An evaluation system for accident prevention measures for plants.

Abstract

To provide an assessment system for plant accident countermeasures capable of enabling effects brought by accident countermeasures to be known.SOLUTION: An assessment system for plant accident countermeasures includes: first acquisition means for acquiring a plurality of risk assessment means for assessing risk of accidents with individually different contents, and accident countermeasure information indicating the contents and countermeasures of the accidents; second acquisition means for acquiring pre-countermeasure plant information and post-countermeasure plant information that indicate respectively states of a plant before and after taking the countermeasures indicated by the accident countermeasure information; individual risk acquisition means for acquiring, for each of the risk assessment means, pre-countermeasure individual risk information indicating an assessment result of the risk based on the pre-countermeasure plant information and post-countermeasure individual risk information indicating an assessment result of a risk based on the post-countermeasure plant information; and individual comparison and determination means for comparing the risk indicated by the post-countermeasure individual risk information and the risk indicated by the pre-countermeasure individual risk information, and determining whether or not there are any post-countermeasure individual risk information having changed in the risk from the pre-countermeasure individual information.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an evaluation system for plant accident countermeasures that evaluates the risk impact of plant accident countermeasures. [Background technology]

[0002] Conventionally, in plants such as nuclear power plants, systems have been used that include a procedure manual database storing multiple procedure manuals, an accident estimation device that estimates an accident based on measurement values ​​(sensor signals) measured by sensors within the plant when an accident occurs, a procedure manual selection device that selects from the procedure manual database a procedure manual that is suitable for resolving the accident estimated by the accident estimation device, and an automatic procedure confirmation device that determines the next operation from the procedure manual selected by the procedure manual selection device, as disclosed in Patent Document 1, allowing plant operators to take measures against the accident in accordance with the operations indicated in the procedure manual selected as a measure to resolve the accident. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2015 / 151267 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional plants described above, risk assessment is sometimes performed based on the details of the accident and the details of the accident countermeasures (the details of the procedure manual in the conventional plants described above) that are configured to match the details of the accident. However, the details of the accident countermeasures may affect the risk of an accident other than the accident that is the subject of the risk assessment, so there is a demand for a more accurate understanding of the impact of the details of the accident countermeasures.

[0005] In view of the above circumstances, an object of the present invention is to provide an evaluation system for accident countermeasures for a plant that can determine the impact of the accident countermeasures. [Means for solving the problem]

[0006] The system for evaluating accident countermeasures for a plant according to the present invention comprises: a plurality of risk assessment means for assessing the risk of accidents of different types, and a first acquisition means for acquiring accident countermeasure information indicating the type of accident and countermeasures; a second acquisition means for acquiring pre-measure plant information indicating the state of the plant before the measures indicated by the accident countermeasure information are taken, and post-measure plant information indicating the state of the plant after the measures indicated by the accident countermeasure information are taken; individual risk acquisition means for acquiring, for each of the plurality of risk assessment means, pre-measure individual risk information indicating a risk assessment result based on the pre-measure plant information and post-measure individual risk information indicating a risk assessment result based on the post-measure plant information; The method includes an individual comparison and judgment means for comparing the risks indicated by the post-measure individual risk information with the risks indicated by the pre-measure individual risk information, and an individual comparison and judgment means for determining whether the multiple post-measure individual risk information include any information whose risk has changed from the pre-measure individual risk information.

[0007] According to the above-described system for evaluating accident countermeasures for a plant, it is possible to know which of multiple accidents (accidents that are the subject of evaluation by each of multiple risk evaluation means) will experience a change in risk due to the influence of accident countermeasures (countermeasures indicated by accident countermeasure information).

[0008] In this way, the evaluation system for plant accident countermeasures configured as described above makes it possible to know the influence of accident countermeasures on various accidents.

[0009] In addition, in the evaluation system for plant accident countermeasures of the present invention, The individual comparison and determination means an individual difference derivation process for deriving an individual difference, which is a difference from the pre-measure plant information, for each of the plurality of post-measure plant information when it is determined that the plurality of post-measure individual risk information includes a risk that has changed from the risk indicated by the pre-measure individual risk information; and an individual exceedance determination process for determining whether or not each of the plurality of individual differences exceeds an individual threshold value indicating an acceptable risk value.

