Nuclear Regulatory Commission § 20.1003
§ 20.1002 Scope. posures to radiation as far below the The regulations in this part apply to dose limits in this part as is practical persons licensed by the Commission to consistent with the purpose for which receive, possess, use, transfer, or dis- the licensed activity is undertaken, pose of byproduct, source, or special taking into account the state of tech- nuclear material or to operate a pro- nology, the economics of improve- duction or utilization facility under ments in relation to state of tech- parts 30 through 35, 39, 40, 50, 60, 61, 70, nology, the economics of improve- or 72 of this chapter. The limits in this ments in relation to benefits to the part do not apply to doses due to back- public health and safety, and other so- ground radiation, to exposure of pa- cietal and socioeconomic consider- tients to radiation for the purpose of ations, and in relation to utilization of medical diagnosis or therapy, to expo- nuclear energy and licensed materials sure from individuals administered ra- in the public interest. dioactive material and released in ac- Annual limit on intake (ALI) means cordance with § 35.75, or to exposure the derived limit for the amount of ra- from voluntary participation in medi- dioactive material taken into the body cal research programs. of an adult worker by inhalation or in- gestion in a year. ALI is the smaller [62 FR 4132, Jan. 29, 1997] value of intake of a given radionuclide in a year by the reference man that § 20.1003 Definitions. would result in a committed effective As used in this part: dose equivalent of 5 rems (0.05 Sv) or a Absorbed dose means the energy im- committed dose equivalent of 50 rems parted by ionizing radiation per unit (0.5 Sv) to any individual organ or tis- mass of irradiated material. The units sue. (ALI values for intake by inges- of absorbed dose are the rad and the tion and by inhalation of selected gray (Gy). radionuclides are given in Table 1, Col- Act means the Atomic Energy Act of umns 1 and 2, of appendix B to 1954 (42 U.S.C. 2011 et seq.), as amended. §§ 20.1001–20.2401). Activity is the rate of disintegration Background radiation means radiation (transformation) or decay of radio- from cosmic sources; naturally occur- active material. The units of activity ring radioactive material, including are the curie (Ci) and the becquerel radon (except as a decay product of (Bq). source or special nuclear material); Adult means an individual 18 or more and global fallout as it exists in the en- years of age. vironment from the testing of nuclear Airborne radioactive material means explosive devices or from past nuclear radioactive material dispersed in the accidents such as Chernobyl that con- air in the form of dusts, fumes, particu- tribute to background radiation and lates, mists, vapors, or gases. are not under the control of the li- Airborne radioactivity area means a censee. ‘‘Background radiation’’ does room, enclosure, or area in which air- not include radiation from source, by- borne radioactive materials, composed product, or special nuclear materials wholly or partly of licensed material, regulated by the Commission. exist in concentrations— Bioassay (radiobioassay) means the (1) In excess of the derived air con- determination of kinds, quantities or centrations (DACs) specified in appen- concentrations, and, in some cases, the dix B, to §§ 20.1001–20.2401, or locations of radioactive material in the (2) To such a degree that an individ- human body, whether by direct meas- ual present in the area without res- urement (in vivo counting) or by analy- piratory protective equipment could sis and evaluation of materials ex- exceed, during the hours an individual creted or removed from the human is present in a week, an intake of 0.6 body. percent of the annual limit on intake Byproduct material means— (ALI) or 12 DAC-hours. (1) Any radioactive material (except ALARA (acronym for ‘‘as low as is special nuclear material) yielded in, or reasonably achievable’’) means making made radioactive by, exposure to the every reasonable effort to maintain ex- radiation incident to the process of
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producing or utilizing special nuclear her employer, in writing, of her preg- material; and nancy and the estimated date of con- (2) The tailings or wastes produced ception. by the extraction or concentration of Decommission means to remove a fa- uranium or thorium from ore processed cility or site safely from service and primarily for its source material con- reduce residual radioactivity to a level tent, including discrete surface wastes that permits— resulting from uranium solution ex- (1) Release of the property for unre- traction processes. Underground ore stricted use and termination of the li- bodies depleted by these solution ex- cense; or traction operations do not constitute (2) Release of the property under re- ‘‘byproduct material’’ within this defi- stricted conditions and the termi- nition. nation of the license. Class (or lung class or inhalation class) Deep-dose equivalent (H ), which ap- means a classification scheme for in- d plies to external whole-body exposure, haled material according to its rate of is the