JP6692273B2 - Emergency response risk assessment device, its risk assessment method, and its risk assessment program - Google Patents

Description

  The embodiment of the present invention relates to an emergency response risk evaluation technique for evaluating a risk during evacuation response when an emergency event occurs in a nuclear power plant.

  As a result of the lessons learned from the severe accident that occurred at the Fukushima Daiichi Nuclear Power Station, operators of nuclear plants have begun voluntary efforts to improve safety by using Probabilistic Risk Assessment (PRA).

  PRA is one of the methods for quantitatively evaluating possible risks. PRA in a nuclear power plant is mainly divided into three levels. Specifically, in Level 1 PRA, an accident scenario that leads to core damage in a nuclear power plant is identified, and the frequency of occurrence of that scenario is evaluated. In addition to Level 1, Level 2 PRA identifies an accident scenario in which a large amount of radioactive material diffuses from the reactor containment vessel, and at the same time the thermal hydraulic power inside the reactor cooling system and in the containment vessel Predict the behavior of radioactive materials and evaluate the types and amounts of radioactive materials released into the environment and their frequencies.

  Finally, in addition to Level 2, Level 3 PRA predicts the environmental migration of radioactive materials released from nuclear power plants in consideration of weather conditions, etc., and evaluates the health effects of the exposure on the general public.

  Based on the evaluation results by these three PRAs, measures for maintaining and improving safety are taken in a nuclear power plant. In particular, formulating an evacuation plan based on the results of the Level 3 PRA and expanding support functions for emergency decision makers are important for safe and smooth evacuation of residents.

(Company) Atomic Energy Society of Japan, Atomic Energy Society standard "Implementation standard for probabilistic safety assessment of nuclear power plants (Level 3 PSA): 2008"

  The conventional risk assessment by Level 3 PRA is to set the protective measures according to the regional disaster prevention plan based on the radiation dose (source term) of radioactive materials that migrate to the environment and the frequency of occurrence, and then to the health effects on the general public. It assesses the risk of death and the risk of death. In other words, Level 3 PRA evaluates the risk to the public after the release of radioactive substances into the environment, and when an emergency event that releases radioactive substances occurs, during actual evacuation response The risk of failure of evacuation was not systematically evaluated according to the scenario of evacuation response.

  Therefore, the Level 3 PRA is insufficient as a function for the business operator to utilize for the voluntary improvement of the safety of the nuclear power plant including the evacuation response. For this reason, a risk assessment method that can systematically analyze the risk of evacuation failure in the event of an emergency event along with the scenario for evacuation response and obtain effective evaluation data for risk reduction is desired. ing.

  The present invention has been made in consideration of such circumstances, and an object thereof is to provide an emergency response risk evaluation technique capable of systematically evaluating the risk at the time of evacuation response when an emergency event occurs in a nuclear power plant. And

  An emergency response risk evaluation apparatus according to an embodiment of the present invention is an emergency response risk evaluation apparatus that evaluates a risk at the time of evacuation response when an emergency event occurs in a nuclear power plant, and in the nuclear power plant, For the emergency event that is expected to occur, the timing when the event that is classified by time zone is expected, and the evacuation group that is classified by the attributes of the evacuees A frequency information setting unit that sets the occurrence frequency of the event, a combination classification unit that obtains an evacuation pattern by combining the three data of the emergency event, the occurrence timing, and the evacuation group, and the occurrence frequency and classification of the emergency event Based on the ratio of each occurrence timing and the existence ratio of each of the evacuation groups in the time period Using an occurrence frequency calculation unit that obtains the occurrence frequency of each of the evacuation patterns, an event success / failure probability setting unit that sets a success / failure probability of success or failure in the event execution with respect to the event executed at the time of the evacuation response, and using the event. The event tree creating unit that creates an event tree using the evacuation failure frequency as a risk index, and the evacuation based on the occurrence frequency and the success / failure probability obtained by the occurrence frequency calculating unit for the scenario of the created event tree. An evacuation failure frequency calculation unit that obtains a failure frequency for each evacuation pattern.

