Accurate tools to model advanced SVEA fuel designs

The introduction of the SVEA-96 Optima generation of advanced boiling water reactor fuel designs implies a further increment in complexity and heterogeneity that needs to be supported by accurate calculation tools. In order to take advantage of the improved economics offered by these modern fuel designs while simultaneously assuring safe and reliable reactor operation, both the reload design process and the online core monitoring procedures must be based on appropriate calculation methods. The modeling of transition cores involving the gradual introduction of these new fuel designs poses a severe challenge for the current core physics methods. Recognizing this, Westinghouse has engaged in a continuing process of improving its core physics calculation packages. This development program is supported by a comprehensive validation effort to demonstrate the accuracy and reliability of the improved methods as well as to identify areas requiring further development. The purpose of this paper is to summarize some of the results of this program.