dose equivalent at a tissue depth clearance from the pulmonary region of 1 cm (1000 mg/cm2). of the lung. Materials are classified as D, W, or Y, which applies to a range of Department means the Department of clearance half-times: for Class D (Days) Energy established by the Department of less than 10 days, for Class W of Energy Organization Act (Pub. L. 95– (Weeks) from 10 to 100 days, and for 91, 91 Stat. 565, 42 U.S.C. 7101 et seq.) to Class Y (Years) of greater than 100 the extent that the Department, or its days. duly authorized representatives, exer- Collective dose is the sum of the indi- cises functions formerly vested in the vidual doses received in a given period U.S. Atomic Energy Commission, its of time by a specified population from Chairman, members, officers, and com- exposure to a specified source of radi- ponents and transferred to the U.S. En- ation. ergy Research and Development Ad- Commission means the Nuclear Regu- ministration and to the Administrator latory Commission or its duly author- thereof pursuant to sections 104 (b), (c), ized representatives. and (d) of the Energy Reorganization Act of 1974 (Pub. L. 93–438, 88 Stat. 1233 Committed dose equivalent (HT,50) means the dose equivalent to organs or at 1237, 42 U.S.C. 5814) and retransferred tissues of reference (T) that will be re- to the Secretary of Energy pursuant to ceived from an intake of radioactive section 301(a) of the Department of En- material by an individual during the ergy Organization Act (Pub. L. 95–91, 91 50-year period following the intake. Stat 565 at 577–578, 42 U.S.C. 7151). Committed effective dose equivalent Derived air concentration (DAC) means (HE,50) is the sum of the products of the the concentration of a given radio- weighting factors applicable to each of nuclide in air which, if breathed by the the body organs or tissues that are ir- reference man for a working year of radiated and the committed dose 2,000 hours under conditions of light equivalent to these organs or tissues work (inhalation rate 1.2 cubic meters (HE,50 = Σ wT HT,50). of air per hour), results in an intake of Constraint (dose constraint) means a one ALI. DAC values are given in Table value above which specified licensee 1, Column 3, of appendix B to §§ 20.1001– actions are required. 20.2401. Controlled area means an area, out- Derived air concentration-hour (DAC- side of a restricted area but inside the hour) is the product of the concentra- site boundary, access to which can be tion of radioactive material in air (ex- limited by the licensee for any reason. pressed as a fraction or multiple of the Critical Group means the group of in- derived air concentration for each dividuals reasonably expected to re- radionuclide) and the time of exposure ceive the greatest exposure to residual to that radionuclide, in hours. A li- radioactivity for any applicable set of censee may take 2,000 DAC-hours to circumstances. represent one ALI, equivalent to a Declared pregnant woman means a committed effective dose equivalent of woman who has voluntarily informed 5 rems (0.05 Sv).
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Distinguishable from background issued by the Environmental Protec- means that the detectable concentra- tion Agency (EPA) under the authority tion of a radionuclide is statistically of the Atomic Energy Act of 1954, as different from the background con- amended, that impose limits on radi- centration of that radionuclide in the ation exposures or levels, or concentra- vicinity of the site or, in the case of tions or quantities of radioactive mate- structures, in similar materials using rial, in the general environment out- adequate measurement technology, side the boundaries of locations under survey, and statistical techniques. the control of persons possessing or Dose or radiation dose is a generic using radioactive material. term that means absorbed dose, dose Government agency means any execu- equivalent, effective dose equivalent, tive department, commission, inde- committed dose equivalent, committed pendent establishment, corporation effective dose equivalent, or total ef- wholly or partly owned by the United fective dose equivalent, as defined in States of America, which is an instru- other paragraphs of this section. mentality of the United States, or any Dose equivalent (HT) means the prod- board, bureau, division, service, office, uct of the absorbed dose in tissue, qual- officer, authority, administration, or ity factor, and all other necessary other establishment in the executive modifying factors at the location of in- branch of the Government. terest. The units of dose equivalent are Gray [See § 20.1004]. the rem and sievert (Sv). High radiation area means an area, ac- Dosimetry processor means an individ- cessible to individuals, in which radi- ual or organization that processes and ation levels could result in an individ- evaluates individual monitoring equip- ual receiving a dose equivalent in ex- ment in order to determine the radi- cess of 0.1 rem (1 mSv) in 1 hour at 30 ation dose delivered to the equipment. centimeters from the radiation source Effective dose equivalent (HE) is the or from any surface that the radiation sum of the products of the dose