Rhines Hall, Rm 125
359 Gale Lemerand
Gainesville, Florida 32611
Please join the Department of Materials Science and Engineering and Nuclear Engineering for light refreshments and a presentation by Justin Watson, associate research professor and associate professor of nuclear engineering at The Pennsylvania State University.
Coupled multiphysics computational methods continue to evolve to meet the needs of the designers, operators and safety regulators, in order to improve predictive accuracy and precision and to evaluate complex operational or accidental scenarios. Not only are the multiphysics solvers becoming more complex but the range of problems they will solve will also grow to include generation IV reactor types. The future of safety analysis will become more complex and thus the researcher and analyst will need to be able to work across many disciplines.
Historically large physics problems have been divided into smaller problems based on the individual physics, typically referred to as Operator Splitting (OS). The analysis of a nuclear reactor for design-basis accidents is performed by a handful of computer codes each solving a portion of the problem, based on the physics involved. The reactor thermal hydraulic response to an event is determined using a system code like TRAC RELAP Advanced Computational Engine (TRACE). The core power response to the same accident scenario is determined using a spatial neutron kinetics code like Purdue Advanced Reactor Core Simulator (PARCS). Industry’s drive to up-rate power for reactors has motivated analysts to move from a conservative approach to design-basis accident towards a best estimate method. To achieve a best estimate calculation efforts have been aimed at coupling the individual physics models to improve the accuracy of the analysis and reduce margins. The current coupling techniques are sequential in nature (i.e. they treat shared data explicitly in time). During a calculation time-step data is passed between the two codes. The individual codes solve their portion of the calculation and converge to a solution before the calculation is allowed to proceed to the next time-step. This talk presents a fully implicit method of simultaneously solving the neutron balance equations, heat conduction equations and the constitutive fluid dynamics equations. The talk also outlines the basic concepts behind the nodal balance equations, heat transfer equations and the thermal hydraulic equations, which will be coupled to form a fully implicit nonlinear system of equations. It presents a monolithic method for the solution of the implicit equation set.