CN109102913B - Design method of fault diagnosis strategy of pressurized water reactor nuclear power plant - Google Patents

Abstract

The invention belongs to the technical field of nuclear power plant operation, and relates to a design method of a fault diagnosis strategy of a pressurized water reactor nuclear power plant. The design method comprises the following steps: (1) determining the range of fault procedures needing to be guided; (2) combing the entry conditions of the guided protocol; (3) determining a diagnostic order; (4) optimizing a diagnosis process based on the common characteristic of the fault symptoms; (5) and (4) obtaining a fault diagnosis strategy initial draft containing the range of the guided procedures and the diagnosis sequence of the guided procedures based on the work of the steps (1) to (4). By utilizing the design method of the fault diagnosis strategy of the pressurized water reactor nuclear power plant, a new fault treatment strategy can be provided by matching with a third generation pressurized water reactor nuclear power unit operation regulation system in order to perfect the treatment measures of the unit under the fault working condition.

Description

Design method of fault diagnosis strategy of pressurized water reactor nuclear power plant

Technical Field

The invention belongs to the technical field of nuclear power plant operation, and relates to a design method of a fault diagnosis strategy of a pressurized water reactor nuclear power plant.

Background

Nuclear power plant systems are complex and have many operating parameters, and once an incident or accident condition occurs, the plant is considered to be in an emergency state, requiring an operator to react quickly, correcting the condition deviation, and taking necessary actions to avoid or mitigate possible consequences. The accident and fault handling rules are important components for realizing the concept of deep defense of the nuclear power plant, whether the design is reasonable or not is directly related to the operation safety of the nuclear power plant, and the advanced accident and fault handling rules can better ensure the safety of a unit and prevent the accident from deteriorating.

At present, the international accident handling regulation framework system of a pressurized water reactor nuclear power plant is mainly divided into an event guidance method, a state guidance method and a symptom guidance method. The ideas and concepts of the accident handling rule framework systems are different to a certain degree. Most of the currently generally adopted accident handling rule framework systems in China are mainly based on event guidance, and only few rules based on state guidance are included for handling over-design basis accidents, so that various complex accident conditions except the design basis accidents cannot be well handled. And a third generation pressurized water reactor nuclear power generating unit which is independently researched and developed in China is supposed to adopt an accident handling regulation system which is different from the prior event guidance.

The change of the accident handling regulation system can generate profound influence on various files related to the accident handling regulation system, wherein the accident handling regulation system and the accident handling regulation system form important operation files of a nuclear power plant deep defense concept, and related change must be carried out according to the change of the accident handling regulation system so as to realize the mutual cooperation with the accident handling regulation system and achieve the effects of supplementing and assisting the accident handling regulation.

The fault procedures of the domestic independently-developed third-generation pressurized water reactor nuclear power units can be divided into two types according to the difference of the entry criteria and the execution priority: one is a fault procedure guided by a diagnostic procedure and having a higher execution priority; the other is a fault procedure that is not guided by the diagnostic procedure and is executed with a lower priority than the previous one. In the actual execution process, when the judgment result of the guiding procedure based on the event-oriented technology is appropriate, the first-class fault procedure is directly executed. Such regulations cover the types of failures, such as electrical system failures, control system failures, lost cooling sources, and leaks.

Under the operation regulation system of a third-generation pressurized water reactor nuclear power unit autonomously developed in China, on one hand, the coverage range of an accident handling regulation is wider, but the pertinence of the accident handling regulation on the unit fault handling without directly triggering shutdown and special actions is slightly inferior, and the optimal countermeasures are difficult to achieve under part of specific fault working conditions; on the other hand, because the number of fault regulations is huge, the types of the related fault working conditions are more, and the optimization aiming at all possible faults is neither economical nor practical; in addition, under the design condition of a digital main control room, the number of entrance conditions and alarms of accident and fault handling regulations is huge, and the types are more. Therefore, in order to perfect the treatment measures of the unit under the fault working condition and match with the operation regulation system of the pressurized water reactor nuclear power unit of the third generation, a new fault treatment strategy needs to be designed.

Disclosure of Invention

The invention aims to provide a design method of a fault diagnosis strategy of a pressurized water reactor nuclear power plant, and provides a new fault treatment strategy by matching with a third-generation pressurized water reactor nuclear power unit operation regulation system in order to perfect the treatment measures of a unit under the fault working condition.

