Document: NUREG-0800
Document ID: 817bb0ad-6fd7-433e-aa2b-b4b3e1166f9c
Document Type: srp
Title: PROBABILISTIC RISK ASSESSMENT AND SEVERE ACCIDENT EVALUATION FOR
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0717/ML071700652.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19.0
CFR Part: 
CFR Title: 

Content:
ection, and operation of the plant. The specific programs establish the staff's acceptance criteria. For example, Section C.I.17.4 of Regulatory Guide 1.206 presents the RAP submittal guidance and SRP Section 17.4 gives the associated staff review guidance, including acceptance criteria. 19.0-8 Revision 2 - June 2007 For designs that have evolved from current plant technology through the incorporation of several features intended to make the plant safer, more available, and easier to operate, the results of the PRA should indicate that the design represents a reduction in risk compared to existing operating plants. The staff review should include a broad (qualitative and quantitative) comparison of risks, by initiating event category, between the proposed design and existing operating plant designs (from which the proposed design evolved) to identify the major design features that contribute to the reduced risk of the proposed design compared to existing plant designs (e.g., passive systems, less reliance on offsite and onsite power for accident mitigation, and divisional separation). The staff review should also consider the impact of data uncertainties on the risk estimates. The uncertainty analysis should identify major contributors to the uncertainty associated with the estimated risks. In addition, the staff review should address the applicant’s risk importance studies that are performed at the system, train, and component level to provide insights about (1) the systems that contribute the most in achieving the low risk level assessed in the PRA, (2) events (e.g., component failures or human errors) that contribute the most to decreases in the built-in plant safety level, and (3) events that contribute the most to the assessed risk. The staff should also review the applicant’s sensitivity studies performed to gain insights about the impact of uncertainties (and the potential lack of detailed models) on the estimated risk. The objectives of the sensitivity