An emergency response risk evaluation method according to an embodiment of the present invention, when an emergency event occurs in a nuclear power plant, is an emergency response risk evaluation method for evaluating the risk during evacuation response, in the nuclear power plant The step of accepting an emergency event that is expected to occur, the timing of occurrence of the event classified by time zone, and the evacuation group classified by the attribute of the evacuee at the data reception unit, and the received emergency event On the other hand , a step of setting the occurrence frequency of the event in the frequency information setting unit, a step of combining the three data of the emergency event, the occurrence timing, and the evacuation group in the combination classification unit to obtain an evacuation pattern, the emergency The frequency of occurrence of the event, the ratio of each of the classified occurrence timings, and the evacuation group during the time period. Determining a frequency of occurrence of each of the evacuation pattern based on flops each occurrence ratios occurrence frequency calculation unit, the evacuation for the corresponding time events to be carried out, the success or failure event success probability the success probability of the event implementation A step of setting in the setting unit, a step of creating an event tree using the event as a risk index of the evacuation failure frequency in the event tree creation unit, and a scenario of the created event tree in the occurrence frequency calculation unit The evacuation failure frequency calculation unit obtains the evacuation failure frequency for each evacuation pattern based on the obtained occurrence frequency and the success / failure probability.

  The embodiment of the present invention provides an emergency response risk evaluation technique capable of systematically evaluating the risk at the time of evacuation response when an emergency event occurs in a nuclear power plant.

The block diagram which shows the structure of the risk evaluation apparatus for emergency response which concerns on this embodiment. FIG. 6 is a diagram showing the occurrence timing of an emergency event and the ratio of each occurrence timing. The figure which shows the group of the evacuation target persons and the existence ratio by evacuation group according to the generation timing. The figure which shows the occurrence frequency corresponding to each of the set emergency event and the emergency event. The figure which shows the evacuation pattern calculated | required from the combination of three data of the event of an emergency, the occurrence timing of an event, and an evacuation group, and the occurrence frequency calculated with respect to each evacuation pattern. For each event to be performed during evacuation response, the parties associated with the event, the evacuation target time for evacuation to be completed before radioactive material is released into the environment, and the success or failure probability of the event within the target time The figure which shows an example. The figure which shows the event tree created based on the set event. Explanatory drawing which shows the method of extracting the scenario with a high evacuation failure frequency, and the event with a large risk contribution in an event tree. A pie chart showing the breakdown by emergency event in the evacuation failure frequency calculated from the event tree. A pie chart showing the breakdown by event occurrence timing in the evacuation failure frequency calculated from the event tree. A pie chart showing the breakdown by evacuation group in the evacuation failure frequency calculated from the event tree. The flowchart which shows the procedure of the risk evaluation method of the emergency response which concerns on this embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
An emergency response risk evaluation apparatus 10 (hereinafter, abbreviated as risk evaluation apparatus 10) according to the present embodiment shown in FIG. 1 is provided by an evacuation target person when an emergency event such as a core melting accident occurs in a nuclear power plant. This is a quantitative evaluation of the risk of evacuation. The risk here means the possibility that the evacuation target person's evacuation fails when an emergency event occurs.

  The risk evaluation device 10 according to the present embodiment obtains an evacuation pattern from a combination of three data of an emergency event that can occur in a plant, an occurrence timing when the event occurs, and a group of evacuation targets. Then, by using an event tree created based on the event that is carried out during the evacuation response, the frequency at which evacuation fails before the radioactive material is released into the environment (evacuation failure frequency) is obtained for each evacuation pattern. This makes it possible to systematically evaluate the risks during evacuation response according to the scenario in the event tree.

  The risk evaluation device 10 according to the present embodiment includes a data reception unit 11, a frequency information setting unit 12, a combination classification unit 13, an occurrence frequency calculation unit 14, an event setting unit 15, a database 16, and an event success / failure probability. At least a setting unit 17, an event tree creation unit 18, an evacuation failure frequency calculation unit 19, a scenario extraction unit 20, a breakdown derivation unit 21, and a data display unit 22 are provided.

  The risk evaluation device 10 is configured as a computer including a data input unit, a storage circuit that holds input data and data such as calculation results, a processing circuit that realizes each function, and a data display unit 22. The data input means is various devices for the user to input various information and data, and is, for example, a mouse, a keyboard, a trackball, a touch panel, or the like. Further, the risk evaluation device 10 can also externally input various information and data relating to risk evaluation via a network such as the Internet.