[0010] According to the evaluation system for accident countermeasures for plants configured as described above, if there is an accident among multiple accidents (accidents that are the subject of evaluation by each of multiple risk assessment means) in which the risk changes as a result of the accident countermeasures, the individual comparison judgment means executes an individual difference derivation process and an individual exceedance judgment process to determine whether there is post-countermeasure individual risk information in which the individual difference from the pre-countermeasure individual risk information (the amount of change from the pre-countermeasure individual risk information) exceeds the individual threshold, making it possible to quickly grasp whether there is post-countermeasure individual risk information in which the risk has changed significantly from the pre-countermeasure individual risk information (i.e., there is an accident in which the accident countermeasures will have a significant impact).

[0011] in this case, The individual comparison and determination means If the individual exceedance determination process determines that none of the multiple individual differences exceed the individual threshold, the process may be configured to execute an individual change determination process to determine the change state of each of the multiple post-measure individual risk information relative to the pre-measure individual risk information.

[0012] This makes it easier to understand the trends in how accident countermeasures affect multiple accidents. [Effects of the Invention]

[0013] As described above, the evaluation system for plant accident countermeasures of the present invention can provide the excellent effect of making it possible to know the impact of accident countermeasures. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a functional block diagram of an evaluation system for accident countermeasures for a plant according to one embodiment of the present invention. [Figure 2] FIG. 2 is a state transition diagram of information handled by the evaluation system for plant accident countermeasures according to the embodiment, showing the state changes that accompany processing until a determination is made as to whether the state is increasing, decreasing, or mixed. [Figure 3] FIG. 3 is a state transition diagram showing the transition of information handled by the evaluation system for accident countermeasures for plants according to the embodiment, and is a state transition diagram showing the state changes that accompany the processing from when it is determined that an increasing state exists until the processing to determine the impact of the accident countermeasures is performed. [Figure 4] FIG. 4 is a state transition diagram showing the transition of information handled by the evaluation system for accident countermeasures for a plant according to the embodiment, and is a state transition diagram showing the state changes that accompany the processing from when it is determined that the state is reduced until the processing to determine the impact of the accident countermeasures is performed. [Figure 5] FIG. 5 is a state transition diagram showing the transition of information handled by the evaluation system for accident countermeasures for plants according to the embodiment, and shows the state changes that accompany the processing from when it is determined that a mixed state exists until the processing to determine the impact of accident countermeasures is performed. [Figure 6] FIG. 6 is a main flowchart showing the flow of processing in the operation of the evaluation system for plant accident countermeasures according to the embodiment. [Figure 7] FIG. 7 is a sub-flowchart showing the flow of the increased-time determination process of the evaluation system for plant accident countermeasures according to the embodiment. [Figure 8] FIG. 8 is a sub-flowchart showing the flow of the reduced-time determination process of the evaluation system for plant accident countermeasures according to the embodiment. [Figure 9] FIG. 9 is a sub-flowchart showing the flow of the mixed-case determination process of the evaluation system for plant accident countermeasures according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an evaluation system for plant accident countermeasures (hereinafter referred to as the evaluation system) according to one embodiment of the present invention will be described with reference to the accompanying drawings.

[0016] The evaluation system according to this embodiment is configured to evaluate whether or not an accident countermeasure for settling a certain accident will increase the risk of another accident.

