Statistical analysis of selected parameters for predicting food chain transport and internal dose of radionuclides. Final report

Compliance with environmental radiological standards promulgated to limit routine releases from nuclear facilities is usually determined through the use of mathematical models which are subject to considerable uncertainty. One way of estimating the uncertainty associated with model predictions is through an analysis of the statistical properties of their input parameters. Results of such analyses for parameters incorporated in US Nuclear Regulatory Commission (NRC) Regulatory Guide 1.109 are presented. The uncertainty in dose prediction resulting from a given concentration of 131I2 in air transported over the pasture-cow-milk pathway is estimated. The NRC recommended generic default values are compared with the statistical distribution of the selected parameters, and the probability of the default values not being exceeded is estimated. The results provide an estimation of actual uncertainties to be expected under real-world conditions in lieu of validation experiments. The relevance of these results to the true uncertainties associated with the parameters and models analyzed in this report is limited because of the qualifying assumptions and the quality of data. However, methods of taking results from these analyses into account when determining compliance with regulatory statutes are discussed