JP6485998B2 - Nuclear fuel management system and method - Google Patents

Description

  The present invention relates to a nuclear fuel management system and method for continuously managing the state of nuclear fuel used in a nuclear reactor.

  A nuclear power plant is constituted by, for example, a nuclear reactor, a steam turbine, a generator, and the like. When a pressurized water reactor (PWR) is applied as the nuclear reactor, the pressurized water reactor uses light water as the reactor coolant and neutron moderator, and uses high-temperature and high-pressure water that does not boil over the entire core. Generate. The steam generator exchanges heat between the high-temperature and high-pressure water (primary cooling water) and the secondary cooling water to generate steam. The steam turbine drives the turbine with the steam, and the generator generates power with the driving force.

  A pressurized water reactor uses a material that generates energy by causing a fission reaction as nuclear fuel, and specifically, heavy nuclides (fissionable nuclides) such as uranium and plutonium are applied. And a pressurized water reactor manufactures a fuel assembly using this heavy nuclide, and a core is constituted by a plurality of fuel assemblies. In this fuel assembly, for example, uranium oxide is baked and solidified into pellets, and a plurality of fuel cladding tubes are filled with the pellets to form fuel rods. The fuel rods are bundled in a grid of about 200 squares. Configured.

  By the way, heavy nuclides such as uranium and plutonium comply with NPT (Nuclear Non-Proliferation Treaty) and the amount is controlled by the country under the safeguards of IAEA (International Atomic Energy Agency). In addition, heavy nuclides generate FP (Fission Products) nuclides as fission products by fission or radioactive decay. The FP nuclides mainly have many nuclides having mass numbers of 90 and 130, and typical ones include cesium-137 and strontium-90.

JP 2005-106540 A

  By the way, if a severe accident occurs in a nuclear power plant or storage facility, radioactive materials may be scattered, so not only the weight of heavy nuclides in the reactor but also the weight of FP nuclides, It is desired to immediately confirm the amount, the decay heat amount, etc. regardless of whether it is operating or stopped. In addition, although there exists what was described in patent document 1 as a technique which evaluates a heavy nuclide and FP nuclide, it does not grasp quantity immediately.

  The present invention solves the above-described problems, and provides a nuclear fuel management system and method that can immediately and appropriately grasp the amount of heavy nuclides and the amount of fission products generated in nuclear fuel and enable continuous management. With the goal.

  In order to achieve the above object, the nuclear fuel management system of the present invention is a nuclear fuel management system that manages nuclear fuel during a period in which it is used in a nuclear reactor and a period in which it is taken out of the nuclear reactor and subjected to a predetermined treatment. The weight of the fission product is calculated at predetermined intervals based on the weight of the heavy nuclide and the power distribution of the core, and the current weight of the heavy nuclide and the weight of the fission product are managed. Is.

  Therefore, by grasping the current weight of the heavy nuclide and the weight of the fission product without using new information, it is possible to increase the efficiency of the treatment, and the weight of the heavy nuclide and the fission product. By managing the weight for each predetermined period, it is possible to continuously grasp the state of the nuclear fuel until the predetermined processing is performed after the nuclear fuel is used in the nuclear reactor.

  In the nuclear fuel management system of the present invention, the radiation amount and decay heat amount are calculated at predetermined intervals based on the weight of the current heavy nuclide and the weight of the fission product, and the current weight of the heavy nuclide and fission generation are calculated. It is characterized by controlling the weight, radiation dose, and decay heat of objects.

  Therefore, it is possible to manage not only the current weight of heavy nuclides and the weight of fission products, but also the radiation dose and decay heat.

  In the nuclear fuel management system of the present invention, during the period when the nuclear fuel is used in the nuclear reactor, the current fission product weight, radiation dose, and decay heat are calculated based on the power distribution of the core and the current heavy nuclide weight. It is characterized by management.

  Therefore, during the period when the nuclear fuel is used in the nuclear reactor, it becomes possible to perform a highly accurate amount management according to the current state of the core, and the safety can be improved.

  In the nuclear fuel management system of the present invention, the weight of the heavy nuclide, the weight of the fission product, and the radiation dose when the nuclear fuel is removed from the nuclear reactor during the period in which the nuclear fuel is removed from the nuclear reactor and the predetermined processing is performed. It is characterized by calculating and managing the current weight of heavy nuclides, the weight of fission products, the amount of radiation, and the amount of decay heat based on the amount of decay heat.

