Method and device for judging dilution stop point in critical process of pressurized water reactor

Abstract

The invention belongs to the field of nuclear power plant reactor physics, and particularly relates to a pressurized water reactor critical process dilution stop point judgment method and device, and the method comprises the steps: obtaining the theoretical reactivity # imgabs0 # of a reactor core before the pressurized water reactor critical process dilution and the theoretical reactivity # imgabs1 # of the reactor core at the dilution stop point; according to # imgabs2 # and # imgabs3 #, 1 / M at the dilution stop point corresponding to the target critical state is obtained through calculation; according to the 1 / M and the source range counting rate # imgabs4 # of the source range channel i before dilution, calculating to obtain a target source range counting rate # imgabs5 # of the source range channel i at the dilution stop point; and when the source range counting rate of the source range channel i in the out-of-pile nuclear measurement system in the dilution process rises to # imgabs6, judging that a dilution stop point is reached, and stopping dilution. The dilution stop point is judged according to the target source range counting rate of the source range channel in the out-of-pile nuclear measurement system in the real-time dilution process, so that the technical problem that the reactivity of the tail end of the control rod group is greatly deviated from the expected value at the final critical time at present is solved.

Description

Technical Field

[0001] This application belongs to the field of reactor physics of nuclear power plants, and specifically relates to a method and device for judging the dilution stop point in the critical process of a pressurized water reactor. Background Art

[0002] Reactor criticality is the process of guiding the reactor from a subcritical state to a critical state to achieve a self-sustaining chain fission reaction. Most domestic pressurized water reactor nuclear power units still use the method of reaching criticality by raising control rods. Judging the dilution stop point is the key to the process of reaching criticality by raising control rods. The accuracy of controlling the dilution stop point directly determines whether the reactor can reach criticality near the target critical state (the reactivity of the control rod group end is 60 pcm), and even affects whether the reactor can become critical.

[0003] Currently, there are mainly two methods for judging the dilution stop point of reaching criticality by raising control rods: Judgment method 1: Stop dilution when the deviation between the boron concentration in the current state calculated from the dilution water volume and the extrapolated critical boron concentration from the dilution water volume reaches the expected value, and this expected value is obtained by converting the sum of the reactivity introduced from the current rod position to the target critical rod position and core mixing; Judgment method 2: The neutron inverse counting rate ratio 1 / M reaches a certain value, which is obtained from historical test data and does not change with the core loading scheme.

[0004] For the existing two judgment methods, due to the change of the existing dilution method and the difference of different cycle core loading schemes, the reactivity of the control rod group end deviates greatly from the expected value (60 pcm) at the final criticality, and the deviation is generally about 100 - 200 pcm, thus affecting the implementation of the subsequent zero-power performance test. Summary of the Invention

[0005] In view of this, this application is committed to providing a method and device for judging the dilution stop point in the critical process of a pressurized water reactor, and judging the dilution stop point through the target source range count rate of the source range channel in the out-of-core nuclear measurement system during the real-time dilution process, so as to solve the technical problem that the reactivity of the control rod group end deviates greatly from the expected value at the final criticality due to the change of the dilution method and the difference of different cycle core loading schemes.

[0006] The first aspect of this application provides a method for judging the dilution stop point in the critical process of a pressurized water reactor, and this method for judging the dilution stop point in the critical process of a pressurized water reactor includes: Step 1: Obtain the theoretical reactivity of the core before dilution in the critical process of the pressurized water reactor according to the design report of the current core loading scheme, the core state before dilution, the core state at the dilution stop point, and the target critical state and the theoretical reactivity of the core at the dilution stop point .

[0007] Step 2: Based on the theoretical reactivity of the core before dilution and the theoretical reactivity of the core at the dilution stop point , calculate the 1 / M at the dilution stop point corresponding to the target critical state by combining with Formula 1 Formula 1

[0008] Step 3: Based on 1 / M and the source range count rate of the i-th source range channel before dilution , calculate the target source range count rate of the i-th source range channel at the dilution stop point by combining with Formula 2 , Formula 2

[0009] Step 4: When the source range count rate of the i-th source range channel in the out-of-core nuclear measurement system during the dilution process rises to the target source range count rate of the i-th source range channel at the dilution stop point , it is determined that the dilution stop point has been reached, and the dilution is stopped

