Strategic and Action Plans for the Implementationof Risk Information Utilization at Nuclear Power Plants

Hokkaido Electric Power Co., Inc.
Tohoku Electric Power Co., Inc.
Tokyo Electric Power Company Holdings
Chubu Electric Power Co., Inc.
Hokuriku Electric Power Co., Inc.
The Kansai Electric Power Co., Inc.
The Chugoku Electric Power Co., Inc.
Shikoku Electric Power Co., Inc.
Kyusyu Electric Power Co., Inc.
The Japan Atomic Power Co. Inc.
Electric Power Development Co., Inc.

February 8th, 20181

Implementation of Risk Information Utilization
We, the nuclear licensees, have been implementing countermeasure work against earthquakes andtsunamis, and installing severe accident countermeasure facilities, as well as improving our risk
management including utilization of Probabilistic Risk Assessment (PRA), based on the lessons learned
from the accident at TEPCO’s Fukushima Daiichi Nuclear Power Station that occurred on March 11, 2011,
as well as relevant international experience. In addition, to address technology development regarding
improvement of PRA and regarding mechanisms of occurrence and methodologies of estimation for
infrequent external natural hazards such as large earthquakes, the licensees and the Central ResearchInstitute of Electric Power Industry have established the Nuclear Risk Research Center (NRRC) within
CRIEPI. The NRRC has been advancing research and development in an integrated fashion.
In the future, the licensees need a framework of risk utilization to identify areas for improvement andimplement effective measures to achieve substantive improvement of plant safety without complacency.
The licensees decided to introduce the risk-informed decision-making (RIDM) process into their
management process at their stations as such a framework.
The objective of introducing the RIDM process is to bring about changes in the existing management
process, where the licensees are primarily responsible for improving plant safety through correctly
monitoring as-built and as-operated plant status, considering the risk significance of findings based on
their own assessment as a decision criterion (risk-informed and performance-based), and implementing
decision-making for improvement in timely manner, while compliance with the regulations is aprerequisite. This management process through the RIDM aims at the status of nuclear power station suchthat all the staff involved with the plant operation, under strong leadership, identify precursors of problems
affecting the safety by broader monitoring, understand the risks without relying solely on limited experts
for the safety assessment, prioritize the problems with the risks as the common yardstick, and resolve
them in a timely manner.
All the licensees have conducted research and analyses on the history and current status of riskinformed activities in the U.S. 1 and other countries, where the RIDM has been instituted, and, as a result,
we have specified the infrastructure and organization needed for the RIDM process, and have recognized
how important the technical capabilities of station organizations are. The introduction of the RIDM
process into our management system in nuclear power plants is a huge challenge, but all the licensees
have extensively discussed the purpose and benefits of the RIDM and the policy of the initiatives in the
future to promote the RIDM process.
This strategic plan is a compilation of the basic policy and action plans as a result of the above
discussion so that the licensees will be able to successfully introduce the RIDM process. Each of thelicensees will implement this strategic plan and will achieve safety improvement of nuclear power plants
through self-disciplinary efforts beyond the regulatory framework.
Satoru Katsuno
Chairman of Federation of Electric Power Companies

