Document: NUREG-0800
Document ID: 74415b71-98a0-4109-9ba7-8a72a89a3d18
Document Type: srp
Title: ULTIMATE HEAT SINK
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070520.pdf
Revision Date: 2023-06
Chapter: 9
Section ID: 9.2.5
CFR Part: 
CFR Title: 

Content:
1996 9.2.5-6 2. Compliance with GDC 5 requires that structures, systems, and components important to safety shall not be shared by nuclear power units unless it can be shown that such sharing will not impair their capability to perform intended safety functions. SRP Section 9.2.5 describes staff positions related to the design of the ultimate heat sink relative to the sharing of structures, systems, and components. GDC 5 applies to any multiple-unit facility in which a portion of the ultimate heat sink is shared by two or more units. Meeting the requirements of GDC 5 provides assurance that, in the event of an active or a passive failure at a multiple-unit site, the sharing of structures, systems, or components of the ultimate heat sink will not affect the safe shutdown of any unit.37 3. Compliance with GDC 44 requires that a system be provided to transfer heat from structures, systems, and components important to safety to an ultimate heat sink. The system 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 design of the ultimate heat sink, including assumptions concerning heat loads, redundancy of components, capability to isolate components, and single failures. Regulatory Guides 1.27 and 1.72 describe guidance acceptable to the staff regarding the design of the ultimate heat sink and of fiberglass piping for spray pond applications. In addition, Branch Technical Position ASB 9-2 describes methods acceptable to the staff for calculating residual decay energy. Meeting the requirements of GDC 44 provides assurance that the ultimate heat sink will function as designed to transfer heat from structures, systems, and components as required under normal and accident conditions, assuming a single failure.38 4. Compliance with GDC 45 requires that the cooling water system be designed to permit appropriate periodic inspection of important components (e.g., heat