Development of the new pin-by-pin core calculation method with embedded heterogeneous assembly calculation

In this paper, the next generation method (NGM), which is being developed in Mitsubishi Heavy Industries, Ltd., is proposed. Our NGM is based on 'On-flight' calculations with 2D cell-heterogeneous transport calculation for generating cell average constants and 3D cell-homogenous pin-by-pin core calculations. A new MOC module, GALAXY, with energy and space dependent boundary condition is being developed as a 2D cell-heterogeneous flux solver. To verify our NGM, whole system calculation was performed against 2D-C5G7 MOX benchmark problem. The result was compared with whole core cell-heterogeneous calculation results. Those results are in good agreement. We confirmed that this method is very effective and useful for parallel computing because heterogeneous calculation of each assembly can be independently performed. (authors)