wR-radiation weighting factor
Factor related to the quality of the radiation used to weight the absorbed dose.
(ICRP 66)
wT-tissue weighting factor
Factor by which the equivalent dose in tissue or organ is weighted to represent the relative contribution of that tissue or organ to the total detriment due to stochastic effects resulting from uniform irradiation of the whole body.
(ICRP 66)
Waiver
Documented authorization to depart from specified requirements.
(ANSI N46.2-1978)
Wall effect
Effect on the result of the measurement due to the presence of the wall of the detector and which depends on its nature and its thickness.
(IEC 50-394-1993)
Wall loss
Deposition of particles in a sampler on surfaces other than those designed for particle collection.
(AM-1993)
Wall-less ionization chamber
Ionization chamber in which the sensitive volume is not defined by walls, but by the lines of force of the electrical field determined by the form and arrangement of the electrodes, and the potential difference between electrodes.
(IEC 50-394-1993)
Warning dosemeter
A device worn on a person which will give a warning, usually audible, when a predetermined level of dose or dose rate has been exceeded.
(ICRP 35)
Warning signs
See radiation precaution signs.
(NCRP 48)
Warning system (of a nuclear reactor)
A system composed of warning assemblies.
(IEC 50-394-1993)
WASH
Report from Washington Headquarters of AEC or subsequent agency
(RAH)
Washout coefficient
A measure of wet deposition per unit air concentration integrated over the entire height of the air column affected by washout.
(NUREG/CR 3332)
Waste
Those low-level radioactive wastes containing source, special nuclear, or byproduct material that are acceptable for disposal in a land disposal facility. For the purposes of this definition, low-level waste has the same meaning as in the Low-Level Waste Policy Act, that is, radioactive waste not classified as high-level radioactive waste, transuranic waste, spent nuclear fuel, or byproduct material as defined in section 11e.(2) of the Atomic Energy Act (uranium or thorium tailings and waste).
(10CFR61.2)
Waste disposal
Disposal of radioactive waste in such a manner that no one can receive undue exposure.
(NCRP 48)
Waste disposal
The disposition of radioactive waste without specific provision for recovery.
(ANSI N1.1-1976)
Waste disposal, ultimate
A two-step operation that comprises the preparation of radioactive waste for final and permanent disposal and the actual placing of the product at the final site. The term commonly applies to the disposal of waste of high activity.
(ANSI N1.1-1976)
Waste form
The radioactive waste materials and any encapsulating or stabilizing matrix.
(10CFR60.2)
Waste package
The waste form and any containers, shielding, packing and other absorbent materials immediately surrounding an individual waste container.
(10CFR60.2)
Waste, radioactive
Useless material contaminated with radioactive substance. It may result from patient's vomitting or excretion, from an accidental spill, or from a planned clean-up procedure.
(NCRP 48)
Waste, radioactive
Equipment and materials (from nuclear operations) which are radioactive and for which there is no further use. Wastes are generally classified as highlevel (having radioactivity concentrations of hundreds to thousands of curies per gallon or cubic foot), low level (in the range of 1 microcurie per gallon or cubic foot), or intermediate (between these extremes).
(USAEC-1974)
Watchman
An individual, not necessarily uniformed or armed with a firearm, who provides protection for a plant and the special nuclear material therein in the course of performing other duties.
(10CFR73.2)
Water boiler
A research reactor whose core consists of a small metal tank filled with uranium fuel in an aqueous solution. Heat is removed by a cooling coil in the core. Not to be confused with boiling water reactor.
(USAEC-1974)
Water carrier
The water carrier is the public or private organization that supplies the barge, towing vessel, and crew. In some instances, the water carrier will consist of a barge operator and a subcontracted towing vessel operator. The water carrier provides transportation services only, loading and securing of the cargo is the responsibility of the slapper, although the function may be delegated to a rigging company by the shipper. In general, the shipper is responsible for the barge during loading and unloading, with the water carrier taking responsibility once underway.
(ANSI N14.24-1985)
Water table
That surface in a groundwater body at which the water pressure is atmospheric.
(10CFR60.2)
Water table
The surface of an unconfined groundwater body at which the water pressure is atmospheric (e.g., the level reached in dug wells.
