in the A large tank or the equivalent239 The mass content of Pu in HP2 has a value that is equivalent to the target. 239 When the Pu mass content P values ​​are very close, i.e. (P-LP2) / (HP2-LP2)<1 / n or (HP2-P) / (HP2-LP2)<1 / n, the raw material selection needs to be redone.

[0041] Preferably, the specific method of step B in step (4) is as follows:

[0042] Based on the equivalent of the isotopic composition after remixing in tank A 239 The equivalent mass content of Pu (LP2) and the isotopic composition after remixing in the B tank 239 The mass content of Pu, HP2, can be obtained by solving the following system of two linear equations in two variables. 239 The target Pu mass content value requires the removal of raw material LW from tank A again. i The mass HW of the raw material was taken out again from tank B. i The system of equations is as follows:

[0043] LW i *LP i +HW i *HP i =P*M、

[0044] LW i +HW i =M,

[0045] At this point, i = 2. Based on the above, the mass LW of raw material taken out from tank A again is... i The mass HW of the raw material was taken out again from tank B. i The appropriate mass of powder is loaded into product container N2, and the equivalent mass of powder in product container N2 is... 239 Pu mass content equals target equivalent 239 Pu mass content P.

[0046] Repeat step (4) n times to finally obtain N. n+2 Raw materials for a product tank that meet the target value.

[0047] The present invention also provides a stable plutonium isotope material for pressurized water reactor uranium-plutonium mixed fuel, which is a stable plutonium isotope material for pressurized water reactor uranium-plutonium mixed fuel obtained by the above method.

[0048] This invention targets uranium-plutonium mixed fuels suitable for pressurized water reactors. It utilizes two characteristic parameters of the raw materials to combine and proportion them to obtain a final homogeneous product, which can make the most of all the raw materials in the product library.

[0049] The method for stabilizing plutonium isotope raw materials by configuring uranium-plutonium mixed fuel for pressurized water reactors as described in this invention has the following significant technical effects:

[0050] This invention configures an equivalent [structure / equivalence] by managing the plutonium isotope composition in two stages. 239 Multiple containers of raw materials with consistent plutonium content and stable plutonium quality are used to manufacture uranium-plutonium blended fuels for pressurized water reactors. This configuration method is not limited by mixing capacity and does not require equivalent raw materials. 239 The amount of Pu should be as close as possible to the target value, so that all the raw materials in the warehouse can be utilized to the fullest extent. Attached Figure Description

[0051] Figure 1 The effective multiplication factor k of the two MOX components generated by the method for configuring uranium-plutonium mixed fuel for pressurized water reactors to stabilize plutonium isotope feedstock in Example 2 is used to configure the MOX components. eff A comparison chart of the calculation results;

[0052] Figure 2 This is a flowchart of the method for stabilizing plutonium isotope raw materials in a pressurized water reactor using a uranium-plutonium mixed fuel in Example 2. Detailed Implementation

[0053] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0054] Example 1

[0055] This embodiment provides a method for configuring a stable plutonium isotope feedstock for a pressurized water reactor uranium-plutonium mixed fuel, the method comprising the following steps:

[0056] Step (1), equivalent 239 Calculation of Pu scaling factor;

[0057] Step (2), raw material preparation, includes the following steps:

[0058] A. Perform equivalent analysis on all raw materials in the product database. 239 The Pu mass content was calculated and sorted, among which the equivalent 239 Pu mass content = 239 Pu quality content + 241 Pu mass content × equivalent 239 Pu scaling factor, specifying the equivalent of uranium-plutonium mixed fuel. 239 The target equivalent of Pu mass content 239 Pu mass content P, the raw materials are divided into equivalent 239 The Pu mass content is less than the target equivalent 239 The raw material I with a Pu mass content P is greater than the target equivalent. 239The raw material II consists of two parts, Pu mass content P;

[0059] B. Calculate and rank the plutonium quality of raw materials I and II respectively, where the plutonium quality Q is... 239 Pu and 241 The sum of the Pu contents yields the average quality Q of plutonium in raw material I. I The average quality Q of plutonium in raw material II II ;

[0060] Step (3), initial raw material selection and mixing, includes the following steps:

[0061] A. Select a predetermined number of single cups of plutonium with the lowest and highest quality, or close to the average quality, from raw material I and fill large container A. Select a predetermined number of single cups of plutonium with the lowest and highest quality, or close to the average quality, from raw material II and fill large container B. The mass of the raw material in each cup is m. The capacity of large container A and large container B is n cups of raw material. The total mass M of large container A and large container B is M = m * n.

[0062] B. Take raw materials from tank A and tank B respectively, and load them into the product tanks, so that the equivalent amount in the product tanks... 239 Pu mass content equals target equivalent 239 With a Pu mass content of P, and the total mass of raw materials in the product tank remaining at M, a uranium-plutonium mixed fuel for pressurized water reactors with a stable plutonium isotope composition is obtained.

