ML20227A390

Enclosure 3 - Risk Explanation FY2020 Risk-Informed Activity Website

ML20227A390
Person / Time
Issue date:	09/11/2020
From:	Office of Nuclear Regulatory Research
To:	Office of Nuclear Material Safety and Safeguards, Office of Nuclear Reactor Regulation, Office of Nuclear Security and Incident Response
Dale Yeilding
Shared Package
ML20227A386	List: ML20227A387 ML20227A388 ML20227A389 ML20227A390
References
Download: ML20227A390 (1)

Text

Annual Request for Risk-Informed Activity Information Risk Explanations The purpose of the Risk-Informed activities website is to provide and inform the public how the agency uses risk-information, risk assessment and Probabilistic Risk Assessment (PRA) in its regulatory decision making. Each of the activities submitted must include an explanation as to why the activity is classified as Risk-Informed and examples of what decisions were made that were based upon risk information. Understand that if purely deterministic considerations are involved, the activity should not be on this public website. This explanation should be at the very beginning of the activity summary description section and again referenced at the beginning of the current years update.

Risk Explanation Content:

a. Use PRA information. Explain how the Licensee PRA information or NRC risk models were used, or

b. If PRA results or methods were not used, explain how results, findings and insights from a risk assessment were used. A risk assessment can consider relevant safety margins, defense-in-depth attributes, success criteria, equipment functionality, reliability and availability. A risk assessment can involve the following:

- Consider the Risk triplet: What can go wrong? How likely is it? What are the consequences? Explain which of these three questions were asked and answered for the activity.

- Provide reference to the frequency of something associated with the activity and how decisions were made associated with those things that are more likely to occur.

Identify the available evidence and the processing of that evidence to quantify the probability and the uncertainties involved. Lacking evidence explain the predictive approach for considering frequency.

- Assess the probable range of outcomes or consequences that are end states of the activity analyses.

- Explain how the activity risk-informed decisions integrated the five key principles:

1) Current Regulations Met, 2) Defense-in-Depth Consistency, 3) Maintenance of Safety Margins, 4) Risk-Informed Analysis, and 5) Performance Monitoring.

- Consider a broader set of potential challenges to safety. Provide a logical means for prioritizing these challenges based on risk significance, operating experience, and/or engineering judgement. Consider a broader set of resources to defend against the challenges and quantify sources of uncertainty in the analysis, while testing the sensitivity of the results to key assumptions.

Enclosure 3