[0010] In a specific embodiment of the present application, the above Step 1 includes the following Steps 1-1 and 1-2

[0011] Step 1-1: Based on the design report of the current core loading scheme and the core state before dilution, calculate the theoretical reactivity of the core before dilution by combining with Formula 3 ; Formula 3

[0012] In Formula 3 is the theoretical reactivity introduced by the control rod group from the fully withdrawn state to the rod position before dilution; is the boron concentration of the core before dilution; is the theoretical critical boron concentration in the fully withdrawn state of the control rod group; DBC is the theoretical boron differential worth under the conditions of the initial stage of core life, hot zero power, and critical boron concentration

[0013] Step 1-2: Based on the design report of the current core loading scheme, the core state at the dilution stop point, and the target critical state, calculate the theoretical reactivity of the core at the dilution stop point ; Formula 4

[0014] In Formula 4 is the theoretical reactivity introduced by the control rod group from the fully withdrawn state (ARO) to the expected target critical rod position

[0015] In a specific embodiment of the present application, the above Step 2 includes the following Steps 2-1 and 2-2

[0016] Step 2-1: Obtain the theoretical reactivity of the core before dilution, the theoretical reactivity of the core at the dilution stop point, and the relationship between 1 / M at the dilution stop point corresponding to the target critical state according to the 1 / M extrapolation formula and the subcritical formula. , the theoretical reactivity of the core at the dilution stop point and the relationship of 1 / M at the dilution stop point corresponding to the target critical state.

[0017] Step 2-2: Calculate the 1 / M at the dilution stop point corresponding to the target critical state (such as the reactivity of the control rod bank end being 60 pcm) according to the theoretical reactivity of the core before dilution , the theoretical reactivity of the core at the dilution stop point and the relationship of 1 / M at the dilution stop point corresponding to the target critical state.

[0018] In a specific embodiment of the present application, the above step 3 includes the following steps 3-1 and 3-2. The above step 4 includes the following step 4-1.

[0019] Step 3-1: Calculate the target source range count rate of the No. 1 source range channel at the dilution stop point according to 1 / M and the source range count rate of the No. 1 source range channel before dilution , in combination with Formula VIII. .

[0020] Formula VIII.

[0021] Step 3-2: Calculate the target source range count of the No. 2 source range channel at the dilution stop point according to 1 / M and the source range count rate of the No. 2 source range channel before dilution , in combination with Formula IX. .

[0022] Formula IX.

[0023] Step 4-1: When the source range count rate of the No. 1 source range channel of the out-of-core nuclear measurement system during the dilution process rises to , and the source range count rate of the No. 2 source range channel rises to , it is determined that the dilution stop point has been reached and the dilution is stopped.

[0024] The second aspect of the present application provides a device for judging the dilution stop point in the critical process of a pressurized water reactor. The device for judging the dilution stop point in the critical process of a pressurized water reactor includes an acquisition module, a calculation module, and a determination module.

[0025] The acquisition module is configured to obtain the theoretical reactivity of the core before dilution in the critical process of a pressurized water reactor according to the design report of the current core loading scheme, the core state before dilution, the core state at the dilution stop point, and the target critical state and the theoretical reactivity of the core at the dilution stop point 。

[0026] A calculation module, configured to calculate, according to the theoretical reactivity of the core before dilution and the theoretical reactivity of the core at the dilution stop point and, in combination with Formula 1, calculate the 1 / M at the dilution stop point corresponding to the target critical state Formula 1; and, according to 1 / M and the source range count rate of the i-th source range channel before dilution and, in combination with Formula 2, calculate the target source range count rate of the i-th source range channel at the dilution stop point , Formula 2.

[0027] A determination module, configured to determine that the dilution stop point has been reached and stop dilution when the source range count rate of the i-th source range channel in the out-of-core nuclear measurement system during the dilution process rises to the target source range count rate of the i-th source range channel at the dilution stop point 。

[0028] The third aspect of the present application provides a computer device. The computer device includes a processor and a memory. The processor is configured to execute a method for determining the dilution stop point in the critical process of a pressurized water reactor according to the first aspect of the present application. The memory is configured to store executable instructions of the processor.

[0029] The fourth aspect of the present application provides a computer-readable storage medium, on which executable instructions of a computer are stored. When the executable instructions are executed by a processor, a method for determining the dilution stop point in the critical process of a pressurized water reactor according to the first aspect of the present application is implemented.