[0063] This embodiment configures an equivalent [structure / equivalence] by managing the plutonium isotope composition in two stages. 239 Multiple containers of raw materials with consistent plutonium content and stable plutonium quality are used to manufacture uranium-plutonium blended fuels for pressurized water reactors. This configuration method is not limited by mixing capacity and does not require equivalent raw materials. 239 The amount of Pu should be as close as possible to the target value, so that all the raw materials in the warehouse can be utilized to the fullest extent.

[0064] Example 2

[0065] like Figure 2 As shown in the figure, this embodiment provides a method for stabilizing plutonium isotope raw materials in pressurized water reactor uranium-plutonium mixed fuel, as described in detail below:

[0066] Step (1), equivalent 239 Pu scaling factor calculation determines the composition of a set of reference plutonium isotopes and the target plutonium mass content, and calculates the equivalent... 239 Pu scaling factor, equivalent 239 The calculation of the Pu scaling factor includes the following steps:

[0067] A. Determine the preset plutonium mass content of the uranium-plutonium mixed fuel assembly. This plutonium mass content is generally proposed by the user. Assume that the preset plutonium mass content is 8.1%.

[0068] B. Using the parameters of the fuel assemblies and core of a pre-defined pressurized water reactor type, calculate the effect of a 1% change in the mass content of odd-numbered plutonium nuclei in the fuel assemblies on the effective multiplication factor k of the fuel assemblies. eff The impact, received 239 Pu、 241 Pu respectively tested the fuel assembly at the beginning of its lifespan. eff The impact value, based on the ratio of the two, will 241 Pu is equivalent to 239 Pu, obtained equivalent 239 The Pu scaling factor is as follows:

[0069] Using parameters of the fuel assemblies and core of a pre-defined pressurized water reactor type, the effective multiplication factor k of the fuel assembly was calculated based on the change in plutonium odd-number nuclear isotope content of the fuel assembly by 1% of the pre-defined mass content. eff The impact, during calculation, 239 The Pu isotope mass content was reduced by 1% and increased by 1% respectively, according to the preset mass content. 241 The mass content of Pu isotopes is reduced by 1% and increased by 1% respectively, while the mass content of other isotopes remains numerically unchanged. Then, the mass content of Pu isotopes is reduced by 1% and increased by 1% respectively. 239 The initial lifespan of the fuel assembly is affected by the decrease of the pre-set mass content by 1% and the increase of the pre-set mass content of Pu isotopes. eff The first average of the absolute values ​​of the changes is taken. 241 The initial lifespan of the fuel assembly is affected by the decrease of the pre-set mass content by 1% and the increase of the pre-set mass content of Pu isotopes. eff The second average of the absolute values ​​of the changes, to eliminate 239 Pu、 241 The variation in Pu isotope content is influenced by the changes in other isotope content due to normalization, ultimately yielding... 239 Pu、 241 Pu respectively tested the fuel assembly at the beginning of its lifespan. eff The impact value, based on the ratio of the two, will 241 Pu is equivalent to 239 Pu, obtained equivalent 239 Pu scaling factor, i.e., equivalent 239 Pu proportional factor = 241 Pu at the beginning of fuel assembly lifespan eff Impact value / 239 Pu at the beginning of fuel assembly lifespan eff The numerical impact value.

[0070] Preferably, the plutonium odd-number nuclear isotope content of the fuel assembly varies by a preset mass content of 0.5-5% and -0.5--5%, respectively.

[0071] Specifically, in this embodiment, using the fuel assembly and core parameters of a preset pressurized water reactor type, a fuel assembly calculation program is used to calculate the fuel assembly. With a plutonium mass content of 8.1%, the odd-numbered plutonium isotopes of the fuel assembly are calculated. 239 Pu、 241 The effective proliferation factor k of fuel assembly is affected by changes in Pu mass content and a preset mass content of 1%. eff The impact, received 239 Pu、 241 Pu respectively tested the fuel assembly at the beginning of its lifespan. eff The influence values ​​are calculated, and the results are shown in Table 1.

[0072] Table 1. Initial k of fuel assembly lifespan eff Calculation results

[0073]

[0074] 241 Pu at the beginning of component lifespan eff The impact value is 670.5. 39 Pu at the beginning of component lifespan eff The influence value is 259. Based on the ratio of the two, 241 Pu is equivalent to 239 Pu, obtained equivalent 239 Pu ratio factor.

[0075] Therefore, equivalent 239 Pu proportional factor = 241 Pu at the beginning of component lifespan eff Impact value / 239 Pu at the beginning of component lifespan eff The impact value is 2.59.

