抄録
A dry method is one of practical methods for decommissioning the TEPCO's Fukushima Daiichi nuclear power station. Japan Atomic Energy Agency (JAEA) has been evaluating the air cooling performance of the fuel debris by using the JUPITER code based on an incompressible fluid model. However, the JUPITER code requires a large computational cost to capture complicated debris’ structures at the actual scale. To accelerate such air cooling analyses, we use the CityLBM code, which is based on the lattice Boltzmann method (LBM) and is highly optimized for GPUs. The CityLBM code is validated against free convective heat transfer experiments at JAEA, and the similar accuracy as the JUPITER code is confirmed regarding the prediction capability of heat transfer and the resulting temperature distributions. It is also shown that the elapse time of a CityLBM simulation on GPUs is reduced to 1/6 compared with that of the corresponding JUPITER simulation on CPUs, when the same number of GPUs and CPUs are used. In a large-scale problem, high performance of 61 × 103 MLUPS (Megalattice update per second) is achieved with 1.95 × 109) mesh on 216 GPUs. The results show that the LBM is promising for accelerating extreme scale thermal convective simulations.
