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:
pplement spent fuel pool cooling. The steam condensing mode of RCIC operation in BWRs (when included in the plant design) provides an alternative to the main condenser or normal RCIC mode of operation during the initial cooldown. Steam from the reactor is transferred to the RHR heat exchangers, where it is condensed. The condensate is piped to the suction side of the RCIC pump, and the RCIC pump returns the condensate to the reactor vessel. The service water system transports the heat removed in the heat exchangers to the ultimate heat sink. Other means of removing decay heat in the event that the RHR system is inoperable have been proposed for some BWRs. These approaches use some of the piping that is used for the steam condensing mode of RCIC. This SRP section also covers these approaches. The RHR system in PWRs is used to cool the core during shutdown operations, including reduced inventory and midloop operations. High RHR system availability and reliability during shutdown conditions are important to mitigating risk and maintaining an appropriate level of safety. This SRP section covers the review of the methods used to ensure high reliability of the RHR system under these conditions. The RCS temperatures and pressure must be decreased from power operating conditions before the low-pressure RHR system can be placed in operation. Therefore, the review of the decay heat removal function must consider all conditions from shutdown at normal RCS power operating pressure and temperature to the cold depressurized condition. Further, as necessary to supplement the review under SRP Section 5.4.13, the reviewer must verify that actions have been taken to ensure the continued availability and high reliability of the decay heat removal system during shutdown operations. The reviewer will also evaluate the requirements for leakage detection and control identified in NUREG-0737, item III.D.1.1. The organization responsible for the instrumentation and control systems reviews