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

8.8
Neutron: Stable particle in a nucleus of very slightly greater mass than a proton but without
nuclear change.
NOx: Oxides of nitrogen, specifically NO and NO 2.
NRC: Nuclear Regulatory Commission.
Nucleus: The inner core of the atom, consisting primarily of neturons and protons, which
make up almost the entire mass of the atom but only a minute part of its volume.
Nuclide: A species of atom characterized by its mass number, atomic number, and nuclear
energy state; to be regarded as a distinct nuclide the atom must be capable of existing
for a measureable lifetime in its nuclear energy state.
Olivine: An olive-green, common rock-forming ferromagnesian silicate mineral of mafic,
Ultramafic, and low-silica igneous rocks.
ONWI: Office of Nuclear Waste Isolation at Battelle Memorial Intitute, Columbus, Ohio;
under contract to DOE.
Operations: Broad classification of waste management activities in terms of their basic
function (e.g., waste storage, treatment, transportation or disposal).
ORNL: Oak Ridge National Laboratory.
Overpack: Secondary (or additional) external containment for packaged nuclear waste.
Outcrop: A part of a body of rock that appears, bare and exposed, at the surface of.the
ground.
Parent Nuclide: A radionuclide that upon disintegration yields a specified nuclide, either
directly or as a later member of a radioactive decay series.
Partition: To separate one (or more) element(s) from one (or more) other element(s). Examples
include the separation of uranium and plutonium from each other, the separation of
actinides and fission products in the waste, and the separation of one fisson product from
the other fission products.
Perihelion: The point in the orbit of a celestial body that is closest to the sun.
Permeability: The quality or state of being permeable. The relative ease with which a
porous medium can transmit a liquid under a hydraulic gradient.
Peridotite: A coarse-grained plutonic igneous rock composed chiefly of the mineral olivine
but also containing considerable amounts of other ferromagnesian minerals.
Plagioclase: The group of common rock-forming feldspar minerals; silicates of varying mixtures
of sodium and calcium.
Pluton: A body of intrusive igneous rock of any shape or size.
Pluvial: Pertaining to a period of time in which rainfall or precipitation is abundant.
PNL: Pacific Northwest Laboratory operated for DOE by Battelle Memorial Institute.
Porosity: That property of a rock or soil which enables the rock or soil to contain water
in voids or interstices, usually expressed in percentage or as a decimal fraction of void
volume as compared to total volume.
Pressurized Water Reactor (PWR): A reactor system that uses a pressurized water primary
cooling system. Steam formed in a secondary cooling system is used to turn turbines to
generate electricity.