appendix o exposure scenarios and unit dose factors ... - Hanford Site

HNF-5636 Rev. 0
HNF-SD-WM-TI-707 Revision 1
A.1.5 Post-Intrusion Resident (HSRAM Residential)
Assume 1 curie H-3 is exhumed from the well shaft and spread over an area of 200 m².
The average soil concentration is computed as before. The same decay factors used for the
Gardener also apply here. Doses from each pathway are shown below.
Inhalation Dose: (resuspended soil)
(3.65E-4 kg/y)(2.222E+7 pCi/kg)(9.60E-8 mrem/pCi)(0.45653 y) = 3.55E-4 mrem
Ingestion Dose: (soil only)
(0.0365 kg)(2.222E+7 pCi/kg)(6.40E-8 mrem/pCi)(0.45653 y) = 0.0237 mrem
External Dose:
(7008 h/y)(2.222E+7 pCi/kg)(225 kg/m²)(0 mrem/h per Ci/m²)(0.45653 y) = 0 mrem
Ingestion Dose: (root uptake only)
(1.4221 mrem/kg)(51 )(0.09)( 3.7 kg)(0.59711) = 14.4 mrem
(1.4221 mrem/kg)(18 )(0.25)(11.0 kg)(0.56216) = 39.6 mrem
(1.4221 mrem/kg)(25 )(0.18)(15.3 kg)(0.56216) = 55.0 mrem
(1.4221 mrem/kg)(3.4)(0.91)(14.6 kg)(0.56216) = 36.1 mrem
Total from root uptake: 145.1 mrem
Ingestion Dose: (rain splash only)
(1.229E-3mrem/d/m²)(18d)(0.407)(1.0)/(2.0kg/m²)( 3.7kg)(0.59711) = 0.0099mrem
(1.229E-3mrem/d/m²)(20d)(0.835)(0.1)/(2.0kg/m²)(11.0kg)(0.56216) = 0.0063mrem
(1.229E-3mrem/d/m²)(20d)(0.857)(0.1)/(3.0kg/m²)(15.3kg)(0.56216) = 0.0060mrem
(1.229E-3mrem/d/m²)(20d)(0.371)(0.1)/(0.8kg/m²)(14.6kg)(0.56216) = 0.0094mrem
Total from rain splash: 0.0317mrem
Total Dose to HSRAM Residential:
3.55E-04 + 0.0237 + 145.1 + 0.0317 mrem = 145 mrem per Ci exhumed
A.2 Low Water Infiltration Exposure Scenarios
Each of the exposure scenarios listed in Table 4 will be evaluated. The external exposures
are not computed for tritium because the external dose rate factor for tritium is zero. Absorption
through the skin is included in the inhalation dose factor for tritium. The main dose pathway in
every case is the drinking water pathway.
It will be assumed in each exposure scenario that the well water concentration is 1 pCi/L.
Thus the doses computed are per pCi/L.
Normally, three significant digits are kept during calculations. Because the spreadsheet
software keeps several digits, agreement with the spreadsheet can only be obtained if 4 or 5
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