[0017] As shown in FIG. 1, the evaluation system 1 of this embodiment includes a plurality of risk evaluation means for evaluating the risk of accidents of different contents, a first acquisition means 2 for acquiring accident countermeasure information indicating the contents of the accident and the contents of the countermeasure, a second acquisition means 3 for acquiring pre-countermeasure plant information indicating the state of the plant before the countermeasure indicated by the accident countermeasure information was taken and post-countermeasure plant information indicating the state of the plant after the countermeasure indicated by the accident countermeasure information was taken, an individual risk acquisition means 4 for acquiring pre-countermeasure individual risk information indicating the evaluation result of the risk based on the pre-countermeasure plant information and post-countermeasure individual risk information indicating the evaluation result of the risk based on the post-countermeasure plant information for each of the plurality of risk evaluation means, and a risk acquisition means 5 for acquiring the pre-countermeasure individual risk information indicating the evaluation result of the risk indicated by the post-countermeasure individual risk information and the pre-countermeasure individual risk information indicating the evaluation result of the risk indicated by the post-countermeasure individual risk information. the individual comparison and determination means 5 for comparing the risks indicated by the plurality of post-countermeasure individual risk information with the risks indicated by the pre-countermeasure individual risk information, the individual comparison and determination means 5 determining whether or not the plurality of post-countermeasure individual risk information includes any information whose risks have changed from the pre-countermeasure individual risk information; an aggregate risk acquisition means 6 for acquiring pre-countermeasure aggregated risk information obtained by aggregating the risks indicated by the plurality of pre-countermeasure individual risk information and post-countermeasure aggregated risk information obtained by aggregating the risks indicated by the plurality of post-countermeasure individual risk information when the individual comparison and determination means 5 determines that the plurality of post-countermeasure individual risk information includes any information whose risks have changed from the pre-countermeasure individual risk information; an aggregated comparison and determination means 7 for comparing the pre-countermeasure aggregated risk information with the post-countermeasure aggregated risk information to determine the impact of the accident countermeasures; and a storage means 8 for storing information.

[0018] The risk assessment means acquired by the first acquisition means 2 is stored in the storage means 8.

[0019] The risk assessment means is configured to derive the risk of a target accident through probabilistic risk assessment (so-called PRA). Note that the risk assessment means may be configured to derive the risk of an accident based on information indicating the state of the plant (plant information before countermeasures are implemented and plant information after countermeasures are implemented).

[0020] The accident countermeasure information acquired by the first acquisition means 2 is stored in the storage means 8.

[0021] The accident countermeasure information is configured to include accident content information indicating the content of the accident and countermeasure information indicating how to take measures against the accident indicated by the accident content information, and the accident content information and the countermeasure information are associated with each other.

[0022] Accident content information is information that indicates the content of an accident that occurs within a plant, such as a nuclear power plant, and countermeasure information is information that indicates countermeasures to be taken against the accident indicated by the accident content information (such as how to operate the facilities and equipment within the plant).

[0023] The pre-measure plant information and post-measure plant information acquired by the second acquisition means 3 are information indicating the state of the facilities and equipment in the plant.

[0024] In addition, the second acquisition means 3 may be configured to acquire the pre-measures plant information directly from the equipment and devices within the plant, or may be configured to read the pre-measures plant information from the storage means 8.

[0025] The post-measure plant information is information derived based on the plant state indicated by the pre-measure plant information and the measures indicated by the accident countermeasure information. For example, if the accident countermeasure information indicates how to operate facilities and equipment within the plant, the post-measure plant information indicates the state of the plant after the operation of the facilities and equipment indicated by the accident countermeasure information is performed on the plant in the state indicated by the pre-measure plant information.

[0026] The individual risk acquisition means 4 is configured to have each of the multiple risk assessment means acquired by the first acquisition means 2 assess the risk of an accident, and to acquire information indicating the risk assessed (derived) by the risk assessment means.

[0027] More specifically, the individual risk acquisition means 4 is configured to provide the pre-measures plant information to the risk assessment means and cause it to execute a process to assess the risk of an accident, thereby acquiring the evaluation results of such process as pre-measures individual risk information, and also to provide the post-measures plant information to the risk assessment means and cause it to execute a process to assess the risk of an accident, thereby acquiring the evaluation results of such process as post-measures individual risk information.

[0028] The pre-measure individual risk information and post-measure individual risk information acquired by the individual risk acquisition means 4 of this embodiment are composed of numerical values ​​that indicate the level of risk.

