CONTAIN calculations of severe accident sequences at the Surry Nuclear Power Plant

CONTAIN is an integrated containment thermohydraulic and aerosol transport code. The choice of the Surry plant provides an opportunity to compare the CONTAIN calculations to those recently performed by Battelle Columbus Laboratories. The accident sequence considered consists of a loss of coolant accident due to a large pipe break in the hot leg, followed by a failure of electric power to all engineered safety features including the emergency core cooling system. Pressure history calculations are shown. Suspended masses of the various aerosol components are shown as a function of time. Airborne masses of Cs and I within the containment are also shown. In contrast to the results reported by Battelle the containment atmosphere in the CONTAIN calculations remained superheated during and after the generation of the highly radioactive aerosols; hence, steam condensation on these aerosols could not occur. It was found that single-cell representation of containment can be a serious oversimplification. For the Surry accident sequence decay heat associated with suspended fusion products does not have significant effects on the release fractions.