JP7383585B2 - Probabilistic risk assessment support method, probabilistic risk assessment support device and program - Google Patents

Description

The present disclosure relates to a probabilistic risk evaluation support method for fire inside a control panel, a probabilistic risk evaluation support device, and a program.

In order to prevent the spread of fires that occur inside control panels, nuclear power plants in Japan cover equipment inside control panels with metal casings, and cover cables with metal-sheathed cables or fluororesin. Measures are being taken to isolate them from fire, such as by using electric wires. Additionally, the effectiveness of this measure has been confirmed through demonstration tests.

The reliability of the separation measures described above is high, and the deterministic evaluation currently being carried out indicates that the measures will definitely succeed. However, it is expected that future efforts to improve safety will require probabilistic risk assessments that quantify the degree of unreliability of the measures in question.

As a conventional method for evaluating the risk of fire inside a control panel, Appendix L of Non-Patent Document 1 discloses a method for evaluating the risk based on the probability of damage to equipment according to the distance between devices within the control panel. In this method, the probability of equipment damage depends only on the distance between the equipment, and it is difficult to incorporate the effects of the above-mentioned separation measures. Furthermore, Non-Patent Document 2 discloses a probabilistic risk assessment method for fires in control panels that is being advanced in the United States. However, this method does not take into account the effects of separation measures. Further, Patent Document 1 discloses a probabilistic risk assessment method for ship disasters, but does not disclose incorporating the effects of isolation measures for fires in control panels into the risk assessment.

Japanese Patent Application Publication No. 2002-288386

"EPRI/NRC-RES Fire PRA Methodology for Nuclear Power Facilities", NUREG/CR-6850, Final Report, March 2020 "Refining and Characterizing Heat Release Rates from Electrical Enclosures During Fire", NUREG-2178, June 2020

There is a need for a method to incorporate the effectiveness of isolation measures implemented within control panels into the risk assessment of control panel fires.

The present disclosure provides a probabilistic risk assessment support method, a probabilistic risk assessment support device, and a program that can solve the above problems.

The probabilistic risk assessment support method of the present disclosure is a probabilistic risk assessment support method for a fire inside a control panel that is executed by a computer, and includes failures that indicate the risk of isolation measures that separate components of the control panel from the fire. A step of reading and displaying support information that supports calculation of the probability from a storage unit, a step of obtaining the inputted failure probability based on the displayed support information, and analyzing the progress of the fire situation caused by the fire. In an event tree diagram as a target event, the step includes a step of setting a branching probability for each event, and a step of outputting the event tree diagram in which the branching probability is set, and a step of setting the branching probability. Then, among the branching probabilities for the predetermined event corresponding to the fire situation when the separation countermeasure is successful, the failure probability is set to the probability that the fire situation is denied.

Further, the probabilistic risk evaluation support device of the present disclosure reads out and displays support information from a storage unit to support calculation of a failure probability indicating the risk of isolation measures for separating components of a control panel from a fire. a support unit; an input reception unit that obtains the failure probability input based on the displayed support information; a branching probability setting unit that sets a branching probability for each event, and an output unit that outputs the event tree diagram in which the branching probability is set, and the branching probability setting unit is configured to set a branching probability for each of the events, and an output unit that outputs the event tree diagram with the branching probability set. The failure probability is set to the probability of denying the fire situation among the branch probabilities for the predetermined event corresponding to the fire situation when the fire situation is successful.

The program of the present disclosure also includes a step of causing the computer to read support information from the storage unit and displaying the support information that supports calculation of failure probability indicating the risk of isolation measures to isolate components of the control panel from fire; a step of obtaining the failure probability input based on the support information; and a step of setting a branching probability for each event in an event tree diagram in which the development of a fire situation caused by the fire is an event to be analyzed. , outputting the event tree diagram in which the branching probabilities are set, and the step of setting the branching probabilities corresponds to the fire situation in which the separation countermeasure is successful among the events. Among the branch probabilities for the predetermined event, the probability of denying the fire situation is subjected to a process of setting the failure probability.

According to the probabilistic risk assessment support method, probabilistic risk assessment support device, and program described above, the effects of separation measures can be incorporated into the probabilistic risk assessment of a fire inside a control panel.