(NCRP 76)
Water, activated
A transient, chemically reactive state created in water by absorbed ionizing radiation.
(RHH)
Water, heavy
Popular name for water of which the hydrogen component is deuterium.
(RHH)
Watt
The unit of power equal to one joule per second. 1W = 1J/1s
(RHH)
Watt
A unit of power in the cgs system equal to 10,000,000 (or 107) ergs/sec. The unit is used in this Handbook in the specification of radiation intensity and dose rates.
(NBS 55)
Wave impedance
See impedence, wave.
(NCRP 67)
Wave motion
The transmission of a periodic motion or vibration through a medium or empty space.
Transverse: Wave motion in which the vibration is perpendicular to the direction of propagation. Longitudinal: Wave motion in which the vibration is parallel to the direction of propagation.
(RHH)
Wave, electromagnetic
A wave characterized by variations of electric and magnetic fields.
(NCRP 67)
Wave, incident
A wave, traveling through a medium in a specified direction, directed toward a reference point, toward a discontinuity in the medium, or toward a medium of different propagation characteristics.
(NCRP 67)
Wave, plane
A wave with parallel planar surfaces of constant phase.
(NCRP 67)
Wave, reflected
A wave in a medium produced by a wave in that medium incident on a discontinuity in the medium or on a boundary of a different medium, excluding the incident wave.
(NCRP 67)
Wave, spherical
A wave with concentric spherical surfaces of constant phase.
(NCRP 67)
Wave, standing
See standing wave.
(NCRP 67)
Wave, transmitted (refracted wave)
A wave produced by an incident wave that continues beyond a discontinuity in a medium or beyond a boundary between two mediums.
(NCRP 67)
Wave, transverse electric (TE)
An electromagnetic wave in which the electric field strength is everywhere perpendicular to the direction of propagation.
(NCRP 67)
Wave, transverse electromagnetic (TEM)
An electromagnetic wave in which the electric field strength is everywhere perpendicular to the magnetic field strength and both lie in a plane perpendicular to the direction of propagation.
(NCRP 67)
Wave, transverse magnetic (TM)
An electromagnetic wave in which the magnetic field strength is everywhere perpendicular to the direction of propagation.
(NCRP 67)
Waveguide
An enclose system capable of guiding electromagentic waves from one place to another. Usually it consists of a hollow metallic tube or solid dielectric material.
(NCRP 67)
Wavelength
Distance between any two similar points of two consecutive waves (l) for electromagnetic radiation. The wavelength is equal to the velocity of light (c) divided by the frequency of the wave (v), l = c/v. The "effective wavelength" is the wavelength of monochromatic x rays which would undergo the same percentage attenuation in a specified filter as the heterogeneous beam under consideration.
(RHH)
Wavelength shifter
Photofluorescent compound used with a scintillating material to absorb photons and emit photons of a longer wavelength, with the purpose of causing more efficient use of the photons by a photomultiplier tube or photocell.
(IEC 50-394-1993)
Weak mixing
A low level of turbulence in the lower atmosphere which inhibits lateral and vertical mixing between an emitted pollutant and the clean air. Often occurring during the night hours, this condition is associated with a positive vertical temperature gradient in the atmosphere.
(NCRP 94)
Weak mixing
A low level of turbulence in the lower atmosphere which inhibits lateral and vertical mixing between an emitted pollutant and the clean air. Often occurring during the night hours, this condition is associated with a positive vertical temperature gradient in the atmosphere.
(NCRP 45)
Wedge factor
The ratio of the absorbed dose at a point on the beam axis (q.v.) with the wedge filer in place, to the dose rate at the same place with the filter removed.
(ICRU 24)
Wedge filter
See filter.
(ICRU 24)
Wedge isodose angle
The angle through which an isodose curve is tilted at the central ray of a beam at a specified depth.
(ICRU 24)
Week
Seven consecutive days starting on Sunday.
(10CFR20.1003)
Week
A period of seven consecutive days.
(10CFR835.2-1998)
Week, calendar
Seven consecutive days.
(NCRP 51)
Week, calendar
Seven consecutive days.
(NCRP 38)
Week, calendar
7 consecutive days.
(NBS 63)
Week, work
A combination of time intervals adding up to 40 hours within 7 consecutive days.