To achieve the object, in a basic embodiment, the present invention provides a design method of a fault diagnosis strategy of a pressurized water reactor nuclear power plant, the design method comprising the steps of:

(1) determining the range of fault procedures needing to be guided (namely fault procedures needing to be diagnosed);

(2) combing the entry conditions of the guided protocol;

(3) determining a diagnostic order;

(4) optimizing a diagnosis process based on the common characteristic of the fault symptoms;

(5) and (4) obtaining a fault diagnosis strategy initial draft containing the range of the guided procedures and the diagnosis sequence of the guided procedures based on the work of the steps (1) to (4).

In a preferred embodiment, the invention provides a design method of a fault diagnosis strategy of a pressurized water reactor nuclear power plant, wherein in step (1), whether a specific fault handling rule needs to be included in a fault rule needing to be guided or not is mainly considered whether the overall operation state of a unit is endangered by the consequence of the fault or only the execution of related system functions is endangered, and the fault rule corresponding to the fault endangering the overall operation state of the unit needs to be included in the fault rule needing to be guided or not.

In a preferred embodiment, the invention provides a design method of a fault diagnosis strategy of a pressurized water reactor nuclear power plant, wherein in the step (2), the inlet conditions used in the diagnosis procedure for entering the relevant guide fault procedure are combed according to the technical content of the guided fault procedure and the inlet condition design of the diagnosis procedure.

In a preferred embodiment, the present invention provides a method for designing a fault diagnosis strategy of a pressurized water reactor nuclear power plant, wherein in the step (3), the diagnosis order is determined to be prioritized as follows: the fault of the signal support system is the first, the fault of the instrument control system is the second, and the fault of the process system is the second.

In a more preferred embodiment, the invention provides a design method of a fault diagnosis strategy of a pressurized water reactor nuclear power plant, wherein for the situation that the number of faults in any classification is still large, the diagnosis sequence is sorted according to the severity degree of fault consequences in the same classification, the fault with the serious consequences is diagnosed preferentially, and the fault with the less serious consequences is diagnosed later.

In a preferred embodiment, the invention provides a design method of a fault diagnosis strategy of a pressurized water reactor nuclear power plant, wherein in the step (4), whether common characteristics exist between faults or not is checked, if the common characteristics exist, the occurrence of the faults is determined to be related to the common characteristics, and the faults without the common characteristics in the symptoms can be eliminated through one-step diagnosis.

In a preferred embodiment, the present invention provides a method for designing a fault diagnosis strategy for a pressurized water reactor nuclear power plant, wherein the method further comprises the steps of:

(6) and verifying and/or confirming the initial draft of the fault diagnosis strategy to obtain a final fault diagnosis strategy.

In a more preferred embodiment, the invention provides a design method of a fault diagnosis strategy of a pressurized water reactor nuclear power plant, wherein in the step (6), problems found in the verification and confirmation process are timely modified.

The method has the advantages that by using the design method of the fault diagnosis strategy of the pressurized water reactor nuclear power plant, a new fault treatment strategy can be provided in order to improve the treatment measures of the unit under the fault working condition and by matching with a third generation pressurized water reactor nuclear power unit operation regulation system.

The invention determines a new fault diagnosis strategy under the operation regulation system of a third-generation pressurized water reactor nuclear power unit, reasonably utilizes related alarm and diagnosis conditions, and comprehensively considers the orderly matched use between a large number of fault regulations and accident regulations, thereby avoiding the influence on the diagnosis strategy possibly caused.

The beneficial effects of the invention are embodied in that:

(1) the design method is used as a universal fault diagnosis strategy analysis method and is suitable for fault diagnosis strategy analysis of similar nuclear power plants;

(2) the principle 1 that the fault procedure corresponding to the fault which endangers the overall operation state of the unit needs to be guided by the fault diagnosis procedure simplifies the workload of fault diagnosis, ensures the safety of the unit and improves the efficiency of the diagnosis work;

(3) the principle 2 ensures the correctness of the diagnosis result and prevents the possibility of misdiagnosis;

(4) principle 3 ensures that faults with greater threat to unit safety can be diagnosed as early as possible, so that an operator can perform intervention as early as possible, and the unit safety is improved;

(5) principle 4 "diagnosis process optimization based on fault symptom commonality characteristics" obviously improves the efficiency of fault diagnosis by preferentially identifying "commonality characteristics of fault symptoms";

(6) the verification and confirmation process of the design method ensures the correctness and rationality of the design of the diagnosis strategy and effectively improves the quality of the design result.

Drawings

FIG. 1 is a flow chart of an exemplary method of designing a fault diagnosis strategy for a pressurized water reactor nuclear power plant of the present invention.

Fig. 2 is a first draft of a fault diagnosis policy obtained by the exemplary design method in the embodiment.

Detailed Description

The following further describes embodiments of the present invention with reference to the accompanying drawings.

