Document: NUREG-0800
Document ID: 50ab8154-2a3c-4c0f-8ce4-06ac83096e5c
Document Type: srp
Title: ULTIMATE HEAT SINK
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550048.pdf
Revision Date: 2023-06
Chapter: 9
Section ID: 9.2.5
CFR Part: 
CFR Title: 

Content:
apability to perform intended safety functions. RG 1.27 describes staff positions on UHS design for sharing of SSCs. GDC 5 applies to any multi-unit facility in which a UHS portion is shared by two or more units. GDC 5 requirements provide assurance that, in an active or a passive failure at a multi-unit site, the sharing of UHS SSCs will not affect the safe shutdown of any unit. 3. GDC 44 requires systems to transfer heat from SSCs important to safety to a UHS. Systems must be able to function under normal and accident conditions, assuming a single failure. GDC 44 applies to this SRP section because the reviewer evaluates the UHS design, including assumptions for heat loads, redundancy of components, capability to isolate components, and single failures. RGs 1.27 and 1.72 describe guidance acceptable to the staff for UHS design and fiberglass piping for spray pond applications. In addition, ANSI/ANS-5.1 describes methods acceptable to the staff for calculating residual decay energy. 9.2.5-6 Revision 3 - March 2007 GDC 44 requirements provide assurance that the UHS will function as designed to transfer heat from SSCs as required under normal and accident conditions, assuming a single failure. 4. GDC 45 requires that the cooling water system be designed to permit appropriate periodic inspection of important components (e.g., heat exchangers and piping) to ensure the integrity and capability of the system. Meeting the requirements of GDC 45 provides assurance that components and equipment of the ultimate heat sink can and will be inspected, thereby ensuring that the system will perform its intended safety function. 5. GDC 46 requires that the cooling water system be designed to permit appropriate periodic pressure and functional testing to ensure the leaktight integrity and operability of its components, as well as the operability of the system as a whole, under conditions as close to the design basis as practical. Meeting the requirements of GDC 46 provides assurance