FIG. 1 is a block diagram illustrating an example of a support device according to an embodiment. FIG. 3 is a diagram illustrating an example of an event tree according to the embodiment. FIG. 3 is a diagram illustrating an example of analysis information for identifying failure factors according to the embodiment. It is a figure showing an example of a decision procedure of a failure probability calculation method concerning an embodiment. It is a flow chart which shows an example of risk evaluation processing concerning an embodiment. It is a figure showing an example of a failure factor setting screen concerning an embodiment. It is a figure showing an example of a failure probability setting screen concerning an embodiment. FIG. 1 is a diagram illustrating an example of a hardware configuration of a support device according to an embodiment.

<Embodiment>
The support device of the present disclosure will be described below with reference to FIGS. 1 to 8.
(composition)
FIG. 1 is a block diagram illustrating an example of a support device according to an embodiment of the present disclosure.
The support device 10 is a device that supports risk assessment of fire inside a control panel of a nuclear power plant or the like. More specifically, the support device 10 supports creation of a risk assessment model such as an event tree used in probabilistic risk assessment. As illustrated, the support device 10 includes an input reception section 11, a control section 12, a risk evaluation model creation section 13, an output section 14, and a storage section 15.
The input receiving unit 11 receives settings of information necessary for risk evaluation. For example, the input accepting unit 11 accepts settings for branch probabilities of event trees used in probabilistic risk evaluation.

The control unit 12 sets the branch probability of the event tree. Specifically, the control unit 12 sets appropriate values for the occurrence probability X and branch probabilities X1 to X8 of the event tree shown in FIG. Reference is now made to FIG. Figure 2 shows an example of an event tree used for probabilistic risk assessment of a fire inside a control panel. The event tree in FIG. 2 is a model of the progress of a fire, with the occurrence of a fire inside the control panel as the initiating event. In the heading section (headline row) of the event tree, events to be analyzed (``single equipment failure?'' to ``successfully extinguishing fire before it spreads to multiple control panels?'') are displayed. In these events, the farther to the right the fire progresses and the area of influence expands. For example, if "Single equipment failure?" is Yes, it indicates that the fire is only affecting one equipment (the equipment that caught fire) in the control panel, and "The fire must be extinguished before the fire spreads to multiple control panels." If "Success?" is No, it indicates that the fire affects multiple control panels. "Fire Scenario" in the rightmost heading section shows the final result of the fire's influence area, and each scenario is associated with a document that explains the end state of the fire. The document contains information on the equipment that will be damaged as a result of the impact range analysis. For example, in a single equipment damage scenario, the equipment that caused the fire (if the fire started from a switch in the control panel) , the relevant switch) is listed as the equipment that will be damaged. The event tree itself illustrated in FIG. 2 has already been disclosed in Non-Patent Document 2, and for example, in the United States, it is being considered to use this event tree to evaluate the risk of fire inside a control panel of a nuclear power plant. However, the risk assessment method under consideration does not take into account the impact of separation measures within the control panel. Therefore, this embodiment provides a method of incorporating the effects and risks of separation measures into the event tree shown in FIG. 2. Specifically, if isolation measures are successful, the area affected by a fire can be confined to only the device where the fire occurred (for example, even if a switch covered with a metal casing ignites, the fire will not start within the metal casing). ), and set the success probability of the separation measure to the branch probability X1 when "Single device failure?" in the event tree in Figure 2 is Yes, and the separation measure fails. The probability is set to branch probability X2 in the case of No. Further, the other branching probabilities X3 to X8 and the probability of occurrence of a fire inside the control panel X are calculated and set using a predetermined method (for example, a conventional method).

The control unit 12 obtains the values of probability X and branch probabilities X3 to X8, and sets them to the corresponding branch probabilities of the event tree in FIG. 2, respectively. Setting of branch probabilities X1 and X2 will be explained next. As shown in FIG. 1, the control section 12 includes a separation measure failure factor setting section 121, a separation measure failure probability setting section 122, and a single device failure probability setting section 123.
In this embodiment, in order to calculate the probability of success and failure of separation measures, (1) the factors causing failure of separation measures are identified for each component (equipment, cables, etc.) in the control panel. (2) For each identified failure factor, calculate the probability that that failure factor will occur. (3) Then, the probability of failure of the separation measure for the entire control panel is calculated by integrating the probability of occurrence for each failure factor. The separation measure failure factor setting unit 121 executes the process related to (1), the separation measure failure probability setting unit 122 executes the process related to (2), and the single equipment failure probability setting unit 123 executes the process related to (3).