An exemplary method for designing a fault diagnosis strategy for a pressurized water reactor nuclear power plant according to the present invention is illustrated in FIG. 1 and includes the following steps.

(1) Determining the extent of a fault protocol requiring a boot, i.e. a fault protocol requiring a diagnosis

The fault diagnosis procedures are large in quantity and various in types, and if all the fault procedures are brought into the guide range of the fault diagnosis procedures, the fault guide procedures are too overstaffed, and the requirements on diagnosis rapidity and timeliness cannot be met. For this reason, important procedures that need to be guided in the fault guidance procedure must be found among a large number of fault procedures.

The criterion as to whether a specific fault handling procedure needs to be included in the scope of a fault diagnosis procedure (principle 1) is primarily to see whether the consequences of the fault endanger the overall operating state of the unit or only the execution of the relevant system functions. And for a fault rule corresponding to a fault which endangers the overall operation state of the unit, the fault rule needs to be guided by a fault diagnosis rule.

(2) Combing entry conditions of a guided protocol

And according to the technical content of the guided procedure and the design of the entrance condition of the guided procedure, combing the diagnosis condition used in the diagnosis procedure for entering the relevant fault procedure.

(3) Determining diagnostic order

One of the important principles of the diagnostic protocol (principle 2) is to prevent misdiagnosis, so that faults with strong independence of signs are diagnosed first. To make a reliable diagnosis, it is necessary to have a reliable signal support system, so the condition of the information support system should be verified first against other types of faults or incidents; secondly, an instrument control system needs to be considered, and a reliable instrument control system is an important guarantee for maintaining the normal operation of a process system; finally, a process system is considered. Therefore, from the standpoint of independence of symptoms, the following is considered for the precedence order of the types of fault procedures guided by the diagnostic strategy:

the fault type A: a signal support class system;

and (3) fault type B: an instrumentation-control type system;

and (3) fault type C: a process system.

Due to the complexity of nuclear power plants, the number of faults of each type remains high after classification according to the fault types. Within each type of fault, the principle of prioritization of fault diagnosis (principle 3) is to prioritize the diagnosis of faults with more severe consequences and to diagnose later the faults with less severe consequences, depending on the severity of the consequences of the fault.

In summary, in the diagnosis guidance procedure, the diagnosis order of the fault is sequentially performed according to the severity of the fault consequence and the symptom independence.

(4) Diagnostic process optimization based on fault symptom commonality characteristics

Through the correlation analysis of the steps (1) and (2), the range and the sequence of important fault procedures needing to guide the procedure diagnosis are determined. However, since the number of guided procedures is still huge, the diagnosis by schedule will not meet the requirement of rapidity of nuclear power plant diagnosis. Therefore, the diagnosis process needs to be further optimized to further improve the diagnosis efficiency on the premise of ensuring the diagnosis accuracy.

As a result of research, although the guided procedures are enormous in number, the guided procedures can be grouped according to a common characteristic of the symptoms. Therefore, when the fault diagnosis is carried out, whether a certain common characteristic (such as working condition applicable to the fault, whether shutdown is caused or not and the like) exists or not can be checked, if the common characteristic exists, the fault is related to the common characteristic, and the fault without the common characteristic in the symptoms can be eliminated through one-step diagnosis. That is, the principle (principle 4) to be considered is to group and diagnose faults according to the common characteristics of fault symptoms or the unit operation characteristics which are not related to the faults so as to improve the diagnosis efficiency.

To perform the above work, table 1 below was introduced as a tool to perform a common signature analysis of the faults. For each fault feature, a 'fault symptom common feature analysis table' needs to be introduced. The behavior of the table is 'operation working conditions of the nuclear power plant', the table is listed as 'fault regulations', and the middle part of the table is different characteristics of the symptoms of the faults corresponding to different fault regulations under corresponding working conditions.

TABLE 1 common characteristics analysis table for fault symptoms

Working condition 1

Operating mode 2 …

Operating mode m

Operating mode m +1

Operating mode m +2

Operating mode m + n

AOP1

X

Y

Y

Y

…

Y

AOP2

Y

Y

Y

X

…

Y

AOP3

Y

Y

Y

X

…

Y

…

…

…

…

…

…

…

AOPj

X

Y

X

X

…

Y

Note: (1) x, Y are different features for a sign of a fault; (2) AOP is the procedure number for the type of fault.

(5) Based on the completed work, the failure diagnosis policy initial draft including the range of the guided procedures and the diagnosis order of the guided procedures can be obtained

(6) Verifying and confirming the primary draft of the fault diagnosis strategy, and timely modifying the problems found in the verification and confirmation process

(7) Obtaining a final fault diagnosis strategy

The application of the above-described exemplary design method of the fault diagnosis strategy for a pressurized water reactor nuclear power plant of the present invention is exemplified as follows.

