3-D COUPLED SIMULATION OF A VVER 1000 WITH PARCS/ATHLET

A new OECD/NEA benchmark entitled “Reactivity compensation with diluted boron by stepwise insertion of control rod cluster” is starting. This benchmark, based on high quality measurements performed at the NPP Rostov Unit 2, aims to validate and assess fidelity multi-physics simulation code capabilities. The Benchmark divided in two phases: assembly wise pin-by-pin resolution steady-state transient problems. Multi-physics requires generation parametrized few-group cross-sections. task used be done deterministic (2-D) lattice codes, but past few years Monte-Carlo SERPENT has demonstrate its ability generate accurate homogenized cross-section without approximations, neither geometry nor nuclear data. Since whole core models for production such libraries would computationally costly (and standard 2-D approach may introduce unnecessary large approximations), 3-D each type infinite radial configurations have been created. These cross-sections are then evaluate effective multiplication factors different diffusion PARCS. results compared reference calculations. In next step, a thermal-hydraulic model system ATHLET applying an assembly-wise description (i.e. one channel per fuel assembly) developed coupled PARCS/ATHLET test paper describes detail techniques parameterized cross section libraries, PARCS model. Additionally, simple exercise presented analysed.