Consistent initalization of pressure and flow parameters for BWR transient analysis at off-rated power and flow conditions

This paper presents a procedure for calculating appropriate loss coefficients and flow distribution parameters to initialize boiling water reactor (BWR) system transient codes. This method achieves a pressure and flow balance while satisfying the constraint that the calculated steady-state flows and pressure drops match the plant performance curves supplied by the user. The methodology has been encoded in the REBAL computer code, which greatly reduces the engineering man-hours required to achieve a properly initialized model. This methodology improves the accuracy and consistency of transient calculations performed at off-nominal power and flow conditions and is particularly useful at the high-power/low-flow conditions typical of BWR stability analysis