A method for implementing reliability qualification tests for nuclear reactor valves

Abstract

This invention provides a method for implementing reliability qualification tests on nuclear reactor valves, relating to the field of valve reliability testing technology. The method includes the following steps: determining a comprehensive statistical test scheme based on progressively decreasing decision risk, wherein the comprehensive statistical test scheme includes m test schemes with progressively decreasing decision risk; eliminating early valve failures through early failure elimination tests; conducting reliability qualification and acceptance tests on the tested valves after early failure elimination based on the comprehensive statistical test scheme; and continuing the reliability qualification and acceptance tests until all tested valves fail, and then evaluating reliability indicators. This invention can solve the problem that existing reliability qualification test standards for exponentially distributed lifetime products are not applicable to other lifetime distribution products.

Description

Technical Field

[0001] This invention relates to the field of valve reliability testing technology, and more specifically, to a method for conducting reliability qualification tests on nuclear reactor valves. Background Technology

[0002] Valves are key power equipment in nuclear reactors, with important functions such as flow regulation, flow control, and sealing, providing crucial guarantees for the safe and reliable start-up, operation, and shutdown of the reactor.

[0003] Conducting reliability qualification tests during the pre-production finalization stage to verify the reliability level of valves is essential, ensuring their reliability during the service life phase. Reliability qualification tests aim to verify the inherent reliability level of a product by simulating actual operating environments. These tests typically rely on statistical theory to verify whether the product's reliability parameters meet specified values. Examples include Mean Time Between Failures (MTBF) and Reliability (R). For on / off valves in nuclear reactors, the MTBF is the MTBF indicator. When designing statistical test schemes based on statistical theory, parameters such as the lower limit of MTBF, the discrimination ratio or upper limit of MTBF, manufacturer risk, and user risk are generally required. However, compared to electronic equipment, the upper limit of MTBF for electromechanical and mechanical equipment is difficult to derive from reliability predictions, and it may not necessarily fail to meet the exponential lifespan distribution assumption (i.e., a constant failure rate). Furthermore, existing reliability qualification test standards (such as GJB899A) are only applicable to products with an exponential lifespan distribution. Primary loop system valves are typical high-reliability electromechanical and mechanical equipment, and there are many types, with different types potentially having different lifespan distributions. Therefore, conducting reliability tests directly based on existing standards for index-based products will lead to significant deviations in the test results. On the other hand, reliability databases for valves in the nuclear energy field are relatively scarce, and compared to electronic equipment, it is difficult to obtain their prior life distribution through large-sample statistical analysis.

[0004] Therefore, it is necessary to improve the reliability qualification test method for conventional valves, solve the problem that the existing reliability qualification test standard for products with exponential life distribution is not applicable to other life distribution products, and realize a valve reliability qualification scheme that is more suitable for valves in the nuclear energy field and has high accuracy. Summary of the Invention

[0005] The purpose of this invention is to provide a method for conducting reliability qualification tests on nuclear reactor valves, which is a valve reliability qualification scheme with high accuracy that is more suitable for valves in the nuclear energy field.

[0006] This invention is achieved through the following technical solution:

[0007] A method for conducting reliability qualification tests on nuclear reactor valves includes the following steps:

[0008] A comprehensive statistical experimental scheme is determined based on the stepwise reduction of decision-making risk. The comprehensive statistical experimental scheme includes m experimental schemes with stepwise reduction of decision-making risk.

[0009] Early failures of valves are eliminated through early failure elimination tests.

[0010] Based on a comprehensive statistical test scheme, reliability assessment and acceptance tests were conducted on the test valves after early fault elimination.

[0011] The reliability qualification and acceptance tests continued until all tested valves failed, and then reliability index assessments were performed.

[0012] Preferably, the method for determining the comprehensive statistical experimental scheme based on progressively reducing decision-making risk is as follows:

[0013] Obtain the lower limit of MTBF (MTBF1) and the highest acceptable value of the producer's risk α. upb The highest acceptable value of user risk β. upb The number of valves under test, n;

[0014] Determine the range of the discrimination ratio d, and determine the total duration of the early fault elimination test based on the lower limit of MTBF test MTBF1;

[0015] Based on the highest acceptable value α of the producer's risk α upb The highest acceptable value of user risk β. upb And by gradually decreasing the step size, k experimental schemes are determined to gradually reduce the decision risk;

[0016] The total test duration T and the number of failures c for each scheme are determined according to the reliability qualification test standards.

