Nuclear Energy Agency Committee on the Safety of Nuclear Installations

The purpose of this paper is to describe a new approach to regulatory oversight of the commercial nuclear power industry that is riskinformed and performance-based. While these concepts can, and have been, used in rulemaking and licensing activities, this paper focuses on the regulatory oversight activities of Assessment, Inspection, and Enforcement. The paper provides a discussion of the deterministic regulatory framework, why the time is ripe for a new paradigm, what is meant by “risk-informed, performance-based,” how a new regulatory oversight process would work, and what the licensee and NRC roles and responsibilities would be. Section I addresses why the time is ripe for a paradigm shift toward the concepts of riskinformed, performance-based oversight. Section II defines the concepts of riskinformed, and performance-based regulatory oversight. Section III discusses the safety framework of the new regulatory oversight process. The objectives of the process are stated; the key success attributes are described; safety expectations and thresholds are defined; and the specific performance indicators and action thresholds are identified. Section IV describes the implementation of the new risk-informed, performance-based regulatory oversight process. The roles and responsibilities of nuclear power plant licensees and the Nuclear Regulatory Commission are described, as well as reporting requirements. PAPER CONTENTS I. TOWARD A NEW PARADIGM OF REGULATORY OVERSIGHT A. Deterministic Regulatory Framework Since the advent of commercial nuclear energy in the early 1960s, regulation of the design and operation of nuclear energy plants has been based on various deterministic criteria. To obtain and maintain an operating license, a licensee must assure that its plant can be placed in a safe condition following a number of postulated design basis accidents. Given the minimal test data and operating experience that existed when these criteria were established, both the postulated accidents and the analytical methods used to evaluate a plant’s response were intentionally conservative. These deterministic criteria also provided the basis for identifying what plant structures, systems, components (SSCs) and activities were important from a safety perspective. Requirements were then established to regulate these “safety-related” SSCs and activities. The implementation of regulations based on the deterministic framework has traditionally been accomplished through a detailed programmatic and prescriptive regulatory approach. This approach focuses on the process of how regulations are implemented, relies on licensee commitments to prescribed implementation methods (or programs), and uses inspection and enforcement to ensure compliance with specific processes and commitments, rather than on the safety intent or objective of the regulations themselves. The determination of compliance depends heavily on a review of records documenting the methods used by the licensee to implement the regulatory requirements. In short, the focus has been on the inputs to the