[0030] The fifth aspect of the present application provides a computer program product, including a computer program / instruction. When the computer program / instruction is executed by a processor, a method for determining the dilution stop point in the critical process of a pressurized water reactor according to the first aspect of the present application is implemented.

[0031] The beneficial effects of the technical solution of the present application are as follows: The method for determining the dilution stop point in the critical process of a pressurized water reactor can more accurately determine the dilution stop point in the process of raising the control rods of a pressurized water reactor to criticality, and the determination method is simple, stable and reliable, and can be widely used. When the unit reaches the critical state by using the method for determining the dilution stop point in the critical process of a pressurized water reactor, the reactivity at the end of the control rod group is close to 60 pcm, which is convenient for carrying out subsequent zero-power performance tests. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The figure shows a schematic flowchart of a method for determining the dilution stop point in the critical process of a pressurized water reactor provided by an embodiment of the present application. Specific Embodiments

[0033] Next, in combination with the accompanying drawings in the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0034] At least one embodiment of the present application provides a method for judging the dilution stop point in the critical process of a pressurized water reactor. The execution subject of the method for judging the dilution stop point in the critical process of the pressurized water reactor can be a processor or a server, etc. Hereinafter, the processor will be taken as an example for illustration. Refer to Figure 1 , and the method for judging the dilution stop point in the critical process of the pressurized water reactor includes the following steps.

[0035] Step 1: According to the design report of the current core loading scheme, the core state before dilution, the core state at the dilution stop point, and the target critical state, obtain the theoretical reactivity of the core of the pressurized water reactor before dilution in the critical process and the theoretical reactivity of the core at the dilution stop point .

[0036] In some embodiments, it can be that the user calculates the theoretical reactivity of the core of the pressurized water reactor before dilution in the critical process and the theoretical reactivity of the core at the dilution stop point according to the design report of the current core loading scheme, the core state before dilution, the core state at the dilution stop point, and the target critical state, and and are manually input into the computer device, so that the processor of the computer device can directly obtain the theoretical reactivity of the core of the pressurized water reactor before dilution in the critical process according to the user input and the theoretical reactivity of the core at the dilution stop point .

[0037] In other embodiments, the processor of the computer device can directly identify or call the corresponding parameters from the design report of the current core loading scheme, the core state before dilution, the core state at the dilution stop point, and the target critical state, and calculate the theoretical reactivity of the core of the pressurized water reactor before dilution in the critical process according to the corresponding parameters and the theoretical reactivity of the core at the dilution stop point .

[0038] It should be noted that and are both in the unit of pcm.

[0039] Step 2: According to the theoretical reactivity of the core before dilution and the theoretical reactivity of the core at the dilution stop point , combined with Formula 1, calculate 1 / M at the dilution stop point corresponding to the target critical state Formula 1

[0040] Step 3: According to 1 / M and the source range count rate of the i-th source range channel before dilution , combined with Formula 2, calculate the target source range count rate of the i-th source range channel at the dilution stop point , Formula 2

[0041] Specifically, according to Formula 2, it can be known that , from which the target source range count rate of the i-th source range channel at the dilution stop point can be calculated .

[0042] Step 4: When the source range count rate of the i-th source range channel in the out-of-core nuclear measurement system during the dilution process rises to the target source range count rate of the i-th source range channel at the dilution stop point , it is determined that the dilution stop point has been reached, and the dilution is stopped

[0043] It should be noted that the neutron measurement in the source range of the reactor is characterized by the source range count rate to represent the neutron flux density and power level. The source range count rate is a kind of pulse count rate

