[Code of Federal Regulations]
[Title 10, Volume 4]
[Revised as of January 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 10CFR835.2]
[Page 534-539]
TITLE 10--ENERGY
CHAPTER III--DEPARTMENT OF ENERGY
PART 835_OCCUPATIONAL RADIATION PROTECTION--Table of Contents
Subpart A_General Provisions
Sec. 835.2 Definitions.
(a) As used in this part:
Accountable sealed radioactive source means a sealed radioactive
source having a half-life equal to or greater than 30 days and an
isotopic activity equal to or greater than the corresponding value
provided in appendix E of this part.
Airborne radioactive material or airborne radioactivity means
radioactive material dispersed in the air in the form of dusts, fumes,
particulates, mists, vapors, or gases.
Airborne radioactivity area means any area, accessible to
individuals, where:
(1) The concentration of airborne radioactivity, above natural
background, exceeds or is likely to exceed the derived air concentration
(DAC) values listed in appendix A or appendix C of this part; or
(2) An individual present in the area without respiratory protection
could receive an intake exceeding 12 DAC-hours in a week.
ALARA means ``As Low As is Reasonably Achievable,'' which is the
approach to radiation protection to manage and control exposures (both
individual and collective) to the work force and to the general public
to as low as is reasonable, taking into account social, technical,
economic, practical, and public policy considerations. As used in this
part, ALARA is not a dose limit but a process which has the objective of
attaining doses as far below the applicable limits of this part as is
reasonably achievable.
Annual limit on intake (ALI) means the derived limit for the amount
of radioactive material taken into the body of an adult worker by
inhalation or ingestion in a year. ALI is the smaller value of intake of
a given radionuclide in a year by the reference man (ICRP Publication
23) that would result in a committed effective dose equivalent of 5 rems
(0.05 sievert) or a committed dose equivalent of 50 rems (0.5 sievert)
to any individual organ or tissue. ALI values for intake by ingestion
and inhalation of selected radionuclides are
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based on Table 1 of the U.S. Environmental Protection Agency's Federal
Guidance Report No. 11, Limiting Values of Radionuclide Intake and Air
Concentration and Dose Conversion Factors for Inhalation, Submersion,
and Ingestion, published September 1988. This document is available from
the National Technical Information Service, Springfield, VA.
Background means radiation from:
(i) Naturally occurring radioactive materials which have not been
technologically enhanced;
(ii) Cosmic sources;
(iii) Global fallout as it exists in the environment (such as from
the testing of nuclear explosive devices);
(iv) Radon and its progeny in concentrations or levels existing in
buildings or the environment which have not been elevated as a result of
current or prior activities; and
(v) Consumer products containing nominal amounts of radioactive
material or producing nominal amounts of radiation.
Bioassay means the determination of kinds, quantities, or
concentrations, and, in some cases, locations of radioactive material in
the human body, whether by direct measurement or by analysis, and
evaluation of radioactive materials excreted or removed from the human
body.
Calibration means to adjust and/or determine either:
(i) The response or reading of an instrument relative to a standard
(e.g., primary, secondary, or tertiary) or to a series of conventionally
true values; or
(ii) The strength of a radiation source relative to a standard
(e.g., primary, secondary, or tertiary) or conventionally true value.
Contamination area means any area, accessible to individuals, where
removable surface contamination levels exceed or are likely to exceed
the removable surface contamination values specified in appendix D of
this part, but do not exceed 100 times those values.
Contractor means any entity under contract with the Department of
Energy with the responsibility to perform activities at a DOE site or
facility.
Controlled area means any area to which access is managed by or for
DOE to protect individuals from exposure to radiation and/or radioactive
material.
Declared pregnant worker means a woman who has voluntarily declared
to her employer, in writing, her pregnancy for the purpose of being
subject to the occupational dose limits to the embryo/fetus as provided
at Sec. 835.206. This declaration may be revoked, in writing, at any
time by the declared pregnant worker.
Derived air concentration (DAC) means, for the radionuclides listed
in appendix A of this part, the airborne concentration that equals the
ALI divided by the volume of air breathed by an average worker for a
working year of 2000 hours (assuming a breathing volume of 2400 m\3\).
