Current through Bulletin 2024-06, March 15, 2024
(1) For
purposes of assessing dose used to determine compliance with occupational dose
equivalent limits, the licensee or registrant shall, when required pursuant to
Section
R313-15-502,
take suitable and timely measurements of:
(a)
Concentrations of radioactive materials in air in work areas; or
(b) Quantities of radionuclides in the body;
or
(c) Quantities of radionuclides
excreted from the body; or
(d)
Combinations of these measurements.
(2) Unless respiratory protective equipment
is used, as provided in Section
R313-15-703,
or the assessment of intake is based on bioassays, the licensee or registrant
shall assume that an individual inhales radioactive material at the airborne
concentration in which the individual is present.
(3) When specific information on the physical
and biochemical properties of the radionuclides taken into the body or the
behavior of the material in an individual is known, the licensee or registrant
may:
(a) Use that information to calculate
the committed effective dose equivalent, and, if used, the licensee or
registrant shall document that information in the individual's record;
and
(b) Upon prior approval of the
Director, adjust the DAC or ALI values to reflect the actual physical and
chemical characteristics of airborne radioactive material, for example, aerosol
size distribution or density; and
(c) Separately assess the contribution of
fractional intakes of Class D, W, or Y compounds of a given radionuclide to the
committed effective dose equivalent. See Appendix B of
10 CFR
20.1001 to 20.2402,(2010), which is
incorporated by reference.
(4) If the licensee or registrant chooses to
assess intakes of Class Y material using the measurements given in Subsections
R313-15-204(1)(b) or R313-15-204(1)(c), the licensee or registrant may delay
the recording and reporting of the assessments for periods up to seven months,
unless otherwise required by Section
R313-15-1202
or Section
R313-15-1203.
This delay permits the licensee or registrant to make additional measurements
basic to the assessments.
(5) If
the identity and concentration of each radionuclide in a mixture are known, the
fraction of the DAC applicable to the mixture for use in calculating DAC-hours
shall be either:
(a) The sum of the ratios of
the concentration to the appropriate DAC value, that is, D, W, or Y, from
Appendix B of
10 CFR
20.1001 to 20.2402,(2010), which is
incorporated by reference, for each radionuclide in the mixture; or
(b) The ratio of the total concentration for
all radionuclides in the mixture to the most restrictive DAC value for any
radionuclide in the mixture.
(6) If the identity of each radionuclide in a
mixture is known, but the concentration of one or more of the radionuclides in
the mixture is not known, the DAC for the mixture shall be the most restrictive
DAC of any radionuclide in the mixture.
(7) When a mixture of radionuclides in air
exists, a licensee or registrant may disregard certain radionuclides in the
mixture if:
(a) The licensee or registrant
uses the total activity of the mixture in demonstrating compliance with the
dose limits in Section
R313-15-201
and in complying with the monitoring requirements in Subsection
R313-15-502(2),
and
(b) The concentration of any
radionuclide disregarded is less than ten percent of its DAC, and
(c) The sum of these percentages for all of
the radionuclides disregarded in the mixture does not exceed 30
percent.
(8) When
determining the committed effective dose equivalent, the following information
may be considered:
(a) In order to calculate
the committed effective dose equivalent, the licensee or registrant may assume
that the inhalation of one ALI, or an exposure of 2,000 DAC-hours, results in a
committed effective dose equivalent of 0.05 Sv (5 rem) for radionuclides that
have their ALIs or DACs based on the committed effective dose
equivalent.
(b) For an ALI and the
associated DAC determined by the nonstochastic organ dose limit of 0.50 Sv (50
rem), the intake of radionuclides that would result in a committed effective
dose equivalent of 0.05 Sv (5 rem), that is, the stochastic ALI, is listed in
parentheses in Table I of Appendix B of
10 CFR
20.1001 to 20.2402,(2010), which is
incorporated by reference. The licensee or registrant may, as a simplifying
assumption, use the stochastic ALI to determine committed effective dose
equivalent. However, if the licensee or registrant uses the stochastic ALI, the
licensee or registrant shall also demonstrate that the limit in Subsection
R313-15-201(1)(a)(ii)
is met.
