Reactor dose response rate setting value real-time calculation method and system under emergency working condition

Abstract

The invention relates to a reactor dose response rate setting value real-time calculation method and system under an emergency working condition, and the method comprises the steps: calculating the dose response rate ag of the unit radioactivity of a gth energy group uniformly distributed in a space to the position of a detector for a selected reactor building, g = 1, 2... G, and G is the total number of energy groups; under the nuclear emergency working condition, the reactor core accumulation amount of the current reactor and the radioactive source item of the corresponding reactor core under certain percentage damage are obtained, the radioactive source item comprises the radioactive activity of each radionuclide and the energy spectrum distribution of the radionuclide, and the radioactive activity of each radionuclide and the energy spectrum distribution of the radionuclide are obtained by combining the ag which is calculated in advance; and calculating to obtain a reactor core damage dose response rate setting value under the current working condition. The nuclear emergency real-time requirement is met, the real reactor core accumulation amount under the nuclear emergency working condition is adopted for calculation, and the working condition applicability is improved.

Description

Technical Field

[0001] The invention relates to the technical field of core damage evaluation, and in particular to a method and system for real-time calculation of a reactor dose response rate setting value under emergency conditions. Background Art

[0002] Core damage refers to various forms of damage to the fuel elements and their supporting structures in the reactor core of a nuclear power plant under abnormal or accident conditions. Damage types include cladding damage of fuel elements, melting of fuel pellets, failure of supporting structures, etc. The integrity and function of the core can be assessed based on the type, scope and severity of the damage.

[0003] The existing core damage assessment method uses the dose response rate of the detector in the reactor containment as one of the main judgment indicators for core damage assessment. In nuclear emergency conditions, the current degree of core damage is obtained by comparing the currently monitored dose response rate with the dose response rate setting value. The traditional method for determining the dose response rate setting value is to calculate the radioactive source term of a certain percentage of core damage based on the designed radioactive material accumulation of the reactor before the accident occurs, and calculate all radioactive source terms together through Monte Carlo method or point nuclear integration method to obtain the corresponding dose response rate setting value. After obtaining the actual core accumulation, the traditional method calculates the dose response rate through Monte Carlo method or point nuclear integration method, which requires a certain amount of calculation time and cannot meet the real-time requirements of nuclear emergency. In addition, the core radioactive material accumulation is significantly different for different reactor operation histories, and the corresponding dose response rate setting values ​​are also different. Therefore, the working condition applicability of the designed radioactive material accumulation for calculation is poor. Therefore, the existing response rate setting value calculation method cannot take into account both real-time performance and accuracy. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a method and system for real-time calculation of a set value of a reactor dose response rate under emergency conditions, aiming to improve the real-time performance and accuracy of the calculation.

[0005] The technical solution adopted by the present invention is as follows:

[0006] The present invention provides a method for real-time calculation of a reactor dose response rate setting value under emergency conditions, comprising:

[0007] For the selected reactor building, calculate the dose response rate a of the unit radioactivity of the g-th energy group uniformly distributed in the space to the detector position g , where g = 1, 2, ..., G, G is the total number of energy groups;

[0008] Under nuclear emergency conditions, the core stockpiles of the current reactor and the corresponding radioactive source items under a certain percentage of core damage are obtained, wherein the radioactive source items include the radioactivity of each radioactive nuclide; and then combined with the pre-calculated a g , the core damage dose response rate setting value under the current operating conditions is calculated by the following formula:

[0009]

[0010] In the formula, A s is the dose response rate setting value corresponding to a certain percentage of damage in the core, A n is the radioactivity of the nth radionuclide, χ n,g is the energy spectrum of the gth energy group of the nth radionuclide, and N is the number of radionuclide types.

[0011] Further technical solutions are:

[0012] The core stockpile of the current reactor and the radioactivity of each radioactive nuclide are obtained through actual operation data of the reactor building.

[0013] The core stock of the current reactor and the radioactivity of each radioactive nuclide are obtained by sampling and testing the reactor building under the current operating condition.

[0014] The Monte Carlo method is used to calculate the g .

[0015] The point kernel integration method is used to calculate the a g .

