Document: NRC Regulatory Guide
Document ID: 46b2c829-ce4c-4a6a-8a01-908725558ffe
Document Type: regulatory_guide
Title: Volcanic Hazards Assessment for Proposed Nuclear Power Reactor Sites + HISTORY - HISTORY 03/2020 – DG-4028-Proposed New Guide
Source: NRC Regulatory Guide Division 4
Source URL: https://www.nrc.gov/docs/ML2000/ML20007D621.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-4.26
CFR Part: 
CFR Title: 

Content:
y Guide (SSG)-21, “Volcanic Hazards in Site Evaluation for Nuclear Installations.” Although IAEA TECDOC 1795 was developed for the siting of nuclear installations, the NRC staff is focusing on the information most relevant to the licensing of new reactors in the United States. The following provides an overview of siting and design considerations for potential volcanic hazards. Volcanic hazards can present a range of physical demands on nuclear SSCs that are important to safety. The magnitude of these demands usually depends on the distance between the proposed site and the source characteristics of the volcanic phenomena. For example, for sites located relatively far from a volcano, volcanic ash fall has the potential to deposit layers of finely pulverized rock that might quickly clog filtration systems, introduce abrasive debris into mechanical systems, and add static loads to structures. Alternatively, sites located close to a new volcano could experience ground displacements on the order of meters and inundation by meters-thick, hot flows (greater than 1,000 degrees Celsius [C]; 1,800 degrees Fahrenheit [F]) of dense lava (2,600 kilograms per cubic meter [kg/m3]; 162 pounds per cubic foot [ft3]). In addition, an individual volcanic eruption potentially can produce multiple hazardous phenomena, each of which might need to be considered in a volcanic hazards assessment. 1 This definition thus includes: nuclear power plants; research reactors (including subcritical and critical assemblies) and any adjoining radioisotope production facilities; storage facilities for spent fuel; facilities for the enrichment of uranium; nuclear fuel fabrication facilities; conversion facilities; facilities for the reprocessing of spent fuel; facilities for the predisposal management of radioactive waste arising from nuclear fuel cycle facilities; and nuclear fuel cycle related research and development facilities. DG-4028, Page 5 • Ash Fall: Many volcanic eruptions eject large