Management of Commercially Generated Radioactive Waste - U.S. ...

8.10
Short-Lived Nuclides: Radioactive isotopes with relatively short half-lives. Usage for
some isotopes varies with the concept being considered (e.g., isotopes with 5-50 year
half-lives are short lived in the context of geologic disposal but long lived in the context
of predisposal operations).
Slurry: A fluid mixture or suspension of insoluble material.
Solidification: Conversion of liquid radioactive waste to a dry, stable solid.
Source Terms: The quantity of radioactive material (or other pollutant) released to the
environment at its point of release (source).
Spent Fuel (SF): Nuclear reactor fuel that has been used to the extent that it can no
longer be used efficiently in a nuclear power plant.
Stock: An igneous intrusion less than 100 km 2 (40 mi 2 ) in surface exposure.
Storage: Retention of waste in some type of manmade device in a manner permitting
retrieval.
Strain: Deformation resulting from applied stress; proportional to stress.
Stratum: Sedimentary bed or layer, regardless of thickness, of homogeneous or gradational
lithology.
Syncline: A fold, the core of which contains stratigraphically younger rocks, and which,
in simplest form, is elongate and concave upward with the two limbs dipping toward each
other.
Tailings: The part of any ore that is regarded as too poor to be treated further.
Tails: In the case of uranium it refers to the depleted uranium left after enrichment
operations.
TBP: Tributyl phosphate, a solvent used in the PUREX fuel reprocessing process.
Technologies: Specific methods for implementing concepts. An example is calcination of
liquid high-level waste by using a spray calciner.
Tectonic: Of, pertaining to, or designating the processes causing, and the rock structures
resulting from, deformation of the earth's crust.
Tectonism (diastrophism):. Crustal movement produced by earth forces, such as the formation
of plateaus and mountain ranges; the structural behavior of an element of the earth's
crust during, or between, major cycles of sedimentation.
Theoretical Density (TD): Maximum density attainable for any given material.
Thermal Regime: The area adjacent to a heat source which is affected by that source.
Trajectory: The curve that an object describes in space in traveling from one point to
another.
Transmissivity: Volume of water flowing through a 1-ft width of aquifer of given thickness
under a unit gradient (1 ft vertically for each 1 ft laterally) and at the viscosity prevailing
in the field. Mathematically, it is the product of permeability and aquifer
thickness.
Transmutation: A nuclear process in which one nuclide is transformed into the nuclide of a
different element. This can be accomplished by bombardment with neutrons or other nuclear
particles.