[0016] The present invention also provides a real-time calculation system for a reactor dose response rate setting value under emergency conditions, comprising:

[0017] The database module is constructed in the following way: for the selected reactor building, the dose response rate a of the unit radioactivity of the g-th energy group uniformly distributed in the space to the detector position is calculated. g , thus constructing a database, where g = 1, 2, …, G, G is the total number of energy groups;

[0018] A radioactive source term acquisition module, which is used to obtain the core inventory of the current reactor and the corresponding radioactive source term under a certain percentage of core damage under nuclear emergency conditions, wherein the radioactive source term includes the radioactivity of each radioactive nuclide;

[0019] A calculation module, which obtains the radioactivity of each radionuclide through the radioactive source acquisition module and combines the radioactivity of each radionuclide obtained by the database module with the radioactivity of each radionuclide obtained by the radioactive source acquisition module. g, the core damage dose response rate setting value under the current operating conditions is calculated by the following formula:

[0020]

[0021] In the formula, A s is the dose response rate setting value corresponding to a certain percentage of damage in the core, A n is the radioactivity of the nth radionuclide, χ n,g is the energy spectrum of the gth energy group of the nth radionuclide, and N is the number of radionuclide types.

[0022] Further technical solutions are:

[0023] The core stockpile of the current reactor and the radioactivity of each radioactive nuclide are obtained through actual operation data of the reactor building.

[0024] The core stock of the current reactor and the radioactivity of each radioactive nuclide are obtained by sampling and testing the reactor building under the current operating condition.

[0025] The Monte Carlo method is used to calculate the g .

[0026] The point kernel integration method is used to calculate the a g .

[0027] The beneficial effects of the present invention are as follows:

[0028] The present invention is based on the fact that the dose response rate is only related to the energy and activity of gamma rays, but not to the radioactive nuclides that produce them, and calculates the dose response rate of each energy group unit radioactive activity to the detector position in advance. And under emergency conditions, after obtaining the real core stockpile, the dose response rate of each nuclide in each energy group of the radioactive source item of a certain percentage of core damage corresponding to the core stockpile is accumulated, and the dose response rate setting value required for the core damage assessment is calculated in real time. The real-time requirements of nuclear emergency core damage assessment are met, and the applicability of working conditions is improved.

[0029] Other features and advantages of the present invention will be set forth in the following description or may be learned by practicing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The figure is a schematic diagram of the calculation logic of the method according to the embodiment of the present invention. DETAILED DESCRIPTION

[0031] The specific implementation of the present invention is described below with reference to the accompanying drawings.

[0032] See also Figure 1This embodiment provides a method for calculating the set value of the reactor dose response rate in real time under emergency conditions. The idea of ​​this method is: by calculating the dose response rate of each energy group unit radioactivity intensity at the detector position in advance; in nuclear emergency conditions, after obtaining the current real core stockpile, by accumulating the dose response rate of each energy group of each nuclide in the radioactive source item of a certain percentage of core damage corresponding to the current real core stockpile, the dose response rate set value required for core damage evaluation can be calculated in real time. Specifically, the following steps are included:

[0033] S1. For the selected reactor building, calculate the dose response rate a of the unit radioactivity of the g-th energy group uniformly distributed in the space to the detector position g , where g = 1, 2,…, G, where G is the total number of energy groups.

[0034] Since the dose response rate is only related to the energy and activity of the gamma ray, but not to the radioactive nuclide that produces it, this step calculates in advance the dose response rate of the unit radioactivity of each energy group to the detector position.

[0035] As a specific implementation method, a is calculated using the Monte Carlo method or the point kernel integration method. g .

[0036] As a specific implementation method, those skilled in the art can use commercial software such as MCNP, MCX, SuperMC, etc. to implement a g calculation operation.

[0037] As a specific implementation, G is generally set to 18;

[0038] S2. Under emergency conditions, the core stock of the current reactor and its corresponding radioactive source term under a certain percentage of core damage are obtained, wherein the radioactive source term includes the radioactivity of each radionuclide; based on the radioactivity of each radionuclide and its energy spectrum distribution, combined with the a pre-calculated in step S1, g , the core damage dose response rate setting value under the current working condition can be obtained by accumulation. The mathematical expression is as follows:

[0039]

[0040] In the formula, A s is the dose response rate setting value corresponding to a certain percentage of damage in the core, A n is the radioactivity of the nth radionuclide, χ n,g is the energy spectrum of the gth energy group of the nth radionuclide, and N is the number of radionuclide types.

[0041] Among them, the energy spectrum of the nuclide χ n,gis fixed.

[0042] As a specific implementation, the core inventory of the current reactor and the radioactivity of each radioactive nuclide may be obtained through actual operation data of the reactor building.

[0043] As a specific implementation, the core inventory of the current reactor and the radioactivity of each radioactive nuclide can be obtained by sampling and testing the reactor building under the current operating conditions.

[0044] As a specific implementation, those skilled in the art may use the ORIGEN program to calculate the core inventory of the current reactor and obtain the radioactivity of each of the radioactive nuclides.

[0045] The calculation method of this embodiment creatively decouples the dose response rate from the composition of the radioactive source term by establishing a relationship between the dose response rate setting value and the unit radioactivity of each energy group. Under emergency conditions, the core damage dose response rate setting value corresponding to the current reactor core accumulation of radioactive material can be obtained in real time, thereby improving the real-time and accuracy of the dose response rate setting value calculation, and further achieving high-quality core damage evaluation.