The separation measure failure factor setting unit 121 presents the user with analysis information (FIG. 3) that supports the task of identifying the failure factor of the separation measure, and sets the failure factor specified by the user for the control panel subject to risk evaluation. Reference is now made to FIG. FIG. 3 is a diagram illustrating an example of analysis information for identifying failure factors according to an embodiment of the present disclosure. The causes of “failure of separation measures (A1)” can be broadly classified into “deficiencies in separation measures (A2)” and “unexpected fire effects (A3).” )”, whether it falls under “inappropriate setting of separation conditions (A4)” or “inappropriate verification test conditions (A5)” or “measures not to satisfy separation conditions (A6)” , classified by. Examples of “inappropriate setting of separation conditions (A4)” or “inappropriate verification test conditions (A5)” include “variation in test specimens (A7),” “setting error in test specimens (A8),” Examples include "environmental conditions (A9)". Examples of “measures that do not satisfy separation conditions (A6)” include “defective products (A10),” “defective construction, omissions in construction (A11),” “deterioration of equipment, omissions in inspections, and repairs (A12),” etc. It is. Moreover, examples of "unexpected fire effects (A3)" include occurrence of "fire exceeding test conditions (A13)" and occurrence of "unexpected fire caused by combustible material (A14)."

The separation countermeasure failure factor setting unit 121 creates a screen (image) displaying the analysis information illustrated in FIG. 3, and displays it on the display device through the output unit 14. The user refers to the analysis information illustrated in FIG. 3 to identify the cause of failure of separation measures implemented for each component (switches, instruments, etc.) within one control panel. If components 1 to 3 for which separation measures have been taken are present in the control panel, the user identifies one or more failure causes among A7 to A14 for each of components 1 to 3. For example, if a demonstration experiment was conducted to prevent a control panel fire by implementing isolation measures on a switch, and the results showed that there were large variations in the effectiveness of the isolation measures for each test piece, the user would be disappointed in the failure of the switch isolation measures. “Test specimen variation (A7)” is identified as a factor. Furthermore, based on past results, if a certain percentage of construction defects have been found during switch isolation measures, the user may consider "defects in construction or omissions" (A11) as the cause of failure in switch isolation measures. )”. In addition, if it is considered that there is a possibility that the separation measures will fail in the event of a fire exceeding the test conditions, the user may select "Fire exceeding the test conditions (A13)" as the cause of the failure of the switch separation measures. Identify. The separation countermeasure failure factor setting unit 121 obtains one or more failure factors identified for each component, and writes and stores the failure factors in the storage unit 15 for each control panel and each component.

The separation measure failure probability setting unit 122 presents the user with procedure information (FIG. 4) indicating a procedure for determining a method for calculating the failure probability of the separation measure. The probability of failure of separation measures is a value indicating the risk of separation measures to separate the components of the control panel from fire, that is, the unreliability of the separation measures. Reference is now made to FIG. FIG. 4 is a diagram illustrating an example of a determination procedure of a failure probability calculation method according to an embodiment of the present disclosure. The user determines a failure probability calculation method for each of the failure factors of the separation countermeasure according to the procedure shown in FIG. 4, and calculates the failure probability using the method suggested therein. According to the procedure information shown in FIG. 4, first, it is determined whether the identified separation measure failure factor (S10) is included in the effects of other failure factors (S11). For example, in the case of countermeasures using steel plates with a simple shape, the effects caused by product defects such as manufacturing defects are considered to be sufficiently small compared to the effects of poor construction or omissions in construction. In this case, it can be represented by the probability of failure of separation measures due to poor construction or omission of construction.

If it is included in the influence of other failure factors (S11; Yes), the failure probability of the failure factor is represented by the failure probability of the other failure factors (S12). For example, if the identified failure factors include "product deficiencies (A10)" and "construction defects, construction omissions (A11)," the user may decide that the failure probability due to "product deficiencies (A10)" is due to "construction failures." It is determined that this will be represented by "Defects, construction omissions (A11)". This makes it possible to simplify the evaluation of failure probability.

If the failure is not included in the influence of other failure factors (S11; No), it is determined whether the failure is related to equipment malfunction or human factors (S13). For example, if the failure cause is A10 to A12 in FIG. 3, the determination is Yes, and if the failure factor is A13 to A14, the determination is No. A7 to A9 are appropriately determined.