(NCRP 51)
Week, work
A combination of time intervals adding up to 40 hours within 7 consecutive days.
(NCRP 38)
Week, work
Any combination of time intervals adding up to 40 hours within 7 consecutive days.
(NBS 63)
Weekly dose
The dose received in any period of 7 consecutive days.
(NBS 66)
Weighted committed dose equivalent (wTHE50,T)
The product of the weighting factor and the committed dose equivalent for a specified tissue.
(ICRP 30)
Weighting
Application of a factor to one particle activity to obtain another activity, e.g., count, surface, volume, or mass.
(AM-1993)
Weighting factor
A factor, wT, representing the proportion of the stochastic risk resulting from a particular tissue to the total risk to the individual when the whole body is irradiated uniformly. The following weighting factors are applicable for this standard:
| Organ or Tissue, T | Weighting Factor, wT |
|---|---|
| Gonads | 0.25 |
| Red Bone Marrow | 0.12 |
| Lung | 0.12 |
| Breast | 0.15 |
| Thyroid | 0.03 |
| Bone Surfaces | 0.03 |
| Remainder | 0.3 |
A value of wT = 0.06 is applicable to each of the five organs or tissues (excluding the skin and the lens of the eye) of the remainder that receive the highest dose equivalents. The exposure of all other remaining tissues is neglected.
(HPS N13.41-1997)
Weighting factor
A tissue-specific factor representing the fraction of the total health risk resulting from uniform whole-body irradiation, attributable to the particular tissue or organ. Weighting factors set forth in 10 CFR § 835.2 are generally appropriate for evaluating doses to members of the public.
(10CFR834.2)
Weighting factor
A factor which represents the proportion of the total stochastic (cancer plus genetic) risk resulting from irradiation to tissue (T) to the total risk, when the whole body is irradiated uniformly. (See ICRP 26, 1977 for values).
(NCRP 93)
Weighting factor (wT)
The ratio of the stochastic risk arising from tissue T to the total risk when the whole body is irradiated uniformly.
(ICRP 30)
Weighting factor (wT)
For an organ of tissue (T) is the proportion of the risk of stochastic effects when the whole body is irradiated uniformly. For calculating the effective dose equivalent, the values of wT are:
| Organ or Tissue | wT |
|---|---|
| Gonads | 0.25 |
| Breast | 0.15 |
| Red Bone Marrow | 0.12 |
| Lung | 0.12 |
| Thyroid | 0.03 |
| Bone Surface | 0.03 |
| Remainder | 0.30 |
| Whole Body | 1.00 |
Weighting Factor (wT)
The fraction of the overall health risk, resulting from uniform, whole body irradiation, attributable to specific tissue (T). The dose equivalent to tissue (HT) is multiplied by the appropriate weighting factor to obtain the effective dose equivalent contribution from that tissue.
(10CFR835.2-1998)
Weighting factor (wT)
The fraction of the overall health risk, resulting from uniform, whole body irradiation, attributable to specific tissue (T). The dose equivalent to tissue, T, is multiplied by the appropriate weighting factor to obtain the effective dose equivalent contribution from that tissue. The weighting factors are as follows:
| Organ or tissue | wT |
|---|---|
| Gonads | 0.25 |
| Breast | 0.15 |
| Red bone marrow | 0.12 |
| Lung | 0.12 |
| Thyroid | 0.03 |
| Bone surfaces | 0.03 |
| Remainder1 | 0.30 |
| Whole body2 | 1.00 |
1 "Remainder" means the five other organs or tissues with the highest dose (e.g., liver, kidney, spleen, thymus, adrenal, pancreas, stomach, small intestine, and upper large intestine). The weighting factor of each remaining organ or tissue is 0.06.
2 For the case of uniform external irradiation of the whole body, a weighting factor (wT) equal to 1 may be used in determination of the effective dose equivalent.