[0076] Step (2), raw material preparation, includes the following steps:

[0077] A. This embodiment assumes that the reprocessed products of spent fuel assemblies containing different enrichment levels (1.8%–4.95%), different unloading fuel consumption, and different cooling times (10–25 years) are used as the raw material library, and that all raw materials in the product library are equivalently processed. 239 The Pu mass content was calculated and sorted, among which the equivalent 239 Pu mass content = 239 Pu quality content + 241 Pu mass content × equivalent 239The Pu ratio factor is typically specified by the user as the equivalent of uranium-plutonium blended fuel. 239 The target equivalent of Pu mass content 239 Pu mass content P, assuming target equivalence 239 Pu mass content P = 0.8, the raw materials are divided into equivalent 239 The raw material consists of two parts: raw material I with a Pu content of less than 0.8% and raw material II with a Pu content of more than 0.8%.

[0078] B. First, determine a set of reference plutonium isotope compositions. Taking the average burnup of spent fuel assemblies with a certain initial enrichment level in domestic pressurized water reactors as an example, the isotopic composition of plutonium after 15 years of cooling is also assumed. 241 The Am content is 1.3%, and the isotopic composition is shown in Table 2. The quality Q of plutonium is... 239 Pu and 241 The sum of the contents of Pu.

[0079] Table 2. Plutonium isotopic composition, %

[0080]

[0081] The plutonium quality of raw material I and raw material II were calculated and ranked separately to obtain the average plutonium quality Q of raw material I. I =0.673 and the average quality of plutonium in feedstock II, Q II =0.715, Q I and Q II As a reference value when selecting raw materials, the final plutonium quality of raw materials I and II is shown in Table 3 and Table 4, respectively. The contents of the tables only show the raw materials selected and used later and omit the plutonium isotope information.

[0082] Table 3. Quality of plutonium in Raw Material I and Raw Material Selection

[0083]

[0084]

[0085]

[0086] Table 4. Plutonium quality and raw material selection for Raw Material II

[0087]

[0088]

[0089] Step (3), initial raw material selection and mixing, includes the following steps:

[0090] A. Select a predetermined number of single cups of plutonium with the lowest and highest quality, or close to the average quality, from raw material I and fill container A. Similarly, select a predetermined number of single cups of plutonium with the lowest and highest quality, or close to the average quality, from raw material II and fill container B. This ensures that the quality of the raw materials in container A is close to the average quality Q of the plutonium in raw material I. I The quality of the raw materials in tank B is close to the average quality Q of plutonium in raw material II. II In this context, the mass of raw material in a single cup is m, and the capacity of both large container A and large container B is n cups of raw material. The total mass M of both large containers A and B is M = m * n. Details are as follows:

[0091] From raw material I, select [n / 2] cups of raw material with the smallest plutonium mass (each cup has a mass of m) in ascending order of plutonium mass, where [*] is the floor operator. Then, from raw material I, select [n / 2] cups of raw material with the largest plutonium mass in descending order of plutonium mass. If n is odd, select the cup closest to Q. I Using a total of n cups of raw materials, the isotopic mass content and equivalent mass of the mixture are calculated by mass averaging. 239 The Pu mass content is LP1, and it is put into large container A for uniform mixing (the capacity of large container A is n cups of raw materials, and the total mass M is M = m * n); from raw material II, select the raw material with the smallest mass [n / 2] cups in order of plutonium mass from smallest to largest, and then select the raw material with the largest mass [n / 2] cups in order of plutonium mass from largest to smallest. If n is odd, then select 1 cup that is closest to Q. II Using a total of n cups of raw materials, the isotopic mass content and equivalent mass of the mixture are calculated by mass averaging. 239 The PU mass content is HP1, and it is put into large tank B for uniform mixing.

[0092] Preferably, LP1 < P < HP1, when the equivalent of the raw materials in tank A is... 239 The equivalent of the raw materials in the LP1 or B tank of Pu mass content 239 The mass content of Pu, HP1, has a value that is equivalent to the target distance. 239 When the Pu mass content P values ​​are very close, i.e. (P-LP1) / (HP1-LP1)<1 / n or (HP1-P) / (HP1-LP1)<1 / n, the raw material selection needs to be redone.

[0093] Specifically, in this embodiment, the 10 cups of raw material with the lowest and highest plutonium quality from each of raw material I are selected and filled into large container A (corresponding to the highest and lowest quality plutonium in raw material I). Similarly, the 10 cups of raw material with the lowest and highest plutonium quality from each of raw material II are selected and filled into large container B (corresponding to the highest and lowest quality plutonium in raw material II). The selection of raw materials is shown in Tables 3 and 4, ensuring that the quality of the raw materials in large container A is close to the average plutonium quality Q of raw material I. I The quality of the raw materials in tank B is close to the average quality Q of plutonium in raw material II. II The raw material has a single cup mass m of 1 kg. Both large containers A and B can hold 20 cups of raw material, with a total mass M of M = 20 kg for both. After mixing, the equivalent mass of container A is... 239 Pu mass content LP1 = 0.757, equivalent to tank B. 239 Pu mass content LP2 = 0.842;

[0094] B. Take raw materials from tank A and tank B respectively, and load them into the product tanks, so that the equivalent amount in the product tanks... 239 Pu mass content equals target equivalent 239 With a Pu mass content of P, and the total mass of raw materials in the product tank remaining at M, a uranium-plutonium mixed fuel for pressurized water reactors with a stable plutonium isotope composition is obtained.