  Therefore, during the period when the predetermined treatment is performed on the spent nuclear fuel, the amount is estimated from the state of the nuclear fuel when it is removed from the nuclear reactor, so that the state of the nuclear fuel can be properly grasped and managed. it can.

  In the nuclear fuel management system of the present invention, the fission reaction rate is calculated based on the weight of the heavy nuclide and the power distribution of the core, and the generation rate of the fission product is calculated based on the fission reaction rate and the yield of the fission product. The weight of the fission product is calculated on the basis of the generation rate and output distribution of the fission product and the detailed combustion chain.

  Accordingly, the weight corresponding to each type of fission product can be calculated with high accuracy.

  In the nuclear fuel management system of the present invention, a first analysis / evaluation apparatus for calculating a weight change amount of a fission product based on a weight change amount of a heavy nuclide and a power distribution change amount of a core for a predetermined period set in advance, And a second analysis / evaluation device for calculating the weights of heavy nuclides and fission products based on the core design analysis calibrated by the output distribution of.

  Therefore, it is possible to select simple amount calculation and high-accuracy amount calculation as necessary.

  Further, the nuclear fuel management method of the present invention is a nuclear fuel management method for managing nuclear fuel during a period in which it is used in a nuclear reactor and during a period in which the nuclear fuel is removed from the nuclear reactor and a predetermined treatment is performed. The weight of the fission product is calculated for each predetermined period based on the output distribution of the above, and the weight of the heavy nuclide and the weight of the fission product are managed in real time.

  Therefore, by grasping the current weight of the heavy nuclide and the weight of the fission product without using new information, it is possible to increase the efficiency of the treatment, and the weight of the heavy nuclide and the fission product. By managing the weight for each predetermined period, it is possible to continuously grasp the state of the nuclear fuel until the predetermined processing is performed after the nuclear fuel is used in the nuclear reactor.

  According to the nuclear fuel management system and method of the present invention, the weight of the fission product is calculated in real time based on the weight of the heavy nuclide and the power distribution of the core during a predetermined process after the nuclear fuel is used in the nuclear reactor. Therefore, the amount of heavy nuclides and the amount of fission products generated in nuclear fuel can be properly grasped and managed continuously.

FIG. 1 is a schematic configuration diagram illustrating a nuclear fuel management system according to the present embodiment. FIG. 2 is a flowchart showing a processing method by the first analysis / evaluation apparatus in the nuclear fuel management system of the present embodiment. FIG. 3 is a flowchart showing a processing method by the second analysis / evaluation apparatus in the nuclear fuel management system of the present embodiment.

  Exemplary embodiments of a nuclear fuel management system and method according to the present invention will be described below in detail with reference to the accompanying drawings. In addition, this invention is not limited by this Example, Moreover, when there exists multiple Example, what comprises combining each Example is also included.

  FIG. 1 is a schematic configuration diagram illustrating a nuclear fuel management system according to the present embodiment, FIG. 2 is a flowchart illustrating a processing method performed by the first analysis evaluation apparatus in the nuclear fuel management system according to the present embodiment, and FIG. 3 illustrates the present embodiment. It is a flowchart showing the processing method by the 2nd analysis evaluation apparatus in the management system of nuclear fuel.

  The nuclear reactor of this embodiment uses heavy nuclides such as uranium and plutonium (fissionable nuclides) as nuclear fuel, and light water as a reactor coolant and neutron moderator, making it a high-temperature and high-pressure water that does not boil over the entire core. This is a pressurized water reactor (PWR) in which this high-temperature high-pressure water is sent to a steam generator to generate steam by heat exchange.

  A nuclear reactor has a core stored therein, and this core is composed of a plurality of fuel assemblies, and the plurality of fuel assemblies are arranged in a geometric shape so as to maintain 90 degrees of symmetry. Yes. The fuel assembly includes a plurality of fuel rods, a plurality of cladding tubes that cover the fuel rods, and a grid that bundles the plurality of cladding tubes, and the inside of the fuel assembly is filled with a moderator (coolant). At the same time, a plurality of control rods and in-core nuclear instrumentation can be inserted.

