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:
mic interface restraint and connected piping up to the first normally closed valve. B. The nonseismic Category I classification can apply to the main steamlines from the seismic interface restraint up to, but not including, the turbine stop valve (including connected piping to the first normally closed valve) if the following criteria are met: i. A dynamic seismic analysis method analyzed the lines to demonstrate their structural integrity under SSE loading conditions. ii. All pertinent quality assurance requirements of Appendix B to 10 CFR Part 50 are applied. iii. For lines used as an MSIV leakage path to the condenser, reliable power sources must be available for control and isolation valves so that a control operator can establish the flowpath, assuming a single active failure. 10.3-7 Revision 4 - March 2007 C. Main steamlines and other main steam system components are assigned a quality group classification in accordance with the criteria of Branch Technical Position 3-1. Technical Rationale The technical rationale for application of these acceptance criteria to the areas of review addressed by this SRP section is discussed in the following paragraphs: 1. GDC 2 requires that SSCs important to safety are designed to withstand the effects of postulated local natural phenomena, such as earthquakes, tornadoes, and floods without loss of the capability to perform their safety functions. 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 reactor coolant system (RCS) pressure during certain transients, steam generator and MSSS overpressure protection, and termination of main steamline break (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