Implementation of The Efficient Multigroup Solution in PARCS for Designing Innovative Cores

The CAMP (Code Application and Maintenance Program) is one of the regulatory researches directed by the US NRC in partnership with more than 20 countries and performs to exchange information on thermal- hydraulic safety issues related to reactor and plant systems. As a part of the international program, the advanced thermal hydraulic system code TRACE has been being developed and qualified by an alliance of various institutions worldwide, in which the neutronics code PARCS has a important role of calculating three-dimensional kinetics solution. The major computational methods needed for solving spatial kinetics problems have been developed and implemented in PARCS to analyze phenomenons occurred in the various reactor models with ensuring solution accuracy and providing high computational efficiency. Among these methods, the CMFD formulation coupled with analytic nodal method based on two-node kernel has been approved to provide the best performance in terms of computing time as well as accuracy for solving problems structured with two energy groups which is appropriate for analyzing the thermal reactors having describe thermal and fast regions. PARCS also provides the numerical methods solving multigroup problems to be applied to the innovative cores such as reactors loading mixed oxide fuels or the fast breed reactors. However, they are not optimized and take a lot of calculating time as much as not applicable for real cores. So, it was planned to implement the efficient multigroup solution in order to improve capability of multigroup calculation in PARCS