  The fuel assembly is formed in a square cross section, and is composed of, for example, 17 × 17 cells. Then, control rods are inserted into 24 cells out of 17 × 17 cells, and in-core nuclear instrumentation is inserted into cells at the center of the assembly. Further, fuel rods are inserted into the other cells, respectively.

  The nuclear fuel management system and nuclear fuel management method according to the present embodiment manages nuclear fuel during a period in which it is used in a nuclear reactor and during a period in which the nuclear fuel is taken out from the nuclear reactor and subjected to predetermined processing. Based on the weight and the power distribution of the core, the weight of fission products (hereinafter referred to as FP nuclides) is calculated for each predetermined period, and the current weight of heavy nuclides and the weight of FP nuclides are managed.

  Further, the nuclear fuel management system and nuclear fuel management method of the present embodiment calculates the radiation dose and decay heat amount for each predetermined period based on the weight of the current heavy nuclide and the weight of the FP nuclide, It manages the weight of heavy nuclides, the weight of FP nuclides, radiation dose, and decay heat.

  Here, the period during which nuclear fuel is used in a nuclear reactor is a period in which nuclear fuel is in the core of the nuclear reactor and power is extracted from the nuclear reactor by performing nuclear fission, that is, a nuclear reactor in a nuclear power plant. This is the driving period. During the operation period of the reactor, the current weight of heavy nuclides, weight of FP nuclides, radiation dose, and decay heat are calculated and managed based on the power distribution of the core.

  On the other hand, the period during which nuclear fuel is removed from the nuclear reactor and subjected to predetermined treatment is the period during which nuclear fuel is used as nuclear fuel removed from the reactor core and stored in an intermediate storage facility such as a fuel pool, This is a period in which spent nuclear fuel is reprocessed in a reprocessing facility, a period in which spent nuclear fuel is finally disposed in a final disposal facility, that is, a treatment period in an intermediate storage facility, a reprocessing facility, or a final disposal facility. During this treatment period, the weight of heavy nuclides, the weight of FP nuclides, the weight of FP nuclides, the amount of radiation and the amount of decay heat based on the weight of heavy nuclides, the weight of FP nuclides, the amount of radiation, and the amount of decay heat when nuclear fuel is removed from the reactor. Is calculated and managed.

  That is, in the nuclear fuel management system of the present embodiment, as shown in FIG. 1, the fuel assembly as nuclear fuel is delivered to the nuclear power plant 11 and stored in the reactor core. Then, after use, it becomes a spent fuel assembly, which is transported from the nuclear power plant 11 to the intermediate storage facility 12, the reprocessing facility 13, and the final disposal facility 14 for various processing.

  The nuclear power plant 11 is provided with a nuclear fuel management device 15. The nuclear fuel management device 15 is connected to an input unit (for example, operation panel) 16, an output unit (for example, a display or printer) 17, and a database (storage unit) 18, and to a neutron flux detector 19 of a nuclear reactor. Has been.

  The nuclear fuel management device 15 is connected to a first analysis evaluation device 21 and a second analysis evaluation device 22. The first analysis / evaluation apparatus 21 calculates the amount of change in the weight of the FP nuclide based on the amount of change in the weight of the heavy nuclide for a predetermined period and the amount of change in the power distribution of the core. The second analysis / evaluation device 22 calculates the weight of the FP nuclide based on the core design data and the power distribution of the core. The operator can select one of the processes of the first analysis evaluation device 21 and the second analysis evaluation device 22 as necessary from the input unit 16.

  As shown in FIG. 2, the first analysis / evaluation device 21 calculates the fission reaction rate based on the change in the weight of the heavy nuclide and the change (measured value) in the power distribution of the core in step S <b> 11. Here, the weight of the heavy nuclide is recorded as management data when the fuel assembly is delivered to the nuclear power plant 11. The neutron flux detector 19 provided in the core detects the neutron flux in the core, and outputs a signal proportional to the output value of the core. Since a plurality of neutron flux detectors 19 are arranged at predetermined intervals in the two-dimensional direction (horizontal direction) of the core, they are processed as output signals in the nuclear fuel assembly, and the power distribution of the core is obtained.

