JPS60147811A - Guidance system of plant operation - Google Patents

Abstract

PURPOSE:To improve the reliability of a plant operation guidance system, by selecting an operation at the safety side of guides, one guide corresponding to a produced phenomenon and the other corresponding to the varying indication of a safety parameter. CONSTITUTION:The plant data 4 of a plant 1 composed of a main system 2 and subsystem 3 is inputted to a parameter varying indication calculating section 5, safety function monitoring section 6, phenomenon discriminating section 7, and a plant responding change measuring section 8. An operation guide determining section 9 determines a safety side operation by fetching discriminated results of a safety parameter varying indication, functional conditions of each subsystem, presence/absence of abnormal/accidental phenomenon, and outputs the determined result as an operation guide 13. An operational effect evaluating section 10 discriminates the presence/absence of an operational effect by using a plant response estimating model 11 and outputs the result as an operational effect evaluating guide 14. The operation guide 13 and operational effect evaluating guide 14 are displayed on an operation guide displaying section 15.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a plant operation guidance system, and particularly to a system that improves the operational reliability of a nuclear power plant.

[Background of the Invention] In general, a nuclear power plant is a large-scale and complex plant consisting of a main system of a reactor, turbine, and generator, and multiple subsystems such as a control system, auxiliary equipment system, and emergency core cooling system. It is a scale system. In nuclear power plants, even if an abnormal over-change or loss of coolant accident occurs, 1. The reactor is configured to be able to shut down safely through reactor scram and automatic activation of the emergency core cooling system, but even after the reactor scram, in order to bring the reactor core to a safe cold shutdown state, it is necessary to It is necessary to operate various subsystems appropriately while monitoring safety parameters such as reactor water level and pressure. Furthermore, in reality, it is difficult to completely eliminate the probability of multiple failures of engineering safety equipment and operator errors. For this reason, research and development have been carried out on plant condition monitoring and diagnosis systems that support operators' appropriate judgment and operation.

[Purpose of the invention]

The purpose of the present invention is to improve man-machine performance by monitoring the status of large-scale and complex systems such as nuclear power plants and presenting diagnostic information, and to provide operational guidance as a form of active information presentation to operators. The goal is to provide a system that does this.

[Summary of the invention]

There are basically two different methods for determining operating guides in operating guidance systems based on conventional technology: event response, which identifies abnormalities and accident events that occur in the plant, and selects operating operations as countermeasures; Either the guidance method or the symptom response guidance method is adopted, which takes in the signs of fluctuations in plant safety parameters and selects operating operations to compensate for the fluctuations.

However, with the former event response method, the possibility of erroneously identifying an event is considered to be very small, but it cannot be completely eliminated, and with the latter symptom response method, the possibility of erroneously identifying an event is extremely low. There is a problem in that it is impossible to completely eliminate the possibility that an inappropriate driving operation will be selected due to transient fluctuations in parameters. However, when using a search logic that combines event response and symptom response in detail as a method for selecting operating operations, it is impossible to create a search logic that is always highly reliable under various fluctuating conditions of the plant state. To solve this problem, the present invention employs a method in which driving operation decisions are made independently of each other by an event response method and a symptom response method, and the results of both are compared to take a safer driving operation7. Improved reliability.

Furthermore, in the present invention, a function for evaluating driving operation effects is added to assist the operator's judgment.

