Validation, assessment, and applications of the CONTAIN computer code

The CONTAIN computer code is a versatile system of phenomenological models for analyzing the physical, chemical, and radiological conditions inside the containment building during severe reactor accidents. The code has been released to more than twenty research institutions in five countries, and is being used in a variety of ongoing research studies. In this paper, we describe recent accomplishments in three areas: (1) Code Validation, which we define as comparison of code predictions with experimental results; (2) Code Assessment, which involves comparisons among computer codes and tests of the code's efficiency and speed for a variety of multi-cell problems (with and without the new implicit solution technique); and (3) Applications, which consist of a number of full-scale accident sequence calculations devised to study one or more aspects of ''integrated'' containment analysis (i.e., the coupled treatment of thermal-hydraulic, aerosol, and fission product phenomena).