[0017] Select m experimental schemes from k experimental schemes to form a comprehensive statistical experimental scheme.

[0018] Preferably, the step size is 10%.

[0019] Preferably, when determining the k test plans that progressively reduce decision risk, it is ensured that each plan meets the following condition: the user risk β is not greater than the producer risk α.

[0020] Preferably, the method for determining the total duration of the early fault elimination test based on the lower limit of MTBF (MTBF1) is that the total test duration is γ times the lower limit of MTBF (MTBF1), where γ is a positive number.

[0021] Preferably, the method for determining the k experimental schemes to progressively reduce decision risk is as follows:

[0022] The producer's risk α and the consumer's risk β are respectively derived from the highest acceptable value α of the producer's risk α. upb And the highest acceptable value β for user risk β upb Initially, by gradually decreasing the step size, k combinations of decision risks are obtained;

[0023] The total test duration T of the i-th test scheme i The total test duration T is less than that of the j-th test scheme. j The number of decision failures c for the i-th test scheme i The number of decision failures c is not greater than that of the j-th test scheme. k , i,j∈[1,k],i <j;

[0024] And the total test duration T of each scheme satisfies:

[0025] Preferably, the method for eliminating early valve failures through early failure elimination testing is as follows:

[0026] Obtain experimental parameters and experimental profiles;

[0027] The test valve is tested based on the comprehensive statistical test scheme. If a fault occurs, the faulty component is replaced and the test continues until the total time of the early fault elimination test is reached.

[0028] Preferably, if during the elimination of early valve failure:

[0029] If a fault is found, the tested valve shall be reset to zero. The fault reset includes fault analysis, formulation and implementation of corrective measures and verification of the effectiveness of the measures.

[0030] If there are no faults, the reliability assessment and acceptance tests shall adopt the results of the early fault elimination tests.

[0031] Preferably, the method for continuing the reliability assessment and acceptance tests until all tested valves fail is as follows:

[0032] Iterate through each of the aforementioned comprehensive statistical test schemes and make an acceptance decision;

[0033] After the acceptance decision is made, the test continues until all the tested valves fail.

[0034] Preferably, the method for making the acceptance decision is as follows:

[0035] Step S301: Assign i an initial value of 1;

[0036] Step S302: Perform the reliability assessment and acceptance test according to the i-th test scheme in the comprehensive statistical test scheme;

[0037] Step S303: If the number of failures r reaches c i Then proceed to step S306; otherwise, proceed to step S304. i Let be the number of decision failures for the i-th test scheme;

[0038] Step S304: If i = m, proceed to step S305; otherwise, set i = i + 1 and return to step S302.

[0039] Step S305: The reliability assessment and acceptance test is completed, and an acceptance decision is made based on the i-th test plan;

[0040] Step S306: If i = 1, proceed to step S307; otherwise, proceed to step S308.

[0041] Step S307: Zero out the faults in the reliability assessment and acceptance test, and then return to step S301 to restart the reliability assessment and acceptance test;

[0042] Step S308: The reliability assessment and acceptance test is completed, and an acceptance decision is made based on the (i-1)th test plan.

[0043] The technical solution of the present invention has at least the following advantages and beneficial effects:

[0044] This invention breaks through the limitation of existing technologies that are only applicable to products with exponential life distribution, and is particularly applicable to electromechanical equipment such as nuclear reactor valves that may not conform to the assumption of a constant failure rate, thereby improving the applicability and scientific nature of the test scheme;

[0045] This invention effectively eliminates early faults by carrying out an early fault elimination phase before formal testing, avoids early failures from affecting the results of formal testing, and improves the ability of the final judgment to reflect the inherent reliability level of the product.

[0046] This invention designs a multi-group statistical experiment combination to progressively reduce decision-making risk, and combines it with a flexible acceptance and zeroing mechanism to take into account the risks of both the producer and the user, thereby improving the adaptability and robustness of the decision and better meeting the needs of engineering practice.

