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:
such RHR systems are designed with redundancy so that they can accomplish their safety functions, assuming a single failure in either the onsite or offsite electric power system. The MSSS may be used 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 the meeting of 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 imposes explicit requirements on the plant regarding the capability to ensure that the core is cooled in the event of an SBO for a determined duration. The MSSS may supply pumps—for example, AFW or reactor core isolation coolant—and provide the decay heat removal capability necessary for core cooling and safe shutdown (nondesign-basis accident), respectively, during an SBO. Its design capability to operate regardless of alternating current power source availability enables performance of these important functions during an SBO. Regulatory Guide 1.155 identifies methods acceptable for complying with the requirements of 10 CFR 50.63. Meeting the requirements of 10 CFR 50.63 and the positions of Regulatory Guide 1.155 provides assurance that the MSSS is capable of supporting core cooling and/or safe shutdown (nondesign-basis accident) in the event of an SBO. III. REVIEW PROCEDURES The reviewer will select material from the procedures described below, as may be appropriate for a particular case. These review procedures are based on the identified SRP acceptance criteria. For deviations from these acceptance criteria, the staff should review the applicant’s evaluation of how the proposed alternatives provide an acceptable method of complying with the relevant NRC