MELCOR modeling of Fukushima unit 2 accident

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

    Abstract

    A MELCOR model of the Fukushima Daiichi unit 2 accident was created in order to get a better understanding of the event and to improve severe accident modeling methods. The measured pressure and water level could be reproduced relatively well with the calculation. This required adjusting the RCIC system flow rates and containment leak area so that a good match to the measurements is achieved. Modeling of gradual flooding of the torus room with water that originated from the tsunami was necessary for a satisfactory reproduction of the measured containment pressure. The reactor lower head did not fail in this calculation, and all the fuel remained in the RPV. 13 % of the fuel was relocated from the core area, and all the fuel rods lost their integrity, releasing at least some volatile radionuclides. According to the calculation, about 90 % of noble gas inventory and about 0.08 % of cesium inventory was released to the environment. The release started 78 h after the earthquake, and a second release peak came at 90 h. Uncertainties in the calculation are very large because there is scarce public data available about the Fukushima power plant and because it is not yet possible to inspect the status of the reactor and the containment. Uncertainty in the calculated cesium release is larger than factor of ten.
    Original languageEnglish
    Title of host publicationProceedings [Elektronski vir] / 22nd International Conference Nuclear Energy for New Europe
    Subtitle of host publicationNENE 2013, Bled, September 9-12
    EditorsLeon Cizelj, Matjaž Leskovar, Mitja Uršič
    Number of pages9
    ISBN (Electronic)978-961-6207-36-2
    Publication statusPublished - 2013
    MoE publication typeA4 Article in a conference publication
    Event22nd International Conference Nuclear Energy for New Europe, NENE 2013 - Bled, Slovenia
    Duration: 9 Sep 201312 Sep 2013

    Conference

    Conference22nd International Conference Nuclear Energy for New Europe, NENE 2013
    Abbreviated titleNENE 2013
    CountrySlovenia
    CityBled
    Period9/09/1312/09/13

    Keywords

    • nuclear safety
    • severe accidents
    • Fukushima
    • MELCOR

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  • Cite this

    Sevón, T. (2013). MELCOR modeling of Fukushima unit 2 accident. In L. Cizelj, M. Leskovar, & M. Uršič (Eds.), Proceedings [Elektronski vir] / 22nd International Conference Nuclear Energy for New Europe : NENE 2013, Bled, September 9-12 [404] http://www.nss.si/proc/nene2013/pdf/NENE2013_404.pdf