Uncertainty issues of the Hanford environmental dose reconstruction project

Staff of the Hanford Environmental Dose Reconstruction (HEDR) Project are estimating (reconstructing) the doses that persons may have received from emissions of radioactive air and water from Hanford-Site nuclear facilities since 1944. A major objective of the project, which is scheduled for completion in 1995, is to quantify the uncertainties of the reconstructed doses. This paper discusses the statistical and uncertainty issues that are being addressed to achieve that objective. Reconstructing doses that occurred up to 45 years ago is fraught with uncertainties related to (1) inadequate historical data on environmental concentrations of radionuclides, (2) reliance on elicitation of expert opinion to provide open-quotes best estimatesclose quotes of model parameter values and their uncertainties, (3) validating spatial-temporal environmental transport and dose models when few data exist for that purpose, (4) evaluating model uncertainties, and (5) establishing credibility for the project when dose uncertainties may be several orders of magnitude. The HEDR Project is funded the US Centers for Disease Control