ML24318B497

The Role of Risk Analysis Research in Safety Decisionmaking

ML24318B497
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Issue date:	11/13/2024
From:	Jonathan Evans NRC/RES/DRA/PRAB
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JONATHAN EVANS 1

THE ROLE OF RISK ANALYSIS RESEARCH IN SAFETY DECISIONMAKING J.E. Evans United States Nuclear Regulatory Commission North Bethesda, United States of America Email: Jonathan.Evans@nrc.gov Abstract In alignment with the strategic vision of the Nuclear Regulatory Commission (NRC) to foster an organizational culture that is engaged, adaptable, and data-driven, the paper underscores the critical role of risk analysis research in implementing a holistic approach to risk and hazard management in the nuclear sector. NRCs Office of Research has advanced methodologies and tools for assessing and prioritizing risks, supporting graded approaches and integrated safety assessments. By leveraging insights from reliability, human factors, and hazard analysis, the research informs regulatory decision-making with an emphasis on the effect of risk analysis. Through the application of modern technologies and data-driven approaches, the research supports the development of adaptive strategies for managing oversight activities, thus ensuring the safe operation of nuclear facilities potentially impacted by multiple hazards. This effort not only aligns with the NRCs goals but also enhances global nuclear safety in an increasingly interconnected and dynamic environment. By prioritizing risk-informed decision-making and leveraging the latest advancements in risk analysis research, the NRC ensures the continued confidence and trust of Agency stakeholders in the safety and security of nuclear facilities.

1.

INTRODUCTION The Energy Reorganization Act of 1974 [1] established the U.S. Nuclear Regulatory Commission (NRC or Agency) as an independent agency responsible for licensing and regulating the commercial use of atomic energy in the United States. These responsibilities were previously held by the Atomic Energy Commission, along with research, development, and nuclear energy policy functions that have since been assumed by the U.S.

Department of Energy (DOE). The same Act also established the fundamental role of the Office of Nuclear Regulatory Research (RES) to engage in or contract for research necessary for licensing and related regulatory functions of the NRC. Further, the law states that the Commission shall appoint a Director of RES. The law requires the RES Director to develop recommendations for research and to engage in conducting research, which the Commission deems necessary for the performance of NRCs licensing and related regulatory functions. The Joint Explanatory Statement of the Committee of Conference on the Energy Reorganization Act of 1974 states, in part: [T]he Commission would have an independent capability for developing and analyzing technical information related to reactor safety, safeguards, and environmental protection in support of the licensing and regulatory process.

In 1977, the Energy Reorganization Act was amended to direct the Commission to develop a long-term plan for projects for the development of new or improved safety systems for nuclear power plants. The role of RES is further promulgated in Title 10, Energy, of the Code of Federal Regulations (10 CFR) Part 1, Statement of Organization and General Information [2], which states that RES:

(a) Plans, recommends, and implements programs of nuclear regulatory research, standards development, and resolution of generic safety issues for nuclear power plants and other facilities regulated by the NRC.

(b) Coordinates research activities within and outside the NRC including appointment of staff to committees and conferences.

(c) Coordinates NRC participation in international standards related activities and national volunteer standards efforts, including appointment of staff to committees.

The Division of Risk Analysis in the RES supports the regulatory mission of the NRC and executes the following strategies to help achieve NRCs safety and security strategic goals:

IAEA-CN-329-181 Develops guidance and other regulatory tools for implementation of the Commissions Policy Statements related to Safety Goals for the Operation of Nuclear Power Plants and the Use of Probabilistic Risk Assessment (PRA) Methods in Nuclear Regulatory Activities; Provides safety perspectives on plant design and operation using probabilistic techniques to identify dominant risk contributors and potential risk management strategies; Provides world class technical support for the implementation of risk-informed regulatory activities and decision making in nuclear safety and security; Conducts research activities to independently confirm the safety of licensees operations and enhance the regulatory framework by addressing changes in technology, science, and policies; Conducts research and development activities and PRA Standards with the other agency program offices and external partners (e.g., universities, international organizations);

Develops and uses PRA-based methodologies, models, and analysis techniques, such as the Standardized Plant Analysis Risk (SPAR) Models, the SAPHIRE (Systems Analysis Programs for Hands-on-Integrated Reliability Evaluations) code and other PRA codes; Performs independent analyses of operational data and assessments of operating experience that are used to estimate and monitor the risk of accidents at NRC licensed facilities and inform NRCs strategic plan goals; Develops and revises regulatory guides in light of knowledge gained from licensing reviews, inspections, operating experience, and research activities; Exchanges information, expertise, operating experiences, and research with domestic and international counterparts to increase awareness of, and respond to, emerging technical issues; to participate in the development, evaluation, and implementation of harmonized standards; to seek common approaches to resolving technical issues; to promote best practices; and to leverage resources through shared research programs.