1

http://criepi.denken.or.jp/jp/nrrc/pdf/ridm_report_en.pdf?v2

2

Comments by the Head of the Nuclear Risk Research Center
As a result of the Fukushima Daiichi accident, Japanese utilities have decided to facesquarely the risks of nuclear power generation and started to improve their risk assessmentand management capability. The utilization of risk information in decision making has been widely
pursued. For example, it has been practiced by American nuclear power utilities andthe U.S. Nuclear Regulatory Commission for several decades.
The language of risk is the appropriate one for assessing and communicating the level ofsafety of a hazardous industrial facility including, of course, nuclear power plants. PRA
views the plant as an integrated system (hardware and human personnel) and answers threefundamental questions: What can go wrong? How likely is it? What are the consequences,
if something goes wrong?
To answer these questions, thousands of potential accident sequences are investigated andtheir likelihoods are assessed. Two very important potential consequences of accidents aredamage to the reactor core and the release of radioactivity from the reactor containment into
the atmosphere. The two risk metrics that correspond to these consequences are the coredamage frequency and large release frequency. Both these metrics are very
valuable communication tools regarding the safety of a plant. This communication is very
effective both among nuclear engineers and with the public. In particular, telling the publicthat a plant is safe because it meets the regulations is a rather obscure statement.
Communicating the risk metrics is much more transparent and easier to understand.
The value of performance-based regulation cannot be overstated. Performance objectives
can be set deterministically, e.g., on pressures and temperatures, and/or probabilistically, e.g., on
the availability of components such as pumps. The utility has the flexibility of choosing
how to meet these objectives without micromanagement from the regulator. This results inmuch more efficient utilization of both the industry’s and the regulator’s resources.
The implementation of risk-informed and performance-based ways of conducting activities
on an industry-wide scale requires much more than good PRA models. There are many technical,
organizational and cultural issues that must be addressed for a successful implementation. The
magnitude of these issues requires a systematic approach to building the necessary infrastructure.
Such an approach is provided in the present plan.
The strategic plan is a major step forward for the Japanese nuclear industry. NRRC has contributed
to the investigation of the RIDM implementation in the U.S. and other countries, the gap analysis
between the US industry and Japanese industry, and the preparation of the draft of this plan. As aresult of extensive discussions inside the industry and between the industry and NRRC, the industry
finalized this strategic plan. It is significant that all the utilities have endorsed it. Its implementation
will lead to risk-informed and performance-based decision making, i.e., a more rational managementof risk.
Dr. George Apostolakis
Head, Nuclear Risk Research Center, Japan3

Introduction
This is a policy statement, which is committed to by the nuclear licensees2 in Japan, to introduce therisk-informed decision-making (RIDM) process into plant design, construction, and operation. This
document consists of two parts: A. Strategic Plan, and B. Action Plan. Part A discusses why thelicensees are introducing this process, what the process is like and its benefits, and how the licensees
will implement this initiative in order to facilitate stakeholders’ understanding. Part B is the action
plan that the licensees are now and will continue to be implementing with the collaboration of theindustry, mainly NRRC and the Japan Nuclear Safety Institute (JANSI), by 2020.

2

The nine electric utilities, J-Power, and JAPC

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A. Strategic Plan
A.1

Motivation

The Fukushima Daiichi accident has led to the promulgation of many regulatory requirements thatthe nuclear licensees (hereinafter referred to as “the licensees” or “we”) are duly implementing, as well
as voluntary efforts to improve safety that we are considering and implementing beyond the regulatory
requirements. This accident has also led us to the realization that we need a broader framework that, in
combination with the regulations, will lead to safety improvements and the continuous management of
the risks3 from nuclear power plants.
An integral part of risk management is the risk-informed decision-making (RIDM) process. This meansthat decision making regarding plant modifications and operations is based on both traditional engineering
assessments as well as insights derived from Probabilistic Risk Assessment (PRA). The licensees also
realize that an important part of risk management is the quantification of risk (accident sequences andtheir frequencies) as provided by PRA. As a result, we have established the Nuclear Risk Research Center(NRRC) within the Central Research Institute of Electric Power Industry (CRIEPI), so that we can develop
plant-specific PRAs of high quality which include the outcomes of the research that the NRRC is
producing.
The objective of introducing the RIDM process is to bring about changes in the existing management
process that is focused on demonstrating plant safety through compliance with the regulations and toestablish a management process of self-disciplinary efforts to improve plant safety through monitoring
the as-built and as-operated plant status, considering the risk significance of possible issues as part of thedecision criteria (risk-informed and performance-based), and implementing decision making for safety
improvement in timely manner.
RIDM is an important process for risk management of nuclear power plants. We have decided to
introduce the RIDM process into the management process at our stations to achieve substantive
improvement of plant safety beyond compliance with the regulations.

A.2

Purpose and Scope of Applications

The purpose of this strategic plan is to provide high-level direction to safety improvement of the nuclear
power plants in Japan that, when implemented, will lead to a sound risk management framework. This
framework will consist of a set of programs and behaviors that will facilitate the use of a structured riskinformed and performance-based process for decision making regarding plant modifications, operations
and maintenance.

