THE 2ND INTERNAL DOSIMETRY INTERCOMPARISON STUDY OF THE US DEPARTMENT-OF-ENERGY

The findings are presented of the second internal dosimetry intercompa rison study for the US Department of Energy (DOE), performed in 1995. As in the first intercomparison study, participants were asked to resp ond to five test exposure scenarios, assess the data provided, and cal culate the resulting internal dose. The main difference between this s tudy and the previous one is that test cases in the present study are more closely related to work performed either previously, or currently , at DOE facilities. The test cases cover both tritium and plutonium e xposures, including single and multiple intakes, and some also involve d chelation treatment. In addition to using test cases based on real e xposure data, an artificial case was created using the new lung model described in ICRP Report 66. Six DOE facilities participated in the pr esent study. The results of this study are similar to those found in t he previous intercomparison, since they show that the main factors con tributing to the Variations in the numerical answers are: interpretati on of bioassay and statistical treatment of bioassay data, the biokine tic models applied, and the computational method used. This study, how ever, further identifies areas that need to be improved to facilitate participation in future intercomparisons, such as improved management commitment for participants' involvement increasing the response time, better presentation of the exposure data, more involvement of the par ticipants in case preparation, and improved instructions to the partic ipants on the amount of information that should be included in the res ponse.