JPH0534681B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a plant operation guidance method, and particularly to a plant operation guidance method that provides guidance on appropriate operation when an abnormality occurs in a plant such as a nuclear power plant. Regarding the method.

[Conventional technology]

Generally, large-scale plants such as nuclear power plants are
Since it is a complex system consisting of a large number of devices and control devices, various methods have been proposed to provide guidance for appropriate driving operations when an abnormality occurs.

Some of these methods include periodic acquisition of plant data to generate information that expresses the causal relationships of abnormalities in a tree-like manner, that is, a cause-effect relationship tree.
There is a way to get driving guidance by searching the Consequence Tree.

FIG. 1 shows an example of a cause-effect relationship tree leading from an abnormality in the water supply control system of a nuclear power plant to a reactor scram. This cause-effect relationship tree combines the cause-and-effect relationships between events or device states called nodes using logic circuits such as OR circuits 3a to 3c and AND circuits 4a to 4c, and delay circuits 5a to 5c to spread the influence of abnormal events. It describes a phenomenon. Event messages 1a-1i and corresponding operation messages 2a-2g are added to each node as necessary. Note that 6a to 6c are device status messages, and ○ in the figure indicates an unobservable point, and ● indicates an observable point.

Next, the terms used in this specification are defined as follows. If the described event or equipment state actually occurs, the corresponding node is said to be active, otherwise it is said to be inactive. Further, a node whose activation or inactivity is determined based on plant data is referred to as an observed node, and a node determined by a logic circuit from the node state below the cause-effect relationship tree is referred to as an unobserved node. Further, the top node of the cause-effect relationship tree is called a top node, and the bottom node is called a primary node.

FIG. 2 shows an example of the configuration of a conventional driving guidance system using the cause-effect relationship tree described above. The process quantity signal 21 detected in the plant 20 is input into the plant data table 13. The abnormality monitoring unit 14 periodically imports plant data corresponding to each observation node of the abnormality cause-effect relationship tree stored in the memory 15 from the plant data table 13, and compares it with a preset threshold value. After comparing and determining whether the observed node is active or inactive, the active or inactive state of the non-observed node is determined, and the active or inactive state of the non-observed node is determined. Next, if a pre-specified node corresponding to an important abnormal event described in the cause-effect relationship tree, that is, an entry node, is active or changes from active to inactive, , outputs a signal to the abnormal event analysis unit 16 using a cause-effect relationship tree.

FIG. 3 is a functional block diagram showing the relationship between the analysis functions of the abnormal event analysis section 16. In an analysis using a cause-effect relationship tree, first, in order to confirm that the abnormal event occurring in the plant matches the abnormality model described by the cause-effect relationship tree, Node setting section 29
Set the node that will be the starting point for the cause-effect relationship tree search. This node is the entry node that triggers the execution of the analysis. After the starting point node, that is, the entry node for the cause-effect related tree search is set, the valid node search unit 22 performs logical judgments on logic circuits and delay circuits from the starting point node for the tree search.
The active nodes are traced back to the bottom of the cause-effect relationship tree, and an active node that satisfies the logic is extracted, and this active node is set as the valid node.
After valid nodes are extracted, the abnormality propagation route determination unit 24 checks whether the extracted valid node group completely indicates a tree path from the primary node to the tree search node starting point node. The causal event determination unit 25 extracts the primary node included in the valid node group and determines the causal event.

After understanding the abnormal ripple phenomenon as described above, future abnormal ripple effects are predicted. First, the potentially active node search unit 23 searches nodes that are currently inactive but are expected to be activated in the future, that is, potential active nodes, from the starting point node of the tree search upwards in the cause-effect relationship tree. Search for. In this case, the search is performed according to the following rules.

When an active or potentially active input point node of a logic circuit satisfies a logic condition; When an input point node of a delay circuit is active or potentially active; A node whose output point is inactive is a potentially active node.

After searching for potentially active nodes, the abnormal propagation prediction unit 26 orders the extracted potentially active nodes from lower nodes to upper nodes. The guidance message selection unit 27 selects the event message attached to each node of the abnormality propagation route, cause event, and abnormality propagation prediction route obtained as described above, and the response attached to each node of the abnormality propagation route. An operation message is selected from the message table and output to the display data processing section 28.
The display unit 17 in FIG. 2 displays the message, abnormality propagation route, causative event, and abnormality propagation prediction route selected from the message table in a predetermined format as driving guidance on, for example, a CRT. The operator 18 visually observes the guidance and inputs the operation input signal 19 to the plant 20 .