For the radionuclides listed in appendix C of this part, the air
immersion DACs were calculated for a continuous, non-shielded exposure
via immersion in a semi-infinite atmospheric cloud. The value is based
upon the derived airborne concentration found in Table 1 of the U.S.
Environmental Protection Agency's Federal Guidance Report No. 11,
Limiting Values of Radionuclide Intake and Air Concentration and Dose
Conversion Factors for Inhalation, Submersion, and Ingestion, published
September 1988. This document is available from the National Technical
Information Service, Springfield, VA.
Derived air concentration-hour (DAC-hour) means the product of the
concentration of radioactive material in air (expressed as a fraction or
multiple of the DAC for each radionuclide) and the time of exposure to
that radionuclide, in hours.
DOE activity means an activity taken for or by DOE in a DOE
operation or facility that has the potential to result in the
occupational exposure of an individual to radiation or radioactive
material. The activity may be, but is not limited to, design,
construction, operation, or decommissioning. To the extent appropriate,
the activity may involve a single DOE facility or operation or a
combination of facilities and operations, possibly including an entire
site or multiple DOE sites.
Entrance or access point means any location through which an
individual could gain access to areas controlled
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for the purposes of radiation protection. This includes entry or exit
portals of sufficient size to permit human entry, irrespective of their
intended use.
General employee means an individual who is either a DOE or DOE
contractor employee; an employee of a subcontractor to a DOE contractor;
or an individual who performs work for or in conjunction with DOE or
utilizes DOE facilities.
High contamination area means any area, accessible to individuals,
where removable surface contamination levels exceed or are likely to
exceed 100 times the removable surface contamination values specified in
appendix D of this part.
High radiation area means any area, accessible to individuals, in
which radiation levels could result in an individual receiving a deep
dose equivalent in excess of 0.1 rem (0.001 sievert) in 1 hour at 30
centimeters from the radiation source or from any surface that the
radiation penetrates.
Individual means any human being.
Member of the public means an individual who is not a general
employee. An individual is not a ``member of the public'' during any
period in which the individual receives an occupational dose.
Minor means an individual less than 18 years of age.
Monitoring means the measurement of radiation levels, airborne
radioactivity concentrations, radioactive contamination levels,
quantities of radioactive material, or individual doses and the use of
the results of these measurements to evaluate radiological hazards or
potential and actual doses resulting from exposures to ionizing
radiation.
Nonstochastic effects means effects due to radiation exposure for
which the severity varies with the dose and for which a threshold
normally exists (e.g., radiation-induced opacities within the lens of
the eye).
Occupational dose means an individual's ionizing radiation dose
(external and internal) as a result of that individual's work
assignment. Occupational dose does not include doses received as a
medical patient or doses resulting from background radiation or
participation as a subject in medical research programs.
Person means any individual, corporation, partnership, firm,
association, trust, estate, public or private institution, group,
Government agency, any State or political subdivision of, or any
political entity within a State, any foreign government or nation or
other entity, and any legal successor, representative, agent or agency
of the foregoing; provided that person does not include the Department
or the United States Nuclear Regulatory Commission.
Radiation means ionizing radiation: alpha particles, beta particles,
gamma rays, X-rays, neutrons, high-speed electrons, high-speed protons,
and other particles capable of producing ions. Radiation as used in this
part, does not include non-ionizing radiation, such as radio- or micro-
waves, or visible, infrared, or ultraviolet light.
Radiation area means any area accessible to individuals in which
radiation levels could result in an individual receiving a deep dose
equivalent in excess of 0.005 rem (0.05 millisievert) in 1 hour at 30
centimeters from the source or from any surface that the radiation
penetrates.
Radioactive material area means any area within a controlled area,
accessible to individuals, in which items or containers of radioactive
material exist and the total activity of radioactive material exceeds
the applicable values provided in appendix E of this part.
Radioactive material transportation means the movement of
radioactive material by aircraft, rail, vessel, or highway vehicle when
such movement is subject to Department of Transportation regulations or
DOE Orders that govern such movements. Radioactive material
transportation does not include preparation of material or packagings
for transportation, monitoring required by this part, storage of
material awaiting transportation, or application of markings and labels
required for transportation.
