Ex-pile detector calibration method, computer equipment and storage medium

Abstract

The present invention relates to a method for calibrating an off-pile detector, comprising: S1: obtaining the detector response factor at each position in the pile by simulating the process of neutron transport from the inside of the pile to the off-pile detector; S2: simulating the theoretical xenon oscillation process to obtain the fission neutron production rate at each position in the pile during the xenon oscillation; S3: obtaining the response current distribution of each off-pile detector during the xenon oscillation according to the detector response factor and the fission neutron production rate; S4: calculating the calibration coefficient using the current distribution. While the present invention cancels the implementation of the on-site xenon oscillation test, it can still provide a complete set of calibration coefficients with sufficient accuracy, reduce the disturbance to the core, reduce the difficulty of controlling the reactor (especially at the end of its life), and thus reduce the pressure on the operating personnel.

Description

Technical Field

[0001] The present invention relates to the field of nuclear power technology, and in particular to an out-of-core detector calibration method, computer equipment and storage medium. Background Art

[0002] In the field of nuclear power, fuel assemblies are core components and also the components with the most concentrated radioactive materials. Fuel assemblies are usually placed in a closed pressure vessel to form the core. In order to monitor the working status of the core, an off-core nuclear radiation detection system is usually configured to monitor the operation process of the core. Among them, the power range detectors set outside the core are mainly used for monitoring (nuclear power, ΔI, TILT, LOCA margin) and protection (OPDT, OTDT, etc.).

[0003] In order to confirm the normal functioning of the extra-core detector, its calibration coefficient needs to be updated regularly during the operation of the core so that the deviations between the measured ΔI, axial power distribution and core power and the actual values ​​are within a reasonable range.

[0004] Traditionally, the power range detector is calibrated by xenon oscillation test. In this xenon oscillation test, the core axial power changes by artificially introducing xenon oscillation, and the partial flux diagram is measured to obtain the axial power distribution in the core and the current value of the power range detector during the xenon oscillation process, and then the detector calibration coefficient and the transmission matrix and sensitivity matrix required for axial power distribution monitoring are determined.

[0005] However, this test method has at least the following defects and problems:

[0006] (1) In the test, it is necessary to adjust the R rod to introduce xenon oscillation with a ΔI variation of 6-8% FP (full power), which will affect the subsequent stable operation of the unit. It is necessary to continue to pay attention to the operating value and intervene to restore the core ΔI to stability. If the intervention is not timely, the ΔI oscillation will diverge, and there is a risk of triggering the core protection signal. Especially at the end of the life cycle, ΔI control is more difficult and risky.

[0007] (2) The frequent use of the in-pile monitoring system during the test increases the risk of probe jamming and accelerates the aging of the detector, which increases the operating and maintenance costs of the in-pile detector system.

[0008] (3) The test lasts about 8-10 hours and requires continuous work by on-site personnel and backup support personnel, which is prone to human risks.

[0009] (4) Boron dilution operation is required during the test, which increases the generation of radioactive waste liquid.

[0010] (5) Starting each power platform to perform the test after the material change will occupy the key path for the unit to increase power, resulting in power generation losses. Summary of the invention

[0011] The technical problem to be solved by the present invention is to provide an out-of-pile detector calibration method, computer equipment and storage medium that do not require on-site xenon oscillation testing.

[0012] The technical solution adopted by the present invention to solve the technical problem is to construct an out-of-pile detector calibration method, comprising the following steps:

[0013] S1: By simulating the process of neutron transport from the pile to the detector outside the pile, the detector response factor at each position in the pile is obtained;

[0014] S2: simulating a theoretical xenon oscillation process to obtain the fission neutron production rate at each position in the pile during the xenon oscillation process;

[0015] S3: obtaining the response current distribution of each of the ex-core detectors during the xenon oscillation process according to the detector response factor and the fission neutron production rate;

[0016] S4: Calculate the calibration coefficient using the current distribution.

[0017] Preferably, in step S1, a process of neutron transport from inside the pile to the detector outside the pile is simulated by a Monte Carlo program.

[0018] Preferably, in step S1, the response of a neutron at a position (x, y, z) in the core on a detector i is:

[0019] R i (x,y,z)=W i (x,y,z)νΣ f Φ(x,y,z) Formula (1)

[0020] Among them, W i (x, y, z) is the response factor of the position (x, y, z) on detector i, Φ(x, y, z) is the neutron fluence rate at the position (x, y, z), Σ f is the fission cross section and ν is the average number of neutrons produced per fission.

