阅读说明：本技术 核电厂安全相关仪表校验类监督项目周期延长的评价方法 (Evaluation method for prolonging cycle of check type supervision project of safety related instrument of nuclear power plant ) 是由 谢征宇 罗文博 唐博文 梁小玉 吴益文 解永奎 张勇 圣国龙 吴顺贵 陈海岳 刘 于 2020-07-07 设计创作，主要内容包括：一种核电厂安全相关仪表校验类监督项目周期延长的评价方法,包括以下步骤：获取安全相关仪表的名义触发整定值NTSP和分析限值AL；根据安全相关仪表的历史校验数据,计算安全相关仪表校验类监督项目在周期延长后的漂移量AD<Sub>C1</Sub>；根据所述漂移量AD<Sub>C1</Sub>计算安全相关仪表校验类监督项目在周期延长后的通道不确定度CU<Sub>C1</Sub>；计算安全相关仪表的安全裕度,其中,安全相关仪表的安全裕度＝AL－CU<Sub>C1</Sub>－NTSP；然后判断安全相关仪表的安全裕度是否大于0,若是,则不调整安全相关仪表的名义触发整定值NTSP。本发明的核电厂安全相关仪表校验类监督项目周期延长的评价方法设计新颖,实用性强。(A nuclear power plant safety related instrument checking supervision project cycle extension evaluation method comprises the following steps: acquiring a nominal trigger setting value NTSP and an analysis limit value AL of a safety-related instrument; according to the historical verification data of the safety-related instruments, calculating the drift amount AD of the safety-related instrument verification supervision items after the period is prolonged C1 (ii) a According to the drift amount AD C1 Calculating channel uncertainty CU of safety related instrument checking supervision items after period is prolonged C1 (ii) a Calculating a safety margin of a safety-related instrument, wherein the safety margin of the safety-related instrument is AL-CU C1 -NTSP; and then judging whether the safety margin of the safety related instrument is larger than 0, if so, not adjusting the nominal trigger setting value NTSP of the safety related instrument. The evaluation method for the cycle extension of the nuclear power plant safety-related instrument check supervision project is novel in design and high in practicability.)

1. A nuclear power plant safety related instrument check supervision project cycle extension evaluation method is characterized by comprising the following steps:

step S1, acquiring a nominal trigger setting value NTSP and an analysis limit value AL of the safety-related instrument;

step S2, calculating the drift AD of the safety-related instrument check supervision item after the period is prolonged according to the historical check data of the safety-related instrument_C1(ii) a According to the drift amount AD_C1Calculating channel uncertainty CU of safety related instrument checking supervision items after period is prolonged_C1；

Step S3, calculating a safety margin of the safety-related instrument, wherein,

safety margin of safety-related instrument AL-CU_C1－NTSP；

And then judging whether the safety margin of the safety related instrument is larger than 0, if so, not adjusting the nominal trigger setting value NTSP of the safety related instrument, and if not, adjusting the nominal trigger setting value NTSP of the safety related instrument.

2. The method for evaluating the cycle extension of the nuclear power plant safety-related instrument check-type supervision project according to claim 1, wherein between the step S1 and the step S2, the method further comprises: determining the acceptable limit AL of the safety-related instrument in the period C0 according to the historical verification data of the safety-related instrument_C0；

Judging whether historical verification data of safety related instruments exist and are larger than an acceptable limit AL or not_C0And calculating greater than acceptable limit AL_C0If the proportion of the AFAL data is less than or equal to 5%, the process proceeds to step S2.

3. The method for evaluating the cycle extension of the nuclear power plant safety-related instrument check supervision project according to claim 2, wherein the acceptable limit AL of the safety-related instrument in the C0 cycle is determined according to the historical check data of the safety-related instrument_C0Comprises the following steps:

obtaining the accuracy of the safety-related meter and the drift amount AD during C0 according to the historical verification data of the safety-related meter during C0_C0And M&TE error, determining acceptable limit AL of safety-related instrument in C0 period_C0。

4. The method for evaluating the cycle extension of the nuclear power plant safety-related instrument check-type supervision project according to claim 3, wherein the evaluation is performed according to the history of the safety-related instrumentChecking data, calculating drift AD of the safety related instrument checking supervision items after the period is prolonged_C1Comprises the following steps:

carrying out normal distribution verification on AFAL data of the safety-related instrument, and if the AFAL data of the safety-related instrument pass the verification, analyzing the drift amount AD of the safety-related instrument during the period C0_C0Obtaining an analysis result through the correlation with time; then, the drift amount AD is calculated based on the analysis result_C0Extrapolating to calculate the drift AD of the safety-related instrument after the period of the check supervision item is prolonged_C1。

5. The method for evaluating the cycle extension of the nuclear power plant safety-related instrument check-type supervision project according to claim 4, wherein AD is obtained according to the drift amount_C1Calculating channel uncertainty CU of safety related instrument checking supervision items after period is prolonged_C1Is calculated according to the ISA RP67.04.02 standard.

