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DOE OSTI · 1261241

Improved Quasi-Static Method: IQS Method Implementation for CFEM Diffusion in Rattlesnake

Prince, Zachary M.·Ragusa, Jean C.·Wang, Yaqi
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Abstract

The improved quasi-static (IQS) method is a transient spatial kinetics method that involves factorizing flux into space- and time-dependent components. These components include the flux’s power and shape. Power is time-dependent, while the shape is both space- and time-dependent. However, the impetus of the method is the assumption that the shape is only weakly dependent on time; therefore, the shape may not require computation at every time step, invoking the quasi-static nature. This paper describes the implementation and testing of IQS as an alternative kinetics solver within Rattlesnake to provide improved time performance with minimal reduction in accuracy.

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22 GENERAL STUDIES OF NUCLEAR REACTORS97 MATHEMATICS AND COMPUTINGACCURACYDIFFUSIONFITIE ELEMENT METHODIMPLEMENTATIONKINETICSPERFORMANCEquasistaticR CODESRattlesnakereactorSHAPESPACE DEPENDENCETESTINGTIME DEPENDENCEtransient

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Prince, Zachary M., Ragusa, Jean C., Wang, Yaqi. 2016-02-29. Improved Quasi-Static Method: IQS Method Implementation for CFEM Diffusion in Rattlesnake. https://doi.org/10.2172/1261241

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