[0021] Preferably, in step S2, the theoretical xenon oscillation process is simulated and constructed by a core design program to obtain the average number of neutrons produced by each fission at each position in the core, the fission cross section and the neutron injection rate. The fission neutron production rate is directly calculated by multiplying the three, which is νΣ in the formula (1): f Φ(x,y,z).

[0022] Preferably, in step S3, the fission neutron production rate is combined with equation (1) to obtain the response distribution R of the out-of-core detector.i,n , where i refers to the detector's serial number in the axial direction, and the value range of i is 1 to 6; n refers to the state point serial number in the xenon oscillation process, and the value range of n is 1 to 8;

[0023] The response distribution R of the ex-core detector is i,n That is, the current distribution I i，n .

[0024] Preferably, in step S2, the axial power distribution P in the pile is also obtained. i，n and axial power offset AO in，n , where i=1~6, n=1~8.

[0025] Preferably, according to the axial power distribution P i，n And the current distribution I i，n Get the transmission matrix [T].

[0026] Preferably, the transmission matrix [T] is obtained by solving The minimum value of X i,l Calculated by the following formula:

[0027] [X]=[T] -1 [COR] -1 [P]

[0028] In the formula, [T] is the 6*6 neutron transport matrix, [COR] is the 6*6 control rod position correction matrix, and [P] is the 8*6 core axial power distribution matrix.

[0029] Preferably, the method further comprises:

[0030] Conduct a full core flux map experiment to obtain the measured current distribution I of the detector. i , measured axial power distribution P i ;

[0031] According to the measured current distribution I i , measured axial power distribution P i And the transmission matrix [T], calculate the sensitivity matrix [S]: The calculation formula is as follows:

[0032] [P]=[COR][T][S][I]

[0033] Wherein, [P] is the 1×6 in-pile measured axial power distribution matrix, [COR] is the 6×6 control rod position correction matrix, and [I] is the 1×6 out-pile measured detector current distribution matrix.

[0034] Preferably, when performing a full core flux diagram experiment, the measured core power Pr and the measured detector upper current I are also obtained. U , lower current I L ;

[0035] The method further comprises: according to K×Pr=I U +I L Solve to get the coefficient K.

[0036] Preferably, in step S3, the fission neutron production rate is combined with the formula (1) to obtain the upper current I U，n and the lower current I L，n ;

[0037] According to the axial power offset AO in，n and the upper current I U，n and the lower current I L，n , according to the formula:

[0038] and AO ex,n =b×AO in,n +a

[0039] The coefficient b is obtained by performing the least squares fit.

[0040] Preferably, when performing a full core flux diagram experiment, the measured in-core axial power offset AO is also obtained. in And the measured external axial power offset AO ex ;

[0041] The method further comprises: according to the measured in-core axial power offset AO in 、The measured out-of-core axial power offset AO ex And the coefficient b, calculate the coefficient a.

[0042] Preferably, the calibration coefficient K is calculated based on the coefficient a, coefficient b and coefficient K and the following formula: U , K L and α.

[0043]

[0044] The present invention also provides a computer device, comprising: a processor and a memory for storing a computer program that can be run on the processor, wherein the processor is used to implement any of the above-mentioned methods for calibrating an out-of-core detector when running the computer program.

[0045] The present invention also provides a computer storage medium storing an executable program, and when the executable program is executed by a processor, any of the above-mentioned methods for calibrating an out-of-pillar detector is implemented.

[0046] The implementation of the present invention has the following beneficial effects: while eliminating the implementation of the on-site xenon oscillation test, the present invention can still provide a complete set of calibration coefficients with sufficient accuracy, reduce disturbances to the core, reduce the difficulty of controlling the reactor (especially at the end of its life), and thus reduce the pressure on operating personnel.

