b f U.S. NUCLEAR REGULATORY COMMISSION STANDARD REVIEW PLAN OFF1CE OF NUCLEAR REACTOR REGULATION 9.2.5 ULTIMATE HEAT SINK REVIEW RESPONSIBILITIES Primary- Auxiliary Systems Branch (ASB) Secondary- None

The ultimate heat sink (UHS) is the source of cooling water provided to dissipate reactor decay heat and essential cooling system heat loads after a normal reactor shutdown or a shutdown following an accident, including LOCA. The design of the VHS must satisfy the requirements of General Design Criteria 2, 5, 44, 45, and 46. The ASB reviews the water sources which make up the ultimate heat sink. This in-cludes the size, type of cooling water supply (e.g., ocean, lake, natural or man-made reservoir, river, or cooling tower), makeup sources to the ultimate heat sink, and the capability of the heat sink to deliver the required flow of cooling water at appropriate temperatures for normal, accident, or shutdown condition of the reactor. The UHS is reviewed to determine that design code requirements, as applicable to the assigned quality classifications and seismic categories, are met. A related area of review is the conveying system, which is generally the service water pump-ing system. The service water system is reviewed under SRP Section 9.2.1. 1. The ultimate heat sink is reviewed with respect to the following considerations: a. The type of cooling water supply. b. The ability to dissipate the total essential station heat load. c. The effect of environmental conditions on the capability of the UHS to furnish the required quantities of cooling water, at appropriate tempera-tures and with any required chemical and purification treatment, for extended times after shutdown. d. The effect of earthquakes, tornadoes, missiles, floods and hurricane winds on the availability of the source water. The UHS is also reviewe