NUMERICAL EVALUATION METHOD OF TDC VALUE OF REACTOR FUEL ASSEMBLY

摘要

PROBLEM TO BE SOLVED: To provide a numerical evaluation method of TDC value capable of rapidly evaluating the mixing performance of a fuel assembly at a low cost to allow the optimum design of a member effective to be performed to improve the mixing performance. SOLUTION: In the determination of TDC (thermal diffusion coefficient) of a reactor fuel assembly that is a parameter defined by a numerical expression shown in the following numerical equation 1, the average vortex heat diffusion coefficient (t )I,J of the reactor fuel assembly to be evaluated is determined by a numerical calculation method using Reynolds average model, and the determined average vortex heat diffusion coefficient (t )I,J is corrected by use of a model of large-scale turbulence structure. In the equation, (t )I,J is the average vortex heat diffusion coefficient in the boundary between sub channels I and J, lI,J is the center-to-center distance between the sub channels I and J, uI,J is the average flow velocity ((jI+uJ)/2) of flow velocities uI and uJ of the sub channels I and J. [Numerical equation 1] TDC1/lI,JuI,J(t )I,J.