[0047] Furthermore, the duration of the calibration test of the off-core detectors is shortened, the situation of reactor engineers working continuously for long periods of time is reduced, and the possibility of human errors is reduced; the situation of the in-core detector probes frequently entering the instrument tube is reduced, thereby reducing the risk of probe jamming and the aging of the detectors themselves, and reducing the maintenance cost of the system; the boron dilution operation during the test is reduced, thereby reducing the generation of radioactive waste liquid; when the off-core detector calibration test is required for each power platform after the material replacement, the time required for power increase can be reduced, thereby increasing the power generation of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0049] Figure 1 It is a flow chart of an embodiment of the method for calibrating an out-of-pillar detector of the present invention. DETAILED DESCRIPTION

[0050] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "back", "up", "down", "left", "right", "longitudinal", "horizontal", "vertical", "horizontal", "top", "bottom", "inside", "outside", "head", "tail", etc. are based on the directions or positional relationships shown in the accompanying drawings, are constructed and operated in a specific direction, and are only for the convenience of describing the present technical solution, rather than indicating that the device or element referred to must have a specific direction, and therefore cannot be understood as a limitation to the present invention.

[0051] It should also be noted that, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected", "fixed", "set" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. When an element is referred to as being "on" or "under" another element, the element can be "directly" or "indirectly" located on the other element, or there may be one or more intermediate elements. The terms "first", "second", "third", etc. are only for the convenience of describing the present technical solution, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", "third", etc. can explicitly or implicitly include one or more of the features. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0052] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0053] like Figure 1 As shown, in one embodiment of the method for calibrating an out-of-core detector of the present invention, the following steps are included:

[0054] S1: By simulating the process of neutron transport from the pile to the detector outside the pile, the detector response factor at each position in the pile is obtained.

[0055] In this embodiment, the process of neutron transport from the core to the detector outside the core is simulated by Monte Carlo program, and the detector response factor at each position in the core is calculated.

[0056] For example, the response of a neutron at position (x, y, z) in the core on detector i is:

[0057] R i (x,y,z)=W i (x,y,z)νΣ f Φ(x,y,z) Formula (1)

[0058] Among them, W i (x, y, z) is the response factor of the position (x, y, z) on detector i, Φ(x, y, z) is the neutron fluence rate at the position (x, y, z), Σf is the fission cross section and ν is the average number of neutrons produced per fission.

[0059] S2: Simulate the theoretical xenon oscillation process to obtain the fission neutron production rate at each position in the pile during the xenon oscillation process.

[0060] In this embodiment, the core design program is used to simulate the theoretical xenon oscillation process to obtain the average number of neutrons produced by each fission at each position in the core, the fission cross section and the neutron injection rate. The fission neutron production rate is directly calculated by multiplying the three, that is, νΣ in formula (1): f Φ(x,y,z).

[0061] Furthermore, the axial power distribution P can be obtained by simulating the theoretical xenon oscillation process through the core design program. i，n and axial power offset AO in，n , where i=1~6, n=1~8.

[0062] Among them, i refers to the axial serial number of the detector. Since the detector has 6 axial segments, the value range of i is 1 to 6; n refers to the state point number in the xenon oscillation process. In the off-pile detector calibration method, 8 state points need to be selected, so the value range of n is 1 to 8.

[0063] S3: Based on the detector response factor and the fission neutron production rate, the response current distribution of each out-of-core detector during the xenon oscillation process is obtained.

[0064] In this embodiment, the fission neutron production rate is combined with equation (1) to obtain the response distribution R of the out-of-core detector: i,n Considering that the detector current is proportional to the response, the response distribution R of the out-of-core detector is i,n That is the current distribution I i，n .

[0065] Furthermore, according to I i,n , we can also get the upper current I U，n and the lower current I L，n , calculated as follows:

[0066]

[0067] S4: Use the current distribution to calculate the calibration coefficient.

[0068] In this embodiment, the calibration coefficients include K U , K L , α and transmission matrix [T], etc.

[0069] The transfer matrix [T] is obtained by solving The minimum value of Xi,l Calculated by the following formula:

[0070] [X]=[T] -1 [COR] -1 [P]

[0071] In the formula, [T] is the 6*6 neutron transport matrix, [COR] is the 6*6 control rod position correction matrix, and [P] is the 8*6 core axial power distribution matrix.

[0072] AO offset according to axial power in，n and the upper current I U，n and the lower current I L，n , according to the formula:

[0073] and

[0074] AO ex,n =b×AO in,n +a

[0075] The coefficient b is obtained by performing the least squares fit.

[0076] Then, a full core flux map experiment was conducted to obtain the measured current distribution I of the detector. i , measured axial power distribution P i , measured core power Pr, measured detector upper current I U , Measured current I at the bottom of the detector L , measured axial power offset AO in the reactor in And the measured external axial power offset AO ex And other parameters.

