Progress of the CORCA-K space-time neutronics simulation code

Space-time neutronics simulation code has been widely applied to accidents analysis of pressurized water reactor power plant and technical service projects such as dynamic rod worth measurement. This paper gives a brief introduction to the progress of the self-dependent developed code CORCA-K. The CORCA-K space-time neutronics simulation code is a part of the code package NESTOR developed by CNPE. The main task of this code is to solve the three dimensional transient neutron diffusion equations with numerical methods. The spatial discretization is done by the Nodal Greens Function method with Neumann boundary condition, to keep consistency with the three dimensional static code CORCA-3D. The temporal discretization is done by the Diagonally Implicit Runge-Kutta method, which can be easily achieved on the basis of backward Euler method, and provides the code the function of automatic time step optimization. The code is verified by the three dimensional LMW/LRA benchmarks and dynamic calculation of unit 3 cycle 5 of Qinshan NPP. The verification shows that the results calculated by CORCA-K agree well with those calculated by referential codes. In addition, the code is more efficient while achieving the same accuracy level.