Analysis of loss-of-flow accidents for the nist research reactor with fuel conversion from heu to leu

J. S. Baek, A. Cuadra, L. Y. Cheng, A. L. Hanson, N. R. Brown, D. J. Diamond

    Research output: Contribution to journalArticle

    2 Citations (Scopus)

    Abstract

    A program is underway to convert the current high-enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel in the 20-MW D2O-moderated research reactor (NBSR) at the National Institute of Standards and Technology. A RELAP5 model has been developed to analyze postulated accidents in the NBSR with the present HEU fuel and a proposed LEU fuel. The model includes the reactor vessel, primary pumps, shutdown pumps, various valves, heat exchangers, and average and hottest fuel elements and flow channels in the region where flow enters through an inner plenum (6 fuel elements) and a region where flow enters through an outer plenum (24 elements). The equilibrium cycle power distributions in the fuel elements were determined based on three-dimensional Monte Carlo neutron transport calculations performed with the MCNPX code. In this paper we discuss safety analyses conducted for the loss-of-flow accidents resulting from either loss of electrical power or inadvertent throttling of flow control valves at the inlets to the inner and outer plena. The analysis shows that the fuel conversion will not lead to significant changes in the safety analysis and that the calculated maximum clad temperatures, minimum critical heat flux ratios, and minimum onset of flow instability ratios assure that there is adequate margin to fuel failure.

    Original languageEnglish (US)
    Pages (from-to)71-86
    Number of pages16
    JournalNuclear Technology
    Volume189
    Issue number1
    DOIs
    StatePublished - Jan 1 2015

    Fingerprint

    Research reactors
    accidents
    Accidents
    reactors
    nuclear fuel elements
    Uranium
    uranium
    safety
    Pumps
    throttling
    pumps
    fuel flow
    control valves
    shutdowns
    Plant shutdowns
    Channel flow
    heat exchangers
    Flow control
    Heat exchangers
    vessels

    All Science Journal Classification (ASJC) codes

    • Nuclear and High Energy Physics
    • Nuclear Energy and Engineering
    • Condensed Matter Physics

    Cite this

    Baek, J. S., Cuadra, A., Cheng, L. Y., Hanson, A. L., Brown, N. R., & Diamond, D. J. (2015). Analysis of loss-of-flow accidents for the nist research reactor with fuel conversion from heu to leu. Nuclear Technology, 189(1), 71-86. https://doi.org/10.13182/NT13-124
    Baek, J. S. ; Cuadra, A. ; Cheng, L. Y. ; Hanson, A. L. ; Brown, N. R. ; Diamond, D. J. / Analysis of loss-of-flow accidents for the nist research reactor with fuel conversion from heu to leu. In: Nuclear Technology. 2015 ; Vol. 189, No. 1. pp. 71-86.
    @article{654c58fb53974fde9f978b3f2f747243,
    title = "Analysis of loss-of-flow accidents for the nist research reactor with fuel conversion from heu to leu",
    abstract = "A program is underway to convert the current high-enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel in the 20-MW D2O-moderated research reactor (NBSR) at the National Institute of Standards and Technology. A RELAP5 model has been developed to analyze postulated accidents in the NBSR with the present HEU fuel and a proposed LEU fuel. The model includes the reactor vessel, primary pumps, shutdown pumps, various valves, heat exchangers, and average and hottest fuel elements and flow channels in the region where flow enters through an inner plenum (6 fuel elements) and a region where flow enters through an outer plenum (24 elements). The equilibrium cycle power distributions in the fuel elements were determined based on three-dimensional Monte Carlo neutron transport calculations performed with the MCNPX code. In this paper we discuss safety analyses conducted for the loss-of-flow accidents resulting from either loss of electrical power or inadvertent throttling of flow control valves at the inlets to the inner and outer plena. The analysis shows that the fuel conversion will not lead to significant changes in the safety analysis and that the calculated maximum clad temperatures, minimum critical heat flux ratios, and minimum onset of flow instability ratios assure that there is adequate margin to fuel failure.",
    author = "Baek, {J. S.} and A. Cuadra and Cheng, {L. Y.} and Hanson, {A. L.} and Brown, {N. R.} and Diamond, {D. J.}",
    year = "2015",
    month = "1",
    day = "1",
    doi = "10.13182/NT13-124",
    language = "English (US)",
    volume = "189",
    pages = "71--86",
    journal = "Nuclear Technology",
    issn = "0029-5450",
    publisher = "American Nuclear Society",
    number = "1",