[0047] This invention continues to test the remaining samples until failure after the test decision is completed, and obtains full life cycle data to provide more accurate and reliable data support for the subsequent evaluation and optimization of indicators such as MTBF and reliability. Attached Figure Description

[0048] Figure 1This is a flowchart illustrating the implementation method of the nuclear reactor valve reliability qualification test provided in Embodiment 1 of the present invention;

[0049] Figure 2 This is a flowchart illustrating the implementation steps of the nuclear reactor valve reliability qualification test method provided in Embodiment 1 of the present invention. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0051] Example 1

[0052] This embodiment provides a method for conducting reliability qualification tests on nuclear reactor valves. (See attached document.) Figures 1-2 This includes the following steps:

[0053] Step S1: Determine a comprehensive statistical test plan based on the progressive reduction of decision risk. The comprehensive statistical test plan includes m test plans with progressively reduced decision risk.

[0054] In this embodiment, the preferred method for determining a comprehensive statistical experimental scheme based on progressively reducing decision-making risk is:

[0055] Step S101: Obtain the lower limit of MTBF (MTBF1) and the highest acceptable value α of the producer's risk α. upb The highest acceptable value of user risk β. upb The number of valves under test, n, generally α upb and β upb All values ​​are the highest possible value of 30%.

[0056] Step S102: Determine the range of the discrimination ratio d, and determine the total duration of the early fault elimination test based on the lower limit of MTBF (MTBF1). As a preferred embodiment, the method for determining the total duration of the early fault elimination test based on the lower limit of MTBF (MTBF1) is that the total test duration is γ times the lower limit of MTBF (MTBF1), where γ is a positive number.

[0057] In this step, the discrimination ratio d is determined as the ratio of the upper limit of MTBF (MTBF1) to the lower limit of MTBF (MTBF0). For mechanical and electromechanical equipment, the lower limit of MTBF (MTBF0) is usually not given, making the discrimination ratio difficult to determine. Furthermore, the discrimination ratio is related to the reliability qualification test duration; a larger discrimination ratio results in a shorter test duration, making the design more difficult to implement; conversely, a smaller discrimination ratio results in a shorter test duration. Therefore, this embodiment uses a discrimination ratio as an interval for statistical test scheme design.

[0058] Step S103: Based on the highest acceptable value α of the producer's risk α upb The highest acceptable value of user risk β. upb By gradually decreasing the step size, k experimental schemes are determined to progressively reduce the decision-making risk.

[0059] As a preferred option, the step size is 10%. Furthermore, when determining the k experimental schemes to progressively reduce decision risk, it is ensured that each scheme meets the following condition: the user's risk β is not greater than the producer's risk α.

[0060] Based on this, the method for determining k experimental schemes to progressively reduce decision-making risk is as follows:

[0061] The producer's risk α and the consumer's risk β are respectively derived from the highest acceptable value α of the producer's risk α. upb And the highest acceptable value β for user risk β upb Initially, by gradually decreasing the step size, k combinations of decision risks are obtained; for example, α upb =20%, β upb With a step size of 10%, the following combinations exist: {α = 20%, β = 20%}, {α = 20%, β = 10%}, and {α = 10%, β = 10%}.

[0062] The total test duration T of the i-th test scheme i The total test duration T is less than that of the j-th test scheme. j The number of decision failures c for the i-th test scheme i The number of decision failures c is not greater than that of the j-th test scheme. k , i,j∈[1,k],i <j。

[0063] Furthermore, due to wear and tear on electromechanical equipment, when designing statistical test schemes, it is necessary to ensure that the test duration for each tested valve is not less than MTBF1. In other words, the total test duration T for each scheme must satisfy:

[0064] In summary, since the lower limit of MTBF test (MTBF1) and the discrimination ratio (d) have already been determined, the parameters for each test scheme include MTBF1, d, α, β, total test duration, and the number of decision failures.

[0065] Among them, the total test duration T and the number of failures c corresponding to each scheme can be determined according to reliability qualification test standards such as GJB899A.

[0066] Step S104: Select m experimental schemes from k experimental schemes to form a comprehensive statistical experimental scheme.

