A DSNP Movable Boundary U-Tube Steam Generator Model

A U-tube steam generator (UTSG) module for the Dynamic Simulator for Nuclear Power Plants is developed. This module is to be used in the simulation of pressurized water reactor (PWR) transients and parametric studies, and it is based on a movable boundary model in which the volumes of the various control volumes are dynamic variables. The UTSG is divided into ten control volumes with movable boundaries between them. The intensive mass and energy balance equations are solved in each control volume, while two integral momentum equations are solved for the primary and secondary flow paths. A homogeneous equilibrium model is assumed in the boiling region. The UTSG model was included in a detailed simulation of the Trojan PWR primary loop. A small loss-of-coolant accident event resulting from a stuck open relief valve transient is presented as an application example.