DOSE TO THE PUBLIC FROM TRITIUM RELEASED TO THE ATMOSPHERE FROM THE LIVERMORE SITE OF LAWRENCE LIVERMORE NATIONAL LABORATORY, 1953 THROUGH 2005

Abstract

Throughout 53 years of operations, an estimated 29,300 TBq of tritium were released to the atmosphere at the Livermore site of Lawrence Livermore National Laboratory (LLNL); about 75% of this was released as tritium gas primarily in two accidental releases. A tritium dose reconstruction was undertaken to chronicle both the annual doses to the public for each year of operations and the doses from seven accidental releases. Although LLNL has always reported releases and calculated doses in compliance with regulatory requirements, annual doses were not calculated prior to 1973, and the only dose reported from an accidental release was that in 1970. Annual doses (means and 95% confidence intervals) for 1953 through 2005 to the most exposed members of the public were calculated using the same equilibrium dose model and assumptions. From 1973 through 2005, predicted tritium concentrations in air were compared with observed mean annual concentrations at one location, and predicted doses were compared with those reported by LLNL. A mean dose with 95% confidence interval was also calculated for each accidental release using an equation derived from extensive experience with a dynamic process-oriented model. Predicted air concentrations were overestimated, on average, by a factor of 1.6, 70% of the doses reported by LLNL in annual compliance documents fell within the predicted confidence intervals, and all predicted doses from routine and accidental releases were well below regulatory limits. The highest annual mean dose to an adult was 34 microSv in 1957; the highest dose from an accidental release was 330 microSv in 1954.