If the failure is not related to equipment malfunction or human factors (S13; No), it is suggested that the probability of failure be estimated by analyzing the mechanism of failure of the separation measure and using engineering judgment (S16). For example, an example that requires analysis and estimation based on engineering judgment is a factor related to the uncertainty of the expected scale of a fire. Regarding the distribution of uncertainty in fire scale, information is presented in Appendix G of Non-Patent Document 1, etc., and this information can be used as a reference to make engineering judgments on the probability of fire occurrence exceeding the verification test conditions for separation measures. It can be carried out. For example, when the user selects S16 in the flowchart of FIG. 4, the separation countermeasure failure probability setting unit 122 enters information such as reference information for engineering judgment of the mechanism of occurrence of the failure factor and an example of actual calculation of the failure probability. You may also create and display a screen with

Further, the procedure information in the procedure shown in FIG. 4 suggests that if the determination in S13 is Yes, it is determined whether statistical data (for example, failure rate, etc.) regarding the success or failure of the failure factor exists ( S14). If statistical data exists (S14; Yes), it is suggested that failure probability is estimated based on the statistical data (S15). For example, when the user selects S15 in the flowchart of FIG. 4, the separation measure failure probability setting unit 122 calculates the failure probability based on statistical data such as the failure rate of each component for which separation measures have been taken and the statistical data. You may also create and display a screen that describes specific examples.

If statistical data does not exist (S14; No), it is suggested that failure probability be estimated with reference to data such as fire reliability and failure rate of similar products (S17). For example, Chapter 11 of Non-Patent Document 1 discloses the unreliability of fireproof walls, penetration seals, and the like. Using this information as a reference, it is possible to estimate the probability of failure for similar products such as fireproof walls and penetration seals used as separation countermeasures. For example, when the user selects S17 in the flowchart of FIG. 4, the separation measure failure probability setting unit 122 displays information such as data such as the reliability of similar products and an example of calculating failure probability using that data. You may also create and display a screen.
The user refers to the procedure information in FIG. 4 and calculates the failure probability for each failure factor. The separation countermeasure failure probability setting unit 122 acquires the failure probability calculated by the user, and writes and stores it in the storage unit 15 for each control panel, component, and failure factor.

The single equipment failure probability setting unit 123 reads the failure probabilities stored by the separation measure failure probability setting unit 122, integrates these, and calculates the failure probability of the separation measure for the entire control panel. For example, if failures in separation measures caused by each failure factor occur independently and without relation to each other, the single equipment failure probability setting unit 123 sums up all the failure probabilities and sets one control panel. Calculate the failure probability of the overall separation measures. If a separation measure fails due to multiple failure factors, the probability of failure for the entire control panel is calculated in consideration of the effects. In this embodiment, the overall failure probability is calculated by summing the failure probabilities for each failure factor. The single equipment failure probability setting unit 123 sets the calculated failure probability of the entire control panel as the branch probability X2 of the event tree in FIG. 2, and sets the branch probability X1 to (100-X2).

The risk evaluation model creation unit 13 creates a screen displaying the event tree shown in FIG. 2 with branch probabilities set, and outputs this screen to the output unit 14.

The output unit 14 outputs the screen created by the control unit 12 (the screen on which various information illustrated in FIGS. 2, 3, and 4 are displayed) to the display device.
The storage unit 15 stores the event tree shown in FIG. 2, information on branch probabilities (failure probabilities) acquired by the input reception unit 11, and the like.

(motion)
FIG. 5 is a flowchart illustrating an example of a control panel fire risk evaluation process according to an embodiment of the present disclosure.
First, the user confirms the design of the control panel to be evaluated (step S21). The user determines whether or not separation measures are being implemented on the control panel (step S22). If the control panel does not have separation measures implemented (step S22; No), the user calculates the single equipment failure probability using a conventional method, for example, based on fire cases in the United States, and inputs it into the support device 10. do. The input receiving unit 11 acquires this value Y and outputs it to the single equipment failure probability setting unit 123. The single device failure probability setting unit 123 sets the value Y to the branch probability X2, and sets the branch probability X1 to (100-Y) (step S231).

