Document: NUREG-0800
Document ID: 243e1ce7-857c-48e4-9eb7-6125311da9be
Document Type: srp
Title: RESIDUAL HEAT REMOVAL (RHR) SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070437.pdf
Revision Date: 2023-06
Chapter: 5
Section ID: 5.4.7
CFR Part: 
CFR Title: 

Content:
REVIEW RESPONSIBILITIES Primary - Reactor Systems Branch (RSB SRXB)1 Secondary - None I. AREAS OF REVIEW The residual heat removal (RHR) system is used in conjunction with the main steam and feedwater systems (main condenser), or the reactor core isolation cooling (RCIC) system in conjunction with the safety/relief valves in a boiling water reactor (BWR), or auxiliary feedwater system in conjunction with the atmospheric dump valves in a pressurized water reactor (PWR) to cool down the reactor coolant system following shutdown. Parts of the RHR system also act to provide low pressure emergency core cooling and are reviewed as described in SRP Section 6.3. Some parts of the RHR system also 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 central to ensuring containment sumps provide a reliable, long-term recirculation cooling capability and RHR pump performance will not be adversely affected by post-LOCA conditions impacting the sumps. The review by RSB SRXB is to ensure that the design of the 2 3 RHR system is in conformance with General Design Criteria 2, 4, 5, 19, and 34. Both PWRs and BWRs have RHR systems which provide long-term cooling once the reactor coolant temperature has been decreased by the main condenser, RCIC, or auxiliary feedwater systems. In both types of plants, the RHR is typically a low pressure system which takes over the shutdown cooling function when the reactor coolant system (RCS) temperature is reduced to DRAFT Rev. 4 - April 1996 5.4.7-2 about 150 C (300 F). Although the RHR system function is similar for the two types of plants, 4 the system designs are different. 5 The RHR system in PWRs takes water from the RCS hot legs, cools it, and pumps it back to the cold legs or core flooding tank nozzles. The suction and discharge lines for the RHR pumps have appropriate valving to