Document: NUREG-0800
Document ID: f1b42595-bded-40aa-9d0a-68db845fc3e8
Document Type: srp
Title: MAIN STEAM SUPPLY SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350073.pdf
Revision Date: 2023-06
Chapter: 10
Section ID: 10.3
CFR Part: 
CFR Title: 

Content:
procedures below are written for typical MSSSs for both direct and indirect cycle plants. The reviewer will select and emphasize material from this SRP section, as may be appropriate for a particular case. 1. There are significant differences in the design of the MSSS for an indirect cycle (PWR) plant as compared to that for a direct cycle (BWR) plant. Further, different portions of the MSSS are safety-related in different plant designs, although the safety functions of the system are much the same in all PWR plants, and also in all BWR plants. The first step in the review of the MSSS, then, is to determine which portions are designed to perform a safety function. For this purpose, the system is evaluated to determine the components and subsystems necessary for achieving safe reactor shutdown in 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. The system description and piping and instrumentation diagrams (P&IDs) are reviewed to verify that they clearly indicate the physical division between each portion. System arrangement drawings are reviewed to identify the means provided for accomplishing system isolation. 3. The SGEB reviews the seismic design bases and MEB reviews the quality and seismic classification as indicated in subsection I of this SRP section. The SAR is reviewed by ASB and PSB to verify that essential portions of the MSSS are designed to Quality Group 8 and/or seismic Category I requirements, and to verify that the design classifications specified meet the acceptance criteria specified in subsection II of this SRP section. In general: a. The main steam lines from the steam generators to the containment isolation valves in PWR plants are classified seismic Category I and Quality-Group B. b. The main steam lines in BWR plants extending