This Safety Guide provides recommendations on geotechnical engineering aspects that are important to the safety of nuclear installations, such as site investigation planning, evaluation of geotechnical hazards, considerations for design and analyses, monitoring of geotechnical parameters, and the application of a graded approach to geotechnical evaluations for nuclear installations other than large nuclear power plants, excluding nuclear waste disposal facilities. This publication is intended for use by operating organizations, licensees and regulatory bodies involved in the licensing of nuclear installations as well as designers and technical support organizations of such installations.