The outline of the present invention is to automatically process data from a plant to present an operation guide for ensuring plant safety and an evaluation result of the effect of the implemented operation to operators. a parameter fluctuation symptom calculation unit that calculates a fluctuation symptom of the safety parameter based on the data;
A safety function monitor unit that identifies the status of plant subsystems, an event discrimination unit that determines events that occur in the plant, a plant response measurement unit that captures changes in plant response due to subsystem activation, and various parameters prepared in advance. A guide database that provides operational guidance for fluctuation symptoms or events that occur in the plant, fluctuation symptoms from the parameter fluctuation symptom calculation unit, system status from the safety function monitor unit, and occurrence in the plant from the event discrimination unit. The operation guide determination unit determines the operation guide based on the event discrimination results, and the results of predicting plant response changes due to subsystem activation using the plant response prediction model and the subsystems from the safety function monitor unit. Operation effect evaluation that determines the effectiveness of operating operations using the system status and event discrimination results that have occurred in the plant from the event discrimination section and the results of actual measurement of plant response changes after subsystem 1 startup from the plant response change measurement section. The above object is achieved by employing a driving guidance system comprising a driving guidance display section, and a driving guidance display section that displays the output of the driving operation guide determination section and the output of the operation effect evaluation section.

[Embodiments of the invention]

Hereinafter, as an example of the present invention, a nuclear power plant,
The operational guidance system of the present invention will be described in detail, with particular reference to a boiling water nuclear power plant.

FIG. 1 is a block diagram showing the basic configuration of a plant operation guidance system according to the present invention.

Plant 1 consists of a main system consisting of a reactor, a containment vessel, a turbine, and a generator, a water supply flow rate control system, a water supply flow control system, a recirculation flow rate control system, etc., an isolation cooling system (RCIC), System 3 consists of auxiliary equipment systems such as the residual heat removal system (RHR), emergency core cooling systems such as the high pressure core spray system (HFO2), the low pressure core spray system (LPC8), and the automatic depressurization system (ADD). It is a combination. Roughly speaking, plant operation is performed by subsystem 3 in order to bring main system 2 to the target state.
Start, stop, or adjust the amount of operation.

The parameter fluctuation symptom calculation unit 5 calculates parameters (out of the plant data 4) necessary for estimating the safety state of the plant, such as reactor water level, reactor pressure, and containment vessel pressure/temperature.
Hereinafter, safety parameters (hereinafter referred to as safety parameters) are taken in periodically, and the deviation from the target value at which the plant is considered to be in a safe state is calculated to obtain fluctuation signs of the safety parameters. The safety function monitor unit 6 inputs subsystem state quantities such as the opening/closing status of valves in each subsystem, pump rotation speed and flow rate from the plant data 4, and determines whether each subsystem is operating, on standby, operating abnormally, or on standby. Determine which state of abnormality it is in. For the determination, a determination logic is created for each subsystem that uses the subsystem state quantity converted into a binary signal, but this is AND.

It consists of a combination of 0 and NOT logic elements. Event determination unit 7
The system reads the plant data 4 and determines whether or not a previously assumed abnormality or accident event has occurred.

The types of abnormalities and accident events are events for which information regarding their occurrence is required when selecting operating operations that will safely bring the plant to cold shutdown, such as reactor coolant spill accident (LOCA) due to pipe rupture, loss of on-site power supply, etc. , loss of water supply flow rate, etc. are assumed. The method for determining the presence or absence of occurrence differs depending on the target event, but a method using noise analysis of plant data or a method using cause-effect tree (OCT) can be used. The plant response change measurement unit 8 is a part that captures response changes in safety parameters due to subsystem activation. The response change measurement method depends on the level of detail of the prediction data obtained from the plant response prediction model described later. For example, if time-series response data can be obtained as prediction data, it is also possible to use time-series measured response data as well. If a measured value of the numerator of the change rate fluctuation of the safety parameter due to the activation of the subsystem can be obtained, the actual measured value of the change rate fluctuation can be similarly calculated and stored.

