Unless otherwise indicated in this subpart, all terms shall have the same meaning as in subpart A of this part.
Accessible environment means:
Active institutional control means:
Annual committed effective dose means the committed effective dose resulting from one-year intake of radionuclides released plus the annual effective dose caused by direct radiation from facilities or activities subject to subparts B and C of this part.
Aquifer means an underground geological formation, group of formations, or part of a formation that is capable of yielding a significant amount of water to a well or spring.
Barrier means any material or structure that prevents or substantially delays movement of water or radionuclides toward the accessible environment. For example, a barrier may be a geologic structure, a canister, a waste form with physical and chemical characteristics that significantly decrease the mobility of radionuclides, or a material placed over and around waste, provided that the material or structure substantially delays movement of water or radionuclides.
Controlled area means:
Disposal system means any combination of engineered and natural barriers that isolate spent nuclear fuel or radioactive waste after disposal.
Dose equivalent means the product of absorbed dose and appropriate factors to account for differences in biological effectiveness due to the quality of radiation and its spatial distribution in the body; the unit of dose equivalent is the "rem" ("sievert" in SI units).
Effective dose means the sum over specified tissues of the products of the dose equivalent received following an exposure of, or an intake of radionuclides into, specified tissues of the body, multiplied by appropriate weighting factors. This allows the various tissue-specific health risks to be summed into an overall health risk. The method used to calculate effective dose is described in appendix B of this part.
Ground water means water below the land surface in a zone of saturation.
Heavy metal means all uranium, plutonium, or thorium placed into a nuclear reactor.
Implementing agency means:
International System of Units is the version of the metric system which has been established by the International Bureau of Weights and Measures and is administered in the United States by the National Institute of Standards and Technology. The abbreviation for this system is "SI."
Lithosphere means the solid part of the Earth below the surface, including any ground water contained within it.
Passive institutional control means:
Performance assessment means an analysis that:
Radioactive material means matter composed of or containing radionuclides, with radiological half-lives greater than 20 years, subject to the Atomic Energy Act of 1954, as amended.
SI unit means a unit of measure in the International System of Units.
Sievert is the SI unit of effective dose and is equal to 100 rem or one joule per kilogram. The abbreviation is "Sv."
Undisturbed performance means the predicted behavior of a disposal system, including consideration of the uncertainties in predicted behavior, if the disposal system is not disrupted by human intrusion or the occurrence of unlikely natural events.
Waste, as used in this subpart, means any spent nuclear fuel or radioactive waste isolated in a disposal system.
Waste form means the materials comprising the radioactive components of waste and any encapsulating or stabilizing matrix.
40 C.F.R. §191.12