(10CFR835.2-1993)
Weighting factors
Fractions used in the calculation of annual and committed effective dose equivalent to equate the risk arising from the irradiation of a tissue to the total risk when the whole body is uniformly irradiated. The weighting factors as defined by NCRP Report No. 91 (NCRP, 1987) are:
| Organ or tissue | Weighting Factora |
|---|---|
| Gonads | 0.25 |
| Breasts | 0.15 |
| Red bone marrow | 0.12 |
| Lungs | 0.12 |
| Thyroid | 0.03 |
| Bone surfaces | 0.03 |
| Remainderb | 0.30 |
| Skinc | 0.01 |
a Factors should not be adjusted to maintain a total of one.
b Remainder means the five other organs with the highest dose (i.e., liver, kidney, spleen, thymus, adrenals, pancreas, stomach, small intestine, upper large intestine or lower large intestine, but excluding skin, lens of the eye and extremities). The weighting factor for each such organ is 0.06.
c Factor to be applied to the mean dose equivalent over the entire skin surface.
(NCRP 114)
Weightless mount
Material on which source material is mounted which results in negligible scattering from the mount.
(NCRP 112)
Welding helmet
A device designed to provide protection for the eyes and face against intense radiant energy and molten metal splatter encountered in the welding and cutting of metals.
(ANSI Z88.2-1980)
Well
A drilled hole in which well logging may be performed. As used in this part, "well" includes drilled holes for the purpose of oil, gas, mineral, groundwater, or geological exploration.
(10CFR39.4)
Well logging
All operations involving the lowering and raising of measuring devices or tools which contain licensed material or are used to detect licensed materials in wells for the purpose of obtaining information about the well or adjacent formations which may be used in oil, gas, mineral, groundwater, or geological exploration.
(10CFR39.4)
Well-moderated
Of a neutronic system: having a moderator-to-fuel volume ratio such that the lower-energy part of the neutron spectrum can be approximated by a Maxwell distribution and such that the thermal neutron temperature is close to the real temperature of the system.
(ANSI N1.1-1976)
Well-type detector
Radiation detector with a well in the sensitive volume in which emitters to be measured are placed, thus providing a large solid angle, of nearly 4p
steradians, for high efficiency detection of beta, gamma or X ray emitters.
(IEC 50-394-1993)
Well-type ionization chamber
Ionization chamber designed for measuring the activity of beta, X or gamma emitters of appreciable volume where the solid angle for detection of the radiation is nearly 4p
steradians, and comprising a central cylindrical well in which the sources to be measured are placed.
(IEC 50-394-1993)
Wet criticality
Reactor criticality achieved with the coolant present.
(USAEC-1974)
Wet deposition
The deposition resulting from the scavenging of particles and gases by precipitation.
(NUREG/CR 3332)
Whole body
For purposes of external exposure, head, trunk (including male gonads), arms above the elbow, or legs above the knee.
(10CFR20.1003)
Whole body
For the purposes of external exposure, head, trunk (including male gonads), arms above and including the elbow, or legs above and including the knee.
(10CFR835.2-1993)
Whole body dose equivalent (Hwb)
The dose equivalent associated with the uniform irradiation of the whole body.
(NCRP 114)
Whole body dose equivalent (Hwb)
The dose equivalent associated with the uniform irradiation of the whole body.
(NCRP 107)
Whole body dose equivalent (Hwb)
The dose equivalent associated with the uniform irradiation of the whole body.
(NCRP 102)
Whole body dose equivalent (Hwb)
The dose equivalent associated with the uniform irradiation of the whole body. Hwb = HE.
(NCRP 101)
Whole-body counter
A device used to identify and measure the radiation in the body (body burden) of human beings and animals; it uses heavy shielding to keep out background radiation and ultrasensitive scintillation detectors and electronic equipment.
(HPJ 60)
Whole-body counter
A device used to identify and measure the radioactivity in the body (body burden) of human beings and animals; it uses heavy shielding to keep out background radiation and measures the body burden with ultrasensitive scintillation detectors and electronic equipment.
(NCRP 65)
Whole-body counter
A device used to identify and measure the radiation in the body (body burden) of human beings and animals; it uses heavy shielding to keep out background radiation and ultrasensitive scintillation detectors and electronic equipment.
(ANSI N1.1-1976)
Whole-body counter
A device used to identify and measure the radiation in the body (body burden) of human beings and animals; it uses heavy shielding to keep out background radiation and ultrasensitive scintillation detectors and electronic equipment.
