A new coarse-mesh radiation transport (COMET) method for modeling and simulation of realistic reactor cores (e.g., operating water reactors) is presented at this colloquium. This innovative method has Monte Carlo accuracy while having computational efficiency that is several orders of magnitude better than achievable by stochastic and fine-mesh deterministic transport methods. Benchmark results in several whole-core problems typical of operating reactors are presented to demonstrate the accuracy and efficient of the method. The new method overcomes many of the limitations inherent in current whole-core (loosely coupled transport/diffusion theory) methods used in the industry. Notable limitations/approximations are single lattice transport theory calculations with approximate boundary conditions (e.g., full specular reflection), cross section homogenization, ad hoc de-homogenization (fuel pin reconstruction) and whole-core homogenized diffusion theory calculations. These approximations breakdown with increasing assembly and core heterogeneities, features encountered in advanced and next generation reactor designs. We first present an overview of current industry methods, research directions and critical gaps in the context of advanced and Generation IV nuclear reactors. The limitations of current methods and reactor design trends are highlighted as motivation for the developments of the advanced radiation transport methods by the Computational Reactor and Medical Physics Group (CRMPG) at Georgia Tech.
Dr. Farzad Rahnema received his PhD from the University of California in Los Angeles in 1981. He joined Georgia Institute of Technology in October 1992 and is currently Professor and Chair of the Georgia Tech Nuclear and Radiological Engineering and Medical Physics Programs. He also holds an adjunct Professor appointment at the Emory University Radiation Oncology Department. From 1981 to 1992, Dr. Rahnema was at General Electric Nuclear Energy and was responsible for Monte Carlo Benchmark Methods and GE’s 3-D Nuclear/Thermal Hydraulics BWR Core Simulator PANACEA used for core design and monitoring. He led the development of three versions (8-10) of the simulator.
Dr. Rahnema’s recent research activity and interest have been in the areas of reactor and medical physics methods development, transport theory, perturbation theory and variational methods. He is a Fellow of the American Nuclear Society (ANS) and Chair of the ANS Mathematics and Computation Division.