  Each function of the risk evaluation device 10 can be realized by the processor executing a predetermined program stored in a storage circuit such as a ROM (Read Only Memory) or a RAM (Random Access Memory). Further, instead of such software processing, it can be realized by hardware such as ASIC (Application Specific Integration Circuit) and FPGA (Field-Programmable Gate Array), and a unit combining software processing and hardware processing or It may be configured as a computer.

  The storage circuit is a storage medium including an external storage device such as an HDD (Hard Disk Drive) or an optical disk device in addition to the ROM and the RAM. The storage circuit including the database 16 stores various information and data related to risk evaluation, and is a program that is executed by a processor included in the processing circuit and that defines a series of processing steps of the risk evaluation processing according to the present embodiment. Etc. are recorded.

  The data display unit 22 is a display device such as a liquid crystal display panel, a plasma display panel, and an organic EL panel, and displays the result of calculation processing related to risk evaluation.

  The data reception unit 11 has three data of an emergency event that is expected to occur in a nuclear power plant, an occurrence timing when the event is expected to occur, which is classified by time zone, and an evacuation group that is classified according to the attributes of the evacuees. Accept.

  Emergency events are various events in a nuclear power plant that may cause radioactive substances to be released into the environment. Examples of emergency events are events such as core meltdown accidents and damage to equipment such as containment vessels. Each of the received emergency events is mutually identified by the event name. The received emergency event may be a plurality of events or one event.

  The occurrence timing is obtained by classifying the timing at which an emergency event is expected to occur according to time zone information. FIG. 2 shows an example of occurrence timings of events classified according to time zone information. As shown in FIG. 2, it is divided into four occurrence timings according to time zone information: daytime (weekdays), daytime (holidays), commuting hours, and nighttime. The time zone information includes a time zone corresponding to one day and a number of days corresponding to one year for one occurrence timing. Further, the data receiving unit 11 receives the ratio of each time zone in one year. The ratio of each time zone may be calculated in the risk evaluation device 10 based on the received time zone information.

  The evacuation group is a group of evacuees to be evacuated when an emergency event occurs according to the attributes of the evacuees. FIG. 3 shows an example of evacuation groups classified according to the attributes of evacuees. As shown in FIG. 3, the evacuation target persons are divided into nine groups, such as at-home persons, movers (public transportation), movers (private cars), movers (home), and the like. In addition, the data receiving unit 11 receives the ratio (presence ratio) of each evacuation group for each time slot of the occurrence timing.

  The frequency information setting unit 12 sets the occurrence frequency of the event for the emergency event received by the data receiving unit 11. The frequency of occurrence of the event may be set based on the occurrence data of past emergency events, or may be the frequency estimated by the user. The frequency of occurrence means the number of times that a target emergency event occurs when the plant operates for one year.

FIG. 4 is a diagram showing the occurrence frequency set for each emergency event. The frequency information setting unit 12 sets the occurrence frequencies N _{A to} N _E for each of the emergency events A to E received by the data receiving unit 11.

  The combination classification unit 13 (FIG. 1) obtains all combinations of three pieces of data including an emergency event, an occurrence timing, and an evacuation group as an evacuation pattern. An evacuation pattern ID is given to each of the evacuation patterns to identify each other.

  For each of the evacuation patterns, the occurrence frequency calculation unit 14 calculates the occurrence frequency of the evacuation pattern based on the occurrence frequency corresponding to the emergency event, the ratio corresponding to the occurrence timing, and the existence ratio corresponding to the occurrence timing in the evacuation group. To do.

  FIG. 5 is a diagram showing an example of three patterns of evacuation patterns, each consisting of an event of an emergency, the timing of occurrence of the event, and an evacuation target group, and the frequency of occurrence calculated for each evacuation pattern. As shown in FIG. 5, the combination classifying unit 13 obtains all combinations of three data of the event of the emergency, the occurrence timing of the event, and the evacuation target group.