The driving operation guide determination unit 9 calculates the safety parameter fluctuation symptoms that are the output of the parameter fluctuation symptom calculation unit 5, the functional status of each subsystem that is the output of the safety function monitor unit 6, and the abnormality that is the output of the event determination unit 7. - The result of determining whether an accident event has occurred is input, the driving operation is determined, and the result is output as the driving operation guide 13. Figure 2 shows the driving operation guide determining section 9.
FIG. 2 is a block diagram showing the processing contents of FIG. The basic processing procedure of the operation guide section is shown in the flowchart in Figure 3, but it is possible to determine the best system for the plant from the operation operations obtained based on the different operation decision methods of symptom response and event response. The basic idea is to select the safest driving maneuver (the safest driving maneuver is given the safest ranking in the driving maneuver ranking database 27, but the driving maneuver that has the greatest effect is considered the safest driving maneuver). . The symptom-based driving operation search unit 22 searches the symptom-based guide database 21 using the safety parameter fluctuation symptoms and the functional status of each subsystem, and determines the symptom-based driving operation 25 . The event response driving operation search unit (9) 24 retrieves the result of determining whether an abnormality/accident event has occurred and the functional status of each subsystem, searches the event response guide database 23, and determines the event response driving operation 26. The basic configuration contents of the symptom handling guide database 21 and the event handling guide database 23 are shown in FIG. In both guide databases, the flow of basic operations for safely bringing a nuclear reactor to cold shutdown and the range of subsystems used in operations are the same. What differs is the logic that determines which subsystem to request activation for each basic driving operation.

Figure 5 shows a flowchart related to the water level securing operation of the symptom response guide database.This is a simplified version of the database actually used by omitting details for convenience of explanation, but it shows the fluctuation symptoms of safety parameters and the sub-systems. The basic idea of searching using the functional state of the system remains unchanged. Further, although FIG. 6 shows a flowchart regarding securing the water level of the event guide database, the same details are omitted. Driving operation selection section 28
are symptom-based driving operations 25 determined using the driving operation ranking database (10) 27.
The safety ranking of the event-based driving operation 26 is compared with the safe driving operation 26, and the safe driving operation is output as the driving operation guide 13. The contents of the driving operation ranking database 27 include the numbers added to the related subsystems shown in FIG. 4 for the driving operations that start the subsystems shown in the flowchart in FIG. 5 and the 70-chart in FIG. 6. Startup of large subsystems is on the safe side. Furthermore, different basic operation operations (for example, water level securing operation and pressure reduction operation) have a higher priority because the upstream side of the basic operation sequence shown in FIG. 4 is the safe side. As described above, in the driving guidance system of the present invention, in selecting a driving operation guide, a driving operation determination method consisting of two different approaches is used to take the safer side, and the reason for this will be described below. In general, the logic used by operators when determining the operational actions to be taken in the event of a plant abnormality or accident is to grasp the type of abnormality or accident that has occurred in the plant and the signs of fluctuation in plant safety parameters. (11) Based on these, it is thought that the vehicle is searching for the optimal driving operation. Moreover, it is thought that the emphasis placed on image information in the method for coarsely combining event information and symptom information is changed depending on the situation.

However, it is difficult to combine event information and symptom information to create detailed and highly reliable logic for determining operational guidance that takes into account changes in plant conditions. On the other hand, with event response guidance that uses only information about the occurring event, it is possible to determine highly efficient driving operations based on the event, but it is not possible to completely eliminate the possibility of erroneously identifying the occurring event. In addition, symptom response guidance that uses only fluctuation symptoms of safety parameters does not have the difficulty associated with identifying events, but it also eliminates the possibility of selecting incorrect operations due to transient fluctuations caused by plant dynamic characteristics. I can't. Therefore, if we choose the safer driving maneuver among the driving maneuvers obtained by both methods (normally, the driving maneuvers obtained by both methods are the same), the driving maneuver decisions of both methods will be incorrect at the same time. Since there is a very low possibility that the vehicle will fail (12), the reliability of driving guidance can be improved.

The operation effect evaluation section 10 uses the response change measurement results of safety parameters due to subsystem activation, which are the outputs of the plant response change measurement section 8 , the functional status of each subsystem, which is the output of the safety function monitor section 6 , and the event judgment section 7 . Abnormality that is output
The results of determining whether an accident event has occurred are taken in, the presence or absence of an operational effect is determined using the plant response prediction model 11, and the result is output as an operational effect evaluation guide 14. □ FIG. 7 is a block diagram showing the processing contents of the operation effect evaluation section 10.

