Borders' Dictionary of Health Physics

U-235
Uranium-235. (See uranium.)
(USAEC-1974)

U.S. Coast guard (USCG)
This military service within the DOT has been delegated the authority for waterborne safety. It promulgates and enforces rules and regulations that pertain to vessel design and operations, vessel manning, casualty investigation, navigational aids, and waterfront facilities. It also provides certain lifesaving and property protection services. The COTP and the officer-in-charge, marine inspection are the local USCG offices with which a shipper and carrier of radioactive materials will deal. These offices are often combined under the commanding officer, marine safety office.
(ANSI N14.24-1985)

U.S. Department of Energy (DOE)
The DOE has responsibility for radioactive materials that are generated within the DOE system and commercial spent fuel under the Nuclear Waste Policy Act of 1982, Public Law 97-425, 42 USC 10101 (NWPA). The DOE is essentially the shipper and the receiver of most of the materials for which it is responsible. This agency uses both public and private carriage for the radioactive materials. The DOE also has the authority to certify packages that are used within or between DOE facilities, but for shipments made under the NWPA, the DOE intends to use NRC-certified packages. The packaging criteria and standards of the DOE are comparable to those promulgated by the NRC. The DOE follows DOT (including USCG) regulations for the transportation of RAM.
(ANSI N14.24-1985)

U.S. Department of Transportation (DOT)
The DOT, acting through the Materials Transportation Bureau (MTB), promulgates rules and regulations pertaining to the packaging and transportation of radioactive materials. For Type B packages, the certification process is under NRC or DOE jurisdiction, as applicable. The DOT focuses on carriage issues.
(ANSI N14.24-1985)

U.S. Nuclear Regulatory Commission (NRC)
This federal agency has a broad statutory authority over transportation of radioactive material similar to that of the DOT. Under a memorandum of understanding between the two agencies, however, NRC limits its activities to performing safety evaluations of packages and issuing certificates of compliance for Type B packages and packages for fissile material. The NRC also prescribes rules for monitoring of packages on receipt, for limiting the exposure of individuals to ionizing radiation, and for in-transit security of certain materials. NRC imposes DOT shipping requirements by reference and inspects against them, and enforces those requirements.
(ANSI N14.24-1985)

Ultimate product
Any special nuclear material in the form of a product that would not be further processed at that licensed location.
(10CFR74.4)

Ultra-Stokesian
Condition in which flow relative to an object is high enough to be outside the Stokes regime.
(AM-1993)

Ultrasonic nebulizer
A nebulizer employing focused sound waves to aerosolize a liquid into droplets.
(AM-1993)

Ultrasonography
A noninvasive diagnostic radiologic imaging technique that uses acoustic radiation and the acoustic properties of biologic structure to picture the structure and function of various organs and tissues of the body.
(BEIR III)

Unanticipated processes and events
Those processes and events affecting the geologic setting that are judged not to be reasonably likely to occur during the period the intended performance objective must be achieved, but which are nevertheless sufficiently credible to warrant consideration. Unanticipated processes and events may be either natural processes or events or processes and events initiated by human activities other than those activities licensed under this part. Processes and events initiated by human activities may only be found to be sufficiently credible to warrant consideration if it is assumed that:
(1) The monuments provided for by this part are sufficiently permanent to serve their intended purpose;
(2) the value to future generations of potential resources within the site can be assessed adequately under the applicable provisions of this part;
(3) an understanding of the nature of radioactivity, and an appreciation of its hazards, have been retained in some functioning institutions;
(4) institutions are able to assess risk and to take remedial action at a level of social organization and technological competence equivalent to, or superior to, that which was applied in initiating the processes or events concerned; and
(5) relevant records are preserved, and remain accessible, for several hundred years after permanent closure.
(10CFR60.2)

Unattached daughters
The short-lived daughter products of radon that are not attached to the ambient aerosol.
(NCRP 97)

Unattached fraction
The fraction of the potential alpha energy concentration of short-lived radon progeny that is not attached to the ambient aerosol.
(ICRP 65)

Unattached fraction
That fraction of the radon decay products, usually ²¹⁸Po (RaA), which has not yet attached to particles.
(NCRP 103)

Unattached fraction
The fraction of the airborne daughter products of radon or thoron that exists as free atoms, or ions, not attached to particles.
(NCRP 97)

Unattached fraction
That fraction of the radon daughters, usually ²¹⁸Po (Radium A) which has not yet attached to a particle. As a free atom, it has a high probability of being retained within the lung and depositing alpha energy when it decays.
(BEIR IV)