Assume that there are four types of faults in a nuclear power plant: the AOP1 is an emergency power distribution board loss fault, the AOP2 is a protection power supply loss fault, the AOP3 is an equipment cooling water loss fault, the AOP4 is an equipment cooling water loss fault, and the AOP5 is a spent fuel pool cooling fault. The design method of the present invention will be described by taking the category 5 fault as an example.

1) Determining a scope of a fault procedure

According to principle 1, AOPs 1, 2, 3, and 4 jeopardize the overall operating state of the unit, requiring entry into a fault diagnosis strategy, whereas AOP5 is not.

2) The inlet conditions for the comb guided protocol are shown in table 2 below:

table 2 entry condition example of guided procedure

Protocol numbering	Inlet conditions
		AOP1	Condition a
AOP2	Condition b
		AOP3	Condition c
AOP4	Condition d

3) Determining order of failure procedures

According to principle 2, the switchboard belongs to a signal support system, and in order to prevent misdiagnosis, AOP1 needs to be prioritized, followed by AOP2, and finally AOP 3/4.

AOP3/4 pertains to equipment cooling water loss failures, divided into total and partial losses, with the severity of principle 3 giving priority to AOP3 followed by AOP 4.

Thereby determining the diagnosis order of AOP1, AOP2, AOP3 and AOP 4.

4) Diagnostic process optimization based on fault symptom commonality characteristics

According to the principle 4, the common characteristic of the fault symptoms or the unit operation characteristic irrelevant to the fault is considered, namely whether the unit operation state is the residual heat removal system access operation or not is judged, and the fault diagnosis is divided into two parts, so that the diagnosis strategy is simplified, and the efficiency is improved.

The diagnostic strategy was developed after validation analysis according to the previous procedure, as shown in table 3 below.

TABLE 3 Fault diagnosis strategy framework and feature analysis

Note: x is the unsuitable working condition, and Y is the suitable working condition.

An example of the initial draft of the resulting fault diagnosis policy is shown in fig. 2.

5) And (4) obtaining a final fault diagnosis strategy after verification and confirmation based on the initial draft of the diagnosis frame determined in the step 4).

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include such modifications and variations. The above-described embodiments are merely illustrative of the present invention, and the present invention may be embodied in other specific forms or other specific forms without departing from the spirit or essential characteristics thereof. The described embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. The scope of the invention should be indicated by the appended claims, and any changes that are equivalent to the intent and scope of the claims should be construed to be included therein.

Claims (5)

1. A design method for a fault diagnosis strategy of a pressurized water reactor nuclear power plant is characterized by comprising the following steps:

(1) determining the range of fault procedures needing to be guided;

(2) combing the entry conditions of the guided protocol;

(3) determining a diagnostic order;

(4) optimizing a diagnosis process based on the common characteristic of the fault symptoms;

(5) obtaining a fault diagnosis strategy initial draft containing the range of the guided procedures and the diagnosis sequence of the guided procedures based on the work of the steps (1) to (4),

wherein:

in the step (3), the determined diagnosis order is classified into: the fault of the signal support system is the first, the fault of the instrument control system is the second, the fault of the process system is the second,

for the situation that the number of the faults in any classification is still large, in the same class of faults, the diagnosis sequence is sorted according to the severity degree of the fault consequences, the fault with the more serious consequences is diagnosed preferentially, the fault with the less serious consequences is diagnosed later,

in the step (4), whether common characteristics exist among the faults is checked, if the common characteristics exist among the faults, the faults are related to the common characteristics, and the faults without the common characteristics in the symptoms can be eliminated through one-step diagnosis.

2. The design method according to claim 1, wherein: in the step (1), whether a specific fault handling procedure needs to be included into a fault procedure needing to be guided is mainly to see whether the consequence of the fault endangers the overall operation state of the unit or only endangers the execution of related system functions, and the fault procedure corresponding to the fault endangering the overall operation state of the unit needs to be included into the fault procedure needing to be guided.

3. The design method according to claim 1, wherein: and (2) combing the inlet conditions used in the diagnosis procedure for entering the relevant guide fault procedure according to the technical content of the guided fault procedure and the inlet condition design of the guided fault procedure.

4. The design method of claim 1, further comprising the steps of:

(6) and verifying and/or confirming the initial draft of the fault diagnosis strategy to obtain a final fault diagnosis strategy.

5. The design method according to claim 4, wherein: and (6) timely modifying the problems found in the verification and confirmation process.

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