A.3

Risk‐Informed and Performance‐Based Decision Making

The management system that implements RIDM is described in Figure A.1. As explained in the figure,there are three main functions: “performance monitoring and analysis,” “risk assessment,” and “decision
making and implementation.”
Performance monitoring and analysis is the process that monitors the performance of structures,
systems, and components, as well as of human actions, of the as-built and as-operated plant. Actual
performance is compared to deterministic and probabilistic criteria and objectives. If issues are raised,
options for resolving them are formulated. If a change in design or operations has been implemented,
3

The concept of risk, as used here, consists of the probability of undesirable consequences and the magnitude of these
consequences. Examples of consequences are damage to the reactor core and the release of various amounts of radioactive
materials to the environment.

5this process monitors its effectiveness also.
Risk assessment encompasses both deterministic and probabilistic elements to assess the options forresolution when problems are observed. Deterministic evaluations include the alignment with thedefense-in-depth philosophy and the maintenance of safety margins. The probabilistic element
consists of the standard PRA results, i.e., accident sequences and their frequencies, as well as the risk
significance of individual potential failure events. The risk assessment also considers new knowledge
and operating experience. The risk assessment provides information to the decision-making process.
In Decision making and implementation, the best option for resolving the issues observed in theperformance monitoring process is identified, utilizing the information from the risk assessment. This
process also implements the decision option that is deemed to be the best.
The three main functions are supported by two programs: the corrective action program (CAP) 4andthe configuration management (CM5) program. CAP finds problems including accident precursors at
the plant, prioritizes them using risk information and deterministic criteria, and corrects them. CM
provides the design requirements and facility configuration information (FCI 6 ) necessary for the
execution of each main function, maintaining three elements of configuration management aligned:
design requirements, FCI, and the physical configuration.

Figure A.1. Concept of risk management through risk-informed and performance-based decision making.

A.4

Basic Policy

The plan consists of two phases.

4 Corrective action program (CAP): Program by the licensees that identifies and resolves the problems, which includes evaluating
safety significance of the problems, prioritizing the measures, and managing processes up to resolution.
5
Configuration management (CM): Program that maintain alignment of three elements; design requirements, physicalconfiguration, and facility configuration information (FCI)
6 Facility configuration information (FCI): Recorded information that describes, specifies, reports, certifies, or provides data or
results regarding the design requirements or design basis, or that pertains to other information attributes associated with thefacility and its structures, systems, and components (ANSI/NIRMA CM-1.0-2015).

6 Phase 1 shall be the period up to about the year 2020 or the plant restart. During this period, thelicensees will develop the necessary technical infrastructure for the introduction of RIDM andestablish a system of risk management to improve plant safety against the risk of internal events. At
the same time, the licensees will utilize risk information assessed by their existing processes andtools of risk assessment to improve their performance as well as risk management skills.
 In Phase 2, the licensees will implement the management system introduced in Phase 1, demonstrate
its effectiveness through the upcoming proposed inspection system7 to be introduced by the Nuclear
Regulation Authority (NRA) in 2020, and continually work to improve it. The licensees will
incorporate RIDM into the following daily plant activities:
 Maintenance program Technical specifications
 Quality assurance system
The licensees will voluntarily modify the operator training program and procedures, and will
enhance the plant’s capability to cope with accidents beyond the design basis.
 For external events (earthquakes, tsunamis, volcanoes, others), the risk assessment will be
deterministic for the time being, i.e., it will consider compliance with the regulations, operating
experience, alignment with the defense-in-depth philosophy, and the maintenance of safety margins.
Probabilistic risk assessment for external events will be introduced as the relevant results of researchand development produced by NRRC and others are becoming available.
 The management system shown in Figure A.1 is also applied to the plants that have not restarted, as
appropriate.
 This strategic plan will be implemented and revised by the licensees, as appropriate, considering
progress of implementation of the RIDM process, as well as research and development of thetechnologies associated with risk management.
Figure A.2 depicts this policy.

Figure A.2. Basic policy for the introduction of RIDM process.