[0029] The individual comparison judgment means 5 is configured to execute an individual difference derivation process that derives the difference (a numerical difference, hereinafter referred to as an individual difference) between each of the multiple post-measure plant information and the pre-measure plant information, an individual exceedance judgment process that judges whether each of the multiple individual differences exceeds an individual threshold indicating an acceptable risk value, and an individual change judgment process that judges the change state of each of the multiple post-measure individual risk information relative to the pre-measure individual risk information when the individual exceedance judgment process judges that none of the multiple individual differences exceeds the individual threshold.

[0030] The individual comparison judgment means 5 is configured to judge that the measures indicated by the accident countermeasure information have no effect on the risk of the accident being evaluated by the risk evaluation means when all of the individual differences derived in the individual difference derivation process are 0 (when the risks of all post-measure plant information have not changed from the pre-measure plant information), that is, when the evaluation results of all risk assessment means have not changed before and after taking measures (measures indicated by the countermeasure information) (see T1 in Figure 2).

[0031] In addition, in T1 to T7 in FIG. 2, the individual risk information before the countermeasure is indicated by V1a, the individual risk information after the countermeasure is indicated by V1b, and the individual difference is indicated by V1c.

[0032] On the other hand, if the individual differences derived in the individual difference derivation process include ones that are not 0 (if the individual risk information after measures includes ones in which the risk has changed compared to the individual risk information before measures), that is, if the evaluation results of multiple risk assessment means include ones that have changed before and after taking measures (measures indicated by the measure information) (see T2 in Figure 2), the individual comparison judgment means 5 executes the individual difference derivation process and the individual exceedance judgment process.

[0033] The individual comparison judgment means 5 is configured to judge that, if it is determined in the individual exceedance judgment process that multiple individual differences exceed the individual threshold value (see T3 in Figure 2), that the countermeasures indicated by the accident countermeasure information increase the risk of the accident being evaluated by the risk assessment means.

[0034] On the other hand, when the individual comparison and determination means 5 determines in the individual exceedance determination process that none of the multiple individual differences exceeds the individual threshold (see T4 in FIG. 2), it executes the individual change determination process.

[0035] The individual comparison judgment means 5 is configured to judge, in the individual change judgment process, whether the multiple pieces of post-measure individual risk information are in an increased state, consisting only of risk that has increased from the pre-measure individual risk information, or of risk that has not changed from the pre-measure individual risk information and risk that has increased from the pre-measure individual risk information (see T5 in Figure 2), whether the multiple pieces of post-measure individual risk information are in a decreased state, consisting only of risk that has decreased from the pre-measure individual risk information, or of risk that has not changed from the pre-measure individual risk information and risk that has decreased from the pre-measure individual risk information (see T6 in Figure 2), or whether they are in a mixed state that is neither an increased state nor a decreased state (see T7 in Figure 2).

[0036] The aggregated risk acquisition means 6 is configured to perform an aggregation process to derive pre-countermeasure aggregated risk information by aggregating multiple pre-countermeasure individual risk information, and post-countermeasure aggregated risk information by aggregating multiple post-countermeasure individual risk information.

[0037] The combined comparison judgment means 7 is configured to be able to execute an increase judgment process that judges the impact of accident countermeasures when the individual comparison judgment means 5 judges the state to be an increase, a decrease judgment process that judges the impact of accident countermeasures when the individual comparison judgment means 5 judges the state to be a decrease, and a mixed judgment process that judges the impact of accident countermeasures when the individual comparison judgment means 5 judges the state to be a mixed state.

[0038] The aggregate comparison judgment means 7 is configured to execute an acquisition process to acquire pre-countermeasure aggregate risk information and post-countermeasure aggregate risk information by having the aggregate risk acquisition means 6 execute an aggregation process in the increase judgment process, an aggregate difference derivation process to derive the difference (aggregated difference) between the pre-countermeasure aggregate risk information and the post-countermeasure aggregate risk information, an increase excess judgment process to determine whether the aggregate difference is less than or equal to an aggregate threshold (increase aggregate threshold) indicating an acceptable risk value, and an increase impact derivation process to derive the impact of accident countermeasures based on the judgment result of the increase excess judgment process.

