Development of integrated dose assessment program for accident analysis of LILW managed in temporary storage facility

In this study a program, INDAC++, was developed to conduct accident analysis on low and intermediate level waste (LILW) managed in a temporary storage facility (TSF). In order to conduct this work, a variety of parameters were considered such as risk factor, radionuclide inventory, atmospheric dispersion factor (χ/Q), dose conversion factor, and so on. The main risk factors leading to arbitrary accidents were developed by the master logic diagram (MLD) method based on a fault tree analysis (FTA). The dose to curie (DTC) method was used to calculate the radionuclide inventory. Then, the release rates with respect to the type of wastes and radionuclides were considered in order to evaluate the amount of radionuclides released by the risk factors. Furthermore, the atmospheric dispersion factor (χ/Q) was calculated by the PAVAN code based on various models and assumptions suggested in the U.S. NRC Regulatory Guide 1.145. The dose assessments for arbitrary accidents originating in the TSF for LILW management are conducted by considering the external exposure dose by radioactive plume and the internal exposure dose by breathing. Synthesizing many parameters, the INDAC++, which is an integrated dose assessment code package for normal reaction operation and for accident analysis of LILW managed in the TSF, was developed using Visual C# in Microsoft Visual Studio.NET 2003. Furthermore, the INDAC++ can calculate the radiological risk with regard to the main risk factors for workers and the public.