Document: NUREG-0800
Document ID: c766e34e-6ea5-45e7-9123-75964d118447
Document Type: srp
Title: REACTOR CORE ISOLATION COOLING SYSTEM (BWR)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070540102.pdf
Revision Date: 2023-06
Chapter: 5
Section ID: 5.4.6
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CFR Title: 

Content:
REVIEW RESPONSIBILITIES Primary - Organization responsible for the review of reactor thermal hydraulic systems in boiling-water reactors Secondary - None I. AREAS OF REVIEW The reactor core isolation cooling (RCIC) system in a boiling-water reactor (BWR) is a safety system that serves as a standby source of cooling water to provide a limited decay heat removal capability whenever the main feedwater system is isolated from the reactor vessel. Abnormal events that could cause such a situation include an inadvertent isolation of all main steamlines, loss of condenser vacuum, pressure regulator failures, loss of feedwater, and loss of offsite power. Chapter 15 of the applicant’s safety analysis report (SAR) analyzes each of these transients. For each of these events, the high-pressure part of the emergency core cooling system (ECCS) provides a backup function to the RCIC system. The performance of this review of the RCIC system ensures conformance with the requirements of General Design Criteria (GDC) 4, 5, 29, 33, 34, and 54. In some plant designs, the RCIC system, in conjunction with the high-pressure core flooder (HPCF) system, may be part of the ECCS. In such cases, the ECCS function of the RCIC system is reviewed under SRP Section 6.3. In addition, the RCIC system may provide the decay heat removal necessary for coping with a station blackout (SBO). The RCIC system capability to perform this function is reviewed as necessary to ensure conformance with 10 CFR 50.63. 5.4.6-2 Revision 2 - March 2007 The RCIC system consists of a steam-driven turbine pump unit and associated valves and piping capable of delivering makeup water to the reactor vessel. Fluid removed from the reactor vessel following a shutdown from power operation is normally made up by the feedwater system, supplemented by inleakage from the control rod drive system. If the feedwater system is inoperable, the RCIC turbine pump unit starts automatically, or the operator starts it from the control room.