Technical Field

The invention relates to the field of periodic tests of nuclear power plants, in particular to an evaluation method for prolonging the period of a nuclear power plant safety-related instrument check supervision project.

Background

With the economic glide in recent years, the availability of the unit is reduced to some extent, and the unit is often temporarily stopped or even in a medium-long term standby state in the field of nuclear power. Typically, a fuel management strategy for 18 month refuelling is implemented in a nuclear power plant, and a single cycle nuclear safety-related periodic test is performed for a maximum period of no more than 20 months. In order to improve the capacity factor of a nuclear power unit, the flexibility of overhaul arrangement and the economic benefit of a power plant, the nuclear power plant hopes to increase the single-cycle operation time (to 24 months) under the restriction of the current long-term low-power operation, so the influence of the extension of a periodic test period needs to be evaluated, the premise that the test period can be extended is that the usability of nuclear safety related equipment can still be guaranteed after the test period is extended, an empirical feedback method is mainly adopted for non-instrument monitoring projects for evaluation, and for safety related instrument checking monitoring projects, because the instrument drift is related to the time and has the restriction of an analysis limit value, the empirical feedback method is not suitable for use, the influence of the extension of the test period on the instrument drift and the trigger setting value is considered, but no related evaluation method exists at present.

Disclosure of Invention

The invention provides an evaluation method for prolonging the period of a nuclear power plant safety-related instrument check supervision project aiming at the technical problems.

The technical scheme provided by the invention is as follows:

the invention provides an evaluation method for prolonging the period of a nuclear power plant safety-related instrument checking supervision project, which comprises the following steps:

step S1, acquiring a nominal trigger setting value NTSP and an analysis limit value AL of the safety-related instrument;

step S2, calculating the drift AD of the safety-related instrument check supervision item after the period is prolonged according to the historical check data of the safety-related instrument_C1(ii) a According to the drift amount AD_C1Calculating channel uncertainty CU of safety related instrument checking supervision items after period is prolonged_C1；

Step S3, calculating a safety margin of the safety-related instrument, wherein,

safety margin of safety-related instrument AL-CU_C1－NTSP；

And then judging whether the safety margin of the safety related instrument is larger than 0, if so, not adjusting the nominal trigger setting value NTSP of the safety related instrument, and if not, adjusting the nominal trigger setting value NTSP of the safety related instrument.

In the above evaluation method for prolonging the period of the nuclear power plant safety-related instrument check supervision project, between step S1 and step S2, the method further includes: determining the acceptable limit AL of the safety-related instrument in the period C0 according to the historical verification data of the safety-related instrument_C0；

Judging whether historical verification data of safety related instruments exist and are larger than an acceptable limit AL or not_C0And calculating greater than acceptable limit AL_C0If the proportion of the AFAL data is less than or equal to 5%, the process proceeds to step S2.

In the evaluation method for prolonging the period of the check supervision project of the safety-related instrument of the nuclear power plant, the acceptable limit AL of the safety-related instrument in the period C0 is determined according to the historical check data of the safety-related instrument_C0Comprises the following steps:

obtaining the accuracy of the safety-related meter and the drift amount AD during C0 according to the historical verification data of the safety-related meter during C0_C0And M&TE error, determining acceptable limit AL of safety-related instrument in C0 period_C0。

In the evaluation method for the cycle extension of the nuclear power plant safety-related instrument check supervision project, the drift amount AD of the safety-related instrument check supervision project after the cycle extension is calculated according to the historical check data of the safety-related instrument_C1Comprises the following steps:

carrying out normal distribution verification on AFAL data of the safety-related instrument, and if the AFAL data of the safety-related instrument pass the verification, analyzing the drift amount AD of the safety-related instrument during the period C0_C0Obtaining an analysis result through the correlation with time; then, the drift amount AD is calculated based on the analysis result_C0Extrapolating to calculate the drift AD of the safety-related instrument after the period of the check supervision item is prolonged_C1。

In the method for evaluating the cycle extension of the nuclear power plant safety-related instrument check supervision project, the AD is calculated according to the drift amount_C1Check monitor for related instruments of computational safetyChannel uncertainty CU of supervising project after cycle extension_C1Is calculated according to the ISA RP67.04.02 standard.

