An improved steam generator model for the SASSYS code

In this paper a new computer model of a steam generator for a liquid metal cooled fast reactor is developed. The new model includes steady-state and transient solutions. It has been incorporated into the SASSYS balance-of-plant model but also exists as a stand-alone code. It is a multi-node moving boundary model with donor-cell spatial differencing and mainly implicit time differencing. New and unique solution techniques are presented for the subcooled and boiling zones as well as for the determination of the location of the boiling crisis point. Results from a reactor trip transient calculated with the code are presented