(USAEC-1974)
Whole-body counting
A technique to measure the internally deposited radionuclides within the body by employing an external radiation detector. Results are generally expressed in the form of percent of a maximum permissible body burden of the nuclide in question. This technique can identify and measure accurately normal body radiation as well as those that are taken into the body due to such things as injection, ingestion, and inhalation from atmospheric releases, medical diagnostic and therapeutic techniques, etc.
(HPJ 60)
Whole-body dose
In this report, used to describe an absorbed dose or dose equivalent from penetrating radiation when the magnitude of the absorbed dose (or dose equivalent) is essentially uniform over the whole body.
(NCRP 94)
Whole-body dose
In this report, used to describe an absorbed dose or dose equivalent from penetrating radiation when the magnitude of the absorbed dose (or dose equivalent) is essentially uniform (within a factor of two) over the whole body.
(NCRP 45)
Whole-body dose equivalent (Hwb)
The dose equivalent that results when the whole body is irradiated and taken, when the irradiation is uniform, as equivalent to the effective dose equivalent, HE.
(NCRP 93)
Whole-body gamma spectrum analyzer
System, including a whole-body internal contamination meter and an amplitude analyzer, and equipment for digital data processing, designed to identify radionuclides present in the human body and to evaluate their respective activities.
(IEC 50-394-1993)
Whole-body internal contamination meter
Equipment, including one or more radiation detectors heavily shielded against ambient ionizing radiation, together with associated assemblies and sub-assemblies, designed to measure the total photon emission from the body.
(IEC 50-394-1993)
Wiener spectra
The most common summary measure of noise is its variance: the mean square departure from the average value. When this variance is analyzed into it Fourier components, the result is called the noise power spectrum or Wiener spectrum.
(NCRP 66)
Wiener spectrum
The frequency content of the noise. The Wiener spectrum, also referred to as the NPS can be expressed in one dimension as:
where n(x) is the noise at location x.
For stationary noise, the Wiener spectrum is the Fourier transform of the noise autocorrelation function.
(ICRU 54)
Wigner effect
In reactor operation, the change in physical properties of graphite resulting from the displacement of lattice atoms by high-energy neutrons and other energetic particles.
(IEC 50-393-1993)
Wigner effect
In reactor operation, the change in physical properties of graphite resulting from the displacement of lattice atoms by high-energy neutrons and other energetic particles.
(ANSI N1.1-1976)
Wigner energy
The energy stored in graphite as a result of its Wigner effect.
(ANSI N1.1-1976)
Wilson cloud chamber
Cloud chamber in which supersaturation of the vapor is produced for a short time by a rapid expansion.
(IEC 50-394-1993)
Window (of a detector)
Portion of a detector which is designed to facilitate the penetration of the required radiation.
(IEC 50-394-1993)
Window counter tube
Counter tube with a portion of its envelope, called the window, of sufficiently low absorption to permit the detection of low penetrating power radiation.
(IEC 50-394-1993)
Window indicator
A device on a cartridge or canister that visually denotes the service life of the cartridge or canister.
(ANSI Z88.2-1980)
Window indicator
A colorimetric indicator for gas mask canisters which denotes the service life for a particular gas.
(ANSI Z88.2-1969)
Windowless photomultiplier tube, windowless multiplier phototube
Photomultiplier tube in which no material is interposed between the source of photons and the target used as photocathode.
(IEC 50-394-1993)
Wipe
See smear.
(ANSI N1.1-1976)
Wipe test
A test for radioactive contamination. A surface is wiped with a small paper or cloth which is then tested for radioactivity.
(NCRP 105)
Wipe test
A test for radioactive contamination in which the suspected surface or area is wiped with a filter paper (or othr substance) which is then immediately tested for the presence of radioactivity.
(NCRP 48)
Work clothing
Work clothing consists of items of apparel, such as coverall, cloth caps, and canvas gloves, that do not provide a significantly greater degree of protection from contamination with toxic materials than do ordinary street clothes.
(ANSI N7.2-1963)
Work factor
The fraction of the personnel working time per week during which an accelerator may be operated without exposing personnel in a given occupied space to weekly radiation levels, above those defined as permissible.
(NBS 55)
Work permits
Work permits are authorizations from the appropriate plant officials to perform specific jobs.
(ANSI N7.2-1963)
Work restriction level
An activity level in the body or excreta at which action is taken to prevent further exposure by removing the employee from areas of potential exposure until exposure evaluation is completed and the exposure rate is such that the employee is approved to return to uranium work.
