Document: NUREG-0800
Document ID: e32f0820-4e33-476e-aa36-4ca8c2c64af0
Document Type: srp
Title: Use of Probabilistic Risk Assessment in Plant-Specific, Risk-Informed Decisionmaking:
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0119/ML011940192.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19.0
CFR Part: 
CFR Title: 

Content:
-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' per reactor year) to maintain an equivalent risk profile or may propose an alternative guideline to LERF that meets the intent of Principle 4. The risk analyses from which the above LERF guidelines were derived are based on U0 2 fueled cores operating at power levels up to 3,800 Mwt and fuel burnups of up to approximately 40,000 MWD/MT. Small increases in power level to a resultant power level SRP 19-20 no more than 3,800Mwt, are not expected to have an appreciable effect on the current LERF guideline. However, power level increases resulting in levels above 3,800 Mwt may need to be evaluated for their impact on these LERF guidelines. Changes in fuel burnup are also not expected to have any appreciable effect on the above LERF guideline since early fatality risks are dominated by the short lived fission products, while high burnup primarily affects the long-lived fission products. However, to better understand these issues, the NRC is convening a study to identify and to determine importance of the phenomena related to high burnup and mixed oxide (MOX) fuels. This study is expected to be published for public comment in June 2001. The NRC staff will use the results to establish the basis for changes (if any) to the current LERF guidelines. As indicated by the shading in Figures I11-1 and 111-2, the change request should be subjected to technical and management reviews which 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 111.2.2.2,