Risk and Performance Concepts in the NRC's Approach to Regulation
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When the NRC "risk-informs" its regulations, we examine both the probability of an event and its possible consequences to understand its importance (risk). In other words, we ask our questions of what can go wrong, how likely it is, and what its consequences might be. The answers guide our requirements and regulatory attention to the issues that are most important to the health and safety of the public and the environment.
Using the skydiving example, suppose the law requires each skydiving company to conduct a risk assessment of its operation and reduce the most significant contributors to accidents. Some companies might reduce accidents by attaching automatic activation devices to the parachutes, while other companies might decide to improve their training of skydivers.
For the NRC, a "risk-informed" approach offers the following benefits:
Enable the NRC to consider a wide variety of accidents.
Give the NRC a way to prioritize those accidents based on public safety, operating experience, and/or engineering judgment.
Consider every reasonable method to prevent or mitigate an accident.
Highlight areas that are not thoroughly understood.
Test the sensitivity of analysis results to key assumptions.
The NRC uses a risk-informed regulatory approach to identify and support additional requirements or regulatory actions, when needed. Risk information can also be used to reduce unnecessary requirements in purely deterministic approaches.
In implementing a risk-informed approach, the NRC considers a set of five key principles, as illustrated in the following figure.
Performance-based regulation focuses on a desired, measurable outcome. That is, a performance-based regulation leads to defined results without direction from the NRC regarding how those results are to be obtained. At the NRC, performance-based regulatory activities focus on identifying performance measures that ensure an adequate safety margin and offer incentives to licensees to improve safety without regulatory intervention.
In our skydiving example, the law might impose a performance requirement (desired outcome) that the parachute must open above an altitude of 5,000 feet. However, the requirement would not specify how the desired outcome must be achieved. That is, the requirement would not mandate the use of a rip-cord, automatic activation device, or other method of opening the parachute above 5,000 feet.
For the NRC, performance-based approach offers the following benefits.
Improves objectivity in decision-making by reducing individual bias.
Improves transparency by more clearly defining goals and objectives.
Increases confidence in the safety of nuclear facilities by defining requirements for which compliance can be demonstrated.
Enhances the effectiveness, efficiency, realism, and timeliness of regulations.
See also Background and Staff Guidance on Performance-Based Regulation.
Risk-Informed, Performance-Based Regulation
A 1999 white paper defined risk-informed, performance-based regulation as follows:
A risk-informed, performance-based regulation is an approach in which risk insights, engineering analysis and judgment (including the principle of defense-in-depth and the incorporation of safety margins), and performance history are used, to (1) focus attention on the most important activities, (2) establish objective criteria for evaluating performance, (3) develop measurable or calculable parameters for monitoring system and licensee performance, (4) provide flexibility to determine how to meet the established performance criteria in a way that will encourage and reward improved outcomes, and (5) focus on the results as the primary basis for regulatory decision-making.
See also a History of the NRC's Risk-Informed Regulatory Programs.
To request additional information, Contact Us About Risk-Informed, Performance-Based Regulation.