[0044] According to the technical solution provided by the embodiment of the present application, by according to the theoretical reactivity of the core before dilution and the theoretical reactivity of the core at the dilution stop point , calculate 1 / M at the dilution stop point corresponding to the target critical state, so as to realize that the empirical value is no longer used to determine 1 / M, and improve the accuracy of 1 / M. By designing that when the source range count rate of the source range channel in the out-of-core nuclear measurement system during the dilution process rises to the source range count rate of the source range channel at the dilution stop point When it reaches this point, it is determined that the dilution stop point has been reached, and dilution is stopped. By judging the dilution stop point in this way, after waiting for the core to be well mixed and the control rods are lifted to criticality, the reactivity at the end of the control rod group during the final actual criticality should basically conform to the expectation, thereby reducing the state adjustment time before the subsequent zero-power performance test and effectively shortening the main overhaul line. In addition, according to the differences in the core loading methods of different cycles of the pressurized water reactor unit, the judgment method for the dilution stop point in the critical process of this pressurized water reactor updates the judgment conditions for the dilution stop point, enabling the reactor to reach criticality near 60 pcm of the reactivity at the end of the control rod group more accurately. The judgment method for the dilution stop point in the critical process of this pressurized water reactor can judge the dilution stop point by the target source range count rate of the out-of-core nuclear measurement system during the dilution process in real time. Compared with the existing method of judging the dilution stop point by extrapolation every 5 minutes or 15 minutes, it effectively avoids the delayed judgment that fails to stop dilution in time. The judgment method for the dilution stop point in the critical process of this pressurized water reactor can make the reactivity at the end of the control rod group closer to 60 pcm by accurately controlling the target critical rod position, reducing the state adjustment time before the subsequent zero-power performance test and effectively shortening the main overhaul line.

[0045] In at least one embodiment of the present application, step 1 above includes the following steps 1-1 and 1-2.

[0046] Step 1-1: According to the design report of the current core loading scheme and the core state before dilution, calculate the theoretical reactivity of the core before dilution by combining formula three ; Formula three.

[0047] In formula three, is the theoretical reactivity introduced by the control rod group from the fully lifted state to the rod position before dilution; is the boron concentration of the core before dilution; is the theoretical critical boron concentration in the fully lifted state of the control rod group; DBC is the theoretical boron differential worth under the conditions of the beginning of core life (BOL), hot zero power (HZP), and critical boron concentration.

[0048] It should be noted that , and DBC can all be obtained from the design report of the current core loading scheme, can be obtained from the core state before dilution. The fully lifted state is the state where all control rods are out of the core (All Rods Clusters Out, ARO). The units of and are both pcm,

[0049] Step 1-2: Calculate the theoretical reactivity of the core at the dilution stop point based on the design report of the current core loading scheme, the core state at the dilution stop point, and the target critical state. ; Formula Four.

[0050] In Formula Four, is the theoretical reactivity introduced by the control rod group from the fully withdrawn state (ARO) to the expected target critical rod position.

[0051] It should be noted that The unit of is pcm.

[0052] In at least one embodiment of the present application, the above Step 2 includes the following Steps 2-1 and 2-2.

[0053] Step 2-1: Obtain the relationship between the theoretical reactivity of the core before dilution , the theoretical reactivity of the core at the dilution stop point and 1 / M at the dilution stop point corresponding to the target critical state according to the 1 / M extrapolation formula and the subcritical formula.

[0054] Specifically, the subcritical formula is as follows, Formula Five: Formula Five.

[0055] In Formula Five, n is the neutron flux density; S is the external neutron source intensity; is the effective multiplication factor; is the neutron mean lifetime.

[0056] The 1 / M extrapolation formula is as follows, Formula Six: Formula Six.

[0057] Substitute Formula Five into Formula Six to obtain Formula Seven: Formula Seven.

[0058] In Formula Seven, is the effective multiplication factor at the dilution stop point; is the effective multiplication factor before dilution.

[0059] It should be noted that the units of n, n0, and n1 are all n / cm 3 ; the unit of S is Bq; The unit of is s. Both Formula Seven and Formula One are the theoretical reactivity of the core before dilution , the theoretical reactivity of the core at the dilution stop point The relationship between 1 / M at the dilution stop point corresponding to the target critical state, and Equation 1 is the simplified equation of Equation 7.

[0060] Step 2-2: According to the theoretical reactivity of the core before dilution , the theoretical reactivity of the core at the dilution stop point and the relationship between 1 / M at the dilution stop point corresponding to the target critical state, calculate 1 / M at the dilution stop point corresponding to the target critical state (such as the reactivity of the control rod bank end being 60 pcm).

[0061] The number of source range channels of different types of pressurized water reactors may be different. For example, some pressurized water reactors have 2 source range channels, and some have 4 source range channels. The following takes the case of 2 source range channels in a pressurized water reactor as an example for illustration.

