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:
scribes the design features that have been incorporated to assure closure of the steam shutoff valves as well as any required operator actions. If the systems that can be used to mitigate the accident were not available, or if the decision were to be made to use other means to shut down the reactor, the reviewer verifies that the SAR describes the securing of these systems to assure positive steam shutoff as well as any required operator actions. G. Assure that, in the event of a postulated SSE in a PWR plant, the design includes the capability to operate atmospheric dump valves remotely from the control room so that cold shutdown can be achieved by using only safety-grade components, assuming a concurrent loss of offsite power (refer to Branch Technical Position 5-4). H. If (N-1) loop operation is anticipated, assure that the MSSS has been evaluated for the effects of (N-1) loop operation on the supply of steam to turbine-driven safety system pumps. 6. The reviewer verifies that the system is designed so that essential functions will be maintained, as required, in the event of adverse environmental phenomena, certain pipe breaks, or loss of offsite power. The reviewer uses engineering judgment and the results of failure modes and effect analyses to determine the following: A. Failure of nonseismic Category I portions of the MSSS or of other systems located close to essential portions of the system—or of nonseismic Category I structures that house, support, or are close to essential portions of the MSSS—does not preclude operation of the essential portions of the MSSS. Reference to SAR sections describing site features and the general arrangement and layout drawings will be necessary, as well as the SAR tabulation of seismic design classifications for structures and systems. Statements in the SAR that confirm that the above conditions are met are acceptable. B. Essential portions of the MSSS are protected from the effects of floods, hurricanes, tornadoes, and