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Recent FRAPCON and FRAPTRAN activity at VTT. Users group meeting V. Tulkki VTT Technical Research Centre of Finland. Recent FRAPCON & FRAPTRAN use at VTT. Statistical studies OECD/NEA benchmark on uncertainty analysis of best estimate modelling of light water reactors Support to STUK
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RecentFRAPCON and FRAPTRANactivity at VTT Users group meetingV. TulkkiVTT Technical Research Centre of Finland
Recent FRAPCON & FRAPTRAN use at VTT • Statistical studies • OECD/NEA benchmark on uncertainty analysis of best estimate modelling of light water reactors • Support to STUK • EPR LBLOCA • Halden LOCA experiment simulations • FRAPTRAN-GENFLO bundle simulations
Statistical studies • FRAPCON used for a statisticalstudy on input interactions • Sobol’ variancedecompositionused in analysis • Providesinformation on higherorderinteractions • Downside: ~106 FRAPCON runs • Traditionalfirst-order ranking methodscommonlyused in sensitivityanalysisnotalwayssufficientdue to complexinteractions • Discussed in OECD/NEA UAM workshops and Halden uncertainty workshop thisfall • ”The importance of input interactions in the uncertainty and sensitivityanalysis of the nuclearfuelbehavior”, T. Ikonen and V. Tulkki, submitted to Nuclear Engineering and Design • Workcontinues with FRAPTRAN analysis
LBLOCA • Comparativeanalysis for STUK on number of failedrodsduring EPR LBLOCA • Regulatoryrequirement <10% • For reference / information to STUK, notpart of officialprocess • System code APROS used for 59 globalsimulations of plantstate • 59x1000 FRAPTRAN/GENFLO subchannelanalysisused with localvariations • Resultsextended to wholecore with neuralnetworks • -> fraction of failedrods • Work in progress
Study on impact of variation of heatingpower for future Halden LOCA test • Also, simulation of the effect of spacergridsimulation • Shouldbeimplementable in the FEA model • Extension of FRAPTRAN/GENFLO hotchannelmode to bundlemodel with severalconcurrent FRAPTRAN simulations • Coupling of FRAPCON to Serpent 2 MC reactorphysicscode via universalmultiphysicsinterface • Use of FRAPTRAN for benchmarkingour FINIX fuelmodule • FINIX initializationfrom FRAPCON restart • FRAPTRAN to beused in IAEA CRP FUMAC and possibly OECD RIA phase II benchmark