[0095] Specifically, in this embodiment, the equivalent solution can be obtained by solving the following system of two linear equations in two variables. 239 The required mass (LW) of raw material taken from tank A to achieve the target Pu mass content value i And the mass HW of raw materials taken out from tank B i The system of equations is as follows:

[0096] LW i *LP i +HW i *HP i =P*M;

[0097] LW i +HW i =M.

[0098] At this time, i = 1, LP i The equivalent of removing raw materials from tank A 239 PU mass content, HP i Equivalent to removing raw materials from tank B 239 Pu mass content; that is, the mass of raw material taken from tank A, LW1 = 9.87, and the mass of raw material taken from tank B, HW1 = 10.13.

[0099] 9.87 kg of powder from container A and 10.13 kg of powder from container B were respectively loaded into product container N1. The equivalent amount in N1... 239 The Pu mass content is equal to the target value of 0.8.

[0100] Step (4), further selection and mixing of raw materials, including the following steps:

[0101] A. From the remaining raw material I, select a predetermined number of single-cup raw materials with the lowest and highest quality plutonium, or those close to the average quality, and fill container A as close to full as possible. From the remaining raw material II, select a predetermined number of single-cup raw materials with the lowest and highest quality plutonium, or those close to the average quality, and fill container B as close to full as possible. This ensures that the quality of the raw materials in container A is close to the average quality Q of plutonium in raw material I. I The quality of the raw materials in tank B is close to the average quality Q of plutonium in raw material II. II The details are as follows:

[0102] The remaining powder mass in tank A is MA1-LW1 = 10.13 kg, and the remaining powder mass in tank B is MB1-HW1 = 9.87 kg. Here, MA1 is the total mass of powder in tank A before reduction, MB1 is the total mass of powder in tank B before reduction, LW1 is the mass of raw material I removed from tank A, and HW1 is the mass of raw material II removed from tank B. MA1 = 20.0 kg, MB1 = 20.0 kg, M-(MA1-LW1) = 9.87 kg, M-(MB1-HW1) = 10.13 kg. Dividing M-(MA1-LW1) and M-(MB1-HW1) by m and rounding them down, we get a1 and b1 respectively. That is, dividing 9.87 and 10.13 by 1 and rounding them down, we get a1 = 9 and b1 = 10. Let MA2 = (MA1 - LW1) + m * a1, MB2 = (MB1 - HW1) + m * b1, where MA2 is the mass of tank A after refilling, and MB2 is the mass of tank B after refilling.

[0103] From the remaining raw material I, select the material with the smallest plutonium mass in ascending order of plutonium mass, using the [a1 / 2] cup. [*] represents the floor operator. Then, from the remaining raw material I, select the material with the largest plutonium mass in descending order of plutonium mass, using the [a1 / 2] cup. If a1 is odd, select the cup closest to Q. I The raw materials were selected, and a total of a1 cups of raw materials were placed into container A. The equivalent isotopic composition of the remixed raw materials in container A was calculated by mass averaging. 239Pu mass content LP2; From the remaining raw material II, select the raw material with the smallest [b1 / 2] cup mass in order of plutonium mass from smallest to largest, and then select the raw material with the largest [b1 / 2] cup mass in order of plutonium mass from largest to smallest. If b1 is odd, then select the 1st cup closest to Q. II The raw materials, totaling b1 cup raw materials, were loaded into container B. The equivalent isotopic composition of the remixed raw materials in container B was calculated by mass averaging. 239 The mass content of Pu is HP2, of which...

[0104]

[0105]

[0106] Where P i For the equivalent of each cup of ingredients 239 Pu mass content, the equivalent of the isotopic composition after remixing in tank A. 239 The equivalent of the isotopic composition after remixing in the Pu mass content LP2 or B large tank 239 The mass content of Pu in HP2 has a value that is equivalent to the target. 239 When the Pu mass content P values ​​are very close, i.e. (P-LP2) / (HP2-LP2)<1 / n or (HP2-P) / (HP2-LP2)<1 / n, the raw material selection needs to be redone.