[0077] Using the measured current distribution I i , measured axial power distribution P i And the transmission matrix [T], according to the formula:

[0078] [P]=[COR][T][S][I]

[0079] Wherein, [P] is the 1×6 in-core axial power distribution matrix, [COR] is the 6×6 control rod position correction matrix, and [I] is the 1×6 out-core detector current distribution matrix.

[0080] The sensitivity matrix [S] is calculated.

[0081] Using the measured core power Pr and the measured detector upper current I U , Measured detector lower current I L， According to the formula: K×Pr=I U +I L

[0082] Solve to get the coefficient K.

[0083] Using the measured in-pile axial power offset AO in , measured external axial power offset AO ex And coefficient b, according to the formula:

[0084] AO ex =b×AO in +a

[0085] The coefficient a is calculated.

[0086] Using coefficient a, coefficient b and coefficient K, according to the formula:

[0087]

[0088] and

[0089]

[0090] Get the calibration coefficient K U , K L and α.

[0091] The method of this embodiment can provide a complete set of calibration coefficients (including K U , K L and α, transmission matrix [T] and sensitivity matrix [S], etc.), the main advantages are as follows:

[0092] (1) It reduces disturbances to the core and makes the operation of the reactor easier (especially at the end of its life), thereby reducing the pressure on operators;

[0093] (2) The duration of the off-core detector calibration test was shortened, which reduced the need for reactor engineers to work continuously for long periods of time and reduced the likelihood of human errors;

[0094] (3) It reduces the frequent entry of the in-pile detector probe into the instrument tube, thereby reducing the risk of probe jamming and the aging of the detector itself, and reducing the maintenance cost of the system;

[0095] (4) Reduce the boronization dilution operation during the test process, thereby reducing the generation of radioactive waste liquid;

[0096] (5) When each power platform needs to undergo an off-core detector calibration test after refueling, the time required to increase power can be reduced, thereby increasing the power generation of the unit.

[0097] An embodiment of the present invention also provides a computer device, which includes a memory, a processor, and computer instructions stored in the memory and executable on the processor; when the processor executes the instructions, the steps of the off-pile detector calibration method are implemented.

[0098] In some embodiments, the memory in the embodiments of the present invention may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct memory bus random access memory (DRRAM). The memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0099] The processor may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in the processor or an instruction in the form of software. The above processor may be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present invention can be implemented or executed. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The steps of the method disclosed in conjunction with the embodiments of the present invention can be directly embodied as being executed by a hardware decoding processor, or executed by a combination of hardware and software modules in a decoding processor. The software module may be located in a mature storage medium in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in a memory, and the processor reads the information in the memory and completes the steps of the above method in conjunction with its hardware.

[0100] In some embodiments, the embodiments described herein may be implemented in hardware, software, firmware, middleware, microcode, or a combination thereof. For hardware implementation, the processing unit may be implemented in one or more application specific integrated circuits (ASIC), digital signal processors (DSP), digital signal processing devices (DSPD), programmable logic devices (PLD), field programmable gate arrays (FPGA), general purpose processors, controllers, microcontrollers, microprocessors, other electronic units for performing the functions of the present application, or a combination thereof.

[0101] For software implementation, the technology of this article can be implemented by modules (such as procedures, functions, etc.) that perform the functions of this article. The software code can be stored in a memory and executed by a processor. The memory can be implemented in the processor or outside the processor.

[0102] Yet another embodiment of the present invention provides a computer storage medium, wherein the computer-readable storage medium stores an executable program, and when the executable program is executed by a processor, the steps of the off-pillar detector calibration method can be implemented.

[0103] In some embodiments, computer storage media may include: USB flash drives, mobile hard disks, read-only memories (ROM), random access memories (RAM), magnetic disks or optical disks, and other media that can store program codes.

[0104] It can be understood that the above embodiments only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, the above technical features can be freely combined without departing from the concept of the present invention, and several deformations and improvements can be made, which all belong to the protection scope of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should belong to the coverage of the claims of the present invention.

