A SUBCHANNEL COARSENING METHOD FOR Serpent2-SUBCHANFLOW APPLIED TO A FULL-CORE VVER PROBLEM

This work presents a methodology to coarsen subchannel models to accelerate largescale Serpent2-SUBCHANFLOW calculations. The method is based on first building a fully detailed subchannel model and then combining subchannels into larger channels with condensed hydraulic parameters. To quantify the accuracy and performance of this scheme, a full-core VVER-1000 problem is simulated with Serpent2-SUBCHANFLOW using two types of coarsened models, as well as a standard subchannel model as reference.