The fission reaction rate for each heavy nuclide is the fission amount (number of fission) of a heavy nuclide per unit time and unit region. The absorption reaction rate for each heavy nuclide is the neutron absorption amount (neutron absorption number) of a heavy nuclide per unit time and unit region, and the capture reaction rate for each heavy nuclide is per unit time and unit region. This is the neutron capture amount (number of neutron captures) of heavy nuclei. A combustion equation of a certain heavy nuclide X (a balance equation of generation and disappearance of the number of nuclides) can be generally expressed as follows.
ΔN _X = −λ _X N _X Δt + λ _Y N _Y Δt−RR _{a, X} Δt + RR _{c, X−1} Δt
Here, Y is the parent nuclide of nuclide X, Δt is the amount of time change from the previous time point, N is the number density of the previous time point, ΔN is the number density change from the previous time point , λ is a decay constant (number of decays per unit time, standard information), RR _{a, X} is an absorption reaction rate (number of nuclides X absorbing neutrons per unit time), RR _{c, X-1} are nuclides It is a capture reaction rate (number of nuclides X-1 capturing neutrons per unit time) of a nuclide (nuclide X-1) whose mass number is 1 smaller than X. Since Nx, Ny, and ΔN _X are known by giving the current heavy nuclide amount, there are two unknowns, RR _{a, X} and RR _{c, X-1} .
Here, there is a certain strong correlation between the absorption reaction rate and the capture reaction rate, and this relationship coefficient (F) is prepared in advance as a database or the like. Using this, the capture cleavage reaction rate for each nuclide is calculated based on the following mathematical formula.
RR _{c, X} = F × RR _{a, X}
By using this relational expression, there is one unknown per combustion equation, and RR _{a, X} can be obtained.
By the way, the following relational expression generally holds among the fission reaction rate, the capture reaction rate, and the absorption reaction rate. The fission reaction rate is calculated by using this relational expression.
RRf _{, X} = RRa _{, X-} RRc _{, X}
Here, RR _{f, X} is the fission reaction rate of heavy nuclide X (the number of nuclide X that undergoes fission per unit time).

In step S12, the first analysis / evaluation apparatus 21 calculates the generation rate of the FP nuclide based on the fission reaction rate and the FP yield (standard information). Here, the FP yield represents how much a certain FP nuclide is distributed with respect to the mass number, and is actually obtained with respect to the maximum amount (theoretical yield) in the FP nuclide that can be theoretically obtained. It is the ratio of the amount (yield) of the material obtained. This FP yield is a value set for each type of FP nuclide, for example, strontium, xenon, iodine, krypton, and cesium. The generation ratio of FP nuclides is calculated based on the following mathematical formula.
FP nuclide generation rate = (fission rate for each heavy nuclide x FP yield for each heavy nuclide)
Total value of all nuclides

In step S13, the first analysis / evaluation apparatus 21 calculates the weight of the FP nuclide based on the generation ratio of the FP nuclide, the core output, and the ultra-detailed combustion chain. The ultra-detailed combustion chain is data described in association with decay series, FP yield, nucleotropy contrast, half-life, etc. in each FP nuclide. The weight of the FP nuclide can be obtained from the following combustion equation. In this case, a combustion equation of a predetermined FP nuclide A (a balance equation of generation and disappearance of the number of nuclides) is represented.
ΔN _A = −λ _A N _A Δt + λ _B N _B Δt−RR _{a, A} Δt + RR _{c, A−1} Δt
_{+ Σ X y A, X RR} f, X Δt
Here, B is the parent nuclide of nuclide A, Δt is the time variation from the previous time point, N is the number density at the previous time point, and ΔN is the number density variation from the previous time point ( Λ is the decay constant (number of decays per unit time, standard information), RR _{a, A} is the absorption reaction rate (number of nuclides A absorbing neutrons per unit time), RR _{c , A-1} is the capture reaction rate of the nuclide (A-1) whose mass number is one smaller than that of the nuclide A (number of nuclides A-1 capturing neutrons per unit time), and y is the FP yield (heavy nuclide). FP nuclide A generation ratio per 1 fission of X). Σ _X y _{A, X} RR _{f, X} is the generation rate of FP nuclides.