[0039] If the combined comparison judgment means 7 judges in the increase excess judgment process that the combined difference is less than or equal to the increase combined threshold (see T8 in Figure 3), it judges in the increase impact derivation process that the individual risk is on the rise, but that the impact of the accident countermeasures on the risk of an accident is small.

[0040] Furthermore, if the combined comparison judgment means 7 judges in the excess judgment process during an increase that the combined difference is not below (exceeds) the combined threshold for increase (see T9 in Figure 3), it judges in the impact derivation process during an increase that the individual risk is on the rise and that the accident countermeasures are increasing the risk of an accident.

[0041] In FIG. 3, the total difference is indicated by V2.

[0042] The combined comparison judgment means 7 is configured to execute the acquisition process, the combined difference derivation process, a reduced excess judgment process that judges whether the combined difference is greater than or equal to a combined threshold (reduced excess threshold) indicating an acceptable risk value, and a reduced impact derivation process that derives the impact of accident countermeasures based on the judgment result of the reduced excess judgment process during the reduced excess judgment process.

[0043] If the combined comparison judgment means 7 judges in the excess judgment process during reduction that the combined difference is not greater than (below) the combined threshold for reduction (see T10 in Figure 4), it judges in the impact derivation process during reduction that the individual risk is tending to decrease and that the accident countermeasures are reducing the risk of an accident.

[0044] Furthermore, if the combined comparison judgment means 7 judges in the excess judgment process during reduction that the combined difference is equal to or greater than the combined threshold for reduction (see T11 in Figure 4), it judges in the impact derivation process during reduction that the individual risks are tending to decrease, but that the impact of accident countermeasures on the risk of accidents is small.

[0045] Note that the total difference is also indicated as V2 in Fig. 4. Furthermore, as shown in Fig. 5, the reduction total threshold may be set to, for example, a negative value.

[0046] The combined comparison determination means 7 performs the combined risk information after the countermeasure is taken, the combined difference derivation process, the combined risk information after the countermeasure is taken, the combined risk information before the countermeasure is taken ... after the countermeasure is taken, the combined risk information after the countermeasure is taken, the combined risk information before the countermeasure is taken, the combined risk information after the countermeasure is taken, the combined risk information after the countermeasure is taken, the combined risk information after the countermeasure is taken, The system is configured to be able to execute a first mixed-time impact derivation process that derives the impact that the countermeasures will have on the accident, a second mixed-time excess determination process that, when it is determined in the mixed-time comparison process that the post-countermeasure aggregate risk information has not been reduced compared to the pre-countermeasure aggregate risk information, determines whether the aggregate difference is equal to or less than a combined threshold (second mixed combined threshold) that indicates an acceptable risk value, which is a combined threshold set separately from the first mixed combined threshold, and a second mixed-time impact derivation process that derives the impact that the countermeasures will have on the accident depending on the determination result of the second mixed-time excess determination process.

[0047] If the combined comparison judgment means 7 judges in the first mixed excess judgment process that the combined difference is not greater than (below) the first mixed combined threshold (see T12 in Figure 5), it judges that although there is a mixture of increases and decreases in the individual risks in the first mixed impact derivation process, the accident countermeasures have reduced the risk of an accident.

[0048] Furthermore, when the combined comparison judgment means 7 judges in the first mixed excess judgment process that the combined difference is equal to or greater than the first mixed combined threshold (see T13 in Figure 5), it judges in the first mixed impact derivation process that the individual risks are a mixture of increases and decreases, and the overall risk is decreasing, but the impact of the accident countermeasures on the risk of an accident is small.

[0049] If the combined comparison judgment means 7 judges in the second mixed excess judgment process that the combined difference is equal to or less than the second mixed combined threshold (see T14 in Figure 5), it judges in the second mixed impact derivation process that the individual risks are a mixture of increases and decreases, and the overall risk is increasing, but the impact of the accident countermeasures on the risk of an accident is small.

[0050] If the combined comparison judgment means 7 judges in the second mixed excess judgment process that the combined difference is not less than (greater than) the second mixed combined threshold (see T15 in Figure 5), it judges in the second mixed impact derivation process that the individual risks are a mixture of increases and decreases, and that the accident countermeasures are increasing the risk of an accident.