Unattached fraction
The fraction of the airborne daughter products of radon or thoron that exists as free atoms, ions, or clusters not attached to particles.
(NCRP 94)

Unattached fraction
The fraction of the airborne daughter products of radon or thoron that exists as free atoms, or ions, not attached to particles.
(NCRP 45)

Unattached RaA (²¹⁸Po) or RaA*
The fraction of the equilibrium amount of RaA which is not attached to ambient aerosol.
(NCRP 78)

Unattached radon decay product
A radon decay product that is not electrostatically attached to dust or particles in the air. Capable of attaching to lung tissue if inhaled.
(RRM)

Unbiased
A measurement of a random variable is called unbiased if it has zero bias; i. e., if the measured value o f the measurement is equal to the expected value of the property being determined.
(HPS N13.30-1996)

Unbiased
A measurement of a random variable is called unbiased if it has a zero bias; i.e., if the expected value of the measurement is equal to the correct value of the property being measured.
(ANSI N13.30-1989D)

Uncertainty
The lack of sureness or confidence in the predictions of models.
(NCRP 123I)

Uncertainty
The range of values within which the true value is estimated to lie. It is a best estimate of possible inaccuracy due to both random and systematic error.
(HPJ 60)

Uncertainty
A measure of how much confidence one has in the accuracy of a measurement. Both random fluctuations, associated with statistical variations inherent to the measurement process, and systematic errors commonly associated with technique or judgment, may contribute to uncertainty.
(NCRP 112)

Uncertainty
The estimated bounds of the deviation from the mean value, generally expressed as a percent of the mean value. Ordinarily taken as the sum of
(1) the random errors at the 95% confidence level and
(2) the estimated upper limit of systematic error.
(ANSI N42.17A-1989)

Uncertainty
The stated, credible limits of a reported value, taking into account two major components of error:
(1) bias, and
(2) the random error attributed to the measurement process.
(ANSI N15.54-1988)

Uncertainty
The stated, credible limits to the likely inaccuracy of a reported value; includes estimates of errors due to measurements, material variability, and a stated combination of estimates of the limits of conceivable systematic errors at a stated confidence level.
(ANSI N15.22-1987)

Uncertainty
The lack of sureness or confidence in the predictions of models.
(NCRP 76)

Uncertainty
A concept employed to describe the inability of a measurement process to measure exactly the correct value.
(ANSI N15.41-1984)

Uncertainty analysis
Analysis of the uncertainty in model predictions.
(NCRP 123I)

Uncertainty analysis
Analysis of the uncertainty in model predictions.
(NCRP 76)

Uncompressed gas
Gas at a pressure not exceeding the ambient atmospheric pressure at the time and location the containment system is closed. All other radioactive gases are considered to be compressed.
(49CFR173.403)

Uncontrolled area
Any area to which access is not controlled for purposes of radiation protection.
(ANSI N43.1-1978)

Uncontrolled area
Any area to which access is not controlled by the licensee for the purpose of protecting individuals from exposure to radiation and radioactive materials.
(ANSI N303-1978)

Undercutting
Penetration of radiation through cracks of shielding barriers or through thin sections of such barriers (e.g., edges of structures), resulting in a greater dose-equivalent rate than that resulting from passage of radiation through the bulk of the shielding barrier.
(NCRP 51)

Undergoing Processing
Performing active operations on material such as chemical transformation, physical transformation, or transit between such operations, to be differentiated from storage or packaging for shipment.
(10CFR73.2)

Underground facility
The underground structure, including openings and backfill materials, but excluding shafts, boreholes, and their seals.
(10CFR60.2)

Underground uranium mine
A man-made underground excavation made for the purpose of removing material containing uranium for the principal purpose of recovering uranium.
(40CFR61.21)

Undermoderated
Of a multiplying system, having a moderator-to-fuel volume ratio less than that which makes some specified reactor parameter an optimum value.
(ANSI N1.1-1976)

Underwater irradiator
An irradiator in which the sources always remain shielded under water and humans do not have access to the sealed sources or the space subject to irradiation without entering the pool.
(10CFR36.2)

Underwater radiography
Industrial radiography performed when the radiographic exposure device and/or related equipment are beneath the surface of the water.
(10CFR34.3)

Uniform exposure
The irradiation is "uniform" when the ratio of maximum dose to minimum dose does not exceed 1.10 and preferably 1.05.
(ICRU 30)

