Underground Facility [Energy] Law and Legal Definition

According to 10 CFR 63.2 [ Title 10 – Energy; Chapter I -- Nuclear Regulatory Commission; Part 63 -- Disposal of High-Level Radioactive Wastes in a Geologic Repository at Yucca Mountain, Nevada; Subpart A -- General Provisions], the term underground facility means “the underground structure, backfill materials, if any, and openings that penetrate the underground structure (e.g., ramps, shafts, and boreholes, including their seals).”