[0046] This embodiment also provides a real-time calculation system for a set value of a reactor dose response rate under emergency conditions corresponding to the calculation method, which comprises:

[0047] The database module is constructed in the following way: for the selected reactor building, the dose response rate a of the unit radioactivity of the g-th energy group uniformly distributed in the space to the detector position is calculated. g , thus constructing a database, where g = 1, 2, …, G, G is the total number of energy groups;

[0048] A radioactive source term acquisition module, which is used to obtain the core inventory of the current reactor and the corresponding radioactive source term under a certain percentage of core damage under nuclear emergency conditions, wherein the radioactive source term includes the radioactivity of each radioactive nuclide;

[0049] A calculation module, which obtains the radioactivity of each radionuclide through the radioactive source acquisition module and combines the radioactivity of each radionuclide obtained by the database module with the radioactivity of each radionuclide obtained by the radioactive source acquisition module. g , the core damage dose response rate setting value under the current operating conditions is calculated by the following formula:

[0050]

[0051] In the formula, A s is the dose response rate setting value corresponding to a certain percentage of damage in the core, A nis the radioactivity of the nth radionuclide, χ n,g is the energy spectrum of the gth energy group of the nth radionuclide, and N is the number of radionuclide types.

[0052] Those skilled in the art can understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for real-time calculation of reactor dose response rate setting value under emergency conditions, characterized in that: include: For the selected reactor building, calculate the dose response rate a of the unit radioactivity of the g-th energy group uniformly distributed in the space to the detector position g , where g = 1, 2, … ,G,G is the total number of energy groups; Under nuclear emergency conditions, the core stockpiles of the current reactor and the corresponding radioactive source items under a certain percentage of core damage are obtained, wherein the radioactive source items include the radioactivity of each radioactive nuclide; and then combined with the pre-calculated a g , the core damage dose response rate setting value under the current operating conditions is calculated by the following formula: In the formula, A s is the dose response rate setting value corresponding to a certain percentage of damage in the core, A n is the radioactivity of the nth radionuclide, χ n,g is the energy spectrum of the gth energy group of the nth radionuclide, and N is the number of radionuclide types.

2. The method for real-time calculation of reactor dose response rate setting value under emergency conditions according to claim 1, characterized in that: The core stockpile of the current reactor and the radioactivity of each radioactive nuclide are obtained through actual operation data of the reactor building.

3. The method for real-time calculation of reactor dose response rate setting value under emergency conditions according to claim 1, characterized in that: The core stock of the current reactor and the radioactivity of each radioactive nuclide are obtained by sampling and testing the reactor building under the current operating condition.

4. The method for real-time calculation of reactor dose response rate setting value under emergency conditions according to claim 1, characterized in that: The Monte Carlo method is used to calculate the g .

5. The method for real-time calculation of reactor dose response rate setting value under emergency conditions according to claim 1, characterized in that: The point kernel integration method is used to calculate the a g .

6. A real-time calculation system for reactor dose response rate setting value under emergency conditions, characterized in that: include: The database module is constructed in the following way: for the selected reactor building, the dose response rate a of the unit radioactivity of the g-th energy group uniformly distributed in the space to the detector position is calculated. g , thereby constructing a database, where g = 1, 2, … ,G,G is the total number of energy groups; A radioactive source term acquisition module, which is used to obtain the core inventory of the current reactor and the corresponding radioactive source term under a certain percentage of core damage under nuclear emergency conditions, wherein the radioactive source term includes the radioactivity of each radioactive nuclide; A calculation module, which obtains the radioactivity of each radionuclide through the radioactive source acquisition module and combines the radioactivity of each radionuclide obtained by the database module with the radioactivity of each radionuclide obtained by the radioactive source acquisition module. g , the core damage dose response rate setting value under the current operating conditions is calculated by the following formula: In the formula, A s is the dose response rate setting value corresponding to a certain percentage of damage in the core, A n is the radioactivity of the nth radionuclide, χ n,g is the energy spectrum of the gth energy group of the nth radionuclide, and N is the number of radionuclide types.

7. The system according to claim 6, characterized in that The core stockpile of the current reactor and the radioactivity of each radioactive nuclide are obtained through actual operation data of the reactor building.

8. The system according to claim 6, characterized in that The core stock of the current reactor and the radioactivity of each radioactive nuclide are obtained by sampling and testing the reactor building under the current operating condition.

9. The system according to claim 6, characterized in that The Monte Carlo method is used to calculate the g .

10. The system according to claim 6, characterized in that The point kernel integration method is used to calculate the a g .

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