The first analysis / evaluation apparatus 21 calculates the radiation dose and the decay heat amount based on the weight of the heavy nuclide and the weight of the FP nuclide. The radiation dose and decay heat amount are calculated based on the following mathematical formula.
Radiation dose = decay constant x nuclide number density x time change amount Collapse heat amount = decay constant x nuclide number density x time change amount x heat amount per radiation dose

The first analysis / evaluation device 21 calculates the current weight of heavy nuclides, the weight of FP nuclides, the amount of radiation, and the amount of decay heat for each predetermined period preset for a plurality of fuel assemblies, and records them in the database 18. To go. At this time, during the operation period of the nuclear reactor, the weight of heavy nuclides decreases due to nuclear fission, while the weight of FP nuclides increases, and the radiation dose and decay heat amount fluctuate. On the other hand, during the nuclear fuel treatment period, since the nuclear fission does not occur, the weight of the heavy nuclide is constant, the weight of the FP nuclide is decreased, and the radiation dose and decay heat are also reduced.

  Further, as shown in FIG. 3, the second analysis / evaluation apparatus 22 calculates 2 for each fuel assembly based on the core design data (physical property values, quantity, cross-sectional area, etc.) and the ultra-detailed combustion chain in step S21. Perform dimensional neutron transport calculations or diffusion calculations. This two-dimensional direction is an XY direction orthogonal to the horizontal direction of the core. In other words, the neutron flux of each detailed region in the fuel assembly is calculated over many groups based on the transport calculation method such as the characteristic method or the diffusion calculation method such as the modern node method using the effective micro cross section.

Thereafter, in step S22, the second analysis / evaluation apparatus 22 performs super detailed combustion calculation of all steps. All steps are performed every predetermined period set in advance, and the heavy nuclide weight and FP nuclide weight of each step are calculated based on the core power. The nuclide weight is calculated based on the following general combustion equation.
_{dN A / dt = -λ A N} A -σ a, A φN A + λ B N B + σ c, C φN C
Here, N _A is the number density of a certain nuclide A, λ _A is the decay constant of nuclide A, σ _{a, A} is the microabsorption cross section of nuclide A (physical quantity indicating the ease of neutron absorption of nuclide A ), Φ is the neutron flux, B is the parent nuclide of nuclide A _{, C} is the nuclide that becomes nuclide A by neutron capture, σ _{c, C} is the micro capture cross section of nuclide C (the capture of neutrons of nuclide C) Physical quantity indicating ease).

  In step S23, the second analysis / evaluation apparatus 22 calculates the nuclear constants of heavy nuclides and FP nuclides for each fuel assembly. That is, using the multi-group neutron flux in the fuel assembly obtained by the nuclide transport calculation as a weight, the effective macro-sectional area of the multi-group in the fuel assembly is reduced and homogenized, and the homogenized macro nuclear constant is calculated. .

  In step S24, the second analysis / evaluation apparatus 22 performs three-dimensional neutron transport calculation or diffusion calculation on the entire core based on the core design data (physical property values, quantity, cross-sectional area, etc.) and the core output, and step S25. The neutron flux distribution is calibrated based on the core power. In other words, the three-dimensional data obtained based on the core design data is corrected using the core power.

  Then, in step S26, the second analysis / evaluation apparatus 22 performs super-detailed combustion calculation of one step (per predetermined period) based on the super-detailed combustion chain. In step S27, the second nuclide and FP nuclide are calculated. Calculate weight, radiation dose, and decay heat. The calculation of the nuclide weight, radiation dose, and decay heat amount is the same as that described above.

  Since the nuclear fuel management device 15 is connected to the first analysis / evaluation device 21 and the second analysis / evaluation device 22, the operator can perform processing by the first analysis / evaluation device 21 and a second analysis / evaluation device as necessary. 22 can be selected. For example, normally, the first analysis / evaluation device 21 simply calculates the weight of the FP nuclide based on the current weight of the heavy nuclide and the power distribution of the core, and continues the weight of the FP nuclide, the radiation dose, and the decay heat amount. When the detailed analysis is required, the second analysis and evaluation device 22 adds the core design data to calculate the weight of the FP nuclide with high accuracy, and continues to calculate the weight of the FP nuclide, the radiation dose, and the decay heat. to manage.