The basic processing steps of the operation effect evaluation section are shown in the flowchart of FIG. The operation effect index calculation unit 31 calculates an operation effect index by comparing the plant response prediction result based on the plant response prediction model with the actual measurement result. The definition of the operation effect index cannot be unambiguously determined by a calculation formula because the format of detailed response information obtained differs depending on the level of detail of the plant response prediction model, but as an example, we will use a model that gives the variation in the rate of change of safety parameters. If we take , it can be expressed by the following formula.

(13) Here, PIJ: Operation effect index (%) of subsystem j regarding safety parameter i.

ΔXIJ: Actual measured value of the change speed fluctuation of the safety parameter i before starting the subsystem j and after reaching the rated operation after starting.

Δ↑IJ=Numerator measurement of the rate of change of safety parameter i according to the plant response evaluation model.

In addition to calculating the operation effect index using the above formula, there is also a method that calculates the ratio of the actual value of the change in the safety parameter after a certain period of time has elapsed from the time the subrestem starts, but basically, Regarding the response change of safety parameters, it is determined by taking the ratio between the actual measured value and the predicted value. The operation effect presence/absence determination unit 33 determines the operation effect index 32. ! ：'Evaluate the operation effect by evaluating the functional status of each subsystem and the result of determining whether an abnormality/accident event has occurred.In addition to outputting the guide 14, if it is determined that model modification is necessary, modify the model. (
14) Modify the plant response prediction model 11 using the data 12. FIG. 9 shows a flowchart of the processing procedure of the operation effect presence/absence determination section. The basic concept of the operation effect determination method used here is that the subsystem is normal as a necessary condition for determining that the subsystem activation has an effect.

The plant response prediction model is a model that assumes that the plant subsystems are functioning normally, so when a subsystem actually becomes abnormal, the abnormality can be detected by the deviation between the actual measured value and the predicted value. However, in reality, it cannot be determined because there are errors in the model. Therefore, if the operating effectiveness index becomes small when the subsystem is normal and the reactor has not experienced a loss of coolant accident (LOCA) that would have obscured the operating effectiveness, it is likely that there is an error in the model. Therefore, the model was modified so that the plant response predictions matched the actual measured data. Based on this decision logic,
It is now possible to provide the guidance system with an operation effect evaluation function based on quantitative judgment using a model (15).

The effects of applying the plant operation guidance system according to the present invention to a boiling water nuclear power plant will be explained using the simulation results of a main steam pipe rupture accident shown in FIG. This simulation assumes that the reactor isolation cooling system (RCIC) and the high pressure core spray system (HFO2) are inoperable, which is a severe condition for the safety of the nuclear reactor. However, the standby error occurs in the HFO before the CIC starts up.
2, it was decided that each operation abnormality would be identified by the safety function monitor after the start-up operation. The reactor scrams due to a main steam pipe rupture, and the operation guidance system is activated, but
The event determination section takes several tens of seconds to identify the occurrence of a main steam pipe rupture accident, and no event response guidance is output.Since the reactor water level is rising due to rapid depressurization due to the rupture, it is possible to identify the occurrence of a main steam pipe rupture accident, so it is possible to identify the occurrence of a main steam pipe rupture accident. Correspondence guidance is also not output. Eventually, the transient water level rise ended, and as a result of the water level decreasing,
Fluctuation symptoms are calculated and provided on the HP as symptom response guidance
The driving operation for starting C8 is determined. Almost simultaneously, (16
) The event determination unit determines the occurrence of an event of pipe rupture or gas phase rupture, and similarly determines the operation to start the HPC 8 as event response guidance. In this case, the event response guidance and the symptom response guidance matched, and the operator was instructed to "secure water level - Activate HPC8" as the operation guide, but even if the water level did not drop due to an error in the water level sensor. Even if the symptom response guidance is not working properly, the event response guidance outputs a precise driving operation guide such as 9 HPC8 activation. Next, HFO2 was started manually, but the assumption was that it would be in cine mode, so the operation effect evaluation unit would guide the operator to ``Small'' rHPcs operation effect: System abnormality occurred, and the operator would immediately take the next response operation. You can move on to preparations. On the other hand, the operation guide decision section also receives information on the HPC8 malfunction from the safety function monitor, searches the event response and gate response guide database, and selects the low-pressure core spray system (LP0) as a new operation guide.
1) Start-up is instructed to the operator. After LPC8 was activated, the reactor water level was on track to recover, and the safety of the reactor was ensured.