[0107] Specifically, in this embodiment, four cups of plutonium with the lowest mass are selected from the remaining raw material I, four cups of plutonium with the highest mass are selected from raw material I, and one cup of plutonium with a mass close to Q is selected. I Nine cups of raw materials were selected and placed into container A, as shown in Table 3. The mass of container A at this time was MA2 = 19.13 kg. The equivalent mass of container A was calculated according to Formula 1. 239 Pu mass content LP2 = 0.758; select 5 cups of raw material with the lowest plutonium mass from raw material II, and then select 5 cups of raw material with the highest plutonium mass from the remaining raw material II, for a total of 10 cups of raw material, and fill them into large container B, as shown in Table 4. The mass of large container B at this time is MB2 = 19.87 kg. The equivalent mass of large container B is calculated according to formula 2. 239 Pu mass content HP2 = 0.841.

[0108] B. Take raw materials from tank A and tank B respectively, and load them into the product tanks, so that the equivalent amount in the product tanks... 239 Pu mass content equals target equivalent 239 The mass content of Pu is P, and the total mass of raw materials in the product tank is still M, thus obtaining an equivalent mass. 239Raw materials with consistent Pu content are used to manufacture uranium-plutonium blended fuels. Details are as follows:

[0109] Based on the equivalent of the isotopic composition after remixing in tank A 239 The equivalent mass content of Pu (LP2) and the isotopic composition after remixing in the B tank 239 The mass content of Pu, HP2, can be obtained by solving the following system of two linear equations in two variables. 239 The target Pu mass content value requires the removal of raw material LW from tank A again. i The mass HW of the raw material was taken out again from tank B. i The system of equations is as follows:

[0110] LW i *LP i +HW i *HP i =P*M、

[0111] LW i +HW i =M,

[0112] Based on the above, the mass LW of raw materials removed from tank A again i The mass HW of the raw material was taken out again from tank B. i The appropriate mass of powder is loaded into product container N2, and the equivalent mass of powder in product container N2 is... 239 Pu mass content equals target equivalent 239 Pu mass content P.

[0113] Specifically, the equivalent of the target can be obtained by solving the following system of two linear equations in two variables. 239 The required mass of raw material to be removed from tank A (LW2 = 9.84 kg) and from tank B (HW2 = 10.16 kg) to achieve the required Pu mass content P is determined by the following steps: 9.84 kg of powder from tank A and 10.16 kg of powder from tank B are respectively loaded into product container N2. The equivalent mass of powder in N2 is... 239 The Pu mass content is equal to the target value of 0.8.

[0114] (5) Repeat step (4) n times to finally obtain N. n+2 The raw materials for the product tanks that meet the target values. Specifically, in this embodiment, the subsequent raw material selection and mixing are carried out, and step (4) is repeated 4 times. The raw material selection is shown in Tables 3 and 4. Product tanks N3, N4, N5, and N6 are obtained in sequence. Assuming that 3 product tanks are needed to produce one MOX component, then 6 product tanks can produce 2 MOX components, that is, N1 to N3 and N4 to N6 each produce one MOX component. The final quality of the 6 product tanks and MOX components is shown in Table 5. The plutonium isotope information is omitted in the table.

[0115] Table 5 Quality of Product Tanks and Components

[0116]

[0117] The method described in this embodiment is a method for stabilizing plutonium isotope raw materials in pressurized water reactor uranium-plutonium mixed fuel.

[0118] This embodiment also provides a stable plutonium isotope material for pressurized water reactor uranium-plutonium mixed fuel, which is a stable plutonium isotope material for pressurized water reactor uranium-plutonium mixed fuel obtained by the above method.

[0119] The above results show that MOX component 1 and MOX component 2 are equivalent. 239 The plutonium mass content was the target value of 0.8 in both cases, with very little difference in plutonium quality and relatively stable isotopic composition. Component calculations were performed on the two MOX components to obtain component k. eff The results, which vary with fuel consumption, further validate the effectiveness of this method. The calculation results are as follows: Figure 1 As shown in the figure, the calculation results show that k of the two components eff The differences are small, with a relative deviation of approximately 0.33%. The main reason for this deviation is the asymmetrical distribution of the raw material samples. MOX fuel, compared to UO2 fuel, does not exhibit any of the characteristics found in its manufacturing process. 235 The uncertainty of U enrichment, typically UO2 fuel has an enrichment uncertainty of 0.5 wt%, compared to the nominal enrichment, the component's k eff There will be some deviation, calculated as 4.45%. 235 The components of U-enrichment, the k generated by enrichment uncertainty eff The deviation is around 0.25%, which shows that the deviation caused by the plutonium isotope composition of MOX fuel is comparable to this and is within an acceptable range.

[0120] This embodiment is for uranium-plutonium mixed fuel suitable for pressurized water reactors. It uses two characteristic parameters of the raw materials to match and proportion them to obtain the final homogeneous product, which can make full use of all the raw materials in the product library.

[0121] This embodiment configures an equivalent [structure / equivalence] by managing the plutonium isotope composition in two stages. 239 Multiple containers of raw materials with consistent plutonium content and stable plutonium quality are used to manufacture uranium-plutonium blended fuels for pressurized water reactors. This configuration method is not limited by mixing capacity and does not require equivalent raw materials. 239 The amount of Pu should be as close as possible to the target value, so that all the raw materials in the warehouse can be utilized to the fullest extent.