Radiological area means any area within a controlled area defined in
this section as a ``radiation area,'' ``high radiation area,'' ``very
high radiation area,'' ``contamination area,'' ``high
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contamination area,'' or ``airborne radioactivity area.''
Radiological worker means a general employee whose job assignment
involves operation of radiation producing devices or working with
radioactive materials, or who is likely to be routinely occupationally
exposed above 0.1 rem (0.001 sievert) per year total effective dose
equivalent.
Real-time air monitoring means measurement of the concentrations or
quantities of airborne radioactive materials on a continuous basis.
Respiratory protective device means an apparatus, such as a
respirator, worn by an individual for the purpose of reducing the
individual's intake of airborne radioactive materials.
Sealed radioactive source means a radioactive source manufactured,
obtained, or retained for the purpose of utilizing the emitted
radiation. The sealed radioactive source consists of a known or
estimated quantity of radioactive material contained within a sealed
capsule, sealed between layer(s) of non-radioactive material, or firmly
fixed to a non-radioactive surface by electroplating or other means
intended to prevent leakage or escape of the radioactive material.
Sealed radioactive sources do not include reactor fuel elements, nuclear
explosive devices, and radioisotope thermoelectric generators.
Source leak test means a test to determine if a sealed radioactive
source is leaking radioactive material.
Stochastic effects means malignant and hereditary diseases for which
the probability of an effect occurring, rather than its severity, is
regarded as a function of dose without a threshold for radiation
protection purposes.
Very high radiation area means any area accessible to individuals in
which radiation levels could result in an individual receiving an
absorbed dose in excess of 500 rads (5 grays) in one hour at 1 meter
from a radiation source or from any surface that the radiation
penetrates.
Week means a period of seven consecutive days.
Year means the period of time beginning on or near January 1 and
ending on or near December 31 of that same year used to determine
compliance with the provisions of this part. The starting and ending
date of the year used to determine compliance may be changed provided
that the change is made at the beginning of the year and that no day is
omitted or duplicated in consecutive years.
(b) As used in this part to describe various aspects of radiation
dose:
Absorbed dose (D) means the energy absorbed by matter from ionizing
radiation per unit mass of irradiated material at the place of interest
in that material. The absorbed dose is expressed in units of rad (or
gray) (1 rad = 0.01 gray).
Committed dose equivalent (HT,50) means the dose
equivalent calculated to be received by a tissue or organ over a 50-year
period after the intake of a radionuclide into the body. It does not
include contributions from radiation sources external to the body.
Committed dose equivalent is expressed in units of rem (or sievert).
Committed effective dose equivalent (HE,50) means the sum
of the committed dose equivalents to various tissues in the body
(HT,50), each multiplied by the appropriate weighting factor
(wT)--that is, HE,50 = [Sigma] wT
HT,50. Committed effective dose equivalent is expressed in
units of rem (or sievert).
Cumulative total effective dose equivalent means the sum of all
total effective dose equivalent values recorded for an individual, where
available, for each year occupational dose was received, beginning
January 1, 1989.
Deep dose equivalent means the dose equivalent derived from external
radiation at a depth of 1 cm in tissue.
Dose is a general term for absorbed dose, dose equivalent, effective
dose equivalent, committed dose equivalent, committed effective dose
equivalent, or total effective dose equivalent as defined in this part.
Dose equivalent (H) means the product of absorbed dose (D) in rad
(or gray) in tissue, a quality factor (Q), and other modifying factors
(N). Dose equivalent is expressed in units of rem (or sievert) (1 rem =
0.01 sievert).
Effective dose equivalent (HE) means the summation of the products
of the dose equivalent received by specified tissues of the body (HT)
and the appropriate weighting factor (wT)--that is,
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HE = [Sigma]wTHT. It includes the dose from radiation sources internal
and/or external to the body. For purposes of compliance with this part,
deep dose equivalent to the whole body may be used as effective dose
equivalent for external exposures. The effective dose equivalent is
expressed in units of rem (or sievert).