(17) [Effects of the Invention] According to the present invention, a driving operation guide corresponding to an occurrence event is provided.
The system searches for driving guides based on different methods, such as driving guides that correspond to changes in safety parameters and driving operation guides that respond to changes in safety parameters, and selects safe driving operations by comparing the two.
Since this method is adopted, it is possible to present a highly reliable driving guide that compensates for the shortcomings of both.

Further, according to the present invention, the effects of operation operations are quantitatively evaluated using a plant response prediction model, and highly reliable operation effect judgments are made using plant subsystem functional status information and occurrence event discrimination information. This is effective in assisting operators in making decisions.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of the plant operation guidance system according to the present invention, FIG. 2 is a block diagram showing the processing contents of the operation guide determination section, and FIG. 3 is a basic diagram of the operation guide determination section. A flowchart diagram showing the processing procedure, Figure 4 is an explanatory diagram showing the basic driving operation sequence and related subsystems (18) of the guide database used in the driving operation guide determination section, and Figure 5 is the water level of the symptom response guide database. Flowchart related to securing operations, Figure 6 is a flowchart related to securing the water level of the event response guide database, Figure 7 is a block diagram showing the processing contents of the operation effect evaluation section, and Figure 8 is the basic processing procedure of the operation effect evaluation section. FIG. 9 is a flowchart showing the processing procedure of the operational effect determination unit, and FIG. 10 is a simulation of a main steam pipe rupture accident when this operation guidance system is applied to a boiling water nuclear power plant. FIG. DESCRIPTION OF SYMBOLS 1... Plant, 2... Main system, 3... Subsystem, 6... Safety function monitor section, 7... Event discrimination section, 8... Plant response change measurement section, 9... - Driving operation guide determining section, 10... Operation effect evaluation section, 11.
...Plant response prediction model, 12...Model correction data, 13...Driving operation guide, 14...Operation effect evaluation guide, 15...Driving guide display section. Agent Patent Attorney Akio Takahashi (19) Hana 1 (2) No. 2m Height 3 Fig. 4 Thatch 50 Half Mouth 7 Fig./1 Mine 3m $9 Concave

Claims (1)

[Claims] 1. In a plant that consists of a main system consisting of the main equipment system and subsystems consisting of the control system, auxiliary equipment system, and safety function system, the part that calculates the fluctuation symptoms by incorporating the safety-related parameters of plan snoring. , a part that incorporates plant data to determine abnormalities and accident events that have occurred in the plant, a part that incorporates plant data to determine the functional status of subsystems, and outputs from these parts, respectively. The results of abnormality/accident event discrimination based on the calculation results of fluctuation symptoms of safety parameters and the results of subsystem functional state discrimination are inserted, and the part that searches the guide database to determine the operation guide and the actual measured data of the plant response due to subsystem startup are used. A part that incorporates the results of the abnormal/accident event determination and the nuclear subsystem functional status determination, and evaluates the effectiveness of the operational operation performed using the plant response prediction value based on the plant response prediction model, and the operation guide. A plant operation guidance system comprising: and a part that displays evaluation results of the operation effect.