The number of nucleons (neutrons and protons) in the nucleus of an atom. Also known as the atomic weight.
The natural radiation that is always present in the environment. It includes cosmic radiation which comes from the sun and stars, terrestrial radiation which comes from the Earth, and internal radiation which exists in all living things. The typical average individual exposur...
The change in reactivity per degree of change in the temperature of nuclear fuel. The physical property of fuel pellet material (uranium-238) that causes the uranium to absorb more neutrons away from the fission process as fuel pellet temperature increases. This acts to stabi...
A system of synchronized power providers and consumers, connected by transmission and distribution lines and operated by one or more control centers. In the continental United States, the electric power grid consists of three systems–the Eastern Interconnect, the Western Inte...
An area of low population density often required around a nuclear installation before it's built. The number and density of residents is of concern in emergency planning so that certain protective measures (such as notification and instructions to residents) can be accomplish...
Volume 1Study of Construction Technologiesand Schedules, O&M Staffingand Cost, Decommissioning Costsand Funding Requirementsfor Advanced Reactor DesignsUnited States Department of EnergyCooperative Agreement DE-FC07-03ID14492Contract DE-AT01-020NE23476Prepared by:May 27, 2004 ...
A traveling wave motion resulting from changing electric or magnetic fields. Familiar electromagnetic radiation range from x-rays (and gamma rays) of short wavelength, through the ultraviolet, visible, and infrared regions, to radar and radio waves of relatively long waveleng...
A company, organization, institution, or other entity to which the NRC or an Agreement State has granted a general license or specific license to construct or operate a nuclear facility, or to receive, possess, use, transfer, or dispose of source material, byproduct material,...
An approach to designing and operating nuclear facilities that prevents and mitigates accidents that release radiation or hazardous materials. The key is creating multiple independent and redundant layers of defense to compensate for potential human and mechanical failures so...
Reactor system components (pumps, valves, heat exchangers, tanks, and piping) that are specifically designed to remove residual heat from the reactor fuel rods in the event of a failure of the normal core cooling system (reactor coolant system).
Settings for automatic protective devices related to those variables having significant safety functions. Where a limiting safety system setting is specified for a variable on which a safety limit has been placed, the setting will ensure that automatic protective action will ...
A reaction that initiates its own repetition. In a fission chain reaction, a fissionablenucleus absorbs a neutron and fissions spontaneously, releasing additional neutrons. These, in turn, can be absorbed by other fissionable nuclei, releasing still more neutrons. A fission c...
A gas-tight shell or other enclosure around a nuclear reactor to confine fission products that otherwise might be released to the atmosphere in the event of an accident. Such enclosures are usually dome-shaped and made of steel-reinforced concrete.
The normal inspection program performed at all nuclear power plants. The program focuses on plant activities that are not adequately measured by performance indicators, on the corrective action program, and on verifying the accuracy of the performance indicators.
Photographic film used to measure exposure to ionizing radiation for purposes of personnel monitoring. The film badge may contain two or three films of differing sensitivities, and it may also contain a filter that shields part of the film from certain types of radiation.
A postulated accident that a nuclear facility must be designed and built to withstand without loss to the systems, structures, and components necessary to ensure public health and safety.
A woman who is an occupational radiation worker and has voluntarily informed her employer, in writing, of her pregnancy and the estimated date of conception (see 10 CFR 20.1003 and 20.1208).
The steady hourly output that generating equipment is expected to supply to system load, exclusive of auxiliary power, as demonstrated by measurements at the time of peak demand (summer). Net summer capacity is measured in watts unless otherwise noted.
Request for Additional Information No.92 (969), Revision 0 10/9/2008 U. S. EPR Standard Design Certification AREVA NP Inc. Docket No. 52-020 SRP Section: 13.06 - Physical Security Application Section: Tier 1, Chapter 3; Tier 2, Chapter 13.6; U.S. EPR Vital Equipment List QU...
A personnel exchange program for foreign regulatory counterparts. This helps the NRC and partners better understand each other’s regulatory programs, capabilities, and commitments and fosters relationships between the NRC and key officials in other countries. The assigne...
Generally, nonmanufacturing business establishments, including hotels, motels, and restaurants; wholesalers and retail stores; and health, social, and educational institutions. However, utilities may categorize commercial service as all consumers whose demand or annual usage ...
The maximum number of years that could be added to a facility's license expiration date to recapture the period between the date the NRC issued the facility's construction permit to the date it granted an operating license. A licensee must submit an application to requ...
As defined in Title 10, Section 20.1003, of the Code of Federal Regulations (10 CFR 20.1003), the CDE (HT,50) is the dose to some specific organ or tissue of reference (T) that will be received from an intake of radioactive material by an individual during the 50-year period ...
A structured group of fuel rods (long, slender, metal tubes containing pellets of fissionable material, which provide fuel for nuclear reactors). Depending on the design, each reactor core may have dozens of fuel assemblies (also known as fuel bundles), each of which contain...
A way of separating chemical substances from a mixed sample by passing the sample, carried by a moving stream of gas, through a tube packed with a finely divided solid that may be coated with a liquid film. Gas chromatography devices are used to analyze air pollutants, blood ...