UNCERTAINTY AND SENSITIVITY ANALYSIS FOR THE ENVIRONMENTAL TRITIUM CODE UFOTRI

Computer models are used for predicting the impact of tritium releases . Their reliability, when experimental data are limited, can be judged from benchmark tests and uncertainty analysis. First results of a par ameter uncertainty and sensibility analysis are presented for the envi ronmental tritium code UFOTRI. The uncertainty range is shown to be le ss than one order of magnitude. The bulk of the variance is contribute d by leaf area index, minimum stomatal resistance, dry and wet yield a nd initial soil moisture. Improvements in model assumptions are sugges ted.