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:
necessary for achieving safe reactor shutdown under all conditions or for performing accident prevention or mitigation functions. 2. The reviewer determines that essential (safety-related) portions of the MSSS are correctly identified and are isolable, to the extent required, from nonessential portions of the system. Review of the system description and the piping and instrumentation diagrams (P&IDs) verifies that they clearly indicate the physical division between the safety-related and nonessential portions of the system. Review of the system arrangement drawings identifies the means provided for accomplishing system isolation. 3. A review of the seismic design bases and the quality and seismic classification is performed, as indicated in Subsection I of this SRP section. The SAR review verifies that essential portions of the MSSS are designed to Quality Group B and/or seismic Category I requirements and confirms that the design classifications specified satisfy the acceptance criteria specified in Subsection II of this SRP section. In general, the following apply: A. Seismic Category I and Quality Group B classifications apply to the main steamlines from the steam generators to the containment isolation valves in PWR plants. B. The main steamlines in BWR plants—extending from the outermost containment isolation valve and connected piping, up to and including the first valve that is either normally closed or capable of automatic closure during all modes of normal reactor operations, but not including the turbine stop and bypass valves—are classified as seismic Category I and are assigned a quality group classification in accordance with Branch Technical Position 3-1. Alternatively, for BWRs containing a shutoff valve (in addition to the two containment isolation valves) in the MSSS, seismic Category I and a quality group classification in accordance with Branch Technical Position 3-2 should apply to that portion of the MSSS extending from the outermost