  In this case, the nuclear fuel management device 15 calculates the current heavy nuclide weight, FP nuclide weight, radiation dose, and decay calorific value data for each fuel assembly for each predetermined period, stores them in the database 18 and accumulates them. Manage. Since the weight of heavy nuclides is reduced by fission, the nuclear fuel management device 15 takes out the weight of the current heavy nuclides from the database 18 when calculating the weight of the FP nuclides in the fuel assembly. .

  During the operation period of the nuclear reactor, the nuclear fuel management device 15 calculates the current heavy nuclide weight, FP nuclide weight, radiation dose, decay heat amount in each fuel assembly in consideration of the power distribution of the core, In the nuclear fuel treatment period, the weight of heavy nuclides in each fuel assembly during the transition period in consideration of the weight of heavy nuclides when removed from the reactor as spent, the weight of FP nuclides, the amount of radiation, and the amount of decay heat Estimate the weight, radiation dose, and decay heat of FP nuclides.

  During the operation period of the nuclear reactor, the nuclear power plant 11 manages the weight of heavy nuclides, the weight of FP nuclides, the radiation amount, and the decay heat amount in each fuel assembly. However, during the nuclear fuel treatment period, the nuclear power plant 11 manages them. However, the data may be transferred to the intermediate storage facility 12, the reprocessing facility 13, and the final disposal facility 14 and managed by each facility.

  In this way, for a given fuel assembly, we continuously manage the weight of heavy nuclides, the weight of FP nuclides, the amount of radiation, and the amount of decay heat from the time it is used in a nuclear reactor until it is disposed of. When an accident occurs in the nuclear power plant 11, the intermediate storage facility 12, the reprocessing facility 13, and the final disposal facility 14, it is possible to grasp the state of the fuel assembly at the accident site at any time, predicting the diffusion of radioactivity, etc. Can be performed at an early stage, and safety can be improved.

  Further, in the intermediate storage facility 12, the reprocessing facility 13, and the final disposal facility 14, it becomes possible to simulate the cooling period of the fuel assembly based on the operation results, and to estimate the radiation amount and decay heat amount of the spent nuclear fuel. Insufficient or excessive facility design can be suppressed.

  As described above, in the nuclear fuel management system and method according to the present embodiment, when the fuel assembly (nuclear fuel) is managed during the period in which the nuclear fuel is used and the period in which the nuclear fuel is taken out from the nuclear reactor and subjected to predetermined processing. Based on the weight of the heavy nuclide and the power distribution of the core, the weight of the FP nuclide is calculated every predetermined period, and the current weight of the heavy nuclide and the weight of the FP nuclide are managed. In this case, the radiation dose and decay heat amount are calculated for each predetermined period based on the weight of the current heavy nuclide and the weight of the FP nuclide, and the weight of the current heavy nuclide, the weight of the FP nuclide, the radiation dose and the decay. The amount of heat is managed.

  Therefore, the current weight of heavy nuclides and the weight of FP nuclides can be grasped without using new information, and the process can be simplified and made more efficient. Further, since the radiation dose and decay heat quantity are managed in addition to the current heavy nuclide weight and FP nuclide weight, the current state of the fuel assembly can be managed with high accuracy. By managing the weight of the heavy nuclide and the weight of the FP nuclide for each predetermined period, the state of the fuel assembly is continuously maintained until the predetermined processing is performed after the fuel assembly is used in the nuclear reactor. Therefore, the diffusion of radioactivity during severe accidents can be predicted early and with high accuracy.

  In the nuclear fuel management system of this embodiment, during the period when the fuel assembly is used in the nuclear reactor, the current heavy nuclide weight, FP nuclide weight, radiation dose, and decay heat amount are calculated based on the power distribution of the core. Manage. Accordingly, each amount in the fuel assembly undergoing fission can be managed with high accuracy, and safety can be improved.

  In the nuclear fuel management system of the present embodiment, the weight of the heavy nuclide and the weight of the FP nuclide when the fuel assembly is removed from the reactor during the period when the fuel assembly is removed from the reactor and the predetermined processing is performed. The current weight of heavy nuclides, the weight of FP nuclides, the amount of radiation and the amount of decay heat are calculated and managed on the basis of the radiation dose and decay heat. Therefore, each quantity is estimated from the state of the fuel assembly when it is taken out from the reactor, and the state of the fuel assembly can be properly grasped and managed.