Then, the occurrence frequency calculation unit 14 calculates the occurrence frequency for each evacuation pattern. For example, the evacuation pattern NO. 1, the emergency event, the occurrence timing, and the evacuation group are the emergency event A, the daytime (weekdays), and the evacuation group I, respectively. Evacuation pattern NO. The occurrence frequency of 1 is three data of the occurrence frequency N _A of the emergency event A, the ratio corresponding to daytime (weekdays): 0.25, and the ratio corresponding to daytime (weekdays) in the evacuation group I: 0.25. Multiply by. In this way, the occurrence frequency is calculated for all evacuation patterns.

Returning to FIG. 1, the description will be continued.
When an emergency event occurs, the event setting unit 15 sets an event that is carried out at the time of evacuation response by a business operator of a nuclear plant, a related organization including a national or local public entity, or an actual evacuation target person. Examples of events include event detection, information sharing with related organizations, and evacuation guidance. These events are setting information for creating an event tree, and are set by the user based on events that were carried out in the past evacuation support.

To each of the events, business person, related organizations, including the national and local governments, and which of the three parties of the evacuees of the information is an event that involved as a party is set in association with each other.

  The database 16 holds data related to evacuation such as the time required for evacuation response when an emergency event occurred in the past and the success or failure of the event performed during evacuation response. The database 16 may be provided in the risk evaluation device 10 or may be connected to the risk evaluation device 10 via a network.

  For each of the events set by the event setting unit 15, the event success / failure probability setting unit 17 sets an evacuation target time for evacuation before the start of release of radioactive material into the environment, and an event within the target time. Set the probability of success or failure of (event probability). The event success / failure probability to be set may be set based on data related to past evacuation held in the database 16, or may be set to a value assumed by the user.

  FIG. 6 shows, for each event set by the event setting unit 15, the parties involved in the event, the evacuation target time for evacuation before the start of release of radioactive material into the environment, and the events within the target time. It is a figure which shows the success / failure probability of.

  As shown in FIG. 6, a party to the event (a business operator, a related organization such as a national or local public entity, or an evacuee) is set for each event to be performed when an emergency event occurs. Then, for each event, the evacuation target time and the probability of the event succeeding or failing within the target time are set.

  The event tree creating unit 18 creates an event tree in which the risk index is the evacuation failure frequency before the release of radioactive material into the environment, based on the event set by the event setting unit 15. Specifically, the events are arranged in the horizontal direction as headings, the occurrence of the evacuation pattern obtained by the combination classification unit 13 is set as the starting event, and the event tree is created by expanding the events depending on the success or failure of the events. The process from the occurrence of the evacuation pattern to the eventual success or failure branch to the final evacuation result is the scenario of the event tree. In addition, the arrangement of the events on the event tree may be arranged in the order in which the events are performed, or the arrangement may be set by the user.

  The evacuation failure frequency calculation unit 19 calculates the evacuation failure frequency using the probability of success or failure of the event with the occurrence frequency of the evacuation pattern as an input value for each scenario on the event tree. The evacuation failure frequency calculation unit 19 calculates the evacuation failure frequency in each scenario on the event tree for all the evacuation patterns obtained by the combination classification unit 13.

  In this way, by calculating the evacuation failure frequency using the event tree for each evacuation pattern, the risk for each scenario can be quantitatively evaluated.

  FIG. 7 is a diagram showing an example of an event tree created from the set events. The events are arranged in the horizontal direction, and each scenario is set by branching depending on the success or failure of the event, starting from the occurrence of the evacuation pattern. The evacuation failure frequency of each scenario is calculated by multiplying the probability of success or failure of the event according to the scenario using the occurrence frequency of the evacuation pattern as an input value.

  The scenario extraction unit 20 extracts a scenario in which the evacuation failure frequency calculated for each evacuation pattern by the evacuation failure frequency calculation unit 19 is higher than a predetermined reference value. The high frequency of evacuation failure means that there is a high risk scenario when responding to evacuation. If there are multiple scenarios that exceed the standard value, multiple scenarios are extracted. The reference value used for scenario extraction is arbitrarily set by the user. Further, among the evacuation failure frequencies calculated for each evacuation pattern, a scenario having the highest evacuation failure frequency may be extracted.

