Document: NUREG-0800
Document ID: ac43f632-9db1-4857-9f56-bfba45965456
Document Type: srp
Title: * These are modifications to a plant’s design, operations, or other activities that require NRC approval. These modifica
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0232/ML023250195.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19
CFR Part: 
CFR Title: 

Content:
. 7). The guidelines discussed above are applicable for full-power, low-power, and shutdown operations. However, during certain shutdown operations when the containment function is not maintained, the LERF guidelines as defined above are not practical. In such cases, the licensee may use more stringent baseline CDF guidelines (e.g., 10-5 per reactor year) to maintain an equivalent risk profile or may propose an alternative guideline to LERF that meets the intent of Principle 4. As indicated by the shading in Figures III-1 and III-2, the change request should be subjected to technical and management reviews that become more intensive as the calculated results approach the region boundaries. The technical review related to the risk evaluation should address the scope, quality, and robustness of the analysis, including consideration of uncertainties. The scope, level of detail, and quality of analysis is further discussed in Sections III.2.2.2, III.2.2.3, and III.2.2.4 of this SRP chapter. The robustness of the results can be determined by developing an understanding of the contributors, the sources of uncertainty that impact the results, and their impact on whether the acceptance guidelines are met. The necessary sophistication of this evaluation depends on both the role the risk assessment plays in the decision and the magnitude of the potential risk impact. For actions justified primarily by traditional engineering considerations and for which minimal risk impact is anticipated, a bounding estimate may be sufficient. For actions justified primarily by PRA considerations for which a substantial impact is possible or is to be offset with compensatory measures, an in-depth and comprehensive PRA analysis is generally needed. III.2.2.5.2 Comparison of Results with Acceptance Guidelines In the context of integrated decisionmaking, the acceptance guidelines should not be interpreted as being overly prescriptive. They are intended to provide an indication, in numerical