Many channels are employed for a whole-core representation. The transient fuel and cladding mechanical behavior model, integrated with fission product production, release, and transport models, provides prediction of fuel element dimensional changes and cladding failure. Fuel and cladding melting and subsequent relocation are described with multiple-component fluid dynamics models, with material motions driven by pressures from coolant vaporization, fission gas liberation, and fuel and cladding vaporization. Reactivity effects from reactor structural temperature changes yielding radial core expansion are modeled. Changes in reactor power level are computed with point kinetics.
Numerical models used in the code modules range from semi-implicit to explicit.
The number of channels is limited only by the size of the computer memory. The physical models in SAS4A are highly detailed numerical representations of reactor accident conditions based on extensive laboratory and test reactor results. SAS4A Version 3.0 is available for production use at Argonne National Laboratory in the Reactor Analysis Division. Earlier versions have been exported to domestic U.S. DOE contractors and to research organizations in foreign countries. System dependent routines may be supplied for dynamic memory allocation, timing, and system and user identification.