Status and validation of the SAS4A accident-analysis code system

The SAS4A code system is a new tool for analyzing the initial phase of Hypothetical Core Disruptive Accidents (HCDAs) up to gross melting or failures of the subassembly walls. The objective in the development of SAS4A is to provide improved analytical models which represent experimentally demonstrated modes of material response in such accident scenarios. This paper discusses recent improvements in the phenomenological models, gives examples of verification and validation efforts that have been conducted, and illustrates the whole core-analysis implications of using this refined modeling capability.