Pre-test calculations for FAL-19 and FAL-20 using the INSPECT code

Pre-test calculations have been carried out for tests FAL-19 and FAL-20. These experiments will be conducted in early 1993 as part of the Falcon test matrix, and have the objective of studying iodine chemistry within the containment under conditions simulating aspects of a severe accident within a light water reactor. In order to make these predictions it was assumed that 10% of the iodine inventory entered the containment as I2, and that in FAL-19 (high humidity in the containment) reaction of I2 with steel was irreversible and in FAL-20 (low humidity) it was reversible. In FAL-20, I2 was predicted to transfer from the steel to paint and sump. Results predict rapid uptake by walls and very little long term volatility apart from a low level of CH3I. A final report of this work will be issued in December 1992 that also takes account of the role of non-aqueous aerosols on the iodine behaviour. (author)