A Scaling Law Verification of the Delft Simulated Reactor (DESIRE)

Abstract

The Interfaculty Reactor Institute (IRI) is studying the fundamental parameters that drive the natural circulation flow core cooling concept that is incorporated in many advanced BWR designs with the DElft Simulated REactor, or DESIRE. This electrically-powered, freon-cooled, two-phase flow loop is an exact scaled replica of a single he1 assembly of the Netherlands' Dodewaard reactor, which used natural circulation for core cooling in normal operation. The water-to-freon scaling law analysis that was used in the design of DESIRE was based upon a simple one-dimensional drift flux model and was never independently verified. The commercial thermal hydraulic code MONA, which contains an advanced two fluid model, was recently added to the suite of analysis tools that are available at IRI. Thus, the addition of MONA allowed IRI to verify the ideal scaling law criteria that were derived based on the simpler drift flux model. This verification also revealed that the he1 rod pitch to diameter ratio of the actual scaled DESIRE facility deviates from an ideal scaled Dodewaard facility, and allowed the effect of this design distortion to be quantified. Finally, the MONA model of the actual DESIRE facility was benchmarked against experimentally measured axial void profiles. This paper describes the results of the DESIRE water-to-freon scaling law analysis verification and the MONA benchmarking activities.