  By extracting the scenario in this way, it is possible to understand the scenario in which the risk of failure of evacuation is high, and it can be utilized as information for reducing the risk at the time of evacuation response.

Furthermore, the scenario extraction unit 20 may extract, in the extracted scenarios, an event that fails as an event that has a large contribution to the risk of failure in evacuation. Each of the event, business person, figure out what national and local governments, or for any related to one of the information is an event in the evacuation group is associated with, the extracted event is due to either party can do.

FIG. 8 is a diagram illustrating a scenario of an event tree having a high evacuation failure frequency and a method of extracting an event having a large risk contribution. Here, the evacuation failure frequency Y ₁ is the highest frequency.

The scenario extracting unit 20 extracts a scenario (dotted line in FIG. 8) on the event tree having the evacuation failure frequency Y ₁ . Then, an event that fails in this scenario, that is, an event related to the national or local public bodies, "correct communication of information to the evacuation target person" is extracted as an event having a large risk contribution.

  The breakdown deriving unit 21 obtains the total of the evacuation failure frequencies calculated using the event tree, and obtains the breakdown (percentage) by emergency event, occurrence timing, or evacuation group in this total.

  FIG. 9 is a pie chart showing the breakdown by emergency event in the evacuation failure frequency calculated using the event tree. From this result, it can be understood that the ratio of the evacuation failure frequency is large in the emergency event A.

  FIG. 10 is a pie chart showing a breakdown by event occurrence timing in the evacuation failure frequency calculated using the event tree. From this result, it is found that the failure frequency of evacuation is high in the nighttime.

  FIG. 11 is a pie chart showing a breakdown by evacuation group in the evacuation failure frequency calculated using the event tree. From this result, it is found that the evacuation group I has a high evacuation failure frequency.

  In this way, by obtaining a breakdown of the evacuation failure frequency, it is possible to understand which emergency event, occurrence timing, or whether the evacuation group failure rate is high, that is, the evacuation risk is high. ..

  Further, the breakdown deriving unit 21 may fix one piece of data in the emergency event, the occurrence timing, and the evacuation group, and obtain a breakdown of the evacuation failure frequency in other data. For example, the emergency event is fixed as the emergency event A, and the breakdown by occurrence timing (or by evacuation target group) is obtained.

  Furthermore, two specific data within the emergency event, the occurrence timing, and the evacuation group may be fixed, and the breakdown of the remaining data may be obtained. For example, the emergency event is fixed as the emergency event A and the occurrence timing is fixed during the daytime (daytime), and the breakdown for each evacuation group is obtained.

  The data display unit 22 displays data related to the event tree such as the evacuation failure frequency calculated using the event tree for each evacuation pattern, the scenario extracted by the scenario extraction unit 20, the event with a large risk contribution, and the breakdown data. To do. Further, the data related to the event tree can be output to the outside from the risk evaluation device 10 via the network.

  FIG. 12 is a flow chart showing the procedure of the risk assessment method for emergency response according to the present embodiment (see FIG. 1 as needed).

  First, the data receiving unit 11 receives an evacuation group classified according to an emergency event, an occurrence timing of an event classified by time zone, and an evacuee attribute (S10). At this time, the data reception part 11 receives the ratio of each time zone in one year. Further, the ratio (presence ratio) of each evacuation group is accepted for each time zone of the occurrence timing.

  The frequency information setting unit 12 sets the occurrence frequency for each of the received emergency events (S11). The occurrence frequency of the event may be set based on the occurrence data of past emergency events, or the frequency estimated by the user may be arbitrarily set.

  The combination classification unit 13 obtains all combinations of the three data of the emergency event, the timing of event occurrence, and the evacuation group as the evacuation pattern. (S12).

  Then, the occurrence frequency calculation unit 14 determines, for each of the evacuation patterns, the occurrence frequency of the evacuation pattern based on the occurrence frequency corresponding to the emergency event, the proportion corresponding to the occurrence timing, and the proportion corresponding to the occurrence timing in the evacuation group. Calculate (S13).

The event success / failure probability setting unit 17 sets the probability of success or failure of the event performed at the time of evacuation response set by the event setting unit 15 (S14). Each of the events, events related to the business person, in connection with the country and one of the information is an event related to any of the relevant organizations in related events, and related to the evacuation group events, including local governments set To be done.