Uniform isotropic model
A model in which the source and target organs are in a homogeneous absorbing material sufficiently large that edge effects are negligible and the activity is uniformly distributed in the source organs.
(MIRD)

Uniformity
The degree of conformity among repeated measurements of the same quantity obtained with different TLD's.
(ANSI N545-1975)

Unilateral approval
Approval by the competent authority of the country of origin only.
(49CFR173.403)

Unions
Unions, in this context, are those collective bargaining organizations representing trades unique to barge operations, which might include the towing vessel crews, rigging crews, and dockworkers. Unions have some significance in this standard because occasionally work rules provide for special treatment of RAM shipments. Other union work rules provide for minimum crew sizes, specified job classifications, or minimum paid hours, but these are more related to the vessel being serviced than to the specific commodity being handled.
(ANSI N14.24-1985)

Unipolar ion field
Region containing ions of only one polarity.
(AM-1993)

Unique purpose
A project, program, or commercial activity which cannot reasonably be accomplished without the use of HEU fuel, and may include:
(1) A specific experiment, program, or commercial activity (typically long-term) that significantly serves the U.S. national interest and cannot be accomplished without the use of HEU fuel;
(2) Reactor physics or reactor development based explicitly on the use of HEU fuel;
(3) Research projects based on neutron flux levels or spectra attainable only with HEU fuel; or
(4) A reactor core of special design that could not perform its intended function without using HEU fuel.
(10CFR50.2)

Unirradiated thorium
Thorium containing not more than 10^-7 grams uranium-233 per gram of thorium-232.
(49CFR173.403)

Unirradiated uranium
Uranium containing not more than 10^-6 grams plutonium per gram of uranium-235 and a fission product activity of not more than 0.25 millicuries of fission products per gram of uranium-235.
(49CFRR173.403)

Unit of amount of substance (mole)
The mole is the amount of substance of a system which contains as many elementray entities as there are atoms in 0.012 kilogram of carbon 12. When the mole is used, the elementary entities must be specified and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles.
(NCRP 82)

Unit of electrical current (ampere)
The ampere is that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross section, and placed 1 meter apart in vacuum, would produce between these conductors a force equal to 2 x 10^-7 newton per meter of length.
(NCRP 82)

Unit of length (meter)
The meter is the length of the path traversed in vacuum by light during the period of 1/299792458 of a second.
(NCRP 82)

Unit of lumninous intensity (candela)
The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 x 10¹² hertz and that has a radiant intensity in that direction of (1/683) watt per steradian.
(NCRP 82)

Unit of mass (kilogram)
It is equal to the mass of the international prototype of the kilogram.
(NCRP 82)

Unit of thermodynamic temperature (kelvin)
The kelvin is the fraction 1/273.16 of the thermodynamic temperature of the triple point of water.
(NCRP 82)

Unit of time (second)
The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium-133 atom.
(NCRP 82)

Unit process
An identifiable segment or segments of processing activities for which the amounts of input and output SSNM are based on measurements.
(10CFR74.4)

United States
When used in a geographical sense, includes Puerto Rico and all territories and possessions of the United States.
(10CFR55.4)

United States
When used in a geographical sense, includes Puerto Rico and all territories and possessions of the United States.
(10CFR110.2)

United States
When used in a geographical sense, includes Puerto Rico and all territories and possessions of the United States.
(10CFR70.4)

United States
When used in a geographical sense, includes Puerto Rico and all territories and possessions of the United States.
(10CFR50.2)

United States
When used in a geographical sense, includes Puerto Rico and all territories and possessions of the United States.
(10CFR40.4)

United States
When used in a geographical sense, includes Puerto Rico and all territories and possessions of the United States.
(10CFR30.4)

United States eligible list
The list of installations described in §75.2 of this part.
(10CFR75.4)

United States Transuranic Registry (USTR)
The United States Transuranic Registry is a national center for the acquisition and dissemination of information about the metabolism of transuranic radionuclides in humans. This is accomplished by study of the distribution, concentration, and retention of transuranic radionuclides through analysis of tissues obtained at autopsy from transuranic workers. These workers who register with the Registry may permit autopsy tissue to be taken or may donate their bodies to the registry for analysis at death.
(HPJ 60)

Units
Becquerel = 1 disintegration/s = 2.7 x 10^-11 Ci
Curie = 3.7 x 10¹⁰ disintegrations/s = 3.7 x 10¹⁰ Bq
Gray = 1 J/kg = 100 rad
Rad = 100 erg/g = 0.01 Gy
Rem = 0.01 Sievert
Sievert = 100 Rem
(BEIR IV)

