Modeling the iodine removal efficiency and temperature behavior for an FADS charcoal filter by FEMLAB

Qin, Z.1, Wren, J.C.1, Moore, C.J.2
1 Department of Chemistry, The University of Western Ontario, London, Ontario, Canada
2 Chalk River Laboratories, Atomic Energy of Canada Limited Chalk River, Ontario, Canada

A key component of the Filtered Air Discharge System in nuclear power reactors is a charcoal filter, intended to remove gaseous fission products, mainly radioiodine, in the unlikely event of an accident.

Models for removal of CH3I and temperature behaviour of a charcoal filter have been described. The CH3I removal model is based on a mass balance equation consisting of CH3I transport due to convection and diffusion and CH3I adsorption-desorption on TEDA impregnated charcoal, and the temperature model is based on heat transfer when a filter is exposed to a dry airflow.

The mathematical models have been solved numerically by the finite element method using the software FEMLAB. The results from the FEMLAB simulation qualitatively reproduce the experimental data. The influence of the parameters, which are difficult to evaluate experimentally, has also been investigated by simulation.