[0062] In at least one embodiment of the present application, the above Step 3 includes the following Steps 3-1 and 3-2. The above Step 4 includes the following Steps 4-1 and 4-2.

[0063] Step 3-1: According to 1 / M and the source range count rate of the No. 1 source range channel before dilution , combined with Equation 8, calculate the target source range count rate of the No. 1 source range channel at the dilution stop point .

[0064] Equation 8.

[0065] Step 3-2: According to 1 / M and the source range count rate of the No. 2 source range channel before dilution , combined with Equation 9, calculate the target source range count of the No. 2 source range channel at the dilution stop point .

[0066] Equation 9.

[0067] It should be noted that , , and are all in cps.

[0068] Step 4-1: When the source range count rate of the No. 1 source range channel of the out-of-core nuclear measurement system during the dilution process rises to , and the source range count rate of the No. 2 source range channel rises to , it is determined that the dilution stop point has been reached, and dilution is stopped.

[0069] The method for judging the dilution stop point in the critical process of this pressurized water reactor has been verified by the initial critical test data of multiple units and multiple cycles, and can enable the reactor to reach criticality more accurately near 60 pcm of the reactivity at the end of the control rod bank. Next, the method for judging the dilution stop point in the critical process of this pressurized water reactor will be illustrated with specific embodiments.

[0070] Embodiment 1: Take a certain unit of a nuclear power plant as an example According to the design report of the current core loading scheme and the core state before dilution, calculate the theoretical reactivity of the core before dilution to be 2144.75 pcm (corresponding to step 1-1); According to the design report of the current core loading scheme, the core state at the dilution stop point, and the target critical state (e.g., reactivity at the end of the control rod bank is 60 pcm, critical rod position * rod bank 199 steps), calculate the theoretical reactivity of the core at the dilution stop point to be 524 pcm (corresponding to step 1-2); 3. According to the 1 / M extrapolation principle and the subcritical formula, calculate 1 / M = 0.244 at the dilution stop point corresponding to the target critical state (reactivity at the end of the control rod bank is 60 pcm, critical rod position * rod bank 199 steps) (corresponding to steps 2-1 and 2-2); 4. According to 1 / M = 0.244 and the source range count rate of the No. 1 source range channel before dilution = 50.7 cps, substitute it into formula two, and calculate the source range count rate of the No. 1 source range channel at the dilution stop point = 207.8 cps. According to 1 / M = 0.244 and the source range count rate of the No. 2 source range channel before dilution = 46.6 cps, substitute it into formula two, and calculate the source range count rate of the No. 2 source range channel at the dilution stop point = 191.0 cps.

[0071] 5. During the dilution process, when the source range count rate of the No. 1 source range channel reaches 207.8 cps and the source range count rate of the No. 2 source range channel reaches 191.0 cps, stop dilution (corresponding to step 4-1). After waiting for the core to be well mixed, raise the rods to reach criticality. Finally, the reactivity at the end of the control rod bank at actual criticality is 35 pcm, and the deviation from the expected 60 pcm is only 25 pcm, which is much smaller than the deviation (100 pcm - 200 pcm) of the existing judgment method.

[0072] The final end reactivity of the method for judging the dilution stop point in the critical process of the pressurized water reactor has a deviation of 25 pcm from the target, and the converted boron concentration deviation is only 3.8 ppm. By diluting and adjusting the control rod group, the end reactivity is brought between 50 pcm and 60 pcm. Since the change in boron concentration is small, there is basically no need to wait, which can meet the core uniformity condition, reduce the core state adjustment time before the subsequent zero-power performance test, effectively shorten the main overhaul time by about 1 hour, and increase the economic benefits of the unit.

[0073] At least one embodiment of the present application further provides a device for judging the dilution stop point in the critical process of a pressurized water reactor. The device for judging the dilution stop point in the critical process of the pressurized water reactor includes an acquisition module, a calculation module, and a determination module.

[0074] The acquisition module is used to obtain the theoretical reactivity of the core before dilution in the critical process of the pressurized water reactor according to the design report of the current core loading scheme, the core state before dilution, the core state at the dilution stop point, and the target critical state and the theoretical reactivity of the core at the dilution stop point .

[0075] The calculation module is used to calculate the 1 / M at the dilution stop point corresponding to the target critical state according to the theoretical reactivity of the core before dilution and the theoretical reactivity of the core at the dilution stop point , in combination with Formula 1 Formula 1; and according to 1 / M and the source range count rate of the i-th source range channel before dilution , calculate the target source range count rate of the i-th source range channel at the dilution stop point in combination with Formula 2 , Formula 2.