    }

    Baek, JS, Cuadra, A, Cheng, LY, Hanson, AL, Brown, NR & Diamond, DJ 2015, 'Analysis of loss-of-flow accidents for the nist research reactor with fuel conversion from heu to leu', Nuclear Technology, vol. 189, no. 1, pp. 71-86. https://doi.org/10.13182/NT13-124

    Analysis of loss-of-flow accidents for the nist research reactor with fuel conversion from heu to leu. / Baek, J. S.; Cuadra, A.; Cheng, L. Y.; Hanson, A. L.; Brown, N. R.; Diamond, D. J.

    In: Nuclear Technology, Vol. 189, No. 1, 01.01.2015, p. 71-86.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Analysis of loss-of-flow accidents for the nist research reactor with fuel conversion from heu to leu

    AU - Baek, J. S.

    AU - Cuadra, A.

    AU - Cheng, L. Y.

    AU - Hanson, A. L.

    AU - Brown, N. R.

    AU - Diamond, D. J.

    PY - 2015/1/1

    Y1 - 2015/1/1

    N2 - A program is underway to convert the current high-enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel in the 20-MW D2O-moderated research reactor (NBSR) at the National Institute of Standards and Technology. A RELAP5 model has been developed to analyze postulated accidents in the NBSR with the present HEU fuel and a proposed LEU fuel. The model includes the reactor vessel, primary pumps, shutdown pumps, various valves, heat exchangers, and average and hottest fuel elements and flow channels in the region where flow enters through an inner plenum (6 fuel elements) and a region where flow enters through an outer plenum (24 elements). The equilibrium cycle power distributions in the fuel elements were determined based on three-dimensional Monte Carlo neutron transport calculations performed with the MCNPX code. In this paper we discuss safety analyses conducted for the loss-of-flow accidents resulting from either loss of electrical power or inadvertent throttling of flow control valves at the inlets to the inner and outer plena. The analysis shows that the fuel conversion will not lead to significant changes in the safety analysis and that the calculated maximum clad temperatures, minimum critical heat flux ratios, and minimum onset of flow instability ratios assure that there is adequate margin to fuel failure.

    AB - A program is underway to convert the current high-enriched uranium (HEU) fuel to low-enriched uranium (LEU) fuel in the 20-MW D2O-moderated research reactor (NBSR) at the National Institute of Standards and Technology. A RELAP5 model has been developed to analyze postulated accidents in the NBSR with the present HEU fuel and a proposed LEU fuel. The model includes the reactor vessel, primary pumps, shutdown pumps, various valves, heat exchangers, and average and hottest fuel elements and flow channels in the region where flow enters through an inner plenum (6 fuel elements) and a region where flow enters through an outer plenum (24 elements). The equilibrium cycle power distributions in the fuel elements were determined based on three-dimensional Monte Carlo neutron transport calculations performed with the MCNPX code. In this paper we discuss safety analyses conducted for the loss-of-flow accidents resulting from either loss of electrical power or inadvertent throttling of flow control valves at the inlets to the inner and outer plena. The analysis shows that the fuel conversion will not lead to significant changes in the safety analysis and that the calculated maximum clad temperatures, minimum critical heat flux ratios, and minimum onset of flow instability ratios assure that there is adequate margin to fuel failure.

    UR - http://www.scopus.com/inward/record.url?scp=84923098519&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=84923098519&partnerID=8YFLogxK

    U2 - 10.13182/NT13-124

    DO - 10.13182/NT13-124

    M3 - Article

    AN - SCOPUS:84923098519

    VL - 189

    SP - 71

    EP - 86

    JO - Nuclear Technology

    JF - Nuclear Technology

    SN - 0029-5450

    IS - 1

    ER -