Geohydrology.

CFR · 2024-01-01 · US · Title 10

(a) (b) (2) The nature and rates of hydrologic processes operating within the geologic setting during the Quaternary Period would, if continued into the future, not affect or would favorably affect the ability of the geologic repository to isolate the waste during the next 100,000 years. (3) Sites that have stratigraphic, structural, and hydrologic features such that the geohydrologic system can be readily characterized and modeled with reasonable certainty. (4) For disposal in the saturated zone, at least one of the following pre-waste-emplacement conditions exists: (i) A host rock and immediately surrounding geohydrologic units with low hydraulic conductivities. (ii) A downward or predominantly horizontal hydraulic gradient in the host rock and in the immediately surrounding geohydrologic units. (iii) A low hydraulic gradient in and between the host rock and the immediately surrounding geohydrologic units. (iv) High effective porosity together with low hydraulic conductivity in rock units along paths of likely radionuclide travel between the host rock and the accessible environment. (5) For disposal in the unsaturated zone, at least one of the following pre-waste-emplacement conditions exists: (i) A low and nearly constant degree of saturation in the host rock and in the immediately surrounding geohydrologic units. (ii) A water table sufficiently below the underground facility such that the fully saturated voids continuous with the water table do not encounter the host rock

official document · source cfr-2024 · id 10:§ 960.4-2-1