Development of integrated system for accident consequence evaluation using Level 2 and Level 3 PRA codes

An integrated system between the THALES2 and the OSCAAR was developed in order to assist in preparing the input file of the OSCAAR. For the result of a state-of-the-art source term analysis with the THALES2, the authors implemented a preliminary analysis using the OSCAAR in order to evaluate the difference in setting of release fraction rates for the radionuclide groups. The effective dose was calculated for some cases by changing of release fraction rates divided into 1h (case 1), 3h (case 2), 5h (case 3), none (case 4) and arbitrary hours (case 5). After that, the ratio of the effective dose for these cases was compared. The result indicates that it was better to set short duration of release stages while the release fraction rates increased sharply. It seems that the case 5 is a better method in order to adapt to various accident scenarios. The method shows that it is useful for reducing the uncertainty in a Level 3 PRA analysis. (author)