equiva- penetrates. lent to the organ or tissue (HT) and the Individual means any human being. weighting factors (wT) applicable to Individual monitoring means— each of the body organs or tissues that (1) The assessment of dose equivalent are irradiated (HE = Σ wT HT). by the use of devices designed to be Embryo/fetus means the developing worn by an individual; human organism from conception until (2) The assessment of committed ef- the time of birth. fective dose equivalent by bioassay (see Entrance or access point means any lo- Bioassay) or by determination of the cation through which an individual time-weighted air concentrations to could gain access to radiation areas or which an individual has been exposed, to radioactive materials. This includes i.e., DAC-hours; or entry or exit portals of sufficient size (3) The assessment of dose equivalent to permit human entry, irrespective of by the use of survey data. their intended use. Individual Monitoring Devices (individ- Exposure means being exposed to ion- ual monitoring equipment) means devices izing radiation or to radioactive mate- designed to be worn by a single individ- rial. ual for the assessment of dose equiva- External dose means that portion of lent such as film badges, the dose equivalent received from radi- thermoluminescent dosimeters (TLDs), ation sources outside the body. pocket ionization chambers, and per- Extremity means hand, elbow, arm sonal (‘‘lapel’’) air sampling devices. below the elbow, foot, knee, or leg Internal dose means that portion of below the knee. the dose equivalent received from ra- Eye dose equivalent applies to the ex- dioactive material taken into the body. ternal exposure of the lens of the eye License means a license issued under and is taken as the dose equivalent at the regulations in parts 30 through 36, a tissue depth of 0.3 centimeter (300 mg/ 39, 40, 50, 60, 61, 70, or 72 of this chapter. cm2). Licensed material means source mate- Generally applicable environmental ra- rial, special nuclear material, or by- diation standards means standards product material received, possessed,
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used, transferred or disposed of under a group, Government agency other than general or specific license issued by the the Commission or the Department of Commission. Energy (except that the Department Licensee means the holder of a li- shall be considered a person within the cense. meaning of the regulations in 10 CFR Limits (dose limits) means the per- chapter I to the extent that its facili- missible upper bounds of radiation ties and activities are subject to the li- doses. censing and related regulatory author- Lost or missing licensed material means ity of the Commission under section licensed material whose location is un- 202 of the Energy Reorganization Act known. It includes material that has of 1974 (88 Stat. 1244), the Uranium Mill been shipped but has not reached its Tailings Radiation Control Act of 1978 destination and whose location cannot (92 Stat. 3021), the Nuclear Waste Pol- be readily traced in the transportation icy Act of 1982 (96 Stat. 2201), and sec- system. tion 3(b)(2) of the Low-Level Radio- Member of the public means any indi- active Waste Policy Amendments Act vidual except when that individual is of 1985 (99 Stat. 1842)), any State or any receiving an occupational dose. political subdivision of or any political Minor means an individual less than entity within a State, any foreign gov- 18 years of age. ernment or nation or any political sub- Monitoring (radiation monitoring, ra- division of any such government or na- diation protection monitoring) means tion, or other entity; and the measurement of radiation levels, (2) Any legal successor, representa- concentrations, surface area concentra- tive, agent, or agency of the foregoing. tions or quantities of radioactive mate- Planned special exposure means an in- rial and the use of the results of these frequent exposure to radiation, sepa- measurements to evaluate potential rate from and in addition to the annual exposures and doses. dose limits. Nonstochastic effect means health ef- Public dose means the dose received fects, the severity of which varies with the dose and for which a threshold is by a member of the public from expo- believed to exist. Radiation-induced sure to radiation or radioactive mate- cataract formation is an example of a rial released by a licensee, or to any nonstochastic effect (also called a de- other source of radiation under the terministic effect). control of a licensee. Public dose does NRC means the Nuclear Regulatory not include occupational dose or doses Commission or its duly authorized rep- received from background radiation, resentatives. from any medical administration the Occupational dose means the dose re- individual has received, from exposure ceived by an individual in the course of to individuals administered radioactive employment in which the individual’s material and released in accordance assigned duties involve exposure to ra- with § 35.75, or from voluntary partici- diation or to radioactive material from pation in medical research programs. licensed and unlicensed sources of radi- Quality Factor (Q) means the modify- ation, whether