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:
REVIEW RESPONSIBILITIES Primary - Organization responsible for the review of power conversion systems Secondary - None I. AREAS OF REVIEW The main steam supply system (MSSS) for both boiling-water reactor (BWR) and pressurized- water reactor (PWR) plants transports steam from the nuclear steam supply system to the power conversion system and various safety-related and nonsafety-related auxiliaries. Portions of the MSSS may be used as a part of the heat sink to remove heat from the reactor facility during certain operations and may also be used to supply steam to drive engineered safety feature (ESF) pumps. The MSSS may also include provisions for secondary system pressure relief in PWR plants. The MSSS for the BWR direct-cycle plant extends from the outermost containment isolation valves up to and including the turbine stop valves and includes connected piping that is 6.4 centimeters (2.5 inches) in nominal diameter and larger, up to and including the first valve that is either normally closed or is capable of automatic closure during all modes of reactor operation. The MSSS for the PWR indirect-cycle plant extends from the connections to the secondary sides of the steam generators, up to and including the turbine stop valves, and includes the containment isolation valves, safety and relief valves, connected piping that is 6.4 centimeters (2.5 inches) in nominal diameter and larger, up to and including the first valve that 10.3-2 Revision 4 - March 2007 is either normally closed or capable of automatic closure during all modes of operation, and the steamline to the auxiliary feedwater (AFW) pump turbine. The review of the MSSS extends from the containment up to the turbine stop valve. The specific areas of review are as follows: 1. The review should verify that portions of the MSSS that are essential for safe shutdown of the reactor or for preventing or mitigating the consequences of accidents are evaluated to determine the following: A. A single malfunction or