Outstanding NE Research Award 2004

Hany S. Abdel-Khalik
Ph.D. Candidate
Department of Nuclear Engineering, NC State University

Project title: Adaptive Core Simulation

Research Advisor: Paul J. Turinsky

Abstract: Use of adaptive simulation is intended to improve the fidelity and robustness of important core attributes predictions such as core power distribution, thermal margins and core reactivity. Adaptive simulation utilizes a selected set of past and current reactor measurements of reactor observables, i.e. in-core instrumentation readings, to adapt the simulation in a meaningful way. A meaningful adaption will result in high fidelity and robust adapted core simulators models. To perform adaption, we propose an inverse theory approach in which the multitudes of input data to the core simulator, i.e. reactor physics and thermal-hydraulic data, are to be adjusted to improve agreement with measured observables while keeping core simulators models unadapted. At a first glance, devising such adaption for typical core simulators with millions of
input and observables data would spawn not only several prohibitive challenges such as the computational burden associated with the required sensitivity-type calculations, but also disparaging concerns such as the possible unphysical adjustments of input data. We demonstrate that the power of our proposed approach is mainly driven by taking advantage of this unfavorable situation. We introduce a novel subspace sensitivity analysis approach and demonstrate its successful use for a typical BWR core simulator adaption problem.