[0076] The determination module is used to determine that the dilution stop point has been reached and stop dilution when the source range count rate of the i-th source range channel in the out-of-core nuclear measurement system during the dilution process rises to the target source range count rate of the i-th source range channel at the dilution stop point .

[0077] The device for judging the dilution stop point in the critical process of the pressurized water reactor is the judging device corresponding to the method for judging the dilution stop point in the critical process of the pressurized water reactor provided in any of the above embodiments of the present application, including the technical features corresponding to the method for judging the dilution stop point in the critical process of the pressurized water reactor, and can achieve the corresponding technical effects, which will not be elaborated here.

[0078] At least one embodiment of the present application further provides a computer device, which includes a processor and a memory. The processor is configured to execute a method for judging the dilution stop point in the critical process of a pressurized water reactor provided in any one of the above embodiments of the present application. The memory is used to store executable instructions of the processor, such as application programs. The number of processors can be one or more. The application programs stored in the memory may include one or more modules each corresponding to a set of instructions. In addition, the processor is configured to execute instructions to execute the method for judging the dilution stop point in the critical process of the above pressurized water reactor.

[0079] The computer device may further include a power supply component configured for power management of the computer device, a wired or wireless network interface configured to connect the computer device to a network, and an input / output (I / O) interface. The computer device can operate based on an operating system stored in the memory, such as Windows Server TM , Mac OSX TM , Unix TM , Linux TM , FreeBSD TM or the like.

[0080] At least one embodiment of the present application further provides a computer-readable storage medium, on which executable instructions of a computer are stored. When the executable instructions are executed by a processor, a method for judging the dilution stop point in the critical process of a pressurized water reactor provided in any one of the above embodiments of the present application is implemented.

[0081] A non-transitory computer-readable storage medium, when the instructions in the storage medium are executed by the processor of the above computer device, enables the above computer device to execute the method for judging the dilution stop point in the critical process of the pressurized water reactor. The method for judging the dilution stop point in the critical process of the pressurized water reactor is executed by an agent program.

[0082] Those of ordinary skill in the art can realize that the algorithm steps of each example described in combination with the embodiments disclosed in the present application can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of the present application.

[0083] At least one embodiment of the present application further provides a computer program product, including a computer program / instructions, and when the computer program / instructions are executed by a processor, a method for judging the dilution stop point in the critical process of a pressurized water reactor provided in any one of the above embodiments of the present application is implemented.

[0084] When the above functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art or a part of this technical solution can be embodied in the form of a computer program product. This computer program product is stored in a storage medium and includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of a method for determining the dilution stop point of a pressurized water reactor critical process in various embodiments of this application. The aforementioned storage medium includes: various media such as USB flash drives, external hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical discs that can store program check codes.

[0085] It should be noted that the combination manner of each technical feature in the embodiments of this application is not limited to the combination manner recorded in the embodiments of this application or the combination manner recorded in the specific embodiments. All the technical features recorded in this application can be freely combined or combined in any manner, unless contradictions occur between them.

[0086] As shown in this application and the claims, unless the context clearly indicates an exceptional situation, words such as "a", "an", and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the term "comprising" only indicates the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0087] The terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0088] The above are only the preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent replacements, etc. made within the spirit and principle of this application shall be included within the protection scope of this application.

Claims

1. A method for determining the dilution stop point in the critical process of a pressurized water reactor, characterized in that, Including: Step 1. Obtain the theoretical reactivity of the pressurized water reactor core before dilution during the critical process according to the design report of the current core loading scheme, the core state before dilution, the core state at the dilution stop point, and the target critical state and the theoretical reactivity of the core at the dilution stop point ; Step 2: According to the theoretical reactivity of the core before dilution and the theoretical reactivity of the core at the dilution stop point , combining with Formula 1, calculate the 1 / M at the dilution stop point corresponding to the target critical state Formula One; Step 3: According to 1 / M and the source range count rate of the i-th source range channel before dilution , calculate the target source range count rate of the i-th source range channel at the dilution stop point by combining with Formula 2 , Formula II; Step 4: When the source range count rate of the i-th source range channel in the in-core nuclear measurement system during the dilution process rises to the dilution stop point, the target source range count rate of the i-th source range channel is reached, it is determined that the dilution stop point has been reached, and the dilution is stopped.

