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Amended Tables RPS 9 and RPS 9.1

The values provided in the amended tables have been derived from the International Commission of Radiological Protection (ICRP) Occupational Intakes of Radionuclides (OIR) Series (ICRP 130, 134, 137 & 141). Australian specific conditions have been considered in the adoption of these values. An equilibrium factor of 0.4 for Rn-222 is assumed as taken from PDF icon Assessment of radon progeny dose conversion factors from measurements in the underground uranium mine at Olympic Dam (Solomon et al 2018)

ARPANSA can provide a worksheet for calculations of site specific dose conversion factors on request, please email infoatarpansa.gov.au

Amended Table 1 RPS 9: Dose conversion factors for mixtures of inhaled radionuclides1

Mixture DCFs for Inhalation2 (mSv/alpha-dps)
1 μm AMAD 5 μm AMAD
Uranium dusts3
Ore Dust5 2.3 x 10-2 1.4 x 10-2
Product Dust5 2.1 X 10-2 1.2 x 10-2
Tailings Dust 2.4 x 10-2 1.4 x 10-2
Thorium dust
Th-232 series 5.8 x 10-2 3.4 x 10-2

Notes:

  1. The values tabulated are derived from ICRP Occupational Intakes of Radionuclides Series (ICRP 130, 134, 137 & 141) based on the most conservative chemical form (Ralph M, Tsurikov N, Cattani M, Impacts of revised dose coefficients for the inhalation of NORM – containing dusts encountered in the Western Australian Mining Industry, J. Radiol. Prot., Vol 40, No. 4, 2020). 
  2. Alpha-dps means the number of alpha-particle disintegrations per second of the mixture. It is assumed there is no retention of radon (0% retention factor, i.e., sample counting occurs after sufficient delay, note this differs from the 100% retention published in Table 1 RPS 9).
  3. It is assumed 0.72% by mass of natural uranium is U-235.
  4. Secular equilibrium is assumed.
  5. Greater than 90% uranium extraction to product is assumed, with greater than 90% rejection of thorium, radium, and decay products to tailings.

Multiplication factor when going from 0% radon retention to other percentages. 

Mixture Radon Retention Percentage in sample1
100% 75% 50% 25% 0%
Ore dust 0.62 0.72 0.81 0.91 1
Product dust 1 1 1 1 1
Tailings dust 0.5 0.62 0.75 0.88 1
Th-232 series 0.5 0.62 0.75 0.88 1

Notes:

  1. If the radon retention factor is known this table can be used to determine the multiplication factor to apply to the DCF from Amended Table 1 above.

Amended Table 2 RPS 9: Dose conversion factors for inhaled radon decay products at mines1

Radionuclides Factor (mSv/mJ) Factor (mSv/mJ.h.m-3)
Radon-222 decay products 2.5 3
Radon-220 decay products 1.25 1.5

Notes:

  1. A breathing rate of 1.2 m3/h is assumed.

Amended Table A1 RPS 9.1: Dose conversion convention for radon/thoron and progeny at mines 

Conversion Conversion factor
Radon-222 Radon-220
From radon progeny exposure to effective dose (mSv/mJ.h.m-3)a  3.0 1.5
From radon exposure to effective dose (mSv/Bq.h.m-3)b,c 6.7 x 10-6 1.1 x 10-4
From radon concentration to annual effective dose (mSv/100 Bq.m-3)d 1.3 22

Notes

a) A breathing rate of 1.2 m3/h is assumed. 

b) Rn-222 equilibrium factor of 0.4 (Solomon et al 2018)

c) Rn-220 equilibrium factor of 1 

d) Assuming 2000 working hours

Amended Table A2 RPS 9.1: Intake-to-dose conversion factors for works for commonly encountered radionuclides in mining and mineral processing

Radionuclide Inhalation Ingestion
Typea einh (1μm) Sv/Bq einh (5μm) Sv/Bq f1b eing Sv/Bq
U-238 S 2.0E-05 1.2E-05 0.002 3.1E-09
Th-234 S 4.9E-09 2.9E-09 5.0E-04 5.9E-10
U-234 S 2.3-05 1.3E-05 0.002 3.5E-09
Th-230 S 2.5E-05 1.5E-05 5.0E-04 6.0E-08
Ra-226 S 2.3E-05 1.3E-05 0.2 1.3E-07
Pb-214 S 1.1E-08 1.4E-08 0.2 7.7E-11
Bi-214 S 1.0E-08 1.4E-08 0.05 4.7E-11
Pb-210 S 1.5E-05 9.2E-06 0.2 3.2E-07
Bi-210 S 8.7E-08 5.7E-08 0.05 1.1E-09
Po-210 S 2.8E-06 1.8E-06 0.1 1.8E-07
           
U-235 S 2.1E-05 1.2E-05 0.002 3.3E-09
Th-231 S 1.7E-10 1.3E-10 5.0E-04 1.7E-11
Pa-231 S 8.4E-05 4.6E-05 5.0E-04 1.8E-07
Ac-227 S 1.1E-04 6.5E-05 5.04E-04 1.7E-07
Th-227 S 3.3E-06 2.1E-06 5.0E-04 1.3E-09
Ra-223 S 3.2E-06 2.2E-06 0.2 4.1E-08
Pb-211 S 1.1E-08 1.3E-08 0.2 1.0E-10
           
Th-232 S 1.0E-04 5.4E-05 5.0E-04 7.0E-08
Ra-228 S 3.7E-05 2.2E-05 0.2 3.4E-07
Ac-228 S 1.3E-08 8.4E-09 5.0E-04 1.6E-10
Th-228 S 3.5E-05 2.3E-05 5.0E-04 3.1E-08
Ra224 S 1.6E-06 1.1E-06 0.2 2.9E-08
Pb-212  S 1.1E-07 9.4E-08 0.2 5.6E-09
Bi-212 S 2.4E-08 2.9E-08 0.05 1.1E-10

Notes:

a) Chemical form/lung absorption type

b) Gut transfer factor