An Assessment of Iodine Chemistry Models in MAAP-CANDU

Abstract

A brief literature review and preliminary assessment of iodine chemistry models in the MAAP- CANDU (Modular Accident Analysis Program for CANDU®* reactors) integrated severe accident code was conducted. This assessment includes a general description of the iodine models, chemical reactions involving iodine (including organic forms of iodine), and the related input and output parameters in MAAP-CANDU. Benchmarking of the MAAP5 light water reactor version using AECL experimental data on iodine behaviour is also briefly discussed. Additionally, iodine chemistry models in other integral severe accident analysis codes, MELCOR and ASTEC, are described and compared to the models in MAAP-CANDU.

Several MAAP-CANDU (v5.00A) simulations were executed examining the impact of crediting the iodine chemistry models on the consequences of a postulated station blackout accident in a generic CANDU 6 plant. The simulation results are discussed and recommendations are made for further assessment of the iodine chemistry models in MAAP-CANDU.