[0067] Step S2: Eliminate early valve failures through an early failure elimination test.

[0068] In this embodiment, the method for eliminating early valve failures through early failure elimination testing is as follows:

[0069] Obtain experimental parameters and experimental profiles;

[0070] The test valve is tested based on the comprehensive statistical test scheme. If a fault occurs, the faulty component is replaced and the test continues until the total time of the early fault elimination test is reached.

[0071] Based on the above solutions, if the early failure of the valve is eliminated:

[0072] If a fault is found, the tested valve will be reset to zero. The fault reset includes fault analysis, formulation and implementation of corrective measures and verification of the effectiveness of the measures, so that the subsequent reliability assessment and acceptance test can start from zero.

[0073] If there is no fault, the reliability assessment and acceptance tests will be based on the results of the early fault elimination tests, and subsequent reliability assessment and acceptance tests will continue on this basis.

[0074] Step S3: Based on the comprehensive statistical test scheme, conduct reliability assessment and acceptance tests on the test valves after the early faults have been eliminated;

[0075] As a preferred option, the method of continuing the reliability assessment and acceptance tests until all tested valves fail is as follows:

[0076] Iterate through each of the aforementioned comprehensive statistical test schemes and make an acceptance decision;

[0077] After the acceptance decision is made, the test continues until all the tested valves fail.

[0078] Preferably, the method for making the acceptance decision is as follows:

[0079] Step S301: Assign i an initial value of 1;

[0080] Step S302: Perform the reliability assessment and acceptance test according to the i-th test scheme in the comprehensive statistical test scheme;

[0081] Step S303: If the number of failures r reaches c i Then proceed to step S306; otherwise, proceed to step S304. i Let be the number of decision failures for the i-th test scheme;

[0082] Step S304: If i = m, proceed to step S305; otherwise, set i = i + 1 and return to step S302.

[0083] Step S305: The reliability assessment and acceptance test is completed, and an acceptance decision is made based on the i-th test plan;

[0084] Step S306: If i = 1, proceed to step S307; otherwise, proceed to step S308.

[0085] Step S307: Zero out the faults in the reliability assessment and acceptance test, and then return to step S301 to restart the reliability assessment and acceptance test;

[0086] Step S308: The reliability assessment and acceptance test is completed, and an acceptance decision is made based on the (i-1)th test plan.

[0087] The above approach, by traversing multiple statistical test combinations and determining at each level whether reliability requirements are met, avoids misjudgments caused by a single criterion, improves the robustness and rationality of the test, and is more suitable for the reliability verification needs of electromechanical equipment such as valves under complex operating conditions. Furthermore, it not only uses statistical judgment as the basis for acceptance but also continues testing after acceptance until all valves fail, thereby obtaining comprehensive lifespan data, which is beneficial for high-precision modeling and evaluation of subsequent reliability parameters (such as MTBF and reliability curves).

[0088] Furthermore, during the trial, the decision-making risk was progressively reduced until a rejection decision was made based on a certain statistical trial plan (specifically, the number of responsible failures occurring during the trial exceeded the number of failures to be rejected, c). When based on α=α upb With β=β upb After a rejection decision is made based on the chosen test plan, a rejection decision is made for the entire test. Simultaneously, the tested valve must be reset to zero before the test is restarted or terminated. In all other cases, an acceptance decision is made for the test. Finally, after a rejection decision is made based on a specific test plan and an acceptance decision is made based on the comprehensive statistical test plan, the reliability assessment test concludes. The remaining tested valves are then tested until a failure occurs.

[0089] Step S4: Continue the reliability assessment and acceptance tests until all tested valves fail, and then evaluate the reliability indicators.

[0090] Some common reliability metrics include MTBF and failure rate.

