A probabilistic estimation of atmospheric tritium dose.

A radiation dose distribution has been calculated for an individual exposed to tritium oxide (tritiated water vapor) in the atmosphere. A specific activity model was used that is similar to that detailed in the Nuclear Regulatory Commission's Regulatory Guide 1.109. The values of 19 parameters are sampled consistent with assigned probability distributions using a Latin Hypercube approach. Dose was estimated assuming a concentration of tritium in atmospheric moisture of 0.13 +/- 0.16 Bq mL-1. Conventional dosimetric methods for tritium that were consistent with the Regulatory Guide result in an estimate of 0.63 microSv for annual exposures to airborne tritiated water. For the same atmospheric tritium concentration, the estimated dose distribution is lognormal and ranges from 0.08-3.2 microSv (at 95% confidence) with a median value of 0.59 microSv and a 95th percentile of 2.6 microSv.