External dose or exposure means that portion of the dose equivalent
received from radiation sources outside the body (i.e., ``external
sources'').
Extremity means hands and arms below the elbow or feet and legs
below the knee.
Internal dose or exposure means that portion of the dose equivalent
received from radioactive material taken into the body (e.g., ``internal
sources'').
Lens of the eye dose equivalent means the external exposure of the
lens of the eye and is taken as the dose equivalent at a tissue depth of
0.3 cm.
Quality factor (Q) means the modifying factor used to calculate the
dose equivalent from the absorbed dose; the absorbed dose (expressed in
rad or gray) is multiplied by the appropriate quality factor.
(i) The quality factors to be used for determining dose equivalent
in rem are as follow:
Quality Factors
------------------------------------------------------------------------
Quality
Radiation type factor
------------------------------------------------------------------------
X-rays, gamma rays, positrons, electrons (including tritium 1
beta particles)............................................
Neutrons, [le]10 keV........................................ 3
Neutrons, 10 keV................................. 10
Protons and singly-charged particles of unknown energy with 10
rest mass greater than one atomic mass unit................
Alpha particles and multiple-charged particles (and 20
particles of unknown charge) of unknown energy.............
------------------------------------------------------------------------
When spectral data are insufficient to identify the energy of the
neutrons, a quality factor of 10 shall be used.
(ii) When spectral data are sufficient to identify the energy of the
neutrons, the following mean quality factor values may be used:
Quality Factors for Neutrons
[Mean quality factors, Q (maximum value in a 30-cm dosimetry phantom),
and values of neutron flux density that deliver in 40 hours, a maximum
dose equivalent of 0.1 rem (0.001 sievert). Where neutron energy falls
between listed values, the more restrictive mean quality factor shall be
used.]
------------------------------------------------------------------------
Neutron
Mean flux
Neutron energy (MeV) quality density
factor (cm-2s-1)
------------------------------------------------------------------------
2.5x10-8 thermal................................. 2 680
1x10-7........................................... 2 680
1x10-6........................................... 2 560
1x10-5........................................... 2 560
1x10-4........................................... 2 580
1x10-3........................................... 2 680
1x10-2........................................... 2.5 700
1x10-1........................................... 7.5 115
5x10-1........................................... 11 27
1................................................ 11 19
2.5.............................................. 9 20
5................................................ 8 16
7................................................ 7 17
10............................................... 6.5 17
14............................................... 7.5 12
20............................................... 8 11
40............................................... 7 10
60............................................... 5.5 11
1x10 2........................................... 4 14
2x10 2........................................... 3.5 13
3x10 2........................................... 3.5 11
4x10 2........................................... 3.5 10
------------------------------------------------------------------------
Shallow dose equivalent means the dose equivalent deriving from
external radiation at a depth of 0.007 cm in tissue.
Total effective dose equivalent (TEDE) means the sum of the
effective dose equivalent (for external exposures) and the committed
effective dose equivalent (for internal exposures).
Weighting factor (wT) means 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. The
weighting factors are as follows:
Weighting Factors For Various Organs and Tissues
------------------------------------------------------------------------
Weighting
Organs or tissues, T factor, wT
------------------------------------------------------------------------
Gonads..................................................... 0.25
Breasts.................................................... 0.15
Red bone marrow............................................ 0.12
Lungs...................................................... 0.12
Thyroid.................................................... 0.03
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Bone surfaces.............................................. 0.03
Remainder 1................................................ 0.30
Whole body 2............................................... 1.00
------------------------------------------------------------------------
1 ``Remainder'' means the five other organs or tissues, excluding the
skin and lens of the eye, with the highest dose (e.g., liver, kidney,
spleen, thymus, adrenal, pancreas, stomach, small intestine, and upper
large intestine). The weighting factor for 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.
Whole body means, for the purposes of external exposure, head, trunk
(including male gonads), arms above and including the elbow, or legs
above and including the knee.
(c) Terms defined in the Atomic Energy Act and not defined in this
part are used consistent with the meanings given in the Act.
[58 FR 65485, Dec. 14, 1993, as amended at 63 FR 59680, Nov. 4, 1998]