Tritium: An Analysis of Key Environmental and Dosimetric Questions.

摘要

This document summarizes new theoretical and experimental data that may affect the assessment of environmental releases of tritium and analyzes the significance of this information in terms of the dose to man. Calculated doses resulting from tritium releases to the environment are linearly dependent upon the quality factor chosen for tritium beta radiation. A reevaluation of the tritium quality factor by the ICRP is needed; a value of 1.7 would seem to be more justifiable than the old 1.0 value. A new exposure model is proposed, based primarily upon the approach recommended by the National Council on Radiation Protection and Measurements. Employing a 'typical' LMFBR reprocessing facility source term, a 'base case' dose commitment to total body (for a maximally exposed individual) was calculated to be 4.0 X 10(sup -2) mSv, with 3.2 X 10(sup -1) mSv of the dose due to intake of tritium. The study analyzes models which exist for evaluating the buildup of global releases of tritium from man-made sources. Scenarios for the release of man-made tritium to the environment and prediction of collective dose commitment to future generations suggest that the dose from nuclear weapons testing will be less than that from nuclear energy even though the weapons source term is greater than that for any of our energy scenarios.