Document: NRC Regulatory Guide
Document ID: 46049842-54a7-40a0-a0cc-ab115059f05e
Document Type: regulatory_guide
Title: Ultimate Heat Sink for Nuclear Power Plants + HISTORY - HISTORY DG-1275 , Proposed Revision 3, published 09/2013 (Rev. 3)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1304/ML13043A624.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.27
CFR Part: 
CFR Title: 

Content:
temporarily unavailable during the operating modes. Harmonization with International and Industry Standards The International Atomic Energy Agency (IAEA) has established a series of safety guides and standards constituting a high level of safety for protecting people and the environment. IAEA safety guides present international good practices and increasingly reflect best practices to help users striving to achieve high levels of safety. Relative to this regulatory guide, IAEA Safety Guide No. NS-G-1.9, “Design of the Reactor Coolant System and Associated Systems in Nuclear Power Plants” (Ref. 7), issued in 2004, addresses UHS design considerations. The NRC has an interest in facilitating the harmonization of standards used domestically and internationally. In this case, there are many similar elements between this RG and the corresponding sections of the safety guide. This RG consistently implements and details the principles and basic safety aspects presented in IAEA Safety Guide No. NS-G-1.9. American National Standards Institute/American Nuclear Society (ANSI/ANS) Standard 2.21- 2012, “Criteria for Assessing Atmospheric Effects on the Ultimate Heat Sink,” (Ref. 8) has been reviewed for applicability to this guide. This ANSI/ANS standard describes atmospheric effects for consideration when designing ultimate heat sinks for safety-related systems at nuclear power plants. Guidance from the ANSI/ANS standard has been incorporated in this guide where appropriate. Documents Discussed in Staff Regulatory Guidance This regulatory guide endorses the use of one or more codes or standards developed by external organizations, and other third party guidance documents. These codes, standards and third party guidance documents may contain references to other codes, standards or third party guidance documents (“secondary references”). If a secondary reference has itself been incorporated by reference into NRC regulations as a requirement, then licensees and