Uncertainties Predicting Radionuclides distribution in ICRP models with random inputs

Standards, such as ICRP 78, give criteria to establish bioassay programs assuming acute and chronic intakes. However, in real situations, the individual daily intake for occupational workers are usually a random variable. We have studied the daily intake data from workers exposed for a long period to UO2 particles. We find that the daily intakes and the concentration values can be fitted to the lognormal distributions. We used an improved method on the approximation of a sum of lognormal distributions to a lognormal distribution is in order to forecast bioassays and its uncertainties. This method can be useful to design and conduct the air control monitoring and the bioassay programs introducing statistical criteria to determine when an bioassay is required and how often should be applied. (Author) 7 refs