[Problem to be solved by the invention]

The driving guidance method using the above-mentioned cause-effect relationship tree is based on the cause of the abnormality, the propagation route,
Since information on propagation prediction and response operations is clearly given, it is an effective means to improve operating efficiency and safety when preventing abnormal spread in a nuclear power plant, for example, but it has the following problems.

First, when deciding on a response operation, since a plurality of response operation guidances are generally output, it is necessary for the operator to select the optimal response operation according to the plant state from among them. For example, as shown in the event message 1i in FIG. 1, when an abnormality occurs in which the water level detector A of the water supply control system swings to the high side, according to the cause-effect relationship tree in FIG. 1, the delay circuit 5c After a delay of ₃ hours due to τ, node 1e, where the water supply or main steam mismatch is large, is activated from node 1i, which is the primary node, and corresponding operation messages 2d, 2e, and 2g are output.

These corresponding operation messages A04, A05, A06
The contents are as follows.

A04: Reduce reactor output.

A05: Switch the water supply control system to manual.

A06: Switch the water level detector to B.

Among these response operations, the simplest operation corresponds to content A06, but whether or not this operation can prevent the abnormality from spreading to the reactor scram of top node 1a depends on this response operation. The determination is made by comparing the time required for the reactor water level to reach a low trip, which is estimated from the rate of change in the reactor water level drop.

However, the information for this judgment cannot be obtained from conventional analysis methods using cause-effect relationships, and it depends on the ability of the operator, which requires appropriate response operations when multiple abnormalities occur. There is a possibility that you will not be able to make a selection.

Furthermore, since the cause-effect relationship tree is created based on the causal relationship at the time of occurrence of the abnormality, it is often impossible to confirm when the abnormality has been recovered by performing a corresponding operation. For example, after a reactor scram occurs due to a low reactor water level trip, the reactor scram does not disappear even if the reactor water level returns to the normal water level. However, in the logical model of the cause-effect relationship tree, the above content is contradictory. Become.

Furthermore, when a node goes from active to inactive,
Since the required time is generally not the same as the reverse case, it is necessary to use different delay times.

An object of the present invention is to provide guidance by selecting the most appropriate response operation message from among a plurality of response operation messages when an abnormality occurs in a plant, and also to predict the plant state after response operation is performed and use the guidance to confirm the operation effect. The purpose of the present invention is to provide a plant operation guidance method that can be used.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a plant operation guidance method that periodically imports plant data and determines operation operations using an abnormality-related tree representing the cause-and-effect relationship of abnormalities. or an equipment operation node whose off state corresponds to the activation or deactivation of the attached node and whose state switching time is input;
A plant state node in which the corresponding operation method when the attached node is activated and the corresponding operation method given the operation time required for the corresponding operation is input, and the input side node is the logic when the output side node is activated. A self-holding logic means that maintains the activation of the output side node even when the condition is not satisfied, and a self-holding logic means that maintains the activation of the output side node when the input side node is activated and the output side node is activated, and when the input side node is inactivated and the output side node is inactive. Using a multi-functional abnormality-related tree with a newly added bidirectional delay means that can set a delay time for each case of activation, a tree corresponding to each state change when a node is activated or deactivated is used. Apply logic judgment of the circuit to determine the propagation or recovery path of an abnormal event that satisfies the causal relationship, and when an abnormality occurs, calculate the margin time for response operations from the sum of the abnormality propagation delay times, and determine the operation required. Plant operation in which the delay time of the response operation effect is determined by searching the time and abnormality recovery time, and when the delay time of the response operation effect is shorter than the implementation margin time of the response operation, the response operation is determined as an effective response operation. This paper proposes a guidance method.

[Effect]

In the present invention, when an abnormality occurs in a plant, the most appropriate response operation message is selected from a plurality of response operation messages for guidance, so that response operations can be executed quickly and reliably without depending on the ability of the operator.