(ANSI/HPS N13.22-1995)
Worker
An individual engaged in activities licensed by the Commission and controlled by a licensee, but does not include the licensee.
(10CFR19.3)
Working level
Any combination of short-lived radon daughters (for radon-222: polonium-216, lead-214, bismuth-214, and polonium-214; and for radon 222: polonium-216. lead-212, bismuth 212, and polonium-212) in 1 liter of air that will result in the ultimate emission of 1.3 x 105 MeV of potential alpha particle energy.
(10CFR20.1003)
Working level
Any combination of the short-lived progeny of radon in one litre of air that will result in the emission of 1.3 x 105 MeV of potential alpha energy.
(ICRP 65)
Working level
Any combination of short-lived radon daughters in one liter of air that will result in the emission of 1.3 x 105 MeV of alpha-particle energy.
(ANSI N42.17B-1989)
Working level
Any combination of short lived radon daughters in 1 liter of air that will result in the ultimate emission of 1.3 x 105 MeV of potential alpha energy. This number was chosen because it is approximately the alpha energy released from the decay of daughters in equilibrium with 100 picocuries of 222Rn.
(BEIR IV)
Working level (WL)
The potential alpha energy concentrations of radon decay products in 1 liter of air, without regard to the degree of equilibrium, that will result in the eventual emission of 1.3 x 105 MeV of alpha particle energy.
(10CFR834.2)
Working level (WL)
A unit of air concentration of potential alpha energy released from radon and its short-lived progeny. One working level is any combination of short-lived radon daughter products in one liter of air that will result in the emission of 1.3 x 105 MeV (million electron volts) of potential alpha energy. 1 WL will result in the emission of 2.08 x 10-5 joules of energy.
(NCRP 118)
Working level (WL)
A unit of air concentration of potential alpha energy released from radon and its daughters. One Working Level is that concentration of radon daughters which has a potential alpha energy release of 1.3 x 105 MeV per liter of air or 2.08 x 10-5 J/m³.
(NCRP 101)
Working level (WL)
Any combination of short-lived radon decay products in one liter of air that will result in the ultimate emission of 1.3 x 105 MeV of potential alpha particle energy.
(NCRP 103)
Working level (WL)
Any combination of short-lived radon daughter products in on liter of air that will result in the emission of 1.3 x 105 MeV of potential alpha energy.
(NCRP 97)
Working level (WL)
Any combination of short-lived radon daughter products in on liter of air that will result in the emission of 1.3 x 105 MeV of potential alpha energy.
(FGR 11)
Working level (WL)
A unit of air concentration of potential alpha energy released from radon and its daughters. One Working Level is that concentration of radon daughters which has a potential alpha energy release of 1.3 x 105 MeV per liter of air or 2.08 x 10-5 J/m³.
(NCRP 93)
Working level (WL)
Any combination of short-lived radon daughters in one liter of air that will result in the emission of 1.3 x 105 MeV of potential alpha energy.
(NCRP 78)
Working level (WL)
Any combination of short-lived radon daughters in one liter of air that will result in the emission of 1.3 x 105 MeV of potential alpha energy.
(BEIR III)
Working level (WL)
Any combination of short-lived radon daughters in 1 liter of air that will result in the ultimate emission of 1.3 x 105 MeV of potential alpha energy.
(BEIR I)
Working level monitor
Monitors used to measure the alpha-energy deposition from the decay of radon daughters. Calibrated in units of working levels.
(ANSI N42.17B-1989)
Working level month
An exposure to 1 working level for 170 hours (2,000 working hours per year/12 months per year = approximately 170 hours per month).
(10CFR20.1003)
Working level month
The cumulative exposure from breathing an atmosphere at a concentration of I WL for a working month of 170 hours.
(ICRP 65)
Working level month (WLM)
The exposure to the equivalent radon daughter concentration of one working level for 170 hours.
(10CFR834.2)
Working level month (WLM)
A unit of exposure to air concentrations of potential alpha energy released from radon daughters. One working level month is defined as the exposure to an average of 1 WL for a working month of 170 hours or 3.5 x 10-3 Jh/m³.
