Document: NUREG-0800
Document ID: 87477809-7581-4701-b6f2-91410029e1c8
Document Type: srp
Title: MAIN STEAM SUPPLY SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0703/ML070380206.pdf
Revision Date: 2023-06
Chapter: 10
Section ID: 10.3
CFR Part: 
CFR Title: 

Content:
acceptable and meets the requirements of GDC 2, 4, 5, and 34 and of 10 CFR 50.63. This conclusion is based on the following: 1. The applicant has met the requirements of (1) GDC 2 with respect to the capability of structures housing the safety-related portion of the system and the safety-related portions of the system to withstand the effects of natural phenomena such as earthquakes, tornadoes, hurricanes, and floods and (2) GDC 4 with respect to the capability of structures housing the safety-related portions of the system and the safety-related portions of the system to withstand the effects of external missiles, internally generated missiles, and pipe whip and jet impingement forces associated with pipe breaks. The essential portions of the MSSS (as identified in the above discussion) are designed to seismic Category I and are housed in a seismic Category I structure that provides protection from the effects of tornadoes, tornado missiles, turbine missiles, and floods. This approach meets Regulatory Guide 1.29, Positions C.1.a, C.1.e, C.2 and C.3 or C.1.f, C.2, and C.3; Regulatory Guide 1.115, Position C.1; and Regulatory Guide 1.117, Appendix Positions 2 and 4. In addition, the system design includes the capability to accommodate water (steam) hammer dynamic loads resulting from rapid closure of system valves (including turbine bypass and stop valves) and safety/relief valve operation, without compromising required safety functions. Water entrainment considerations include provisions for drain pots, line sloping, and valve operation. The applicant will review operating and maintenance procedures to alert plant personnel to the potential for, and means to minimize, water (steam) hammer occurrences. This commitment is stated in the applicant’s SAR. 2. The applicant has met the requirements of GDC 5 with respect to the capability of shared systems and components important to safety to perform required safety functions. The NRC staff has reviewed the