# 10 C.F.R. § 20.1003 (2026): Definitions

> Federal · Regulations · In force

URL: https://www.frixlaw.com/law-library/statutes/CFR_T10_P20_S20_1003

## Section

- **Citation:** 10 C.F.R. § 20.1003 (2026)
- **Heading:** Definitions
- **Jurisdiction:** Federal
- **Kind:** Regulations
- **Status:** In force
- **Text as of:** August 14, 2026
- **Source:** Compiled text
- **Location:** Title 10 CFR: Energy / Chapter I / Part 20 / Subpart A / § 20.1003: § 20.1003   Definitions.

## Text

As used in this part: Absorbed dose means the energy imparted by ionizing radiation per unit mass of irradiated material. The units of absorbed dose are the rad and the gray (Gy). Accelerator-produced radioactive material means any material made radioactive by a particle accelerator. Act means the Atomic Energy Act of 1954 (42 U.S.C. 2011 et seq. ), as amended. Activity is the rate of disintegration (transformation) or decay of radioactive material. The units of activity are the curie (Ci) and the becquerel (Bq). Adult means an individual 18 or more years of age. Airborne radioactive material means radioactive material dispersed in the air in the form of dusts, fumes, particulates, mists, vapors, or gases. Airborne radioactivity area means a room, enclosure, or area in which airborne radioactive materials, composed wholly or partly of licensed material, exist in concentrations— (1) In excess of the derived air concentrations (DACs) specified in appendix B, to §§ 20.1001-20.2401, or (2) To such a degree that an individual present in the area without respiratory protective equipment could exceed, during the hours an individual is present in a week, an intake of 0.6 percent of the annual limit on intake (ALI) or 12 DAC-hours. Air-purifying respirator means a respirator with an air-purifying filter, cartridge, or canister that removes specific air contaminants by passing ambient air through the air-purifying element. ALARA (acronym for “as low as is reasonably achievable”) means making every reasonable effort to maintain exposures to radiation as far below the dose limits in this part as is practical consistent with the purpose for which the licensed activity is undertaken, taking into account the state of technology, the economics of improvements in relation to state of technology, the economics of improvements in relation to benefits to the public health and safety, and other societal and socioeconomic considerations, and in relation to utilization of nuclear energy and licensed materials in the public interest

## Nearby sections

- [10 C.F.R. § 20.1001 (2026) § 20.1001   Purpose.](https://www.frixlaw.com/law-library/statutes/CFR_T10_P20_S20_1001.md)
- [10 C.F.R. § 20.1002 (2026) § 20.1002   Scope.](https://www.frixlaw.com/law-library/statutes/CFR_T10_P20_S20_1002.md)
- [10 C.F.R. § 20.1003 (2026) § 20.1003   Definitions.](https://www.frixlaw.com/law-library/statutes/CFR_T10_P20_S20_1003.md)
- [10 C.F.R. § 20.1004 (2026) § 20.1004   Units of radiation dose.](https://www.frixlaw.com/law-library/statutes/CFR_T10_P20_S20_1004.md)
- [10 C.F.R. § 20.1005 (2026) § 20.1005   Units of radioactivity.](https://www.frixlaw.com/law-library/statutes/CFR_T10_P20_S20_1005.md)
- [10 C.F.R. § 20.1006 (2026) § 20.1006   Interpretations.](https://www.frixlaw.com/law-library/statutes/CFR_T10_P20_S20_1006.md)
- [10 C.F.R. § 20.1007 (2026) § 20.1007   Communications.](https://www.frixlaw.com/law-library/statutes/CFR_T10_P20_S20_1007.md)
- [10 C.F.R. § 20.1008 (2026) § 20.1008   Implementation.](https://www.frixlaw.com/law-library/statutes/CFR_T10_P20_S20_1008.md)
- [10 C.F.R. § 20.1009 (2026) § 20.1009   Information collection requirements: OMB approval.](https://www.frixlaw.com/law-library/statutes/CFR_T10_P20_S20_1009.md)

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Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/CFR_T10_P20_S20_1003. Check the current official text before relying on it. Not legal advice.