Burnup chain compression method preserving neutronics, decay photon source term and decay heat calculation results

A burnup chain compression method, preserving neutronics, decay photon source term and decay heat calculation results, is developed based on the generalized perturbation theory (GPT), to reduce calculation burden for the practical reactor physics simulations. In this method, a certain number of target nuclides which have significant effect on calculation accuracy of the three applications are first selected according to their contribution to the neutron reaction rate, decay heat and decay photon intensity. Then, nuclides important for the accuracy of the nuclide number densities of the target nuclides are selected according to the contribution function calculated based on the GPT. A fine burnup chain containing 1547 nuclides based on ENDF/B-VII.0 is compressed to a burnup chain including 557 nuclides. The compressed burnup chain is adopted to calculate a couple of typical fuel assembly and pin cell problems of PWR. The results are compared with those based on the fine burnup chain. The numerical results show that the compressed burnup chain achieves high accuracy for neutronics, decay photon source term and decay heat calculation, simultaneously.