Document: NUREG-0800
Document ID: 3920f9d9-6b13-4389-baba-228cd8755549
Document Type: srp
Title: NUREG-0800
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340653.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6
CFR Part: 
CFR Title: 

Content:
nd by performing appropriate confirmatory analyses. It is not necessary to perform accident pressure calculations for every plant. The CSB will ascertain, however, that the adequacy of the applicant's calculational 6.2.1.1.A-4 Rev. 2 - July 1981 model has been demonstrated. The CSB determines that the applicant has identi- fied the pipe break(s) resulting in the highest containment pressure and tempera- ture. Hot leg, cold leg (pump suction), and cold leg (pump discharge) pipe breaks of the reactor coolant system, and secondary system steam and feedwater line breaks, should be analyzed by the applicant. The CSB reviews the assump- tions used to determine that the analyses are acceptably conservative. The CSB performs confirmatory containment response analyses when necessary using the CONTEMPT-LT computer code (References 6 and 7). 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 contain- ment design pressure and containment depressurization time, are analyzed. However, if in the judgment of the CSB the worst break has not been identified, other pipe breaks will be analyzed. The CSB 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 CSB determines whether the most severe condition has been identified and whether the analysis was done in a conservative manner. If the primary containment is not designed to withstand the maximum external pressure, the CSB will evaluate the accepta- bility 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 1CSB, the administrative controls and instrumentation and