CONTAIN code calculations for the LA-4 experiment

The CONTAIN code is a system-level analysis tool developed for the USNRC, and is intended for best-estimate prediction of conditions which might occur in the containment building of a nuclear power plant during a severe accident. A key feature of the code is that it models the containment phenomena in an integrated manner. In particular, the CONTAIN code models some of the complex ways that thermal hydraulics and aerosol phenomena interact with each other. The Light Water Reactor Aerosol Containment Experiment (LACE) progarm is a program to aid researchers in their understanding of thermal hydraulic and aerosol behavior within containments. The purpose of this paper is to report on best-estimate LA-4 post-test calculations that have been completed with the most recent version of the CONTAIN code, version 1.11. An analysis of experimental data and review of the blind post-test CONTAIN calculations is used to justify a re-calculation of the experiment and to establish a best-estimate calculation. The best-estimate calculation shows that reasonably good agreement between thermal hydraulic predictions and data can be obtained with the current CONTAIN models by varying experimental parameters within their uncertainties. Furthermore, with the recently added solubility model for hygroscopic aerosols, the best-estimate calculation gives aerosol behavior that is in good agreement with aerosol data. 10 refs., 16 figs