In the case of a control panel on which separation measures have been implemented (step S22; Yes), the user instructs the support device 10 to start a risk evaluation process for separation measures (step S23). The input receiving unit 11 receives the input of this instruction, and the control unit 12 starts the risk evaluation process for the separation countermeasure. First, the separation countermeasure failure factor setting unit 121 displays a setting screen for the separation countermeasure failure factor (step S24). An example of the setting screen is shown in FIG. FIG. 6 is a diagram illustrating an example of a failure factor setting screen according to an embodiment of the present disclosure. For example, on the failure factor setting screen 100, identification information and names of the plant and control panel to be evaluated can be input. Input field 101 is configured so that identification information and names of components such as switches, instruments, cables, etc. that are equipped with isolation measures existing in the control panel can be input freely. The configuration is such that one or more pieces of identification information (A7 to A14 in FIG. 3) of the cause of failure can be input for each failure factor (A7 to A14 in FIG. 3).

Next, the separation measure failure factor setting unit 121 displays information that supports identification of the failure factor (step S25). For example, when the analysis information display button 102 is pressed on the failure factor setting screen 100 in FIG. 6, the separation measure failure factor setting section 121 creates a screen displaying the analysis information illustrated in FIG. displays this screen. The user refers to the analysis information, identifies possible failure causes for each component, and inputs the identified failure causes into the input field 101. When the user presses the registration button 103, the input reception unit 11 acquires the input failure factor, and the separation measure failure factor setting unit 121 associates the input failure factor with the plant, control panel, and component. The data is written to the storage unit 15 and saved (step S26).

Next, the separation measure failure probability setting unit 122 displays a setting screen for setting failure probabilities for each failure factor (step S27). An example of the setting screen is shown in FIG. FIG. 7 is a diagram illustrating an example of a failure probability setting screen according to the embodiment. For example, on the failure probability setting screen 200, identification information and names of the plant and control panel to be evaluated can be input. The input field 201 is configured so that a failure probability can be input for each failure factor input on the failure factor setting screen 100.

Next, the separation measure failure probability setting unit 122 displays information that supports quantifying the failure probability (step S28). For example, when the procedure information display button 202 is pressed on the failure probability setting screen 200 in FIG. displays this screen. The user refers to the procedure information, determines a failure probability calculation procedure for each component and failure factor, and calculates the failure probability. The user inputs the calculated failure probability into the input field 201. When the user presses the registration button 203, the input reception unit 11 acquires the input failure probability, and the separation measure failure probability setting unit 122 sets the input failure probability to the plant, control panel, component, and failure factor. It is written and stored in the storage unit 15 in association with the above (step S29).

Next, the single device failure probability setting unit 123 integrates the failure probabilities for each failure factor and calculates the single device failure probability (step S30). For example, when all failure probabilities are stored in the storage unit 15, the single equipment failure probability setting unit 123 reads out the failure probabilities input on the failure probability setting screen 200 from the storage unit 15, and adds them all up. At the same time, the failure probability P of the isolation measures for fire inside the control panel in the control panel to be evaluated is calculated. The single device failure probability setting unit 123 sets the failure probability P to the branch probability X2, and sets the branch probability X1 to (100-P).

Next, the control unit 12 acquires and stores other branch probability settings (step S31). For example, the control unit 12 creates a setting screen 300 (not shown) and displays this setting screen 300 on a display device using the output unit 14. On the setting screen 300, identification information and names of the plant and control panel to be evaluated can be input. In addition, on the setting screen 300, the probability of occurrence of a fire inside the control panel (X), the probability of whether the fire effect is limited or not (X3, X4), and in the case of failure to extinguish, whether only a single control panel is damaged or not. There are input fields for inputting the probability (X5, do. The input receiving unit 11 acquires the input value, and the control unit 12 writes and stores the input value in the storage unit 15 in association with X, X3 to X8 (step S31). Next, the risk evaluation model creation unit 13 reads the values of X, X1 to X8 stored in the storage unit 15 and the event tree shown in FIG. The set event tree diagram is created (step S32). The output unit 14 outputs the event tree diagram as a display device or an electronic file (step S33).
Using the support device 10, the user repeatedly performs the above process for each control panel included in the plant. This makes it possible to create a probabilistic risk assessment model for fire inside the control panel for each control panel.

