A SMART-IST Assessment for Radionuclide Release in the Wolsong 1 NPP

Recently, SMART-IST (VER-0.310) code has been introduced to assess the Wolsong 1 refurbishment. The SMART-IST (Simple Model for Aerosol Removal and Transport - Industry Standard Toolset) computer code models radionuclide in CANDU reactor containments during postulated accidents. This code is designed to predict nuclide behaviour within containment considering various aspects such as releases of nuclides from the primary heat transport system, transport of nuclides among various rooms in containment, removal of nuclides from the containment atmosphere through various removal mechanisms, changes in nuclides resulting from radioactive decay and build-up, and releases of nuclides to the outside atmosphere through containment escape paths. SMART-IST models radioiodine in more detail than other nuclides using the IMOD-2 model developed at AECL. IMOD-2 was incorporated into the overall mathematical framework of SMART-IST as a module modeling the chemical transformations between various iodine species and mass transfer of these species among gas, aqueous and adsorbed phases in containment. IMOD-2 model is very sensitive for paint and chemical information. This paper presents an overview of the SMART-IST code, and also presents the result of parameter study of IMOD-2 model to decide analysis value for small break (SB) LOCA without ECC