2. The method for determining the dilution stop point in the critical process of a pressurized water reactor according to claim 1, wherein Step 1 includes: Step 1-1: Calculate the theoretical reactivity of the core before dilution according to the design report of the current core loading scheme and the core state before dilution, in combination with Formula 3 ; Formula III, In Equation 3, is the theoretical reactivity introduced by the control rod group from the fully withdrawn state to the rod position before dilution; is the boron concentration in the core before dilution; is the theoretical critical boron concentration in the fully withdrawn state of the control rod group; DBC is the theoretical boron differential worth under the conditions of the initial core life, hot zero power, and critical boron concentration. Step 1-2: Calculate the theoretical reactivity of the core at the dilution stop point based on the design report of the current core loading scheme, the core state at the dilution stop point, and the target critical state. ; Formula Four, In Equation 4, is the theoretical reactivity introduced by the control rod group from the all-rod-out state (ARO) to the expected target critical rod position.

3. The method for determining the dilution stop point in the critical process of a pressurized water reactor according to claim 1, characterized in that, Step 2 includes: Step 2-1: Obtain the theoretical reactivity of the core before dilution according to the 1 / M extrapolation formula and the subcritical formula , the theoretical reactivity of the core at the dilution stop point and the relationship of 1 / M at the dilution stop point corresponding to the target critical state; Step 2-2: According to the theoretical reactivity of the core before dilution , the theoretical reactivity of the core at the dilution stop point and the relationship formula of 1 / M at the dilution stop point corresponding to the target critical state, calculate 1 / M at the dilution stop point corresponding to the target critical state (such as the reactivity of the end of the control rod group being 60 pcm).

4. The method for judging the dilution stop point in the critical process of a pressurized water reactor according to claim 1, characterized in that, Step 3 includes: Step 3-1: According to 1 / M and the source range count rate of the No. 1 source range channel before dilution , and in combination with Formula VIII, calculate the target source range count rate of the No. 1 source range channel at the dilution stop point , Formula VIII, Step 3-2: According to 1 / M and the source range count rate of the No. 2 source range channel before dilution , combined with Formula 9, calculate the target source range count of the No. 2 source range channel at the dilution stop point , Formula Nine; Step 4 includes: Step 4-1: When the source range count rate of the No. 1 source range channel of the in-core nuclear measurement system during the dilution process rises to , and the source range count rate of the No. 2 source range channel rises to , it is determined that the dilution stop point has been reached, and the dilution is stopped.

5. A device for judging the dilution stop point in the critical process of a pressurized water reactor, characterized in that, Including an acquisition module, a calculation module and a determination module, An acquisition module, configured to acquire the theoretical reactivity of the core before dilution in the critical process of a pressurized water reactor according to the design report of the current core loading scheme, the core state before dilution, the core state at the dilution stop point, and the target critical state and the theoretical reactivity of the core at the dilution stop point ; Calculation module, configured to calculate, according to the theoretical reactivity of the core before dilution and the theoretical reactivity of the core at the dilution stop point , and calculate 1 / M at the dilution stop point corresponding to the target critical state by combining with Formula 1 Formula 1; and based on 1 / M and the source range count rate of the i-th source range channel before dilution , the target source range count rate of the i-th source range channel at the dilution stop point is calculated by combining formula two , Formula II; A determination module, configured to determine that the dilution stop point has been reached and stop dilution when the target source range count rate of the i-th source range channel in the in-core nuclear measurement system during the dilution process rises to the dilution stop point for the i-th source range channel.

6. A computer device, characterized in that, Including: A processor for executing a method for judging the dilution stop point in a critical process of a pressurized water reactor according to any one of claims 1 to 4; And A memory for storing executable instructions of the processor.

7. A computer-readable storage medium having computer-executable instructions stored thereon, characterized in that, When the executable instructions are executed by the processor, a method for judging the dilution stop point in a critical process of a pressurized water reactor according to any one of claims 1 to 4 is implemented.

8. A computer program product, comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by the processor, a method for judging the dilution stop point in a critical process of a pressurized water reactor according to any one of claims 1 to 4 is implemented.

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