A.5

Stakeholders
In addition to the utilities, there are several stakeholders who would benefit from this plan. They
include the vendors, academia, , NRA, local residents, and the general public. The industry will engage
in dialogues with the stakeholders to explain why the risk management system is introduced and what

7 NRA received the report of the Integral Regulatory Review Service (IRRS) mission by IAEA in April, 2016, and based on therecommendations provided in the report, prepares the introduction of a regulatory inspection framework that is performancebased and risk informed with reference to Reactor Oversight Process (ROP) of the U.S. Nuclear Regulatory Commission.

7

the safety benefits are.

A.6

Benefits
Perhaps the most important benefit is the use of the risk language. This facilitates communication
among the utility’s organizations, as well as among the stakeholders. The ensuing debates andarguments will be much more meaningful because the various risk metrics will provide a better
understanding of the overall level of plant safety and of the risk significance of individual issues.
The early identification of problems and their resolution according to their risk significance is amajor benefit. The licensees will be able to focus resources on what is really important from a plantrisk perspective, thus managing safety effectively and efficiently.
Another major benefit is the ability to evaluate the risk reduction that proposed plant modifications
would effect. This will allow for meaningful rational decisions that do not waste resources on issues
that have no or minimal effect on plant safety.
The primary objective of the Strategic Plan is to manage the risk related to public health and safety
as shown in A.2. However, an additional benefit to the utilities is that they can also avoid events that,while they do not threaten plant safety, may lead to problems with the regulators, the public, or serious
financial loss.

A.7

Infrastructure
The implementation of this Strategic Plan requires changes in our management (e.g., switchingfrom a regulatory compliance mindset to an excellence-focused mindset), as well as the establishmentof business infrastructures such as various processes and protocols. These are discussed in more detailin the Action Plan that accompanies this Strategic Plan.

8

B. Action Plan
B.1

Preamble

The implementation of the Strategic Plan requires that the licensees establish processes to train
personnel on the utilization of risk information in combination with deterministic considerations. The
culture of the organizations should shift from a strictly regulatory compliance one to a culture whose
focus is managing risks and achieving excellence in operations. Ownership of plant safety by the line
organizations, such as operations and maintenance, and more involvement of management (in both
corporate offices and stations) should be pursued.
According to the basic policy of the Strategic Plan, this action plan should be implemented by thelicensees during Phase 1. The licensees will develop the necessary business processes to establish thefunctions necessary for introducing RIDM process, as well as the appropriate infrastructures.
Each licensee is expected to prepare for the proposed regulatory inspections to be introduced in FY
2020, and for the expansion of RIDM process thereafter. The regulatory inspections are planned to bechanged to risk-informed and performance-based ones, therefore, the utilities will demonstrate our riskinformed and performance-based management system during this change.
Sections B.2 through B.6 provide specific time tables for the activities necessary for introducing the
RIDM process. The activities where the responsible organization is specified as “Common to all” areimplemented by NRRC or JANSI, or joint efforts by NRRC or JANSI and the licensees together. The
activities where the responsible organization is specified as “individual” are to be incorporated into theindividual licensee’s business plan.
B.1.1

Leadership and Safety Culture

Prerequisites for the successful implementation of this strategic plan are as follows: Top management
issues a statement that safety is the first priority and encourages the implementation of RIDM process
throughout the organization. Managers communicate to the employees their expectations based on thisstatement, oversee the implementation of RIDM process, and actively look for risk-significant
conditions and behaviors to reinforce the expectations. Employees are encouraged to have aquestioning attitude, to proactively identify risks and performance issues, and to communicate freely
with their colleagues and management. Entire station organizations are involved in the project toestablish the processes and infrastructures for RIDM process.
B.1.2

Training

Human resources are key to the successful implementation of RIDM process. The processes andinfrastructures necessary for RIDM are implemented and supported by station personnel. To facilitate
the introduction of the RIDM process, it is important that training programs be developed in alignment
with the processes and the associated procedures that are established.
Personnel attend courses and workshops on the fundamentals of probability theory and statistics,
PRA, and RIDM. RIDM examples from other countries are studied to learn about the challenges thathave been faced and how decisions have been made. In this context, the NRRC report “Risk-Informed
Decision Making: A Survey of United States Experience,” published in 2017, is useful.
Not all personnel are expected to be PRA professionals, i.e., capable to develop a PRA and perform
uncertainty and sensitivity analyses. A small group of such professionals is sufficient; they are
responsible for maintaining and updating the PRA and to answer questions that require PRA expertise.
Most personnel, e.g., in maintenance, engineering, and operations, are trained to understand the insightsfrom the PRA and how they should be used in a RIDM process.

