PERFORMANCE OF WHOLE CORE PIN-BY-PIN CALCULATIONS BY DOMAIN DECOMPOSITION THROUGH ALTERNATE DISSECTIONS IN STEADY STATE AND TRANSIENT CALCULATIONS

摘要

Domain decomposition through alternate dissections methodology is applied to solve the transport corrected fine mesh finite difference multigroup diffusion problem at the homogenized pin-cell scale level for full cores including a nodal acceleration. Problems are solved in parallel computer architectures and the efficiency of the coding and method is addressed for steady state problems with thermal-hydraulic feedback and transients without thermal-hydraulic feedback on the cross sections for the moment.The main objective is to be able to compute full core problems using reasonable computing times and resources, but obtaining higher detail in the flux and power distribution, with the ability to lead to detailed values of other variables such as burnup. The diffusion code COBAYA3 is able to use this development together with the cross sections feedback capability already implemented to couple with the parallelized thermal-hydraulics code COBRA-TF using the same domain decomposition approach. Computations are performed for the PWR M0X/UO_2 Core Transient Benchmark in 8 energy groups.