Simple method to predict power level and core flow rate of boiling water reactors by using one-point core model.

A simple one-point core model has been developed to predict startup and load following features of boiling water reactors (BWRs). The variables used in this model are core thermal power, core flow rate, xenon concentration and control rod pattern, where the last variable is expressed in terms of the corresponding thermal power at the rated core flow. The number of parameters to be identified is only three, and they are determined by flow control line, xenon reactivity coefficient and power reactivity coefficient. These parameters can be adjusted by using the actual operating data of BWR plants. The accuracy of the one-point core model was evaluated in some typical startup operations of a reference 800 MWe class BWR. The prediction errors of the model were within 2% of relative power in comparison with results of a three-dimensional BWR core simulator and within 3% in comparison with the operating data. Use of this one-point core model, with xenon-iodine maps, should successfully predict reactor conditions...