La. Admin. Code tit. 33 § XV-413

Current through Register Vol. 50, No. 9, September 20, 2024

Section XV-413 - Determination of Internal Exposure

A. For purposes of assessing dose used to determine compliance with occupational dose equivalent limits, the licensee or registrant shall, when required pursuant to LAC 33:XV.431, take suitable and timely measurements of:

1. concentrations of radioactive materials in air in work areas;

2. quantities of radionuclides in the body;

3. quantities of radionuclides excreted from the body; or

4. combinations of these measurements.

B. Unless respiratory protective equipment is used, as provided in LAC 33:XV.442, 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.

C. 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:

1. 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;

2. upon prior approval of the department, 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

3. 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 LAC 33:XV.499.Appendix B.

D. If the licensee or registrant chooses to assess intakes of Class Y material using the measurements given in LAC 33:XV.413.A.2 or 3, the licensee or registrant may delay the recording and reporting of the assessments for periods up to seven months, unless otherwise required by LAC 33:XV.486 or 487. This delay permits the licensee or registrant to make additional measurements basic to the assessments.

E. 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:

1. the sum of the ratios of the concentration to the appropriate DAC value (that is, D, W, or Y) from LAC 33:XV.499.Appendix B for each radionuclide in the mixture; or

2. the ratio of the total concentration for all radionuclides in the mixture to the most restrictive DAC value for any radionuclide in the mixture.

F. 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.

G. When a mixture of radionuclides in air exists, a licensee or registrant may disregard certain radionuclides in the mixture if:

1. the licensee or registrant uses the total activity of the mixture in demonstrating compliance with the dose limits in LAC 33:XV.410 and in complying with the monitoring requirements in LAC 33:XV.431.B;

2. the concentration of any radionuclide disregarded is less than 10 percent of its DAC; and

3. the sum of these percentages for all of the radionuclides disregarded in the mixture does not exceed 30 percent.

H. When determining the committed effective dose equivalent, the following information may be considered:

1. 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; and

2. for an ALI and the associated DAC determined by the nonstochastic organ dose limit of 0.5 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 LAC 33:XV.499.Appendix B. 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 LAC 33:XV.410.A.1.b is met.

La. Admin. Code tit. 33, § XV-413

Promulgated by the Department of Environmental Quality, Nuclear Energy Division, LR 13:569 (October 1987), amended by the Office of Air Quality and Radiation Protection, Radiation Protection Division, LR 19:1421 (November 1993), amended by the Office of Environmental Assessment, Environmental Planning Division, LR 26:2575 (November 2000).

AUTHORITY NOTE: Promulgated in accordance with R.S. 30:2001 et seq.