Cold neutron tomography of annular coolant flow in a double subchannel model of a boiling water reactor

J. L. Kickhofel, R. Zboray, M. Damsohn, A. Kaestner, E. H. Lehmann, H. M. Prasser

    Research output: Contribution to journalArticlepeer-review

    21 Scopus citations


    Dryout of the liquid coolant film on fuel pins at the top of boiling water reactor (BWR) cores constitutes the type of heat transfer crisis relevant for the conditions of high void fractions. It is a limiting factor in the thermal power, and therefore the economy, of BWRs. Ongoing research on multiphase annular flow, specifically the liquid film thickness, is fundamental not only to nuclear reactor safety and operation but also to that of evaporators, condensers, and pipelines in a general industrial context. We have performed cold neutron tomography of adiabatic air water annular flow in a scaled up model of the subchannel geometry found in BWR fuel assemblies today. All imaging has been performed at the ICON beamline at the neutron spallation source SINQ at the Paul Scherrer Institut in Switzerland. Neutron tomography is shown to excel in investigating the interactions of air water two phase flows with spacer vanes of different geometry. The high resolution, high contrast measurements provide spatial distributions of the coolant on top of the surfaces of the spacer, including the vanes, and in the subchannel downstream of the spacers.

    Original languageEnglish (US)
    Pages (from-to)297-304
    Number of pages8
    JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
    Issue number1
    StatePublished - Sep 21 2011

    All Science Journal Classification (ASJC) codes

    • Nuclear and High Energy Physics
    • Instrumentation


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