Modelo computacional paralelo baseado em GPU para cálculo do campo de vento de um sistema de dispersão atmosférica de radionuclídeos

Abstract

In order to improve the prediction of atmospheric dispersion of radionuclide (ADR) in vicinity of Central Nuclear Almirante Alvaro Alberto (CNAAA) Brazilian Nuclear Power Plants (NPP), a more refined computational system is under development. To achieve desired refinement, the required computational effort increases in such a way that system's execution by current computers leads to prohibitive processing time. Aiming to accelerate execution of such refined system, allowing its effective use in real-time prediction of ADR, a GPU-based parallel approach has been proposed. Basically, the ADR system used in CNAAA is comprised by 4 main modules (programs): Source Term, Wind Field, Plume Dispersion and Plume Projection modules. This work is focused on the Wind Field module, which uses a mass-consistent approach, based on Winds Extrapolated from Stability and Terrain (WEST) model. Due to the strong sequential nature of the algorithm, domain decomposition by a 3D-RedBlack partitioning was proposed and a new parallel GPU-based algorithm was implemented using the Compute Unified Device Architecture (CUDA) and C programming language. As a result, the execution time of a fine-grained simulation decreased from about 450 seconds (running on an Intel-I7) to 5,60 seconds (running on a GTX-680 GPU). Here, the most important issues of the parallel implementation, their optimization, as well as comparative results, are presented and discussed.