Exploiting Hardware-Accelerated Ray Tracing for Monte Carlo Particle Transport with OpenMC Justin Lewis Salmon, Simon McIntosh Smith Department of Computer Science University of Bristol Bristol, U.K. fjustin.salmon.2018,
[email protected] Abstract—OpenMC is a CPU-based Monte Carlo particle HPC due to their proliferation in modern supercomputer transport simulation code recently developed in the Computa- designs such as Summit [6]. tional Reactor Physics Group at MIT, and which is currently being evaluated by the UK Atomic Energy Authority for use on A. OpenMC the ITER fusion reactor project. In this paper we present a novel port of OpenMC to run on the new ray tracing (RT) cores in OpenMC is a Monte Carlo particle transport code focussed NVIDIA’s latest Turing GPUs. We show here that the OpenMC on neutron criticality simulations, recently developed in the GPU port yields up to 9.8x speedup on a single node over a Computational Reactor Physics Group at MIT [7]. OpenMC 16-core CPU using the native constructive solid geometry, and is written in modern C++, and has been developed using up to 13x speedup using approximate triangle mesh geometry. Furthermore, since the expensive 3D geometric operations re- high code quality standards to ensure maintainability and quired during particle transport simulation can be formulated consistency. This is in contrast to many older codes, which as a ray tracing problem, there is an opportunity to gain even are often written in obsolete versions of Fortran, and have higher performance on triangle meshes by exploiting the RT grown to become highly complex and difficult to maintain.