6 Colo. Code Regs. § 1007-1-4.6
Current through Register Vol. 47, No. 11, June 10, 2024
Section 6 CCR 1007-1-4.6 - Occupational Dose Limits for Adults4.6.1 The licensee or registrant shall control the occupational dose to individual adults, except for planned special exposures pursuant to 4.11, to the following dose limits: 4.6.1.1 An annual limit, which is the more limiting of: (1) The total effective dose equivalent being equal to 0.05 Sv (5 rem); or(2) The sum of the deep dose equivalent and the committed dose equivalent to any individual organ or tissue other than the lens of the eye being equal to 0.5 Sv (50 rem).4.6.1.2 The annual limits to the lens of the eye, to the skin of the whole body, and to the skin of the extremities, which are: (1) A lens dose equivalent of 0.15 Sv (15 rem), and(2) A shallow dose equivalent of 0.5 Sv (50 rem) to the skin of the whole body or to the skin of any extremity.4.6.2 Doses received in excess of the annual limits, including doses received during accidents, emergencies, and planned special exposures, shall be subtracted from the limits for planned special exposures that the individual may receive during the current year and during the individual's lifetime. See 4.11.5.1 and 4.11.5.2.4.6.3 Assigned dose equivalent. 4.6.3.1 When the external exposure is determined by measurement with an external personal monitoring device, the deep-dose equivalent must be used in place of the effective dose equivalent, unless the effective dose equivalent is determined by a dosimetry method approved by the NRC.4.6.3.2 The assigned deep dose equivalent must be for the part of the body receiving the highest exposure.4.6.3.3 The assigned shallow dose equivalent must be the dose averaged over the contiguous 10 square centimeters of skin receiving the highest exposure.4.6.3.4 The deep-dose equivalent, lens dose equivalent, and shallow dose equivalent may be assessed from surveys or other radiation measurements for the purpose of demonstrating compliance with the occupational dose limits, if the individual monitoring device was not in the region of highest potential exposure, or the results of individual monitoring are unavailable.4.6.3.5 In the case of occupational exposures to x-rays with accelerating voltages of less than 145 kVp and where the worker utilizes lead garment protection, the registrant may calculate the assigned dose equivalent using methods discussed in NRC Regulatory Information Summary (RIS) 2002-061, other methods as specifically approved by the Department, or by use of the following equation: 1 NRC RIS 2002-06, Evaluating Occupational Dose For Individuals Exposed To NRC-licensed Material And Medical X-Rays, April 16, 2002 (http://www.nrc.gov/; ML021000613).
(1) Lead apron and no thyroid collar: assigned deep dose equivalent = 0.06 x (collar dose - waist dose) + waist dose
(2) Lead apron and thyroid collar: assigned deep dose equivalent = 0.02 x (collar dose - waist dose) + waist dose
4.6.4 Derived air concentration (DAC) and annual limit on intake (ALI) values are presented in Table 4B1 of Appendix 4B and may be used to determine the individual's dose and to demonstrate compliance with the occupational dose limits. See 4.46.4.6.5 Notwithstanding the annual dose limits, the licensee shall limit the soluble uranium intake by an individual to 10 milligrams in a week in consideration of chemical toxicity. See footnote 3 of Appendix 4B.4.6.6 The licensee or registrant shall reduce the dose that an individual may be allowed to receive in the current year by the amount of occupational dose received while employed by any other person. See 4.10.3.1 and 4.10.5.Colorado Register, Vol 37, No. 14. July 25, 2014, effective 8/14/201438 CR 02, January 25, 2015, effective 2/14/201538 CR 05, March 10, 2015, effective 3/30/201538 CR 12, June 25, 2015, effective 7/15/201538 CR 14, July 25, 2015, effective 8/14/201539 CR 02, January 25, 2016, effective 2/14/201639 CR 16, August 25, 2016, effective 9/14/201639 CR 22, November 25, 2016, effective 12/15/201640 CR 11, June 10, 2017, effective 6/30/201740 CR 20, October 25, 2017, effective 11/14/201742 CR 24, December 25, 2019, effective 1/14/202043 CR 14, July 25, 2020, effective 8/14/202043 CR 18, September 25, 2020, effective 10/15/202044 CR 11, June 10, 2021, effective 7/15/202144 CR 14, July 25, 2021, effective 8/14/202145 CR 22, November 25, 2022, effective 12/15/202246 CR 21, November 10, 2023, effective 12/15/2023