Suggested Guide for Geotechnical Sampling and Testing of Backfill and Borrow for Safety Related Nuclear Structures

For licensing, design, and construction of nuclear facilities, the investigation of engineering properties of soil borrow and backfill materials is a regulatory requirement, for they impact the performance of these facilities. For instance, the U.S. Nuclear Regulatory Commission (NRC) specifically requires that all applications for nuclear power plants address the source, quantity, static, and dynamic engineering properties of borrow and backfill materials. However, in the nuclear industry, a clear road map does not exist for meeting these requirements. As such, planning, investigation, and/or processes that are needed to address these regulatory requirements become a challenge to applicants. The absence of such a road map can also result in incomplete or unnecessary investigations, licensing cycles, and/or delays. This paper outlines a recommended practice, including steps to design a geotechnical sampling and laboratory investigation program toward addressing these regulatory requirements, with nuclear quality assurance and licensing requirements in perspective. While the steps in this paper may serve as useful guides, requirements vary from project to project; therefore, all efforts should be on developing an investigation program that is project specific in order to meet the actual project objectives. Additionally, this paper provides guidance on presenting the investigation results in regulatory documents.