(effect)
At nuclear power plants in Japan, as a measure to prevent the spread of fire, devices installed in the central control board (MCB), such as switches, are made of steel plates, and electric wires are made of flame-retardant fluororesin. Countermeasures are being taken such as using coverings. Currently, proposed methods for assessing the risk of fire inside a control panel include the evaluation method using a damage probability curve based on the distance between devices in a control panel (non-responsive) proposed by the U.S. Nuclear Regulatory Commission (NRC). There are evaluation methods based on Patent Document 1) and event trees (Non-Patent Document 2). However, none of these methods takes into account the effects and risks of separation measures adopted at domestic plants, and it is difficult to conduct a detailed risk assessment of fires inside control panels at domestic plants using conventional methods. . In contrast, according to the present embodiment, by setting the risk of the isolation measure to the branch probability of a single device failure in the event tree, it is possible to evaluate the effectiveness of the isolation measure. Separation measures have a rich track record in plants in Japan, and if conventional methods were used to evaluate risks for each plant, the risk evaluation would be overly conservative, but according to this embodiment, Fire risk assessment can be performed more precisely than before.

Further, according to the support device 10 of the present embodiment, risk evaluation is performed at low cost by analyzing the failure factors of separation measures, examining the probability that these failure factors may occur, and setting the failure probability. can do.

FIG. 8 is a diagram illustrating an example of a hardware configuration of a support device according to an embodiment of the present disclosure.
The computer 900 includes a CPU 901, a main storage device 902, an auxiliary storage device 903, an input/output interface 904, and a communication interface 905.
The support device 10 described above is implemented in a computer 900. Each of the above-mentioned functions is stored in the auxiliary storage device 903 in the form of a program. The CPU 901 reads the program from the auxiliary storage device 903, expands it to the main storage device 902, and executes the above processing according to the program. Further, the CPU 901 reserves a storage area in the main storage device 902 according to the program. Further, the CPU 901 secures a storage area in the auxiliary storage device 903 to store the data being processed according to the program.

Note that a program for realizing all or part of the functions of the support device 10 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed. Processing may be performed by a functional unit. The "computer system" here includes hardware such as an OS and peripheral devices. Furthermore, the term "computer system" includes the homepage providing environment (or display environment) if a WWW system is used. Furthermore, the term "computer-readable recording medium" refers to portable media such as CDs, DVDs, and USBs, and storage devices such as hard disks built into computer systems. Further, when this program is distributed to the computer 900 via a communication line, the computer 900 that received the distribution may develop the program in the main storage device 902 and execute the above processing. Further, the above program may be one for realizing a part of the above-mentioned functions, and further may be one that can realize the above-mentioned functions in combination with a program already recorded in the computer system. . The support device 10 may be configured by a plurality of computers 900.

As described above, several embodiments according to the present disclosure have been described, but all these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included within the scope and gist of the invention as well as within the scope of the invention described in the claims and its equivalents.

<Additional notes>
The probabilistic risk assessment support method, probabilistic risk assessment support device, and program described in each embodiment can be understood, for example, as follows.

(1) The probabilistic risk assessment support method according to the first aspect is a probabilistic risk assessment support method for a fire inside a control panel that is executed by a computer, and includes separating components of the control panel from the fire. A step of reading and displaying support information (such as FIGS. 3 and 4) from the storage unit that supports calculation of failure probability indicating the risk of the countermeasure, and obtaining the input failure probability based on the displayed support information. a step of setting a branching probability for each event in an event tree diagram in which the evolution of a fire situation caused by the fire is an event to be analyzed; and outputting the event tree diagram in which the branching probability is set. and in the step of setting the branch probability, among the branch probabilities for a predetermined event corresponding to the fire situation when the separation measures are successful, The failure probability is set to the probability of denying the situation.
This makes it possible to limit the impact of a fire to a single device and incorporate the effectiveness of isolation measures to prevent the spread of fire into the risk assessment of fires inside control panels. This allows risk assessments to be more refined than the results of probabilistic fire risk assessments that are publicly available. As a result, it is possible to reduce risk evaluation.

(2) The probabilistic risk assessment support method according to the second aspect is the probabilistic risk assessment support method according to (1), in which the step of displaying the support information is based on the cause of the failure of the separation measure. reading analysis information that supports identification from a storage unit and displaying it; obtaining the input cause of failure based on the displayed analysis information; and quantifying the risk based on the cause of failure. The method further comprises the step of reading out from the storage section and displaying procedure information indicating a procedure for determining a method.
Thereby, it is possible to set the failure probability of separation measures according to the support information.