9

B.2

Performance Monitoring and Analysis

B.2.1

Monitoring and analysis of the performance of systems, structures, and components (SSC)





B.2.2



Define the scope of SSCs with risk significance and the associated parameters. Decisionthresholds will be defined using the design and operating margin information, as well as PRA.
Monitor the performance within the scope and understand the trends and identify the precursors
to degraded performance.
Analyze the condition and trends of degradation of SSCs, predict the time of deviation from thelimiting condition, specify the issues, and develop actions to address the issues.
Monitoring and analysis of human and organizational performance
Monitor the performance of operators and workers at field evolutions, identify the issues, anddevelop resolutions for the issues
Monitor organizational performance through performance indicators, self-assessment, trending of
information reported to CAP including operating experience and near-misses, identify issues, anddevelop resolutions for these issues
Action(1) Establish the process
Review overseas standards, establish
standard process
Internalize standard process

FY2017
1H
2H

Organization

FY20181H
2H

FY20191H
2H

Common toall
Individual(2) Develop technical infrastructures,
tools, & manuals
Establish performance indicators
Develop tools & manuals(3) Develop human resources

B.3

Risk Assessment

B.3.1

Deterministic Assessment

Common toall
Individual
Individual

Deterministic risk assessment assesses specified issues and options for resolution from thefollowing viewpoints;Compliance with the regulations
Consideration of operating experience and new knowledge
Alignment with defense-in-depth philosophy
Maintenance of safety margins

Design control process is important for deterministic risk assessment. Design control process is tobe improved through establishment of configuration management program described in B.6.

10

Action(1) Establish the process
Reviewoverseas
standards,
establish standard process
Internalize standard process(2) Develop technical infrastructures,
tools, & manuals
Develop tools & manuals(3) Develop human resources

B.3.2




Organization

FY20171H
2H

FY20181H
2H

FY20191H
2H

Common toall
Individual

Individual
Individual

Probabilistic Assessment
Analyze hazards and the success criteria for the functions that respond to these hazards throughprobabilistic methods, and quantitatively assess overall plant risk (CDF, CFF, LERF, etc.) andthe risk contribution of each SSC or operator action.
Remove conservatism included in the deterministic analysis from the PRA as much as possible,and do the PRA based on the conditions reflecting the as-built and as-operated plant status.

Action(1) Establish processes
Internalize standard process(2) Develop technical infrastructures,
tools, & manuals【Enhance PRA model】【Reliability parameters】
Develop a guide for plant‐specificdata collection
Collect plant‐specific data
Establish plant specific parameters
Develop domestic genericparameters【PRA peer review】
Develop a peer review guide,
establish peer review system
Trial and actual implementation ofpeer review(3) Develop human resources
Develop in‐house human resources
Develop domestic generic training
programs for PRA practitioners and
PRA users

Organization

FY20171H
2H

FY20181H
2H

FY20191H
2H

Individual
Individual
Common toall
Individual
Individual
Common toall
Common toall
Common toall
Individual
Common toall

B.4 Decision Making and Implementation
The process identifies and implements the best option for the resolution of issues considering
information from risk assessment including its uncertainty as well as other information.

