Undesirable radioactive material (with a potentially harmful effect) that is either airborne or deposited in (or on the surface of) structures, objects, soil, water, or living organisms (people, animals, or plants) in a concentration that may harm people, equipment, or the en...
A degradation mechanism caused by the simultaneous action of cyclic, tensile stress. Fatigue may culminate in crack initiation and growth that may cause fracture after enough cycles.
A characterization of the driving force for fracture at the tips of a crack.
Formation of a crack before it is detectable by usual nondestructive examination techniques and before it can be analyzed using fracture mechanics.
A large heat exchanger designed to cool exhaust steam from a turbine below the boiling point so that it can be returned to the heat source as water. In a pressurized-water reactor, the water is returned to the steam generator. In a boiling-water reactor, it returns to the rea...
Any area with dose rates greater than 100 millirems (1 millisievert) in one hour 30 centimeters from the source or from any surface through which the ionizing radiation penetrates. Areas at licensee facilities must be posted as "high radiation areas" and access into these are...
The process of safely closing a nuclear power plant (or other facility where nuclear materials are handled) to retire it from service after its useful life has ended. This process primarily involves decontaminating the facility to reduce residual radioactivity and then releasi...
A nuclear reactor in which water is boiled using heat released from fission. The steam released by boiling then drives turbines and generators to produce electrical power. BWRs operate similarly to electrical plants using fossil fuel, except that the BWRs are heated by nuclear...
A term that is used by pressurized water reactors for a reactor scram (see Scram).
A breeder reactor in which the fission chain reaction is sustained by thermal neutrons.
The portion of the natural background radiation that is emitted by naturally occurring radioactive materials, such as uranium, thorium, and radon in the earth.
The condition for increasing the level of operation of a reactor. The rate of fission neutron production exceeds all neutron losses, and the overall neutron population increases.
A powerful short-ranged attractive force that holds together the particles inside an atomic nucleus.
Specifies that information applicable to the particular field was not included in the event report.
The international system (SI) unit for dose equivalent equal to 1 Joule/kilogram. 1 sievert = 100 rem. Named for physicist Rolf Sievert.
A term that may be used for referring to the reactor coolant system.
A human resources measurement equal to one staff person working full-time for one year.
Individual pieces that, when joined together, make a piping system. Examples include straight pipes, welds, elbows, tees, nozzles, and valves.
One of two elements in a two-part pricing method used in capacity transactions (the other element is the energy charge). The capacity charge, sometimes called the demand charge, is assessed on the capacity (amount of electric power) being purchased.
The determination of kinds, quantities, or concentrations and, in some cases, locations of radioactive material in the human body, whether by direct measurement (in vivo counting) or by analysis and evaluation of materials excreted or removed (in vitro) from the human body.
A unit of power (in the international system of units) defined as the consumption or conversion of one joule of energy per second. In electricity, a watt is equal to current (in amperes) multiplied by voltage (in volts).
A neutron that has (by collision with other particles) reached an energy state equal to that of its surroundings, typically on the order of 0.025 eV (electron volts).
Reactors used for research, training, and test purposes, and for the production of radioisotopes for medical, industrial, and academic uses. For additional information, see Research and Test Reactors.
A radiation instrument in which an electronic detection system receives pulses that are proportional to the number of ions formed in a gas-filled tube by ionizing radiation.
A thimble-sized ceramic cylinder (approximately 3/8-inch in diameter and 5/8-inch in length), consisting of uranium (typically uranium oxide, UO2), which has been enriched to increase the concentration of uranium-235 (U-235) to fuel a nuclear reactor. Modern reactor cores in...