(3) The probabilistic risk assessment support method according to the third aspect is the probabilistic risk assessment support method of (2), in which the analysis information indicates that the separation measures are insufficient or the fire impact is unexpected. The causes of failure are classified according to , and in the case of insufficient separation measures, the causes of failure are further classified according to whether inappropriate separation conditions were set or measures that did not satisfy the separation conditions were executed. .
This makes it possible to thoroughly examine the causes of failure of separation measures. Further, it is possible to eliminate variations in specific causes of failure and to standardize them.

(4) The probabilistic risk assessment support method according to the fourth aspect is the probabilistic risk assessment support method of (2) to (3), in which the procedure information indicates that the cause of the failure is (judgment 1) Whether or not it is included in the influence of other factors, (Judgment 2) Whether it is related to equipment malfunction or human factors, and (Judgment 3) Whether or not there is statistical data regarding the success or failure of the relevant factor. , a method for calculating the failure probability is presented for each of the classifications.
This allows the probability of failure to be calculated. Furthermore, it is possible to eliminate variations in the method of calculating failure probabilities and to standardize them.

(5) The probabilistic risk assessment support method according to the fifth aspect is the probabilistic risk assessment support method of (2) to (4), in which the procedure information includes (method 1) the probability of failure. ) Representing the failure probability of other failure factors; (Method 2) Calculating the failure probability through engineering judgment of the mechanism of occurrence of the failure factor; (Method 3) Calculating the reliability of similar products against fire. A procedure for determining which method to use to calculate the failure probability is presented: (Method 4) Calculating the failure probability based on statistical data.
This allows the probability of failure to be calculated. Furthermore, it is possible to eliminate variations in the method of calculating failure probabilities and to standardize them.

(6) The probabilistic risk assessment support method according to the sixth aspect is the probabilistic risk assessment support method according to (5), in which the step of displaying the procedure information includes the method 2, the method 3, Regarding method 4, reference information for calculating the failure probability is read from the storage unit and displayed.
This facilitates calculation of failure probability.

(7) A probabilistic risk assessment support method according to a seventh aspect is the probabilistic risk assessment support method according to (1) to (6), wherein in the step of obtaining the failure probability, the separation countermeasure is In the step of obtaining the failure probability for each failure factor and setting the branching probability, a value that integrates the failure probabilities for each failure factor is set as the branching probability for the predetermined event.
By integrating the failure probabilities of possible failure factors within the control panel, it is possible to set the failure probability of separation measures for the entire control panel.

(8) A probabilistic risk assessment support method according to an eighth aspect is the probabilistic risk assessment support method of (1) to (7), in which the predetermined event is a single equipment failure.
This makes it possible to incorporate the effects and risks of separation measures into the previously proposed risk assessment model for fires inside control panels.

(9) The probabilistic risk evaluation support device (support device 10) according to the ninth aspect stores support information that supports calculation of failure probability indicating the risk of isolation measures to separate components of a control panel from a fire. A failure probability calculation support unit (control unit 12) that reads out and displays the failure probability calculation support unit 15, an input reception unit that acquires the failure probability input based on the displayed support information, and the progress of the fire situation caused by the fire. In an event tree diagram in which a phenomenon to be analyzed is an event, a branching probability setting unit (control unit 12) sets a branching probability for each event, and an output unit 14 outputs the event tree diagram in which the branching probability is set. , and the branch probability setting unit (control unit 12) sets the branch probability for a predetermined event corresponding to the fire situation when the separation countermeasure is successful among the events. The failure probability is set to the probability of denying the fire situation.

(10) The program according to the tenth aspect includes a step of causing the computer 900 to read support information from the storage unit and display it for supporting the calculation of failure probability indicating the risk of isolation measures for separating the components of the control panel from the fire. and obtaining the input failure probability based on the displayed support information, and determining the branching probability for each event in an event tree diagram in which the evolution of the fire situation caused by the fire is an event to be analyzed. and a step of outputting the event tree diagram in which the branch probability is set, and the step of setting the branch probability includes the step of setting the branch probability when the separation countermeasure is successful. Among the branch probabilities for the predetermined event corresponding to the fire situation, a process of setting the failure probability to a probability that negates the fire situation is executed.