[0051] Note that the combined difference is also indicated by V2 in Fig. 5. As shown in Fig. 5, the first mixing combined threshold may be set to, for example, a negative value, and the second mixing combined threshold may be set to, for example, a positive value.

[0052] The configuration of the evaluation system of this embodiment is as described above. Next, the operation of the evaluation system 1 will be described.

[0053] As shown in Figure 6, in the evaluation system 1, the first acquisition means 2 acquires multiple risk assessment means and accident countermeasure information (S1), and the second acquisition means 3 acquires pre-countermeasure plant information and post-countermeasure plant information (S2).

[0054] Next, the individual risk acquisition means 4 acquires pre-measure individual risk information indicating the risk evaluation results based on the pre-measure plant information and post-measure individual risk information indicating the risk evaluation results based on the post-measure plant information for each of the multiple risk assessment means (S3).

[0055] Then, the individual comparison and determination means 5 compares the plurality of pieces of post-measure individual risk information with the plurality of pieces of pre-measure individual risk information. More specifically, the individual comparison and determination means 5 executes an individual difference derivation process to derive an individual difference for each of the plurality of pieces of post-measure plant information, and derives a comparison result based on the value of the individual difference.

[0056] If all of the individual differences derived in the individual difference derivation process are 0 (if the risks of all post-measure plant information have not changed from the pre-measure plant information), that is, if the evaluation results of all risk assessment means have not changed before and after taking measures (measures indicated by the countermeasure information), the individual comparison judgment means 5 judges that the measures indicated by the accident countermeasure information have no effect on the risk of the accident being evaluated by the risk assessment means (S5).

[0057] On the other hand, if the individual differences derived in the individual difference derivation process include any that are not 0 (if the post-measure plant information includes risks that have changed from the pre-measure plant information), that is, if the evaluation results of multiple risk assessment means include any that have changed before and after taking measures (measures indicated by the measure information) (No in S4), then the individual difference derivation process and individual exceedance determination process are executed.

[0058] The individual comparison judgment means 5 is configured to determine that, in the individual exceedance judgment process, if it is determined that multiple individual differences exceed the individual threshold value (Yes in S6), it judges that the measures indicated in the accident countermeasure information increase the risk of the accident being evaluated by the risk assessment means (S7).

[0059] On the other hand, when the individual comparison and determination means 5 determines in the individual exceedance determination process that none of the multiple individual differences exceeds the individual threshold value (No in S6), it executes the individual change determination process.

[0060] Then, the summation comparison determination means 7 executes a process according to the execution result of the individual change determination process by the individual comparison determination means 5.

[0061] More specifically, if the result of the individual change judgment process by the individual comparison judgment means 5 is an increasing state (Yes in S8), the summation comparison judgment means 7 executes an increasing state judgment process (S9), if the result of the individual change judgment process by the individual comparison judgment means 5 is a decreasing state (No in S8 and Yes in S10), the summation comparison judgment means 7 executes a decreasing state judgment process (S11), and if the result of the individual change judgment process by the individual comparison judgment means 5 is a mixed state (No in S8 and No in S10), the summation comparison judgment means 7 executes a mixed state judgment process (S12).

[0062] When the aggregate comparison judgment means 7 executes the increase judgment process (S9), it causes the aggregate risk acquisition means 6 to execute the aggregation process in the acquisition process (S13), executes the aggregate difference derivation process, and executes the increase excess judgment process, as shown in Figure 7.

[0063] If the combined comparison judgment means 7 judges in the increase excess judgment process that the combined difference is less than or equal to the increase combined threshold (Yes in S14), it judges in the increase impact derivation process that the individual risk is on the rise, but that the impact of the accident countermeasures on the risk of an accident is small (S15).

[0064] On the other hand, if the aggregate comparison judgment means 7 determines in the increase excess judgment process that the aggregate difference is not below (exceeds) the increase aggregate threshold (No in S14), it determines in the increase impact derivation process that the individual risk is on the rise and that the accident countermeasures are increasing the risk of an accident (S16).

