Iodine behavior in steam generator tube rupture accidents

This report identifies the results of a program aimed at developing a computer code for use in the analysis of the behavior of iodine during steam generator tube rupture (SGTR) accidents in pressurized water reactors (PWR's). The program was directed towards the identification of the several processes that play a role in the transport and deposition behavior of iodine from its point of escape at the primary system break to its point of release to the environment, the development of models to describe these processes and the incorporation of these models into a computer code. Preliminary calculations performed using the computer code indicate that iodine contained in the water droplets that are formed as the primary coolant flashes could be a major source of iodine released to the atmosphere during an SGTR accident. Additionally, the assumed chemical form of the iodine, molecular or ionic, appears to be extremely important in determining the consequences of the accident.