11

Action(1) Establish processes
Review overseas standards, establish
standard process
Internalize standard processes(2) Develop technical infrastructures, tools, &manuals
Trial estimation, establish thresholds
Develop tools & manuals(3) Develop human resources
Develop a domestic training program fordecision‐makers
Develop in‐house human resources

Organization

FY20171H
2H

FY20181H
2H

FY20191H
2H

Common toall
Individual
Common toall
Individual
Common toall
Individual

B.5

Corrective Action Program (CAP)

B.5.1

Collect information including minor issues from various sources

 Ensure condition reports to be reported by all levels of station personnel including precursors,minor issues of both SSCs and human performance, as well as non-conformance information.
B.5.2

Screen the issues with focus on nuclear safety Identify issues of safety significance out of condition reports, and address the issues appropriately basedon their safety significance (consider their resolutions, and implement root cause analysis and corrective
actions if the issues are significant), as well as manage and utilize the remaining minor issues within thesystem.
ActionOrganization(1) Establish processes
Review overseas standards, establish
standard process
Internalize standard process

Common toall
Individual(2) Develop technical infrastructures, tools,& manuals
Develop tools & manuals

Individual(3) develop human resources

Individual

B.6

Configuration Management

B.6.1

Collect facility configuration information

FY20171H
2H

FY20181H
2H

FY20191H
2H

 Collect and organize the information of SSCs within the scope including design requirements,
design and operating margins, drawings, and associated documents
12 Respond in a timely manner to SSC configuration changes due to degradation of components,
modifications, etc.

B.6.2

Ensure the alignment of configuration

 Ensure the alignment of design requirements, FCI, and the physical configuration, and ensure that
SSCs are installed and maintained as intended in the design.

ActionFY2017
1H
2H

Organization

FY20181H
2H

FY20191H
2H(1) Establish processes
Review overseas standards, establish
standard process
Internalize standard process(2) Develop technical infrastructures, tools, &manuals
Develop tools & manuals(3) develop human resources

Common toall
Individual
Individual
Individual
Individual

B.7 Other Initiatives Related to Interaction with Stakeholders
B.7.1

Risk Communication with the Public

Risk communication is expected to enhance the public’s understanding of the way nuclear power
plant organizations manage risk. For such a purpose, it is important for the licensees to first present
to the public (1) our perspective on risks inherent to nuclear power plants, (2) our policies toaddress those risks and the current status of risk management, and (3) our vision for the future.
Following these communications, the licensees need to have a dialogue with and receive feedback
from the public.
B.7.2 Development of a Collaborative Relationship between Industry and Academia
For a collaborative relationship between the industry and academia, it is important for theindustry to contribute to the standards that the academic societies develop.
From the perspective of RIDM, it is important that the risk assessments be realistic without
unnecessary conservatisms. There are, however, large gaps between what actually occurs at theplants and the safety assessment based on conservative assumptions, as demonstrated in the Niigata
Chuetsu earthquake, where little damage occurred at the Kashiwazaki-Kariwa Nuclear Power
Station.
These gaps are attributed to the fact that actual plant behavior may not be well understood,
therefore, the research to be conducted from now on is different from the past where theconventional approach was to confirm the assumed margins under conservative assumptions.
The industry will make efforts to produce outcomes more transparent and technically more
realistic by presenting them at academic meetings. In addition, the industry will cooperate with theacademic societies to standardize these research outcomes.

13B.7.3Development of the Relationship with the Regulator for expanding RIDM Applications

The objective of introducing and implementing RIDM process is to improve the safety of nuclear
plants by continuous risk management. The licensees acknowledge that the objective of theregulatory authority is the same and that it is possible to have a meaningful discussion of RIDM
implementation with the regulator.
The licensees’ plan is to develop the infrastructures of RIDM process and to introduce a risk
management system in the daily operation and maintenance at stations during Phase 1. Then, in
Phase 2, the licensees plan to verify the effectiveness of the management system and to introduce
RIDM processes to the technical specifications of stations and other requirements. To be successful
with this plan, it is necessary for the licensees to actively prove the effectiveness of the RIDM
process. For that purpose, it is also important to appropriately understand and learn from
implementation experience of the proposed nuclear regulatory inspection reform, which is planned
to be effective in 2020.
From the viewpoint of safety improvement, the licensees are responsible for their plants’ risk
management. On the other hand, if the directions that the regulator and the licensees pursue aredifferent, it will be difficult to establish activities toward safety improvement. Therefore, thelicensees will engage in a dialogue with the regulator in order to ensure that we both have the same
perspective on risk management and future directions, for instance, regarding the thresholds ofperformance indicators or the significant determination process.

14