It should be noted that the responsibility for the safety of nuclear power plants and for the safe use, storage, and disposal of radioactive material lies with the licensees. Accordingly, the industry and related organizations must develop and provide the necessary data and information to support their safety assessments. Whereas RES generally conducts a more limited scope of confirmatory research, to examine methodologies, technical application, key uncertainties and assumptions in those safety assessments. The research can be directed expressly by the Commission in the case of certain issues that relate to safety and security policy issues, but more frequently is performed at the request of the NRC offices responsible for licensing and inspection.

The Energy Reorganization Act permits RES to enter into cooperative research agreements with international and domestic organizations, provided that the agency maintains its independence and remains free from the perception of conflicts of interest with licensees. Through such agreements, RES can share the costs of experimental programs, acquire data, and develop and verify analytical tools to fully understand and characterize the safety and security of nuclear facilities and nuclear materials users. International and domestic cooperative programs have been developed in many research areas to minimize duplication of effort. This enhances the NRCs ability to make sound regulatory and safety decisions based on worldwide scientific knowledge that promotes the effective and efficient use of agency resources.

2.

STRATEGIC ALIGNMENT WITH NRCS VISION NRCs Fiscal Years 2022-2026 Strategic Plan [3] defines its three strategic goals as:

(a) Ensure the safe and secure use of radioactive materials.

(b) Continue to foster a healthy organization.

(c) Inspire stakeholder confidence in the NRC.

The Strategic Plan provides an overview of the NRCs responsibilities and lays out the plans, strategies, and key activities that will be used to achieve the agencys strategic goals. As outlined in the Strategic Plan, the NRCs mission is to license and regulate the Nations civilian use of radioactive materials, to provide reasonable assurance of adequate protection of public health and safety, to promote the common defense and security, and to protect the environment.

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The NRCs main regulatory functions are to:

Establish standards and regulations; Issue licenses, certificates, and permits; Ensure compliance with established standards and regulations; Issue adjudicatory decisions; Conduct research and risk and performance assessments to support regulatory decisions.

The current strategic plan also introduces a new vision statement: [T]he NRC demonstrates the Principles of Good Regulation through effective, responsive, and timely regulatory actions, consistent with our organization values and our open, collaborative work environment.

To fulfil this vision, risk analysis in RES has to be conducted with a forward-thinking approach that integrates cutting-edge methodologies and tools. This involves continuously improving our understanding of the risks associated with the use of radioactive materials and ensuring that our regulatory frameworks remain adaptive and robust. By leveraging advancements in technology, data analytics, and scientific research, RES can support the NRC in making informed regulatory decisions that not only meet current standards but also anticipate future challenges. This proactive stance will ensure that the NRC remains a leader in nuclear safety and security while maintaining public trust and confidence.

3.

ROLE OF NRCS OFFICE OF RESEARCH In alignment with this strategic vision, the NRCs Office of Research (RES) plays a pivotal role in implementing a holistic approach to risk and hazard management in the nuclear sector. The research risk analysis groups have developed advanced methodologies and tools for assessing and prioritizing risks, supporting graded approaches and integrated safety assessments. These efforts, when considered together, promote innovation and enhances regulatory frameworks.

3.1.

Advanced Methodologies and Tools RES employs Probabilistic Risk Assessment (PRA) to evaluate and gain insights on risks associated with nuclear power plants. PRA involves estimating the likelihood of various accident scenarios and their potential consequences, providing insights into the strengths and weaknesses of plant designs and operations. The SAPHIRE (Systems Analysis Programs for Hands-on Integrated Reliability Evaluations) code is a critical tool used by the NRC to create and analyze these PRAs. SAPHIRE allows for detailed modeling of plant systems and accident sequences, facilitating comprehensive risk assessments. Additionally, the Standardized Plant Analysis Risk (SPAR) models, which are plant-specific risk models, utilize event-tree and fault-tree methodologies to standardize risk evaluations across different plants. Together, SAPHIRE and SPAR enable the NRC to implement a holistic approach to risk evaluation, providing tools to support regulatory decisions related to the safety and reliability of nuclear facilities.