Claims

1. A method for calibrating an out-of-pile detector, characterized in that: The following steps are involved: S1: By simulating the process of neutron transport from the core to the detector outside the core, the detector response factor at each position in the core is obtained; wherein, in step S1, the response of the neutron at the position (x, y, z) in the core on the detector i is: R i (x, y, z) = W i (x, y, z)νΣ f Φ(x, y, z) Equation (1) Among them, W i (x, y, z) is the response factor of the position (x, y, z) on detector i, Φ(x, y, z) is the neutron fluence rate at the position (x, y, z), Σ f is the fission cross section, ν is the average number of neutrons produced per fission; S2: Simulate and construct the theoretical xenon oscillation process to obtain the fission neutron production rate at each position in the reactor during the xenon oscillation process; wherein, in the step S2, the theoretical xenon oscillation process is simulated and constructed by the core design program to obtain the average number of neutrons, fission cross section and neutron injection rate produced by each fission at each position in the core, and the fission neutron production rate is directly calculated by multiplying the three, which is νΣ in the formula (1) f Φ(x,y,z); S3: obtaining the response current distribution of each of the ex-core detectors during the xenon oscillation process according to the detector response factor and the fission neutron production rate; S4: Calculate the calibration coefficient using the current distribution.

2. The method for calibrating an out-of-pile detector according to claim 1, characterized in that: In step S1, the process of neutron transport from the in-pile to the out-pile detector is simulated by a Monte Carlo program.

3. The method for calibrating an out-of-core detector according to claim 1, characterized in that: In step S3, the fission neutron production rate is combined with equation (1) to obtain the response distribution R of the out-of-core detector. i,n , where i refers to the detector's serial number in the axial direction, and the value range of i is 1 to 6; n refers to the state point serial number in the xenon oscillation process, and the value range of n is 1 to 8; The response distribution R of the ex-core detector is i,n That is, the current distribution I i，n .

4. The method for calibrating an out-of-pile detector according to claim 3, characterized in that: In step S2, the axial power distribution P is also obtained. i，n and axial power offset AO in，n , where i=1~6, n=1~8.

5. The method for calibrating an out-of-core detector according to claim 4, characterized in that: According to the axial power distribution P i，n And the current distribution I i，n Get the transmission matrix [T].

6. The method for calibrating an out-of-pile detector according to claim 5, characterized in that: The transfer matrix [T] is solved by The minimum value of X i,l Calculated by the following formula: [X]=[T] -1 [COR] -1 [P] In the formula, [T] is the 6*6 neutron transport matrix, [COR] is the 6*6 control rod position correction matrix, and [P] is the 8*6 core axial power distribution matrix.

7. The method for calibrating an out-of-pile detector according to claim 6, characterized in that: The method further includes: A full core flux map experiment is conducted to obtain the measured current distribution I of the detector. i , measured axial power distribution P i ; According to the measured current distribution I i , measured axial power distribution P i And the transmission matrix [T], the sensitivity matrix [S] is calculated, and the calculation formula is as follows: [P]=[COR][T][S][I] Wherein, [P] is the 1×6 in-pile measured axial power distribution matrix, [COR] is the 6×6 control rod position correction matrix, and [I] is the 1×6 out-pile measured detector current distribution matrix.

8. The method for calibrating an out-of-core detector according to claim 7, characterized in that: When conducting a full core flux diagram experiment, the measured core power Pr and the measured detector upper current I are also obtained. U , lower current I L ; The method further comprises: according to K×Pr=I U +I L Solve to get the coefficient K.

9. The method for calibrating an out-of-pile detector according to claim 8, characterized in that: In step S3, the fission neutron production rate is combined with the formula (1) to obtain the upper current I U，n and the lower current I L，n ; According to the axial power offset AO in，n and the upper current I U，n and the lower current I L，n , according to the formula: and AO ex,n =b×AO in,n +a The coefficient b is obtained by least squares fitting.

10. The method for calibrating an out-of-core detector according to claim 9, characterized in that: During a full core flux diagram experiment, the measured in-core axial power offset AO was also obtained. in And the measured external axial power offset AO ex ; The method further comprises: according to the measured in-core axial power offset AO in 、The measured out-of-core axial power offset AO ex And the coefficient b, calculate the coefficient a.

11. The method for calibrating an out-of-core detector according to claim 10, characterized in that: According to the coefficient a, coefficient b and coefficient K and the following formula, the calibration coefficients Ku, KL and α are calculated.

12. A computer device, characterized in that: include: A processor and a memory for storing a computer program that can be run on the processor, wherein the processor is used to implement the method for calibrating an out-of-core detector as described in any one of claims 1 to 11 when running the computer program.

13. A computer storage medium, characterized in that: An executable program is stored, and when the executable program is executed by a processor, the method for calibrating an out-of-core detector according to any one of claims 1 to 11 is implemented.

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