Units^a
Becquerel (SI) = 1 disintegration/s = 2.7 x 10^-11 Ci
Curie = 3.7 x 10¹⁰ disintegrations/s = 3.7 x 10¹⁰ Bq
Gray (SI) = 1 J/kg = 100 rad
Rad = 100 erg/g = 0.01 Gy
Rem = 0.01 Sievert
Sievert (SI) = 100 Rem
^aInternational Units are designated SI.
(BEIR V)

Unloading, discharging
The removal of fuel from a nuclear reactor.
(IEC 50-393-1993)

Unopened receipts
Receipts not opened by the licensee, including receipts of sealed sources, and receipts opened only for sampling and subsequently maintained under tampersafing.
(10CFR74.4)

Unplanned release
The accidental release of radioactive material into the environment.
(ICRP 29)

Unprotected source
Sealed source which, for use, is removed or exposed from the shielding by mechanical or other means.
(ANSI N542-1977)

Unqualified opinion
A statement that the material balance report is presented fairly and in conformity with generally accepted safeguards accounting principles consistently applied.
(ANSI N15.11-1983)

Unquenched sample
A popular expression which connotes a counting sample that contains minimum of colored species and chemical impurities which would reduce the light output from the scintillators.
(ANSI N42.15-1980)

Unrefined and unprocessed ore
Ore in its natural form prior to any processing, such as grinding, roasting or beneficiating, or refining.
(10CFR40)

Unrestricted area
An area, access to which is neither limited nor controlled by the licensee.
(10CFR20.1003)

Unrestricted area
Any area, access to which is not controlled by the licensee for purposes of protection of individuals from exposure to radiation and radioactive materials, and any area used for residential quarters.
(10CFR60.2)

Unrestricted linear energy transfer
The unrestricted linear energy transfer is defined by ICRU as

where dE is the energy lost by a charged particle in traversing a distance dl.
(ICRP 60)

Unrestricted release (of property)
Release of an item or real property from DOE control.
(10CFR834.2)

Unsafe failure
Failure which reduces the probability of initiation of appropriate safety action by the protection system should an abnormal condition arise in the reactor.
(IEC 50-393-1993)

Unsaturated zone
The zone between the land surface and the regional water table. Generally, fluid pressure in this zone is less than atmospheric pressure, and some of the voids may contain air or other gases at atmospheric pressure. Beneath flooded areas or in perched water bodies the fluid pressure locally may be greater than atmospheric.
(10CFR60.2)

Unsaturated zone
The portion of a porous medium where the interconnecting interstices are only partially filled with fluid.
(NCRP 76)

Unsaturated zone
The portion of porous media in the ground where the interconnecting interstices are only partially filled with fluid.
(NUREG/CR 3332)

Unscattering (neutron)
Any scattering collision in which the scattered neutron gains kinetic energy. It is important only in the thermal energy range.
(ANSI N1.1-1976)

Unsealed source
A radioactive source which is not a sealed source.
(ANSI N1.1-1976)

Unsharpness
A measure of the inability of the image to reproduce faithfully the boundary of a given contrast.
(NCRP 68)

Unsharpness
A measure of the inability of the image to reproduce faithfully the boundary of a given contrast.
(NCRP 66)

Unstable isotope
A radioisotope.
(USAEC-1974)

Unwanted radiation
Any ionizing radiation other that which the instrument is designed to detect.
(ANSI N323-1978)

Uptake
(1) The passage of material from the location of intake into the body fluids.
(2) The quantity of radioactive material taken up by the systemic circulation.
(3) The quantity of radioactive material taken up by a specific body organ.
(ANSI/HPS N13.22-1995)

Uptake
Quantity of a radionuclide taken up by the systemic circulation, e.g., by absorption from compartments in the respiratory or gastrointestinal tracts.
(NCRP 118)

Uptake
Quantity of a radionuclide taken up by the systemic circulation, e.g., by injection into the blood, by absorption from compartments in the respiratory or gastrointestinal tracts, or by absorption through the skin or through wounds in the skin.
(NCRP 87)

Uraniferous
Of or containing uranium.
(RRM)

Uranium
A naturally radioactive element. In natural ores, it consists of 0.7 percent ²³⁵U, 99.3 percent ²³⁸U, and a small amount of ²³⁴U.
(NCRP 118)