10...Support device 11...Input reception unit 12...Control unit 121...Separation measure failure factor setting unit 122...Separation measure failure probability setting unit 123...Single equipment failure probability setting unit 13...Risk evaluation model creation unit 14...Output unit 15...Storage unit 900...Computer 901...CPU
902... Main storage device 903... Auxiliary storage device 904... Input/output interface 905... Communication interface

Claims (10)

A probabilistic risk assessment support method for fire inside a control panel executed by a computer, the method comprising:
reading out and displaying support information from the storage unit to support calculation of a probability of failure indicating the risk of isolation measures to isolate components of the control panel from fire;
obtaining the input failure probability based on the displayed support information;
In an event tree diagram in which the development of a fire situation caused by the fire is an event to be analyzed, a step of setting a branching probability for each event;
outputting the event tree diagram in which the branch probabilities are set;
has
In the step of setting the branching probability, among the branching probabilities for a predetermined event corresponding to the fire situation when the separation countermeasure is successful, the probability of denying the fire situation is set; setting the failure probability;
Probabilistic risk assessment support method. The step of displaying the support information includes:
reading and displaying analysis information from a storage unit to support identification of the cause of failure of the separation measure;
obtaining the inputted cause of failure based on the displayed analysis information;
reading from the storage unit and displaying procedure information indicating a procedure for determining a method for quantifying risk based on the cause of failure;
The probabilistic risk assessment support method according to claim 1, comprising: In the analysis information, the cause of the failure is classified as insufficient separation measures or unexpected fire effects, and in the case of insufficient separation measures, it is determined whether inappropriate separation conditions were set or separation conditions were not set properly. The cause of the failure is classified depending on whether an unsatisfactory countermeasure was taken.
The probabilistic risk assessment support method according to claim 2. The procedure information includes whether the cause of the failure is (Judgment 1) included in the influence of other factors, (Judgment 2) whether it is related to equipment malfunction or human factors, (Judgment 3) Classified according to the presence or absence of statistical data regarding the success or failure of the factor, and a method of calculating the failure probability is presented for each classification.
The probabilistic risk evaluation support method according to claim 2 or 3. In the procedure information, regarding the failure probability, (method 1) representing the failure probability of another failure factor, (method 2) calculating the failure probability by engineering judgment of the mechanism of occurrence of the failure factor. , (Method 3) Calculating the failure probability with reference to data showing the fire reliability of similar products, (Method 4) Calculating the failure probability based on statistical data. The procedure for determining whether to calculate is presented.
The probabilistic risk evaluation support method according to any one of claims 2 to 4. In the step of displaying the procedure information,
For the method 2, the method 3, and the method 4, reading reference information for calculating the failure probability from a storage unit and displaying it;
6. The probabilistic risk assessment support method according to claim 5. In the step of obtaining the failure probability,
Obtaining the failure probability for each cause of failure of the separation measure,
In the step of setting the branch probability,
setting a value that integrates the failure probabilities for each failure factor as the branching probability for the predetermined event;
The probabilistic risk evaluation support method according to any one of claims 1 to 6. the predetermined event is a single equipment failure;
The probabilistic risk evaluation support method according to any one of claims 1 to 7. a failure probability calculation support unit that reads out and displays support information from a storage unit to support calculation of a failure probability indicating the risk of isolation measures for separating components of the control panel from fire;
an input receiving unit that obtains the input failure probability based on the displayed support information;
In an event tree diagram in which the development of a fire situation caused by the fire is an event to be analyzed, a branching probability setting unit that sets a branching probability for each event;
an output unit that outputs the event tree diagram in which the branch probabilities are set;
has
The branch probability setting unit sets the probability of denying the fire situation to the probability of denying the fire situation among the branch probabilities for the predetermined event corresponding to the fire situation when the separation countermeasure is successful. set the probability,
Probabilistic risk assessment support device. to the computer,
reading out and displaying support information from the storage unit to support calculation of a probability of failure indicating the risk of isolation measures to isolate components of the control panel from fire;
obtaining the input failure probability based on the displayed support information;
In an event tree diagram in which the development of a fire situation caused by the fire is an event to be analyzed, a step of setting a branching probability for each event;
outputting the event tree diagram in which the branch probabilities are set;
has
In the step of setting the branching probability, among the branching probabilities for a predetermined event corresponding to the fire situation when the separation countermeasure is successful, the probability of denying the fire situation is set; a process for setting the failure probability;
A program to run.

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