  The event tree creation unit 18 creates an event tree in which the risk index is the evacuation failure frequency before the release of radioactive material into the environment based on the set event (S15).

  The evacuation failure frequency calculation unit 19 calculates the evacuation failure frequency using the evacuation pattern occurrence frequency and the event success / failure probability for each scenario on the event tree (S16). The evacuation failure frequency calculation unit 19 calculates the evacuation failure frequency for all the evacuation patterns obtained by the combination classification unit 13.

  The scenario extraction unit 20 extracts a scenario in which the evacuation failure frequency calculated for each evacuation pattern is higher than a predetermined reference value. Further, the scenario extraction unit 20 extracts an extracted scenario in which the event fails as an event having a large contribution to the risk of failure in evacuation (S17).

  The breakdown deriving unit 21 obtains the total of evacuation failure frequencies calculated using the event tree, and obtains the breakdown of each emergency event, occurrence timing, or evacuation group in this total (S18).

  Then, the data display unit 22 displays data related to the event tree, such as the failure frequency of evacuation calculated using the event tree for each evacuation pattern, the scenario extracted by the scenario extraction unit 20, the event with a large risk contribution, and the breakdown data. Is displayed (S19).

  As described above, in the present embodiment, when an emergency event such as a core melting accident occurs in a nuclear power plant, the evacuation response by the plant operator, the country that directs and supervises the accident response outside the plant, the local government, etc. It is possible to consistently evaluate the risks hidden in the three evacuation measures, the evacuation measures by the organization and the evacuation measures related to the evacuees who carry out the evacuation. For this reason, it is possible to determine an improvement point that is effective in reducing the risk at the time of evacuation response to an emergency event, and it is possible to reduce the frequency of failure of evacuation before the radioactive material is released into the environment.

  In the conventional Level 3 PRA, risk assessment is performed based on the amount of radioactive material released and the exposure dose. However, there is a risk of hindering communication among business operators, related organizations such as national and local governments, and groups with different public positions over the criteria for determining allowable values.

  On the other hand, in the present embodiment, the evaluation target is the timing of evacuation by setting the risk index to the evacuation failure frequency before the radioactive material is released into the environment. For this reason, the amount of radioactive material released and the value of exposure dose are not necessary, so that measures for risk reduction in an emergency can be efficiently examined.

  According to the emergency response risk evaluation device of the above-described embodiment, the evacuation pattern is obtained from the three combinations of the emergency event, the occurrence timing of the event, and the evacuation group, and the occurrence frequency is calculated for each evacuation pattern. Then, the evacuation failure frequency is calculated for each evacuation pattern from the event tree created based on the event that is carried out during the evacuation response. As a result, it is possible to systematically evaluate the risk at the time of evacuation response when an emergency event occurs in a nuclear power plant.

  Although the embodiment of the present invention has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and the gist of the invention, and are also included in the invention described in the claims and the scope equivalent thereto.

  It should be noted that the program executed by the risk evaluation device 10 is provided by incorporating it in a ROM or the like in advance. Alternatively, this program is provided as an installable or executable file stored in a computer-readable storage medium such as a CD-ROM, a CD-R, a memory card, a DVD, or a flexible disk. May be. Further, the program executed by the risk evaluation device according to the present embodiment may be stored in a computer connected to a network such as the Internet, and downloaded and provided via the network. The risk evaluation device can also be configured by combining separate modules that independently exhibit the respective functions of the constituent elements, connected to each other by a network or a dedicated line, and combined.

  10 ... Risk evaluation device, 11 ... Data receiving unit, 12 ... Frequency information setting unit, 13 ... Combination classification unit, 14 ... Occurrence frequency calculation unit, 15 ... Event setting unit, 16 ... Database, 17 ... Event success / failure probability setting unit, 18 ... Event tree creation unit, 19 ... Evacuation failure frequency calculation unit, 20 ... Scenario extraction unit, 21 ... Breakdown derivation unit, 22 ... Data display unit.