Uranium
Symbol U. A radioactive element with atomic number 92 and, as found in natural ores, an atomic weight of approximately 238. The two principal natural isotopes are ²³⁵U (0.7% of natural uranium), which is fissionable, and ²³⁸U (99.3% of natural uranium). Natural uranium also includes a minute amount of ²³⁴U. Uranium is the basic raw material of nuclear energy.
(HPJ 60)

Uranium
Refers normally to ²³⁸U, although about 0.7% is ²³⁵U, the fissionable component, which is present in the natural state.
(ENV RAD)

Uranium (metallurgy)
(1) Alpha uranium: an allotropic modification of uranium metal which is stable below approximately 660^oC. It has an orthorhombic crystal structure.
(2) Beta uranium: an allotropic modification of uranium which is stable above approximately 770^oC. It has a body-centered cubic structure.
(ANSI N1.1-1976)

Uranium byproduct material or tailings
The waste produced by the extraction or concentration of uranium from any ore processed primarily for its source material content. Ore bodies depleted by uranium solution extraction and which remain underground do not constitute byproduct material for the purposes of this subpart.
(40CFR61.251)

Uranium enrichment
(See isotopic enrichment.)
(USAEC-1974)

Uranium enrichment facility
(1) Any facility used for separating the isotopes for uranium or enriching uranium in the isotope 235, except laboratory scale facilities designed or used for experimental or analytical purposes only; or
(2) Any equipment or device, or important component part especially designed for such equipment or device, capable of separating the isotopes of uranium or enriching uranium in the isotope 235.
(10CFR150.2)

Uranium Enrichment Facility
(1) Any facility used for separating the isotopes of uranium or enriching uranium in the isotope 235, except laboratory scale facilities designed or used for experimental or analytical purposes only; or
(2) Any equipment or device, or important component part especially designed for such equipment or device, capable of separating the isotopes of uranium or enriching uranium in the isotope 235.
(10CFR110.2)

Uranium Enrichment Facility
(1) Any facility used for separating the isotopes for uranium or enriching uranium in the isotope 235, except laboratory scale facilities designed or used for experimental or analytical purposes only; or
(2) Any equipment or device, or important component part especially designed for such equipment or device, capable of separating the isotopes of uranium or enriching uranium in the isotope 235.
(10CFR51.14)

Uranium fuel cycle
The operations of milling of uranium ore, chemical conversion of uranium, isotopic enrichment of uranium, fabrication of uranium fuel, generation of electricity by a light-water cooled nuclear power plant using uranium fuel. and reprocessing of spent uranium fuel to the extent that these activities directly support the production of electrical power for public use. Uranium fuel cycle does not include mining operations, operations at waste disposal sites, transportation of radioactive material in support of these operations, and the reuse of recovered non-uranium special nuclear and by product materials from the cycle.
(10CFR20.1003)

Uranium hexafluoride
[Symbol UF₆] A volatile compound of uranium and fluorine. UF₆ gas is the process fluid in the gaseous diffusion process. (See isotope separation.)
(USAEC-1974)

Uranium milling
Any activity that results in the production of byproduct material as defined in this part.
(10CFR40.4)

Uranium ore
A mineral deposit that can be mined to recover uranium.
(RRM)

Uranium series
The naturally radioactive series that starts with ²³⁸U.
(ENV RAD)

Uranium series (sequence)
The series of nuclides resulting from the radioactive decay of uranium-238, also known as the uranium-radium series. The end product of the series is lead-206. Many man-made nuclides decay into this sequence. (See decay, radioactive; radioactive series.)
(USAEC-1974)

Uranium sinker bar
A weight containing depleted uranium used to pull a logging tool toward the bottom of a well.
(10CFR39.4)

Uranium tetrafluoride
[Symbol UF₄] A solid green compound called green salt. An intermediate product in the production of uranium hexafluoride. (See uranium hexafluoride.)
(USAEC-1974)

Uranium trioxide
[Symbol UO₃] An intermediate product in the refining of uranium, also called orange oxide.
(USAEC-1974)

Uranium urinalysis (urine analysis, urine bioassay, urine assay)
Analysis of urine samples for the presence of uranium.
(ANSI/HPS N13.22-1995)

Uranium-Natural, Depleted, Enriched
(1) Natural uranium means uranium with the naturally occurring distribution of uranium isotopes (approximately 0.711 weight percent uranium-235, and the remainder by weight essentially uranium-238).
(2) Depleted uranium means uranium containing less uranium-235 than the naturally occurring distribution of uranium isotopes.
(3) Enriched uranium means uranium containing more uranium-235 than the naturally occurring distribution of uranium isotopes.
(10CFR71.4)