in the possession of the ing factor (listed in tables 1004(b).1 and licensee or other person. Occupational 1004(b).2 of § 20.1004) that is used to de- dose does not include dose received rive dose equivalent from absorbed from background radiation, from any dose. medical administration the individual Quarter means a period of time equal has received, from exposure to individ- to one-fourth of the year observed by uals administered radioactive mate- the licensee (approximately 13 rials and released in accordance with consective weeks), providing that the § 35.75, from voluntary participation in beginning of the first quarter in a year medical research programs, or as a coincides with the starting date of the member of the public. year and that no day is omitted or du- Person means— plicated in consecutive quarters. (1) Any individual, corporation, part- Rad (See § 20.1004). nership, firm, association, trust, es- Radiation (ionizing radiation) means tate, public or private institution, alpha particles, beta particles, gamma
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rays, x-rays, neutrons, high-speed elec- Shallow-dose equivalent (HS), which trons, high-speed protons, and other applies to the external exposure of the particles capable of producing ions. Ra- skin or an extremity, is taken as the diation, as used in this part, does not dose equivalent at a tissue depth of include non-ionizing radiation, such as 0.007 centimeter (7 mg/cm2) averaged radio- or microwaves, or visible, infra- over an area of 1 square centimeter. red, or ultraviolet light. Sievert (See § 20.1004). Radiation area means an area, acces- Site boundary means that line beyond sible to individuals, in which radiation which the land or property is not levels could result in an individual re- owned, leased, or otherwise controlled ceiving a dose equivalent in excess of by the licensee. 0.005 rem (0.05 mSv) in 1 hour at 30 cen- Source material means— timeters from the radiation source or (1) Uranium or thorium or any com- from any surface that the radiation bination of uranium and thorium in penetrates. any physical or chemical form; or Reference man means a hypothetical (2) Ores that contain, by weight, one- aggregation of human physical and twentieth of 1 percent (0.05 percent), or physiological characteristics arrived at more, of uranium, thorium, or any by international consensus. These combination of uranium and thorium. characteristics may be used by re- Source material does not include spe- searchers and public health workers to cial nuclear material. standardize results of experiments and to relate biological insult to a common Special nuclear material means— base. (1) Plutonium, uranium-233, uranium Rem (See § 20.1004). enriched in the isotope 233 or in the Residual radioactivity means radio- isotope 235, and any other material activity in structures, materials, soils, that the Commission, pursuant to the groundwater, and other media at a site provisions of section 51 of the Act, de- resulting from activities under the li- termines to be special nuclear mate- censee’s control. This includes radio- rial, but does not include source mate- activity from all licensed and unli- rial; or censed sources used by the licensee, (2) Any material artificially enriched but excludes background radiation. It by any of the foregoing but does not in- also includes radioactive materials re- clude source material. maining at the site as a result of rou- Stochastic effects means health effects tine or accidental releases of radio- that occur randomly and for which the active material at the site and previous probability of the effect occurring, burials at the site, even if those burials rather than its severity, is assumed to were made in accordance with the pro- be a linear function of dose without visions of 10 CFR part 20. threshold. Hereditary effects and can- Respiratory protective device means an cer incidence are examples of apparatus, such as a respirator, used to stochastic effects. reduce the individual’s intake of air- Survey means an evalulation of the borne radioactive materials. radiological conditions and potential Restricted area means an area, access hazards incident to the production, to which is limited by the licensee for use, transfer, release, disposal, or pres- the purpose of protecting individuals ence of radioactive material or other against undue risks from exposure to sources of radiation. When appropriate, radiation and radioactive materials. such an evaluation includes a physical Restricted area does not include areas survey of the location of radioactive used as residential quarters, but sepa- material and measurements or calcula- rate rooms in a residential building tions of levels of radiation, or con- may be set apart as a restricted area. centrations or quantities of radioactive Sanitary sewerage means a system of material present. public sewers for carrying off waste Total Effective Dose Equivalent (TEDE) water and refuse, but excluding sewage means the sum of the deep-dose equiva- treatment facilities, septic tanks, and lent (for external exposures) and the leach fields owned or operated by the committed effective dose equivalent licensee. (for internal exposures).