[0122] Example 3

[0123] This embodiment provides a method for configuring uranium-plutonium mixed fuel for pressurized water reactors to stabilize plutonium isotope raw materials. The difference between this method and the method for configuring uranium-plutonium mixed fuel for pressurized water reactors in Embodiment 2 is as follows:

[0124] In step (1), the plutonium odd-number nuclear isotope content of the fuel assembly in step B changes by a preset mass content of +0.5% and -0.5%, respectively.

[0125] This embodiment configures an equivalent [structure / equivalence] by managing the plutonium isotope composition in two stages. 239 Multiple containers of raw materials with consistent plutonium content and stable plutonium quality are used to manufacture uranium-plutonium blended fuels for pressurized water reactors. This configuration method is not limited by mixing capacity and does not require equivalent raw materials. 239 The amount of Pu should be as close as possible to the target value, so that all the raw materials in the warehouse can be utilized to the fullest extent.

[0126] Example 4

[0127] This embodiment provides a method for configuring uranium-plutonium mixed fuel for pressurized water reactors to stabilize plutonium isotope raw materials. The difference between this method and the method for configuring uranium-plutonium mixed fuel for pressurized water reactors in Embodiment 2 is as follows:

[0128] In step (1), the plutonium odd-number nuclear isotope content of the fuel assembly in step B changes by a preset mass content of +5% and -5%, respectively.

[0129] This embodiment configures an equivalent [structure / equivalence] by managing the plutonium isotope composition in two stages. 239 Multiple containers of raw materials with consistent plutonium content and stable plutonium quality are used to manufacture uranium-plutonium blended fuels for pressurized water reactors. This configuration method is not limited by mixing capacity and does not require equivalent raw materials. 239 The amount of Pu should be as close as possible to the target value, so that all the raw materials in the warehouse can be utilized to the fullest extent.

[0130] The above embodiments are merely illustrative examples of the present invention. The present invention may also be implemented in other specific ways or forms without departing from its spirit or essential characteristics. Therefore, the described embodiments should be considered illustrative rather than limiting in any respect. The scope of the present invention should be defined by the appended claims, and any variations equivalent to the intent and scope of the claims should also be included within the scope of the present invention.

Claims

1. A method for preparing stable plutonium isotope feedstock for pressurized water reactor uranium-plutonium mixed fuel, characterized in that, The method includes the following steps: Step (1), equivalent 239 Calculation of Pu scaling factor; Step (2), raw material preparation, includes the following steps: A. Perform equivalent analysis on all raw materials in the product database. 239 The Pu mass content was calculated and sorted, among which the equivalent 239 Pu mass content = 239 Pu quality content + 241 Pu mass content × equivalent 239 Pu scaling factor, specifying the equivalent of uranium-plutonium mixed fuel. 239 The target equivalent of Pu mass content 239 Pu mass content P, the raw materials are divided into equivalent 239 The Pu mass content is less than the target equivalent 239 The raw material I with a Pu mass content P is greater than the target equivalent. 239 The raw material II consists of two parts, Pu mass content P; B. Calculate and rank the plutonium quality of raw materials I and II respectively, where the plutonium quality Q is... 239 Pu and 241 The sum of the Pu contents yields the average quality Q of plutonium in raw material I. I The average quality Q of plutonium in raw material II II ; Step (3), initial raw material selection and mixing, includes the following steps: A. Select a predetermined number of single cups of plutonium with the lowest and highest quality, or close to the average quality, from raw material I and fill large container A. Select a predetermined number of single cups of plutonium with the lowest and highest quality, or close to the average quality, from raw material II and fill large container B. The mass of the raw material in each cup is m. The capacity of large container A and large container B is n cups of raw material. The total mass M of large container A and large container B is M = m * n. B. Take raw materials from tank A and tank B respectively, and load them into the product tanks, so that the equivalent amount in the product tanks... 239 Pu mass content equals target equivalent 239 With a Pu mass content of P, and the total mass of raw materials in the product tank remaining at M, stable plutonium isotope raw materials for pressurized water reactor uranium-plutonium mixed fuel are obtained.

2. The method for stabilizing plutonium isotope raw materials for pressurized water reactor uranium-plutonium mixed fuel according to claim 1, characterized in that, The equivalent of step (1) 239 The calculation of the Pu scaling factor includes the following steps: A. Determine the preset plutonium mass content of the uranium-plutonium mixed fuel assembly; B. Using the parameters of the fuel assemblies and core of a pre-defined pressurized water reactor type, calculate the effect of changes in the plutonium odd-number nuclear isotope mass content of the fuel assemblies on the effective multiplication factor k of the fuel assemblies, based on the pre-defined mass content. eff The impact, received 239 Pu、 241 Pu respectively tested the fuel assembly at the beginning of its lifespan. eff The impact value, based on the ratio of the two, will 241 Pu is equivalent to 239 Pu, obtained equivalent 239 Pu proportional factor.