[0091] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for conducting reliability qualification tests on nuclear reactor valves, characterized in that, Includes the following steps: A comprehensive statistical experimental scheme is determined based on the stepwise reduction of decision-making risk. The comprehensive statistical experimental scheme includes m experimental schemes with stepwise reduction of decision-making risk. Early failures of valves are eliminated through early failure elimination tests. Based on a comprehensive statistical test scheme, reliability assessment and acceptance tests were conducted on the test valves after early fault elimination. Continue the reliability qualification and acceptance tests until all tested valves fail, and then evaluate the reliability indicators. The method for determining a comprehensive statistical experimental scheme based on progressively reducing decision-making risk is as follows: Obtaining the lower limit of MTBF (MTBF1) and the manufacturer's risk. The highest acceptable value User risks The highest acceptable value The number of valves under test, n; Determine the range of the discrimination ratio d, and determine the total duration of the early fault elimination test based on the lower limit of MTBF test MTBF1; Based on producer risk The highest acceptable value User risks The highest acceptable value And by gradually decreasing the step size, k experimental schemes are determined to gradually reduce the decision risk; The total test duration T and the number of failures c for each scheme are determined according to the reliability qualification test standards. Select m experimental schemes from k experimental schemes to form a comprehensive statistical experimental scheme.

2. The method for implementing a reliability qualification test for a nuclear reactor valve according to claim 1, characterized in that, The step size is 10%.

3. The method for implementing a reliability qualification test for a nuclear reactor valve according to claim 1, characterized in that, When determining the k test plans that progressively reduce decision risk, ensure that each plan meets the following user risk criteria. No greater than the aforementioned producer risk .

4. The method for implementing a reliability qualification test for a nuclear reactor valve according to claim 1, characterized in that, The method for determining the total duration of early fault elimination tests based on the lower limit of MTBF (MTBF1) is as follows: the total test duration is equal to the lower limit of MTBF1. times, It is a positive number.

5. The method for implementing a reliability qualification test for a nuclear reactor valve according to claim 4, characterized in that, The method for determining the k trial schemes to progressively reduce decision risk is as follows: Manufacturer risk and user risks Risks from the production side The highest acceptable value And user risks The highest acceptable value Initially, by gradually decreasing the step size, k combinations of decision risks are obtained; The total test duration of the i-th test scheme The total test duration is less than that of the j-th test scheme. The number of decision failures for the i-th test scheme The number of decision failures is not greater than that of the j-th test scheme. , ; Furthermore, the total test duration T of each scheme satisfies the following: .

6. The method for implementing a reliability qualification test for a nuclear reactor valve according to claim 1, characterized in that, The method for eliminating early valve failures through early failure elimination testing is as follows: Obtain experimental parameters and experimental profiles; The test valve is tested based on the comprehensive statistical test scheme. If a fault occurs, the faulty component is replaced and the test continues until the total time of the early fault elimination test is reached.

7. The method for implementing a reliability qualification test for a nuclear reactor valve according to claim 6, characterized in that, If the early failure of the valve is eliminated: If a fault is found, the tested valve shall be reset to zero. The fault reset includes fault analysis, formulation and implementation of corrective measures and verification of the effectiveness of the measures. If there are no faults, the reliability assessment and acceptance tests shall adopt the results of the early fault elimination tests.

8. The method for implementing a reliability qualification test for a nuclear reactor valve according to claim 1, characterized in that, The method for continuing the reliability qualification and acceptance tests until all tested valves fail is as follows: Iterate through each of the aforementioned comprehensive statistical test schemes and make an acceptance decision; After the acceptance decision is made, the test continues until all the tested valves fail.

9. The method for implementing a reliability qualification test for a nuclear reactor valve according to claim 8, characterized in that, The method for making the acceptance decision is as follows: Step S301: Assign i an initial value of 1; Step S302: Perform the reliability assessment and acceptance test according to the i-th test scheme in the comprehensive statistical test scheme; Step S303: If the number of failures r reaches If so, proceed to step S306; otherwise, proceed to step S304. Let be the number of decision failures for the i-th test scheme; Step S304: If i=m, proceed to step S305; otherwise, set i=i+1 and return to step S302. Step S305: The reliability assessment and acceptance test is completed, and an acceptance decision is made based on the i-th test plan; Step S306: If i=1, proceed to step S307; otherwise, proceed to step S308. Step S307: Zero out the faults in the reliability assessment and acceptance test, and then return to step S301 to restart the reliability assessment and acceptance test; Step S308: The reliability assessment and acceptance test is completed, and an acceptance decision is made based on the (i-1)th test plan.

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