The integration of SAPHIRE and SPAR into the NRCs PRA framework enhances the agencys ability to proactively identify and mitigate potential risks, independent of the licensees PRA model. By using these tools, the NRC can simulate a wide range of operational scenarios and assess the effectiveness of various safety measures. This approach allows for the identification of vulnerabilities that might not be apparent through traditional deterministic methods. Moreover, the continuous updating and refinement of SPAR models ensures that risk assessments remain current with the latest licensee plant modifications and operational data. The independence of SAPHIRE and SPAR from industry tools is particularly useful as it ensures unbiased and objective risk assessments. While SPAR models are benchmarked against licensees models, this independence allows the NRC to maintain a high level of credibility and trust in its evaluations, as the tools are developed and maintained by the NRC and its contractors. Consequently, development of such tools facilitates making impartial regulatory decisions, which is crucial for maintaining public confidence in the safety of nuclear power plants. This dynamic and iterative process supports a culture of continuous improvement in nuclear safety, ultimately contributing to the protection of public health and the environment.

3.2.

Graded Approaches and Integrated Safety Assessments The integration of a graded approach and comprehensive safety assessment within the NRCs regulatory framework offers significant benefits, enhancing both the efficiency and effectiveness of nuclear safety oversight.

By tailoring regulatory requirements based on the risk significance of activities, the NRC ensures that higher-risk operations receive more focused scrutiny, while lower-risk activities are managed with appropriate oversight. This

IAEA-CN-329-181 strategic allocation of resources is bolstered by independent research efforts, which continuously advance safety technologies and methodologies, and by leveraging operating experience to refine regulatory practices based on real-world data. The Accident Sequence Precursor (ASP) program further strengthens this framework by systematically identifying and addressing potential precursors to severe accidents, thereby enhancing the NRCs capabilities to identify vulnerabilities.

Together, these measures significantly bolster the agencys capabilities to evaluate and make regulatory decisions concerning the safety and resilience of nuclear facilities to a wide range of hazards. By prioritizing regulatory focus and incorporating lessons from past events, facilities are better prepared to mitigate potential threats, ensuring robust defenses against both common and rare incidents. Demonstrating a commitment to rigorous safety practices reassures the public that nuclear facilities are managed with the highest standards of safety and reliability, fostering trust in the regulatory system and the nuclear industry as a whole.

3.3.

Insights from Reliability, Human Factors, and Hazard Analysis Reliability analysis, human factors, and hazard analysis supports an enhanced understanding of risk. Reliability analysis ensures that licensees are maintaining risk-significant systems and components such that they perform their intended functions when called upon, reducing the likelihood of failures. By identifying and addressing potential weaknesses, reliability analysis helps maintain high standards of operational performance. Human factors focuses on optimizing the interaction between people and technology, ensuring that systems are user-friendly and that human errors are minimized. This involves designing controls, interfaces, and procedures that align with system and human capabilities as well as limitations, thereby enhancing overall safety and efficiency. Hazard analysis systematically identifies potential hazards and evaluates their possible impacts, enabling the implementation of effective risk mitigation strategies. By understanding and addressing the root causes of potential incidents, hazard analysis helps prevent accidents and ensures robust defenses against a wide range of threats.

Together, these approaches and infrastructure developed through regulatory research create a comprehensive safety framework that prioritizes both technical and human elements. By integrating reliability analysis, human factors, and hazard analysis, the NRC can ensure that nuclear facilities are well-prepared to handle both routine operations and unexpected events. This approach not only enhances the safety and resilience of nuclear facilities but also promotes public confidence.

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4. CONCLUSION In conclusion, the integration of risk analysis research is integral to advancing a holistic approach to risk and hazard management in the nuclear sector. By enhancing methodologies and tools for risk assessment, the NRC is better equipped to support a balanced approach to innovation and safety. The application of modern technologies and data-driven strategies ensures that regulatory decision-making is informed by a comprehensive understanding of risks, thereby bolstering the resilience of nuclear facilities.

This approach not only aligns with the NRCs strategic vision but also fosters global collaboration and the adoption of best practices in nuclear safety. As the nuclear sector continues to evolve, the emphasis on adaptive strategies and stakeholder confidence will be crucial in maintaining the safety and security of nuclear facilities.

Ultimately, the advancements in risk analysis research underscore the NRCs commitment to safeguarding public health and the environment, reinforcing trust and confidence in the regulatory process.

REFERENCES

[1] Energy Reorganization Act of 1974, Public Law 93-438, 88 Stat. 1233 (1974).

[2] U.S. Code of Federal Regulations, Statement of Organization and General Information, Part 1, Chapter I, Title 10, Energy (10 CFR 1), as announced in the Federal Register at 52 FR 31602, August 21, 1987, and as amended at 63 FR 69544, December 17, 1998.

[3] U.S. Nuclear Regulatory Commission, NRC: Strategic Plan - Fiscal Years 2022-2026, NUREG-1614, Vol. 8, April 4, 2022, Agencywide Documents Access and Management System (ADAMS) Accession No. ML22067A170.