The evaluation method for the cycle extension of the nuclear power plant safety-related instrument check supervision items is a whole set of analysis and evaluation flow and a thought taking unit safety margin as a judgment basis, the uncertainty (including drift) of a safety-related instrument channel after the cycle extension can be comprehensively analyzed by applying the flow, the instrument drift analysis and the uncertainty calculation can adopt a universal method, the focus of analysis and evaluation is concentrated on the most concerned safety margin of a power plant and a supervision party, and the influence on the safety-related instrument check supervision items after the cycle extension is positively analyzed and evaluated. The evaluation method for the cycle extension of the nuclear power plant safety-related instrument check supervision project is novel in design and high in practicability.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 illustrates a flow chart of a method for evaluating a nuclear power plant safety-related instrument check-type supervision project cycle extension according to a preferred embodiment of the present invention;

fig. 2 shows a schematic diagram of the relationship between the safety limit SL, the analysis limit AL, the safety system setting LTSP, the nominal trigger setting NTSP and the normal operation limit OL.

Detailed Description

The technical problem to be solved by the invention is as follows: the premise that the periodic test period related to the single-cycle nuclear safety can be prolonged is that the usability of equipment related to the nuclear safety can still be guaranteed after the test period is prolonged, an empirical feedback method is mainly adopted for evaluating non-instrument supervision projects, for safety-related instrument check supervision projects, the influence of the test period prolongation on the instrument drift and trigger setting values is considered due to the fact that the instrument drift is related to time and has the constraint of an analysis limit value, the empirical feedback method is not suitable to be used, and no related evaluation method exists at present. The technical idea of the invention for solving the technical problem is as follows: by combining the method for determining the instrument drift analysis, the uncertainty calculation and the instrument channel trigger setting value, a set of analysis and evaluation method suitable for prolonging the period of the safety-related instrument check supervision project is developed, the influence of the nuclear power plant safety-related instrument check supervision project period prolongation on the safety margin of the nuclear power plant is reasonably evaluated, the test period is further reasonably prolonged, the capacity factor of a nuclear power unit and the flexibility of overhaul arrangement are improved on the premise of ensuring the nuclear safety level, and the economic benefit of the nuclear power plant is improved.

In order to make the technical purpose, technical solutions and technical effects of the present invention more clear and facilitate those skilled in the art to understand and implement the present invention, the present invention will be further described in detail with reference to the accompanying drawings and specific embodiments.

As shown in fig. 1, fig. 1 is a flowchart illustrating a method for evaluating a cycle extension of a nuclear power plant safety-related instrument check supervision project according to a preferred embodiment of the present invention. The embodiment provides an evaluation method for prolonging the period of a nuclear power plant safety-related instrument checking supervision project, which comprises the following steps:

step S1, acquiring a nominal trigger setting value NTSP and an analysis limit value AL of the safety-related instrument;

as shown in fig. 2, fig. 2 shows a schematic diagram of the relationship between the safety limit SL, the analysis limit AL, the safety system setting LTSP, the nominal trigger setting NTSP and the normal operation limit OL. The safety limit SL is used to guarantee the integrity of the physical barrier, preventing uncontrolled radioactivity release. The analysis limit AL is used to ensure that the safety limit SL is not exceeded. The analysis limit SL is obtained from an accident analysis model and takes into account factors such as process delay, control rod insertion time, reactivity changes and meter response time. The safety system settings LTSP are used to ensure that the protective action is initiated before the process conditions reach the analysis limit SL, so that the consequence limit of the design reference event can be brought within the range determined by the safety analysis. The nominal trigger setting NTSP is a value preset in the valuator assembly, and when the monitored variable reaches a preset value, the state of the valuator output will change. In addition, in fig. 2, CU represents channel uncertainty; safety Margin is represented by Safety Margin; operating Margin represents the Operating Margin.

In this step, the nominal trigger setting value NTSP is mainly used to protect the actual measurement process parameters from shutdown or safety action before reaching the safety limit value SL, which includes the uncertainty of the instrument, and the magnitude of the uncertainty is specified by the system safety setting value in the technical specification.