In addition, since the plant state after the corresponding operation is predicted and guidance is provided to confirm the operation effect, there will be no contradiction between the predictions made by the logical model of the cause-effect relation tree and the actual state of the plant. .

〔Example〕

Multi-Functional cause-effect relationship tree representing the causal relationship of abnormalities used in the present invention
The Cause-Consequence Tree is based on the conventional cause-effect relationship tree, but it has a new logic circuit and delay circuit that describe the causal relationship when an abnormality disappears, and has corresponding operations and device operation information. There's a lot going on.

FIG. 4 shows an example of application of the multifunctional cause-effect relationship tree to an abnormality in the reactor water supply control system. The following four points differ from the conventional cause-effect relationship tree.

First, a self-holding AND circuit 7 and a self-holding OR circuit 8 are employed. Once the output side of the circuit is activated, the self-holding AND circuit 7 or the self-holding OR circuit 8 maintains its active state even if the logic condition on the input side of the circuit no longer holds true.

Second, bidirectional delay circuits 11a to 11c are employed. In these bidirectional delay circuits, the delay times τ ₁ to _{τ 3} at the bottom right surrounded by a bold frame represent the time delay of propagation from the lower node to the upper node at the time of node activation, and the delay time at the upper left τ ₁ ′ to τ ₃ ′ represent the time delay of propagation from a lower node to an upper node when a node returns from active to inactive.

Thirdly, device operation information 9a to 9c was adopted.
In this device operation information, when the device status is in the lower right state surrounded by a bold frame, the attached node is determined to be active, and when the device status is in the lower left state, it is determined to be inactive, and the numerical value surrounded by a circle is determined to be active. , represents the time required to switch the device from one of these two states to the other.

Fourth, corresponding operation information 10a, 10b is adopted. This corresponding operation information can be deactivated in the required time indicated by the number enclosed in a circle if the node to which it is attached is activated and the corresponding operation for the message entered is performed. Indicates that it is possible. The determination of whether a node has been activated or not, that is, whether an event has occurred, is made by comparing the plant data for observed nodes with a preset threshold, and for non-observed nodes, it is determined whether or not the cause has occurred. Activate and execute logic circuits from node states below the result-related tree.

Note that 12a and 12b are monitoring messages.

The main differences between the multifunctional cause-effect relationship tree of the present invention and the conventional cause-effect relationship tree are as follows: a. Distinguish between corresponding operation/equipment operation information and monitoring messages, and determining the time required for corresponding operation/equipment operation information. (b) Incorporation of bidirectional transition information of node states into logic circuits and delay circuits. These provide information necessary for the corresponding operation selection function and operation confirmation function.

The features of the analysis method for obtaining the necessary driving guidance using the multifunctional cause-effect relationship tree of the present invention are as follows: c. Changing the node search logic according to the state transition of the node; d. For selecting the corresponding operation. A function for evaluating the margin time until an abnormality spreads to the top node by searching for a delay circuit, and a node search function for confirming corresponding operations are added.

FIG. 5 is a block diagram showing the relationship between functions for analyzing abnormal events using a multifunctional cause-effect relationship tree. Parts corresponding to those in FIG. 3 are given the same reference numerals. The tree search starting point node setting unit 29 sets the entry node that triggered the analysis execution as the starting point node. When the starting point node of the tree search is in an active state, the valid node search unit 22 traces the active node from this starting point node while making logic judgments of the logic circuit and the delay circuit, and moves backwards toward the bottom of the tree. , an active node that satisfies the logic is extracted and this active node is set as a valid node. The abnormality spread route determination unit 24 verifies that the extracted valid node group completely represents the tree route from the primary node to the starting point node of the tree search.
The causal event determining unit 25 extracts a primary node from the valid node group and determines the causal event. When the starting point node of the tree search is an active node, the potential active node search unit 23 searches from this starting point node upward in the tree according to the conventional potential active node search rules for cause-effect related trees. Potentially active nodes are extracted according to similar rules. The abnormal propagation prediction unit 26 orders the extracted potentially active nodes from the lowest to the highest.