(NCRP 101)
Working level month (WLM)
The cumulative exposure equivalent to exposure to one working level for a working month (170 hours).
(NCRP 103)
Working level month (WLM)
A unit of exposure corresponding to a concentration of radon decay products of 1 WL for 170 working hours (1 work month).
(FGR 11)
Working level month (WLM)
The cumulative exposure equivalent to exposure at one working level for a working month of 170 hours.
(NCRP 97)
Working level month (WLM)
A unit of exposure to air concentrations of potential alpha energy released from radon daughters. One working level month is defined as the exposure to an average of 1 WL for a working month of 170 hours or 3.5 x 10-3 Jh/m³.
(NCRP 93)
Working level month (WLM)
The cumulative exposure equivalent to exposure to one working level for a working month (170 hours).
(NCRP 78)
Working level month (WLM)
Inhalation of air with a concentration of 1 WL of radon daughters for 170 working hours results in an exposure of 1 WLM.
(BEIR I)
Working level ratio (WLR)
A ratio that compares the concentration of decay products to the concentration of radon. The WLR may be computed using the formula:
(ENV RAD)
Working papers
Records kept by the auditor of the procedures followed, the tests performed, the information obtained, and the conclusions reached pertinent to the audit.
(ANSI N15.38-1982)
Working standard
In this report, a stable or easily reproducible source or radioactivity used to test the operating status of an instrument.
(NCRP 97)
Workload
Total weekly exposure dose of the useful beam at 1 m from the nearest surface of the source (r/week at 1 m).
(NBS 73)
Workload
The output of a radiation machine or a radioactive source integrated over a suitable time and expressed in appropriate units.
(NBS 59)
Workload (W)
The degree of use of a radiation source. For x-ray machines operating at tube potentials below 500 kV, the workload is usually expressed in milliampere minutes per week. For gamma beam therapy sources and for photon-emitting equipment operating at 500 kV or above, the workload is usually stated in terms of the weekly kerma of the useful beam at one meter from the source and is expressed in grays per week at one meter.
(NCRP 107)
Workload (W)
The degree of use of a radiation source. For x-ray machines operating at tube potentials below 500 kV, the workload is usually expressed in milliampere minutes per week. For gamma beam therapy sources and for photon-emitting equipment operating at 500 kV or above, the workload is usually stated in terms of the weekly kerma of the useful beam at one meter from the source and is expressed in grays per week at one meter.
(NCRP 102)
Workload (W)
The degree of use of an x-ray or gamma-ray source. For therapy x-ray machines, W is usually expressed in terms of mA min week-1 (below 4 MeV) and rem m² week-1 (above 4 Mev).
(NCRP 51)
Workload (W)
The degree of use of an x-ray or gamma-ray source. For x-ray equipment operating below 4 MV, the weekly workload is usually expressed in milliampere-minutes. For gamma-ray beam therapy sources, and for x-ray equipment operating at 4 MV or above, the workload is usually stated in terms of the weekly exposure of the useful beam at one meter from the source and is expressed in roentgens (R m²).
(NCRP 49)
Worst plausible use scenario
Any scenario deemed credible, over the long term, e.g., beyond several hundred years.
(10CFR834.2)
Written directive
An order in writing for a specific patient or human research subject, dated and signed by an authorized user prior to the administration of a radiopharmaceutical or radiation, except as specified in paragraph (6) of this definition, containing the following information:
(1) For any administration of quantities greater than 30 microcuries of either sodium iodide I-125 or I-131: the dosage;
(2) For a therapeutic administration of a radiopharmaceutical other than sodium iodide I-125 or I-131: the radiopharmaceutical, dosage, and route of administration;
(3) For gamma stereotactic radiosurgery: target coordinates, collimator size, plug pattern, and total dose;
(4) For teletherapy: the total dose, dose per fraction, treatment site, and overall treatment period;
(5) For high-dose-rate remote afterloading brachytherapy: the radioisotope, treatment site, and total dose; or
(6) For all other brachytherapy:
(i) Prior to implantation: the radioisotope, number of sources, and source strengths; and
(ii) After implantation but prior to completion of the procedure: the radioisotope, treatment site, and total source strength and exposure time (or, equivalently, the total dose).
(10CFR35.2)
Note: References shown in ()