  In the nuclear fuel management system of this embodiment, the fission reaction rate is calculated based on the weight of heavy nuclides and the power distribution of the core, the generation rate of FP nuclides is calculated based on the fission reaction rate and the FP yield, and the measurement period The burnup is calculated based on the power distribution of the reactor core, and the weight of the FP nuclide is calculated based on the FP nuclide generation rate, burnup, and ultra-detailed combustion chain. Therefore, the weight corresponding to each type in the FP nuclide can be calculated with high accuracy.

  In the nuclear fuel management system of the present embodiment, the first analysis / evaluation device 21 for calculating the weight of the FP nuclide based on the current weight of the heavy nuclide and the power distribution of the core, and the core design analysis calibrated by the power distribution of the core. And a second analysis / evaluation apparatus 22 for calculating the weight of heavy nuclides and FP nuclides based on the above. Therefore, it is possible to select simple amount calculation and high-accuracy amount calculation as necessary.

DESCRIPTION OF SYMBOLS 11 Nuclear power plant 12 Intermediate storage facility 13 Reprocessing facility 14 Final disposal facility 15 Nuclear fuel management device 16 Input unit 17 Output unit 18 Database 19 Neutron flux detector 21 First analysis evaluation device 22 Second analysis evaluation device

Claims (6)

In a nuclear fuel management system for managing the weight of heavy nuclides and the weight of fission products in a nuclear fuel during a period of use in a nuclear reactor and a period of time when the fuel is taken out of the nuclear reactor and subjected to predetermined processing,
Based on the power distribution in the reactor core to calculate the weight of the amount of change in the heavy nuclides every predetermined period, to calculate the fission reaction rate on the basis of the output distribution and the amount of change in the weight of the current of the heavy nuclides of the reactor core, the fission Calculate the fission product generation rate based on the reaction rate and fission product yield,
To calculate the weight of the fission products on the basis of the fission occurrence rate of the product and the power distribution of the reactor core super detailed combustion chain,
Calculate the burnup based on the measurement period and the power distribution of the core,
Comprising a first analysis evaluation device;
A nuclear fuel management system. 2. The nuclear fuel management system according to claim 1, wherein a radiation dose and a decay heat amount are calculated and managed at predetermined intervals based on a weight of the heavy nuclide and a weight of the fission product. In the period in which the nuclear fuel is used in the reactor, the current of the the weight of the heavy nuclides calculated based on the power distribution of the reactor core, and the weight of the calculated the fission products using the fission reaction rate management system of the nuclear fuel of claim 2, wherein the managing by calculating the decay heat and the radiation dose based on. In the period in which the nuclear fuel is removed from the reactor predetermined processing is performed, the disintegration and the weight and the radiation dose of the weight and the fission products of heavy nuclides of when the nuclear fuel has been removed from the reactor management system of the nuclear fuel according to claim 2, characterized in that manages to calculate the decay heat by weight of the current of the heavy nuclides and weight and the radiation dose of the fission products on the basis of heat. Based on the core design data, the power distribution of the core, and the ultra-detailed combustion chain, the neutron transport calculation or diffusion calculation is performed every predetermined period, and then the ultra-detailed combustion calculation is performed to determine the weight of the heavy nuclide and fission products. 5. The apparatus according to claim 1, further comprising a second analysis / evaluation apparatus that calculates a weight , wherein the process performed by the first analysis / evaluation apparatus and the process performed by the second analysis / evaluation apparatus can be selected . The nuclear fuel management system according to one. In a nuclear fuel management method for managing the weight of heavy nuclides and the weight of fission products in a nuclear fuel during a period in which the nuclear fuel is used and a period in which a predetermined treatment is performed after being taken out of the nuclear reactor,
Based on the power distribution in the reactor core to calculate the weight of the amount of change in the heavy nuclides every predetermined period, to calculate the fission reaction rate on the basis of the output distribution and the amount of change in the weight of the current of the heavy nuclides of the reactor core, the fission Calculate the fission product generation rate based on the reaction rate and fission product yield,
To calculate the weight of the fission products on the basis of the fission occurrence rate of the product and the power distribution of the reactor core super detailed combustion chain,
Calculate the burnup based on the measurement period and the power distribution of the core,
A method for managing nuclear fuel.

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