DEVELOPMENT OF BURNUP CREDIT EVALUATION METHODS AT JAERI

A guide material to introduce the burnup credit in Japan has been prepared and published in the name of a Guide Introducing Burnup Credit, Preliminary Version. In this Guide, correction factors expressed by C/E (ratio of calculated over measured isotopic composition) are prepared for applying to the results calculated by the ORIGEN 2.1 depletion code. A total of 38 sets of PIE data from PWR such as Obrigheim, Genkai-1, Mihama-3 and Takaham-3 have been used for this calculation. In addition, two simplified evaluation methods, “Equivalent Uniform Burnup” and “Equivalent Initial Enrichment”, have been developed and prepared to perform criticality safety analysis by the ORIGEN2.1 depletion code and the KENO-Va criticality code without any detailed assumption.