Document: NUREG-0800
Document ID: df555092-9cd0-4ad6-83d5-0351a2e7e5a3
Document Type: srp
Title: Revision 3 - March 2007
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0636/ML063600402.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6
CFR Part: 
CFR Title: 

Content:
ry review organization performs confirmatory containment response analyses when necessary. The purpose of these analyses is to confirm the applicant's predictions of the response of the containment to loss-of-coolant accidents and main steam and feedwater line breaks. In general, only the limiting pipe breaks, i.e., the pipe breaks which establish the containment design pressure and containment depressurization time, are analyzed. However, if in the reviewer's judgment the worst break has not been identified, other pipe breaks will be analyzed. 6.2.1.1.A-8 Revision 3 - March 2007 5. The primary review organization reviews analyses of the external pressure of the containment structure caused by pressure and temperature changes inside the containment due to inadvertent operation of containment heat removal systems. The primary review organization determines whether the most severe condition has been identified and whether the analysis was done in a conservative manner. For plants at the construction permit (CP) or design certification (DC) stage of review the external design pressure margin should be at least 10%. For plants at the operating license (OL) stage of review, the maximum expected external pressure should be less than the containment external design pressure. In general, the maximum expected external pressure should be approximately the same as at the construction permit or design certification stage of review. However, revised or upgraded analytical models or minor changes in the as-built design of the plant may result in a decrease in the margin. If the primary containment is not designed to withstand the maximum external pressure, the primary review organization will evaluate the acceptability of the provisions made in the plant design to mitigate or withstand the consequences of the above postulated events, and will evaluate in conjunction with the primary reviewer for SRP Section 7.5, the administrative controls and instrumentation and control