Claims (7)

A risk assessment device for emergency response, which assesses the risk during an evacuation response when an emergency event occurs in a nuclear plant,
An emergency event that is expected to occur in the nuclear power plant, an occurrence timing when an event occurrence that is classified by time zone is assumed, and a data receiving unit that receives an evacuation group that is classified by the attributes of the evacuees,
A frequency information setting unit for setting the occurrence frequency of the received emergency event,
A combination classification unit that obtains an evacuation pattern by combining three data of the emergency event, the occurrence timing, and the evacuation group,
An occurrence frequency calculation unit that obtains the occurrence frequency of each of the evacuation patterns based on the occurrence frequency of the emergency event, the ratio of the divided occurrence timings, and the existence ratio of each of the evacuation groups in the time period,
An event success / failure probability setting unit that sets a success / failure probability of success or failure in event execution for the event to be executed at the time of evacuation response,
An event tree creation unit that creates an event tree that uses the failure frequency of evacuation as a risk index based on the event,
With respect to the scenario of the created event tree, an evacuation failure frequency calculation unit that determines the evacuation failure frequency for each evacuation pattern based on the occurrence frequency and the success / failure probability obtained by the occurrence frequency calculation unit, is provided. A characteristic risk assessment device for emergency situations. To each of the events, business travelers, national and local governments, or to claim 1, wherein said one of the information is an event which is performed by any of the evacuation group is set in association with Risk assessment device for emergency response described.   The scenario extraction unit that extracts the scenario of the event tree in which the evacuation failure frequency calculated by the evacuation failure frequency calculation unit is higher than a predetermined reference value is provided. Emergency response risk assessment device.   The risk assessment device according to claim 3, wherein the scenario extraction unit extracts the event that fails in the extracted scenario as the event that has a large contribution to the risk of failure in evacuation. ..   The breakdown deriving unit that obtains a breakdown for each emergency event, for each occurrence timing, or for each evacuation group in the evacuation failure frequency calculated for each evacuation pattern using the event tree. 5. The risk assessment device for emergency response according to claim 4. A risk assessment method for emergency response, which assesses the risk during an evacuation response when an emergency event occurs in a nuclear plant,
An emergency event that is expected to occur in the nuclear power plant, an occurrence timing when an event occurrence that is classified for each time zone is assumed, and a step of receiving an evacuation group that is classified by the attributes of the evacuees in the data reception unit ,
For the received emergency event, a step of setting the occurrence frequency of the event in a frequency information setting unit ,
Combining the three data of the emergency event, the occurrence timing, and the evacuation group in a combination classification unit to obtain an evacuation pattern,
Occurrence frequency of the emergency event, a step of obtaining the occurrence frequency of each of the evacuation patterns on the basis of the existence ratio of each of the evacuation groups in the time zone, and the evacuation group in the time period,
A step of setting a success / failure probability of success or failure in the event execution in the event success / failure probability setting unit with respect to the event executed at the time of evacuation response;
A step of creating an event tree using the event as a risk index of the failure frequency of evacuation, in an event tree creating unit ,
For the scenario of the created event tree , a step of obtaining the evacuation failure frequency for each evacuation pattern by the evacuation failure frequency calculation section based on the occurrence frequency obtained by the occurrence frequency calculation section and the success / failure probability. An emergency risk assessment method characterized by the following. On the computer,
An emergency event that is expected to occur in a nuclear power plant, an occurrence timing that is expected to occur in each time zone, and a step of receiving an evacuation group that is classified according to the attributes of the evacuees,
Setting a frequency of occurrence of the received emergency event,
A step of obtaining an evacuation pattern by combining three data of the emergency event, the occurrence timing, and the evacuation group,
Occurrence frequency of the emergency event, a step of obtaining the occurrence frequency of each of the evacuation patterns on the basis of the existence ratio of each of the evacuation groups in the time zone, and the evacuation group in the time period,
Steps for setting success or failure probability of success or failure in the event implementation for the event implemented at the time of evacuation response,
Creating an event tree using the event as a risk index of evacuation failure frequency,
For the scenario of the created event tree, the step of obtaining the evacuation failure frequency for each of the evacuation patterns based on the occurrence frequency and the success / failure probability obtained by the occurrence frequency calculation unit is executed. A timely risk assessment program.

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