Use charge
An annual rental charge assessed by the Atomic Energy Commission for inventories of enriched fissionable material.
(USAEC-1974)

Use factor (beam direction factor) (U)
Fraction of the workload during which the useful beam is directed at the barrier under consideration.
(NCRP 102)

Use factor (beam direction factor) (U)
Fraction of time during which the radiation under consideration is directed at a particular barrier.
(NCRP 49)

Use factor (U)
The fraction of the workload during which the useful beam is pointed in the direction under consideration.
(NBS 73)

Use period
The period of time between issuance and readout of the dosimeter in routine operations.
(ANSI N13.15-1985)

Use-as-is
A disposition permitting acceptance of a nonconforming item without remedial action when it can be established that the item is satisfactory for its intended use.
(ANSI N46.2-1978)

Useful beam
See radiation.
(NCRP 102)

Useful beam
See radiation.
(NCRP 49)

Useful beam
All radiation from an x-ray tube assembly which emerges through the port, diaphragm, or cone.
(ANSI N537-1976)

Useful beam
See direct beam.
(NCRP 48)

Useful beam
The radiation that passes through the window, aperture, cone or other collimating device of the source housing.
(NBS 73)

Useful beam
That part of the primary radiation that passes through the aperture or collimator of the radiation source enclosure.
(NBS 55)

Useful beam
That part of the primary radiation that passes through the aperture, cone, or other collimator. In those accelerators on which these devices are not used, the useful beam consists of the primary radiation.
(NBS 54)

Useful beam (of radiation)
That part of the radiation from a target which emerges from the source and its housing through an aperature, diaphragm, or collimator.
(NCRP 51)

Useful energy range
The set or range of continuous energies for a specific type of radiation in which the instrument meets specified criteria.
(ANSI N42.17C-1989)

Useful energy range
The set or range of continuous energies for a specific type of radiation in which the instrument meets specified criteria.
(ANSI N42.17B-1989)

Useful energy range
The set or range of continuous energies for a specific type of radiation in which the instrument meets specified criteria.
(ANSI N42.17A-1989)

Useful life (of a detector)
Operational life, under irradiation and environmental conditions restricted within specified limits, after which the detector characteristics exceed the specified tolerances.
(IEC 50-394-1993)

Useful life (of a sensor)
Operational life under irradiation and environmental conditions restricted within specified limits, after which the sensor characteristics exceed specified tolerances ; expressed in terms of incident particle fluence, time, etc.
(IEC 50-393-1993)

User
Physicians and others responsible for the radiation exposure of patients.
(NCRP 102)

User
The person or organization routinely using the TL dosimetry badge.
(ANSI N13.15-1985)

User
Any individual who personally utilizes or manipulates a source of radiation.
(NCRP 49)

User
A person, organization, or institution having administrative control over one or more installations or mobile sources.
(NBS 73)

Utilization facility
Any nuclear reactor other than one designed or used primarily for the formation of plutonium or U-233.
(10CFR50.2)

Utilization facility
A utilization facility as defined in the regulations contained in Part 50 of this chapter.
(10CFR30.4)

Utilization facility
Any nuclear reactor, other than one that is a production facility, and the following major components of a nuclear reactor:
(1) Pressure vessels designed to contain the core of a nuclear reactor;
(2) Primary coolant pumps;
(3) Fuel charging or discharging machines; and
(4) Control rods.
A utilization facility does not include the steam turbine generator portion of a nuclear power plant.
(10CFR110.2)

Utilization facility
Any nuclear reactor other than one designed or used primarily for the formation of plutonium or U235 and any other equipment or device determined by rule of the Commission to be a utilization facility within the purview of subsection 11cc of the Act.
(10CFR170.3)

Utilization facility
(1) Any equipment or device, except an atomic weapon, determined by rule of the Commission to be capable of making use of special nuclear material in such quantity as to be of significance to the common defense and security, or in such manner as to affect the health and safety of the public, or peculiarly adapted for making use of atomic energy in such quantity as to be of significance to the common defense and security, or in such manner as to affect the health and safety of the public; or
(2) any important component part especially designed for such equipment or device as determined by the Commission.
(10CFR150.2)

Utilized area factor (U)
The effective area of pasture grazed daily by a herbivore.
(NCRP 76)

Note: References shown in ()