Document: NUREG-0800
Document ID: 32179098-f78d-4852-9c29-1e5e3abb2705
Document Type: srp
Title: RISK-INFORMED DECISION MAKING:  TECHNICAL SPECIFICATIONS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0703/ML070380228.pdf
Revision Date: 2023-06
Chapter: 16
Section ID: 16.1
CFR Part: 
CFR Title: 

Content:
figurations. With plant equipment risk contribution evaluated, the licensee can assess whether TS or procedure enhancements are required to avoid risk-significant situations. In addition, compensatory actions that can mitigate any corresponding increase in risk (e.g., backup equipment, increased surveillance frequency, or procedural and training upgrades) should offset the risk with certain configurations. These compensatory actions should be evaluated in the first tier where practical. In addition, Tier 2 for TS changes should be reviewed for whether the guidance of RG 1.177, Position 2.3.6, is followed. (3) Tier 3: Risk-Informed Configuration Risk Management for TS AOT Changes. Tier 3 focuses on licensee programs for whether the risk impact of out-of-service equipment is appropriately evaluated prior to and during any maintenance activity. A viable program can uncover risk-significant plant equipment outage configurations promptly during normal plant operation by quantitatively evaluating the impact on plant risk of, for example, equipment unavailability, operational activities like testing or load dispatching, or weather conditions. The need for a third tier stems from the difficulty in ascertaining in Tier 2 all possible risk-significant configurations encountered over extended periods of plant operation. In addition, Tier 3 should review TS changes for whether the guidance of RG 1.177, Position 2.3.7, is followed. 16.1-13 Revision 1 - March 2007 (ii) Risk Evaluation for STIs. The reviewer should ensure that the licensee identifies the STIs to be evaluated; determines the risk contribution of the subject STIs; determines the risk impact from the change to the STIs; and evaluates the sensitivities and uncertainties in the STI evaluations. Additional detailed guidance on the evaluation of proposed STI changes is in the following subsections. (iii) Risk Evaluation for All TS Changes. The scope and the level of PRA necessary for the evaluation of a TS change fully