3. The method for stabilizing plutonium isotope raw materials for pressurized water reactor uranium-plutonium mixed fuel according to claim 2, characterized in that, In step B of step (1), the plutonium odd-number nuclear isotope content of the fuel assembly is changed by preset mass content of 0.5-5% and -0.5--5%, respectively.

4. The method for stabilizing plutonium isotope raw materials for pressurized water reactor uranium-plutonium mixed fuel according to claim 2, characterized in that, The specific method of step B in step (1) is as follows: Using parameters of the fuel assemblies and core of a pre-defined pressurized water reactor type, the effects of changes in the plutonium odd-number nuclear isotope content of the fuel assemblies and the pre-defined mass content on the effective multiplication factor k of the fuel assemblies were calculated. eff The impact, during calculation, 239 The Pu isotope mass content was reduced by decreasing the preset mass content and increased by increasing the preset mass content, respectively. 241 The mass content of Pu isotopes was reduced by a preset mass content and increased by a preset mass content, respectively, while the mass contents of other isotopes remained numerically unchanged. Then, the mass contents were taken as follows: 239 The initial lifespan of the fuel assembly is affected by both decreasing and increasing the pre-set mass content of Pu isotopes. eff The first average of the absolute values ​​of the changes is taken. 241 The initial lifespan of the fuel assembly is affected by both decreasing and increasing the pre-set mass content of Pu isotopes. eff The second average of the absolute values ​​of the changes is finally obtained. 239 Pu、 241 Pu respectively tested the fuel assembly at the beginning of its lifespan. eff The impact value, based on the ratio of the two, will 241 Pu is equivalent to 239 Pu, obtained equivalent 239 Pu scaling factor, i.e., equivalent 239 Pu proportional factor = 241 Pu at the beginning of fuel assembly lifespan eff Impact value / 239 Pu at the beginning of fuel assembly lifespan eff The numerical impact value.

5. The method for stabilizing plutonium isotope raw materials for pressurized water reactor uranium-plutonium mixed fuel according to claim 1, characterized in that, The specific method of step A in step (3) is as follows: From raw material I, select the material with the smallest plutonium mass in ascending order of quality, using [n / 2] cups. Here, [*] represents the floor operator. Then, from raw material I, select the material with the largest plutonium mass in descending order of quality, using [n / 2] cups. If n is odd, select the cup closest to Q. I Using a total of n cups of raw materials, the isotopic mass content and equivalent mass of the mixture are calculated by mass averaging. 239 The Pu mass content is LP1, and it is put into large container A for uniform mixing; from raw material II, select the raw material with the smallest mass [n / 2] cup in order of plutonium mass from smallest to largest, and then select the raw material with the largest mass [n / 2] cup in order of plutonium mass from largest to smallest. If n is odd, then select 1 cup that is closest to Q. II Using a total of n cups of raw materials, the isotopic mass content and equivalent mass of the mixture are calculated by mass averaging. 239 The PU mass content is HP1, and it is put into large tank B for uniform mixing.

6. The method for stabilizing plutonium isotope raw materials for pressurized water reactor uranium-plutonium mixed fuel according to claim 5, characterized in that, In step A of step (3), LP1 < P < HP1, when the equivalent of the raw materials in tank A is... 239 The equivalent of the raw materials in the LP1 or B tank of Pu mass content 239 The mass content of Pu, HP1, has a value that is equivalent to the target distance. 239 When the Pu mass content P values ​​are very close, i.e. (P-LP1) / (HP1-LP1)<1 / n or (HP1-P) / (HP1-LP1)<1 / n, the raw material selection needs to be redone.

7. The method for stabilizing plutonium isotope raw materials for pressurized water reactor uranium-plutonium mixed fuel according to claim 1, characterized in that, The specific methods for taking raw materials from tank A and tank B and loading them into the product tanks in step B of step (3) are as follows: The equivalent can be obtained by solving the following system of two linear equations in two variables. 239 The required mass (LW) of raw material taken from tank A to achieve the target Pu mass content value i And the mass HW of raw materials taken out from tank B i The system of equations is as follows: LW i *LP i +HW i *HP i =P*M、 LW i +HW i =M, Where i = 1, LP i The equivalent of removing raw materials from tank A 239 PU mass content, HP i Equivalent to removing raw materials from tank B 239 Pu quality content; Based on the mass LW1 of raw material taken from tank A and the mass HW1 of raw material taken from tank B obtained above, the corresponding mass of raw material powder is loaded into the product tank. The equivalent mass in the product tank... 239 Pu mass content equals target equivalent 239 Pu mass content P.