Step S2, calculating the drift AD of the safety-related instrument check supervision item after the period is prolonged according to the historical check data of the safety-related instrument_C1(ii) a According to the drift amount AD_C1Calculating channel uncertainty CU of safety related instrument checking supervision items after period is prolonged_C1；

Calculating the drift AD of the safety related instrument after the period of the check supervision item is prolonged according to the historical check data of the safety related instrument_C1Comprises the following steps:

collecting data of preanalyzed safety-related instruments and similar instruments, grouping the data, processing the grouped data according to a uniform format, then analyzing abnormal data, carrying out normal distribution verification on AFAL data of the safety-related instruments, and then calculating the drift amount AD of the safety-related instruments during the period of C0_C0Analyzing the correlation of the drifting time of the instrument to obtain an analysis result; then AD is analyzed based on the analysis result_C0Proper extrapolation is carried out to calculate the drift AD of the safety-related instrument after the period of the check supervision item is prolonged_C1。

Furthermore, the channel uncertainty of the safety related instrument of the nuclear power plant can be generally summarized into several types such as pressure, temperature, flow and liquid level measuring channels according to different calculation objects. The method of instrument channel uncertainty is based primarily on the square root of the sum of squares method (SRSS) and the algebraic sum method given in the ISARP67.04.02 standard. In this embodiment, the AD is based on the drift amount_C1Calculating channel uncertainty CU of safety related instrument after verification type supervision item period is prolonged_C1Is calculated according to the ISA RP67.04.02 standard.

Step S3, calculating a safety margin of the safety-related instrument, wherein,

of safety-relevant instrumentsSafety margin AL-CU_C1－NTSP；

And then judging whether the margin of the safety-related instrument is larger than 0, if so, not adjusting the nominal trigger setting value NTSP of the safety-related instrument, and if not, adjusting the nominal trigger setting value NTSP of the safety-related instrument or taking other measures.

Before step S1, the method for evaluating the cycle extension of the nuclear power plant safety-related instrument check supervision project further includes:

and S0, screening the applicability of the safety-related instrument, and judging whether the safety-related instrument is suitable for using a drift analysis method, if so, entering the step S1, and if not, considering other methods for conservative evaluation.

Here, if the historical verification data for the new safety-related instrument is insufficient, or the safety-related instrument does not require an uncertainty calculation/analysis limit, or the safety function of the safety-related instrument has a significant margin, the safety-related instrument is not suitable for using the drift analysis method.

Further, the evaluation method for the cycle extension of the nuclear power plant safety-related instrument check supervision project further includes, between step S1 and step S2: determining the acceptable limit AL of the safety-related instrument in the period C0 according to the historical verification data of the safety-related instrument_C0；

Judging whether historical verification data of safety related instruments exist and are larger than an acceptable limit AL or not_C0And calculating greater than acceptable limit AL_C0If the proportion of the AFAL data is less than or equal to 5%, the step S2 is entered; if the occupancy of the AFAL data is greater than 5%, then other options need to be evaluated, including but not limited to modifying design benchmarks, modifying settings, modifying verification procedures, replacing meters, or maintaining the supervision requirements of C0 for the current cycle.

Wherein, the acceptable limit AL of the safety-related instrument in the period C0 is determined according to the historical verification data of the safety-related instrument_C0Comprises the following steps:

obtaining accuracy of the safety-related instrument based on historical verification data of the safety-related instrument during C0Amount of drift AD during C0_C0And M&TE(Material&Test equipment) error, determining the acceptable limit AL of the safety-relevant instrument in the C0 period_C0。

Here, the acceptable limit AL during the safety-relevant meter C0_C0Is determined by the correlation technician based on the accuracy of the safety-related instrumentation, the amount of drift during C0, and M&The TE error is determined empirically.

The evaluation method for the cycle extension of the nuclear power plant safety-related instrument check supervision items is a whole set of analysis and evaluation flow and a thought taking unit safety margin as a judgment basis, the uncertainty (including drift) of a safety-related instrument channel after the cycle extension can be comprehensively analyzed by applying the flow, the instrument drift analysis and the uncertainty calculation can adopt a universal method, the focus of analysis and evaluation is concentrated on the most concerned safety margin of a power plant and a supervision party, and the influence on the safety-related instrument check supervision items after the cycle extension is positively analyzed and evaluated. The evaluation method for the cycle extension of the nuclear power plant safety-related instrument check supervision project is novel in design and high in practicability.

While the present invention has been described with reference to the embodiments shown in the drawings, the present invention is not limited to the embodiments, which are illustrative and not restrictive, and it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the invention as defined in the appended claims.