[0065] When the aggregate comparison judgment means 7 executes the reduced-time judgment process (S11), it causes the aggregate risk acquisition means 6 to execute the aggregate process in the acquisition process (S17), executes the aggregate difference derivation process, and executes the reduced-time excess judgment process, as shown in Figure 8.

[0066] If the combined comparison judgment means 7 judges in the excess judgment process during reduction that the combined difference is not greater than (below) the combined threshold for reduction (No in S18), it judges in the impact derivation process during reduction that the individual risk is tending to decrease and that the accident countermeasures are reducing the risk of accidents (S19).

[0067] On the other hand, if the combined comparison judgment means 7 determines in the reduction excess judgment process that the combined difference is greater than or equal to the reduction combined threshold (YES in S18), it determines in the reduction impact derivation process that the individual risks are tending to decrease, but that the impact of accident countermeasures on the risk of accidents is small (S20).

[0068] When the combined comparison determination means 7 executes the mixed time determination process, as shown in Figure 9, it causes the combined risk acquisition means 6 to execute the combined process in the acquisition process (S21), executes the combined difference derivation process, and executes the mixed time comparison process.

[0069] When the combined comparison determination means 7 determines in the mixed comparison process that the post-measure combined risk information has decreased compared to the pre-measure combined risk information (Yes in S22), it executes the first mixed excess determination process.

[0070] If the combined comparison judgment means 7 judges in the first mixed excess judgment process that the combined difference is not greater than (below) the first mixed combined threshold (No in S23), it judges that although there is a mixture of increases and decreases in the individual risks in the first mixed impact derivation process, the accident countermeasures have reduced the risk of an accident (S24).

[0071] On the other hand, if the combined comparison judgment means 7 judges in the first mixed excess judgment process that the combined difference is equal to or greater than the first mixed combined threshold (Yes in S23), it judges in the first mixed impact derivation process that the individual risks are a mixture of increases and decreases, and that the risk has decreased, but that the impact of the accident countermeasures on the risk of an accident is small (S25).

[0072] When the combined comparison determination means 7 determines in the mixed comparison process that the post-measure combined risk information has not been reduced relative to the pre-measure combined risk information (No in S22), it executes a second mixed excess determination process.

[0073] If the combined comparison judgment means 7 judges in the second mixed excess judgment process that the combined difference is equal to or less than the second mixed combined threshold (Yes in S26), it judges in the second mixed impact derivation process that the individual risks are a mixture of increases and decreases, and that the risk is increasing, but that the impact of the accident countermeasures on the risk of an accident is small (S27).

[0074] On the other hand, if the combined comparison judgment means 7 judges in the second mixed excess judgment process that the combined difference is not less than (greater than) the second mixed combined threshold (No in S26), it judges in the second mixed impact derivation process that there is a mixture of increases and decreases in the individual risks, and that the accident countermeasures are increasing the risk of accidents (S28).

[0075] In this way, the evaluation system 1 of this embodiment is able to derive the influence that the countermeasures indicated by the accident countermeasure information will have on various accidents that may occur in the plant.

[0076] As described above, according to the evaluation system 1 of this embodiment, it is possible to determine by the individual comparison judgment means whether or not the measures against accidents that occur within the plant (measures indicated by the countermeasure information in the accident countermeasure information) are causing changes in the risk of the accident that is the target of the measures and the risk of other accidents, and therefore it is possible to determine which of the accidents that are the target of the measures and other accidents will cause a change in risk when accident countermeasures are taken.

[0077] Therefore, the evaluation system 1 of this embodiment has the excellent effect of being able to know the influence of accident countermeasures on various accidents, which makes it possible to make comprehensive judgments and contributes to improving the safety of the plant.