8. The method for stabilizing plutonium isotope raw materials for pressurized water reactor uranium-plutonium mixed fuel according to claim 1, characterized in that, The process after step (3) also includes: Step (4), subsequent raw material selection and mixing, includes the following steps: A. Select the lowest and highest quality plutonium, or the number of single cups of plutonium close to the average value from the remaining raw material I and fill the large container A as close to full as possible. Select the lowest and highest quality plutonium, or the number of single cups of plutonium close to the average value from the remaining raw material II and fill the large container B as close to full as possible. B. Take raw materials from tank A and tank B respectively, and load them into the product tanks, so that the equivalent amount in the product tanks... 239 Pu mass content equals target equivalent 239 The mass content of Pu is P, and the total mass of raw materials in the product tank is still M, thus obtaining an equivalent mass. 239 Raw materials with consistent Pu content are used to manufacture uranium-plutonium mixed fuels.

9. The method for stabilizing plutonium isotope raw materials for pressurized water reactor uranium-plutonium mixed fuel according to claim 8, characterized in that, The process after step (4) also includes: Step (5) continues with the subsequent raw material selection and mixing, repeating step (4) a preset number of times to obtain an equivalent... 239 Raw materials with consistent Pu content are used to manufacture uranium-plutonium mixed fuels.

10. The method for stabilizing plutonium isotope feedstock in a pressurized water reactor uranium-plutonium mixed fuel according to claim 8, characterized in that, The specific method for step A in step (4) is as follows: The remaining powder in tank A is MA1-LW1, and the remaining powder in tank B is MB1-HW1, where MA1 is the total mass of powder in tank A before it decreased, MB1 is the total mass of powder in tank B before it decreased, LW1 is the mass of raw material taken from tank A, and HW1 is the mass of raw material taken from tank B. Divide M-(MA1-LW1) and M-(MB1-HW1) by m and round down, denoted as a1 and b1 respectively. Let MA2 = (MA1-LW1) + m*a1, MB2=(MB1-HW1)+m*b1, where MA2 is the mass of tank A after refilling, and MB2 is the mass of tank B after refilling. From the remaining raw material I, select the raw material with the smallest mass [a1 / 2] cup in order of plutonium quality from smallest to largest, where [*] is the floor operator. Then, from the remaining raw material I, select the raw material with the largest mass [a1 / 2] cup in order of plutonium quality from largest to smallest. If a1 is odd, then select the cup closest to Q. I The raw materials were selected, and a total of a1 cups of raw materials were placed into container A. The equivalent isotopic composition of the remixed raw materials in container A was calculated by mass averaging. 239 Pu mass content LP2; From the remaining raw material II, select the raw material with the smallest [b1 / 2] cup mass in order of plutonium mass from smallest to largest, and then select the raw material with the largest [b1 / 2] cup mass in order of plutonium mass from largest to smallest. If b1 is odd, then select the 1st cup closest to Q. II The raw materials, totaling b1 cup raw materials, were loaded into container B. The equivalent isotopic composition of the remixed raw materials in container B was calculated by mass averaging. 239 The mass content of Pu is HP2, of which... Where P i For the equivalent of each cup of ingredients 239 Pu mass content, the equivalent of the isotopic composition after remixing in tank A. 239 The equivalent of the isotopic composition after remixing in the Pu mass content LP2 or B large tank 239 The mass content of Pu in HP2 has a value that is equivalent to the target. 239 When the Pu mass content P values ​​are very close, i.e. (P-LP2) / (HP2-LP2)<1 / n or (HP2-P) / (HP2-LP2)<1 / n, the raw material selection needs to be redone.

11. The method for stabilizing plutonium isotope raw materials for pressurized water reactor uranium-plutonium mixed fuel according to claim 8, characterized in that, The specific method for step B in step (4) is as follows: Based on the equivalent of the isotopic composition after remixing in tank A 239 The equivalent mass content of Pu (LP2) and the isotopic composition after remixing in the B tank 239 The mass content of Pu, HP2, can be obtained by solving the following system of two linear equations in two variables. 239 The target value for Pu mass content requires the original mass (LW) to be removed from tank A again. i The mass HW of the raw material was taken out again from tank B. i The system of equations is as follows: LW i *LP i +HW i *HP i =P*M、 LW i +HW i =M, At this point, i = 2. Based on the above, the mass LW of raw material taken out from tank A again is... i The mass HW of the raw material was taken out again from tank B. i The appropriate mass of powder is loaded into the product container, and the equivalent mass in the product container... 239 Pu mass content equals target equivalent 239 Pu mass content P.

12. A plutonium isotope stabilizer for a pressurized water reactor uranium-plutonium mixed fuel, characterized in that, It is a stable plutonium isotope feedstock for pressurized water reactor uranium-plutonium mixed fuel obtained by the method described in any one of claims 1 to 11.

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