Next, in the case where the starting point node of the tree search is an active node, the corresponding operation execution margin calculation unit 39 sequentially traces the potentially active nodes from this starting point node, and routes the path to the highest node of the potentially active nodes. Add all the delay times when activating the bidirectional delay circuits to find 〓 ⁱ τ _i , and subtract the elapsed time Δt from activation time t ₀ of the starting point node to current time t from this 〓 ⁱ τ _i Then, find the margin time Δt* for carrying out the corresponding operation. That is, the corresponding operation execution margin time Δt* is determined by the following equation.

Δt*= 〓 ⁱ τ _i −Δt ...(1) However, Δt=t−t ₀ .

In other words, Equation (1) expresses the corresponding operation execution margin time Δt* for the highest node of potentially active nodes.
This is the formula to find. In other words, it is predicted that if the necessary response operation is not performed, an event corresponding to the top node of the potentially active nodes will occur after Δt* time from the current time.

In the case where the starting node of tree search is an active node, the corresponding operation range determining unit 34 performs logical judgment of the logic circuit and bidirectional delay circuit from this starting point node, and moves backwards toward the bottom of the tree by tracing the active node. Go up and extract the corresponding operation information or operation device information attached to the active node.
In this case, if you reach a self-holding logic circuit on the way,
Since operation information attached to a lower level than this is ineffective in preventing abnormality from spreading, the search for a lower level is discontinued.

The self-holding logic circuit was introduced to solve the problem that logical consistency is not satisfied when a node changes from active to inactive (at the time of event recovery) in the tree-based event propagation model of conventional technology. It is. In other words, as mentioned above, the self-holding logic circuit can also describe the causal relationship when an abnormality disappears, and it uses a tree to analyze the event in order to confirm the operation effect after the corresponding operation is performed. , is effective for predicting plant conditions.

A corresponding operation effect delay time calculation section 40 connected to the corresponding operation range determining section 34 uses each active node to which each corresponding information or device operation information extracted by the corresponding operation range determining section 34 is attached as a starting point. ,
The sum of all the delay times from activation to deactivation of the bidirectional delay circuits on the path leading to the starting point node of the tree search 〓 ⁱ τ′ _i 〕 _K and the time required for this operation δt _K are expressed as follows: By adding as shown in the equation, the corresponding operation effect delay time Δt _K of the operation information k is determined.

Δt _K = [〓τ′ _i ] _K + δt _K ...(2) In order to prevent the potential node from becoming activated, that is, to prevent the event from occurring, it is necessary to perform some corresponding operation. In general, it is necessary to consider the time required to implement a countermeasure operation and the delay time until the effect actually appears, and judge whether or not the countermeasure operation will be enough. Conventional driving guidance methods only display candidates for corresponding operations, leaving the above decisions to the driver. However, it is considered difficult to always make such judgments accurately in emergencies.

Therefore, in the driving guidance method of the present invention, such a judgment is automatically made by comparing the above-mentioned spare time for carrying out the corresponding operation Δt* and the corresponding operation effect delay time Δt _K.

If the corresponding operation selection unit 41 extracts the operation information in which the corresponding operation effect delay time Δt _K is shorter than the corresponding operation execution margin time Δt* from among the extracted operation information, and a plurality of pieces of operation information still remain. selects the corresponding operation information or device operation information attached to the lowest node among these pieces of operation information as the corresponding operation guidance. This is because, in general, in a cause-effect relationship tree, events corresponding to lower nodes are considered to be more minor, and the effects of corresponding operations attached to those events on the plant are also considered to be less.

Further, the corresponding operation confirmation search unit 35 uses the starting node of the tree search as a starting point and executes logical judgments in the logic circuit and the bidirectional delay circuit, while tracing nodes that have become active or inactive, and moves toward the bottom of the tree and A search is performed toward the top of the tree, and nodes that are active or become inactive are extracted. Note that the logic circuit and the logic decision rule for the bidirectional delay time in this case are changed depending on the states of the input side and the output side.

The bidirectional delay circuit is a component of the cause-effect relationship tree necessary to make the above decision. Note that the delay time is set based on knowledge of the phenomenon of interest and the results of dynamic characteristic analysis, and is not determined freely.

The analysis result information aggregation unit 42 aggregates the information output from each functional block in the form of a message or graphic display, and transfers it to the display data processing unit 28 as driving guidance information. Then, it is displayed as a driving guide on the CRT tube of the display section 17 in FIG.

