抄録
We have developed a best-estimate transient analysis code TRACT, for licensing transient analyses for current BWR plants and the development of next-generation BWR system. In addition to the POST-BT correlations, capability of modeling all fuel bundles individually in a reactor core and several models required for BWR licensing transient analyses, TRACT adopts a modified one-group neutron kinetics model as well as a three-group neutron kinetics model with the advanced nodal method. For both kinetic models, an improved quasi-static method is used as it is found to be suitable for evaluation of rapidly varying phenomena in postulated transient analyses. With the modified one-group kinetic model, TRACT has been validated through a number of analyses for separate effects tests (SETs), component effects tests (CETs), integral system effects tests (IETs), and BWR plant tests. From these analyses, the results for the SPERT-III test, the Peach Bottom-2 turbine trip test, and a BWR5 load rejection test are presented. The three-group kinetic model was applied to an ABWR MSIV full closure analysis to check the operation. It is confirmed that the calculated power change during the incident was similar to the one analyzed by the modified one-group neutron kinetic model.
