Document: NUREG-0800
Document ID: 3ab8ae04-e11b-4993-a907-f644301c5af2
Document Type: srp
Title: MAIN STEAM SUPPLY SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070577.pdf
Revision Date: 2023-06
Chapter: 10
Section ID: 10.3
CFR Part: 
CFR Title: 

Content:
heat sink during certain transients and accidents, limiting RCS pressure during certain transients, steam generator and MSSS overpressure protection, and termination of MSLB events. For BWRs, the MSSS provides fission product isolation during and following postulated accidents, and for BWRs without a MSIVLCS, fission product retention and holdup during and following an accident. For multiple unit sites, the MSSSs may be cross- connected between units for startup, maintenance, or other related purposes. For such shared systems, the licensee must show that each MSSS can perform all of its required safety functions for its respective unit. Meeting GDC 5 will ensure that shared MSSSs at multiple unit sites will be able to carry out their respective safety functions regardless of malfunctions in the opposite unit. 4. GDC 34 requires that a residual heat removal system be provided to remove decay and residual heat from the reactor and maintain the fuel and reactor coolant pressure boundary within design limits. GDC 34 further requires that such residual heat removal systems be designed with redundancy such that they can accomplish their safety functions assuming a single failure in either the onsite or offsite electric power system. The MSSS may be utilized for safety functions such as removing decay heat or supplying steam to engineered safety feature pumps. The design of such MSSS safety functions must support meeting fuel and reactor coolant pressure boundary design limits by providing sufficient cooldown capacity and suitable power supply and redundancy to assure functionality during a loss of offsite power. Meeting GDC 34 ensures that the MSSS can fulfill its safety functions related to decay heat removal and cooling of the reactor. 5. 10 CFR 50.63 invokes explicit requirements on the plant regarding the capability to ensure that the core is cooled in the event of a station blackout for a determined duration. The MSSS may supply pumps (e.g., AFW or RCIC) and provide