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:
ovides (1) for BWRs, fission product isolation during and following postulated accidents and (2) for BWRs without an MSIVLCS, fission product retention and holdup during and following an accident. The MSSS must perform its safety functions while withstanding natural phenomena that may reasonably be expected to occur at the plant site. Regulatory Guide 1.29 provides specific guidance for determining those SSCs that should be designated seismic Category I and therefore designed to meet the SSE. Regulatory Guide 1.117 includes specific guidance for determining the SSCs that should be designed to withstand the effects of a design-basis tornado. Meeting the requirements of GDC 2 and the positions of Regulatory Guide 1.29 and Regulatory Guide 1.117 will ensure that the MSSS can perform its required safety functions in the event of adverse natural phenomena. 2. GDC 4 requires that SSCs important to safety are designed to withstand potential dynamic effects, such as missile impact, pipe whip, and jet impingement caused by equipment failure or events outside the plant. The MSSS safety functions are specific to plant design and may include steam supply to safety-related auxiliaries and ESF pumps, provision of a heat sink during certain transients and accidents, limiting of RCS pressure during certain transients, steam generator and MSSS overpressure protection, and termination of MSLB events. The MSSS provides (1) for BWRs, fission product isolation during and following postulated accidents and (2) for BWRs without an MSIVLCS, fission product retention and holdup during and following an accident. The MSSS must perform its safety functions while withstanding the harshest effects of postulated plant equipment failures, such as pipe rupture, or potential external events, such as an airplane crash. Regulatory Guide 1.115 provides specific guidance for protecting safety-related SSCs from low-trajectory missiles resulting from turbine failure. Meeting the requirements of GDC 4 and