Document: NUREG-0800
Document ID: c5cd8519-169f-4fec-9d25-9ddb3ba73f52
Document Type: srp
Title: RESIDUAL HEAT REMOVAL (RHR) SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550002.pdf
Revision Date: 2023-06
Chapter: 5
Section ID: 5.4.7
CFR Part: 
CFR Title: 

Content:
REVIEW RESPONSIBILITIES Primary - Organization responsible for review of reactor thermal hydraulic systems in PWRs and BWRs Secondary - None I. AREAS OF REVIEW The residual heat removal (RHR) system is used to cool the reactor coolant system (RCS) during and following shutdown. For RCS cooldown, it is used in conjunction with (1) the feedwater systems by steaming to the main condenser, (2) the reactor core isolation cooling (RCIC) system in conjunction with the safety/relief valves in a boiling-water reactor (BWR), or (3) the auxiliary feedwater system in conjunction with the atmospheric dump valves or steaming to the main condenser in a pressurized-water reactor (PWR). Parts of the RHR system also act to provide low-pressure emergency core cooling and are reviewed as described in SRP Section 6.3. In addition, some parts of the RHR system provide containment heat removal capability and are reviewed as described in SRP Section 6.2.2. The reviews of SRP Section 6.2.2 also address PWR sump and BWR RHR suction screen inlet design and evaluation guidance to ensure that the containment sumps provide a reliable, long-term recirculation cooling capability and that conditions impacting the sumps after a loss-of-coolant accident (LOCA) will not adversely affect RHR pump performance. The reviewer of this SRP section will ensure that the design of the RHR system conforms with General Design Criteria (GDC) 2, 4, 5, 19, and 34 in Appendix A to 10 CFR Part 50 or similar requirements in the principle design criteria incorporated into the plant licensing basis. Both PWRs and BWRs have RHR systems that provide long-term cooling once the main condenser, RCIC, or auxiliary feedwater systems have decreased the RCS temperature. In both existing plant types, the RHR is typically a low-pressure system that provides shutdown cooling when the RCS temperature is reduced to about 150 EC (300 EF). Although the RHR system function is similar for the two plant types, the system designs are