Appendix B - Insoluble Metal Tritide Benchmark

DOE-HDBK-1184-2004

APPENDIX B INSOLUBLE METAL TRITIDE BENCHMARK

This is a benchmark calculation of dose and excretion following an intake of a type M Insoluble

Metal Tritide (IMT) using the ICRP 66 respiratory tract model and ICRP 78 systemic model. The

calculations were implemented in MathCad 200011 and Excel 9712. (Note that when performing

internal dose estimated for the purpose of demonstrating compliance with 10 CFR Part 835, the

tissues weighting factors specified in 10 CFR Part 835 must be used.) A basic knowledge of

Mathcad syntax will facilitate the study of this benchmark, but anyone having experience with a

higher level language (e.g., FORTRAN) should be able to follow the calculations.

First, load in definitions and subroutines from the file FUNCTIONS.MCD. The content of this file

is given in the end of this appendix.

The physical decay constant for tritium in units of 1/day is given by

ln(2)

λ = (12.3 365)

The deposition of the SMT aerosol in the compartments of the respiratory tract is a function of

the AMAD of the aerosol and is calculated with the subroutine "Depo" (which is defined in the

next appendix). For occupational exposure, an AMAD of 5 :m is assumed.

AMAD = 5

D = Depo(AMAD)

The initial content q0 of the compartments are defined below. The initial content of any

compartment not explicitly defined has a value of zero because the initial content of the last

compartment (i.e., urine) is defined as zero13. The intake of the SMT ISMT is defined as unity and

the intake of HTO IHTO as zero. Intakes of HTO are modeled as direct instantaneous

depositions into the blood compartment.

Ismt ≡ 1

Ihto ≡ 0

i = AI1 .. ET1

q0 = Ismt⋅D

urine

= Ihto

blood

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