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Unrestricted area means an area, ac- Whole body means, for purposes of ex- cess to which is neither limited nor ternal exposure, head, trunk (including controlled by the licensee. male gonads), arms above the elbow, or Uranium fuel cycle means the oper- legs above the knee. ations of milling of uranium ore, chem- Working level (WL) is any combina- ical conversion of uranium, isotopic tion of short-lived radon daughters (for enrichment of uranium, fabrication of radon-222: polonium-218, lead-214, bis- uranium fuel, generation of electricity muth-214, and polonium-214; and for by a light-water-cooled nuclear power radon-220: polonium-216, lead-212, bis- plant using uranium fuel, and reproc- muth-212, and polonium-212) in 1 liter essing of spent uranium fuel to the ex- of air that will result in the ultimate tent that these activities directly sup- emission of 1.3×10 5 MeV of potential port the production of electrical power alpha particle energy. for public use. Uranium fuel cycle does Working level month (WLM) means an not include mining operations, oper- exposure to 1 working level for 170 ations at waste disposal sites, trans- hours (2,000 working hours per year/12 portation of radioactive material in months per year=approximately 170 support of these operations, and the hours per month). reuse of recovered non-uranium special Year means the period of time begin- nuclear and byproduct materials from ning in January used to determine the cycle. compliance with the provisions of this Very high radiation area means an part. The licensee may change the area, accessible to individuals, in starting date of the year used to deter- which radiation levels could result in an individual receiving an absorbed mine compliance by the licensee pro- dose in excess of 500 rads (5 grays) in 1 vided that the change is made at the hour at 1 meter from a radiation source beginning of the year and that no day or from any surface that the radiation is omitted or duplicated in consecutive penetrates. years.
NOTE: At very high doses received at high [56 FR 23391, May 21, 1991, as amended at 57 dose rates, units of absorbed dose (e.g., rads FR 57878, Dec. 8, 1992; 58 FR 7736, Feb. 9, 1993; and grays) are appropriate, rather than units 60 FR 36043, July 13, 1995; 60 FR 48625, Sept. of dose equivalent (e.g., rems and sieverts)). 20, 1995; 61 FR 65127, Dec. 10, 1996; 62 FR 4133, Jan. 29, 1997; 62 FR 39087, July 21, 1997] Week means 7 consecutive days start- ing on Sunday. § 20.1004 Units of radiation dose. Weighting factor w , for an organ or T (a) Definitions. As used in this part, tissue (T) is the proportion of the risk the units of radiation dose are: of stochastic effects resulting from ir- radiation of that organ or tissue to the Gray (Gy) is the SI unit of absorbed total risk of stochastic effects when dose. One gray is equal to an absorbed the whole body is irradiated uniformly. dose of 1 Joule/kilogram (100 rads). For calculating the effective dose Rad is the special unit of absorbed dose. One rad is equal to an absorbed equivalent, the values of wT are: dose of 100 ergs/gram or 0.01 joule/kilo- ORGAN DOSE WEIGHTING FACTORS gram (0.01 gray). Rem is the special unit of any of the Organ or tissue wT quantities expressed as dose equiva- Gonads ...... 0.25 lent. The dose equivalent in rems is Breast ...... 0.15 equal to the absorbed dose in rads mul- Red bone marrow ...... 0.12 Lung ...... 0.12 tiplied by the quality factor (1 rem=0.01 Thyroid ...... 0.03 sievert). Bone surfaces ...... 0.03 Sievert is the SI unit of any of the Remainder ...... 1 0.30 Whole Body ...... 2 1.00 quantities expressed as dose equiva- lent. The dose equivalent in sieverts is 1 0.30 results from 0.06 for each of 5 ``remainder'' organs (excluding the skin and the lens of the eye) that receive the equal to the absorbed dose in grays highest doses. multiplied by the quality factor (1 2 For the purpose of weighting the external whole body dose (for adding it to the internal dose), a single weighting Sv=100 rems). factor, wT=1.0, has been specified. The use of other weighting factors for external exposure will be approved on a case-by- (b) As used in this part, the quality case basis until such time as specific guidance is issued. factors for converting absorbed dose to
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