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DOE OSTI · 23178706

Development and benchmarking of transient nodal code SIMULATE5-K neutron kinetics solver

Bahadir, Tamer
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Abstract

SIMULATE5-K is Studsvik's next generation best estimate transient code. The time dependent diffusion equation is solved with a nodal method consistent with that implemented in the licensed core design code SIMULATE5. Arbitrary number of neutron and delayed neutron precursor groups can be used. For the solution of the spatial problem, the coupling coefficients used to relate the node leakages are found by first converting the time dependent diffusion equation to a static diffusion equation with the use of flux and delayed neutron precursor dynamic frequencies. Once the static-like equations are obtained, the multi-group analytical nodal model is used to obtain the coupling coefficients, expressing the node leakage in terms of adjacent node average fluxes. The coupling coefficients are then inserted into the time dependent nodal balance equation. For the time integration, the time dependent neutron balance equation is solved with the frequency transformation method. The treatment of the temporal dependence yields a fixed source problem which can be solved utilizing the existing fixed-source methodology. The primary purpose of this paper is to describe the neutron kinetics methodology implemented in SIMULATE5-K. The accuracy of the method is demonstrated for a series of well-known, neutronic-only benchmark problems. (author)

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21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTSBENCHMARKSCOMPUTERIZED SIMULATIONMULTIGROUP THEORYNEUTRON DIFFUSION EQUATIONREACTOR KINETICS EQUATIONSS CODESTRANSIENTSVALIDATIONWATER COOLED REACTORS

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Bahadir, Tamer. 2022-07-01. Development and benchmarking of transient nodal code SIMULATE5-K neutron kinetics solver. https://www.osti.gov/biblio/23178706

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