[0078] Furthermore, if there is an accident among multiple accidents (accidents that are the subject of evaluation by each of multiple risk assessment means) in which the risk changes as a result of the impact of accident countermeasures, the individual comparison judgment means 5 executes an individual difference derivation process and an individual exceedance judgment process before executing the individual change judgment process by the individual comparison judgment means 5 and the processing by the aggregate risk acquisition means 6 and aggregate comparison judgment means 7, thereby determining whether there is post-countermeasure individual risk information in which the individual difference from the pre-countermeasure individual risk information (the amount of change from the pre-countermeasure individual risk information) exceeds the individual threshold value, thereby making it possible to quickly know whether there is post-countermeasure individual risk information in which the risk has changed significantly from the pre-countermeasure individual risk information (i.e., there is an accident that will be significantly affected by the accident countermeasures).

[0079] Furthermore, when the individual exceedance determination process determines that none of the multiple individual differences exceed the individual threshold, the individual comparison determination means 5 is configured to execute an individual change determination process to determine the change state of each of the multiple individual risk information after measures relative to the individual risk information before measures, making it easier to grasp the trend of changes that accident countermeasures have on multiple accidents.

[0080] In the individual change determination process of the individual comparison and determination means 5 of this embodiment, the tendency of the change that the accident countermeasures have on a plurality of accidents is determined as an increasing state or a decreasing state.

[0081] The plant accident countermeasure evaluation system 1 of the present invention is not limited to the above embodiment, and it goes without saying that various modifications can be made within the scope of the present invention.

[0082] Although not specifically mentioned in the above embodiment, the evaluation system 1 may be configured to also determine whether or not to implement the accident countermeasures indicated by the accident countermeasures information when it is determined that the measures in the accident countermeasures information increase the risk of an accident, or may be configured to derive change content (i.e., content of measures against accidents) that does not increase the risk of an accident indicated by the accident content information by changing the change information of the accident countermeasures information, or to optimize accident countermeasures so as to minimize the overall risk of an accident.

[0083] Furthermore, methods for comprehensively assessing the risk of multiple accidents are not limited to the method of adding up the individual risk information described above. For example, methods that weight and add up the information according to the magnitude of the impact, methods that take into account the profile of individual risk information even when there is no significant change in the total risk value, and methods that add qualitative considerations to the quantitative assessment results and make judgments can also be used. [Explanation of symbols]

[0084] 1...Evaluation system, 2...First acquisition means, 3...Second acquisition means, 4...Individual risk acquisition means, 5...Individual comparison and judgment means, 6...Total risk acquisition means, 7...Total comparison and judgment means, 8...Storage means, V1a...Individual risk information before countermeasure, V1b...Individual risk information after countermeasure, V1c...Individual difference, V2...Total difference

Claims

[Claim 1] a plurality of risk assessment means for assessing the risk of accidents of different types, and a first acquisition means for acquiring accident countermeasure information indicating the type of accident and countermeasures; a second acquisition means for acquiring pre-measure plant information indicating the state of the plant before the measures indicated by the accident countermeasure information are taken, and post-measure plant information indicating the state of the plant after the measures indicated by the accident countermeasure information are taken; individual risk acquisition means for acquiring, for each of the plurality of risk assessment means, pre-measure individual risk information indicating a risk assessment result based on the pre-measure plant information and post-measure individual risk information indicating a risk assessment result based on the post-measure plant information; an individual comparison and determination means for comparing the risks indicated by the post-measure individual risk information with the risks indicated by the pre-measure individual risk information, and determining whether or not the plurality of post-measure individual risk information includes information whose risk has changed from the pre-measure individual risk information, The individual comparison and determination means an individual difference derivation process for deriving an individual difference, which is a difference from the pre-measure plant information, for each of the plurality of post-measure plant information when it is determined that the plurality of post-measure individual risk information includes a risk that has changed from the risk indicated by the pre-measure individual risk information; an individual exceedance determination process for determining whether each of the plurality of individual differences exceeds an individual threshold value indicating an acceptable risk value; The individual comparison and determination means and when the individual exceedance determination process determines that none of the plurality of individual differences exceeds the individual threshold, an individual change determination process is executed to determine a change state of each of the plurality of post-measure individual risk information relative to the pre-measure individual risk information. An evaluation system for accident prevention measures for plants.

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