In addition, in the description of the above embodiments, the characteristic parts of the present invention were mainly explained, but the present invention has the following features:
Needless to say, it has the function of investigating the cause of an abnormality and predicting its spread in the conventional driving guidance method using a cause-effect relationship tree.

FIG. 6 is a diagram showing the results of simulating an abnormality in the water supply control system by programming the method of the present invention using a computer. The initial cause event was an event in which the water level detector A of the water supply flow rate control system was swung to the high side. Approximately 20 seconds after the abnormality occurs, switching operation guidance from water level detector A to water level detector B is output, and as a result of the operator's switching operation,
It is understood that the function of the water supply control system has returned to normal.

〔Effect of the invention〕

According to the present invention, when an abnormality occurs in a plant, it is possible to select the most appropriate response operation message from among a plurality of response operation messages for guidance.

In addition, since the plant state after the corresponding operation is predicted and guidance is provided to confirm the operation effect, there will be no contradiction between the predictions made by the logical model of the cause-effect relation tree and the actual state of the plant. .

[Brief explanation of the drawing]

Figure 1 is a diagram showing an example of a cause-effect relationship tree leading from an abnormality in the water supply control system of a nuclear power plant to a reactor scram, and Figure 2 is an example of the configuration of a conventional operation guidance system using a cause-effect relationship tree. 3 is a functional block diagram showing the relationship between the analysis functions of the abnormal event analysis unit, and FIG. 4 is a diagram showing an example of application of the multifunctional cause-effect relationship tree of the present invention similar to the above-mentioned example. Figure 5 is a block diagram showing the relationship between functions for analyzing abnormal events using a multi-functional cause-effect relationship tree, and Figure 6 shows the results of simulating an abnormality in a water supply control system by programming the method of the present invention using a computer. FIG. 1... Event message, 2... Corresponding operation message, 3... OR circuit, 4... AND circuit, 5...
...Delay circuit, 6...Equipment status message, 7...
Self-holding AND circuit, 8...Self-holding OR circuit,
9a to 9c...equipment operation information, 10a, 10b...
...Corresponding operation information, 11a-11c...Bidirectional delay circuit, 12a, 12b...Monitoring message, 13
... Plant data table, 14 ... Abnormality monitoring section, 15 ... Memory, 16 ... Abnormal event analysis section,
17...Display unit, 18...Operator, 19...Operation input signal, 20...Plant, 22...Valid node search unit, 23...Potentially active node search unit, 24...Abnormality spread route determination Part, 25...Cause event determination part, 26... Abnormality propagation prediction part, 27...
...Guidance message selection section, 28...Display data processing section, 29...Starting point node setting section, 34
. . . Corresponding operation range determination unit, 35 …… Corresponding operation confirmation search unit, 39 …… Corresponding operation execution margin calculation unit,
40... Corresponding operation effect delay time calculation unit, 41...
Corresponding operation selection section, 42...Analysis result information aggregation section.

Claims (1)

[Scope of Claims] 1. A plant operation guidance method that periodically imports plant data and determines operation operations using an abnormality-related tree that represents the cause-and-effect relationship of abnormalities, which provides: A device operation node that corresponds to the activation or deactivation of an attached node and in which the required state switching time is input, a corresponding operation method when the attached node is activated, and the required operation time for the corresponding operation are given. a plant state node into which a corresponding operation method is input; a self-maintaining logic means that maintains the activation of the output side node even if the input side node does not satisfy a logical condition when the output side node is activated;
A new bidirectional delay means that can set delay times for each case when the input side node is activated and the output side node is activated and when the input side node is deactivated and the output side node is deactivated. Using the multifunctional anomaly-related tree added to the tree, we apply the logical judgment of the tree circuit according to each state change when a node is activated or deactivated to find the spread or recovery path of an abnormal event that satisfies the causal relationship. When an abnormality occurs, calculate the margin time for implementing response operations from the sum of the abnormality propagation delay times, search the required operation time and abnormality recovery time to determine the delay time for the response operation effect, and perform the corresponding response. A plant operation guidance method characterized by determining a response operation as an effective response operation when the delay time of the response operation effect is shorter than the execution time of the operation.