Gabrielli, F.

Hoefer, A.

Pauli, E.

Sanchez-Espinoza, V. H.

Stakhanova, A.

English

KITopen

Preliminary Uncertainty and Sensitivity Analysis of the ASTEC simulations results of a MBLOCA scenario at a Generic KONVOI Plant using FSTC toolThe 10th European Review Meeting on Severe Accident Research (ERMSAR2022), Akademiehotel, Karlsruhe, Germany, May 16-19, 2022Stakhanova A, Gabrielli F, Sanchez-Espinoza V. H - Karlsruhe Institute of Technology (KIT)Pauli E, Hoefer A - Framatome GmbHERMSAR Talk 327www.kit.eduKIT – The Research University in the Helmholtz AssociationThe 10th European Review Meeting on Severe Accident Research (ERMSAR2022), Akademiehotel, Karlsruhe, Germany, May 16-19, 2022Slide 1/9- Work is made in cooperation with Framatome GmbH in the frame of WAME project- WAME project (2019-2022) was financed by the Federal Ministry of Economics Affairs andClimate Action (BMWi) in the frame of activity ‘Maintaining Competence in NuclearTechnology’Main goal of the project: develop methodology and the tool for fast source term prediction incase of severe accidentMore details about prediction algorithm and its application examples: in talk 311 “Prediction ofthe Radiological Consequences of a Severe Accident Scenario in a Generic KONVOI NuclearPower Plant ”IntroductionThis talk is focused on U&S analysis of severe accident simulations Generic KONVOI NPP MBLOCA scenario up to basemat rupture SA code: ASTEC 2.2b Tool for U&S analysis – in-house Fast Source Term Calculation (FSTC)FSTC tool info:- Python language- Modular structure- Coupled with ASTEC SA code- Sampling – SRS, LHS- Option of correlated uncertain input parameters- Pearson, Spearman, distance correlation coefficientsThe 10th European Review Meeting on Severe Accident Research (ERMSAR2022), Akademiehotel, Karlsruhe, Germany, May 16-19, 2022Slide 2/9Fast Source Term Calculation (FSTC) tool Scheme of FSTC tool in frame of performing source term prediction Scheme of the part of FSTC tool in frame of U&S analysisThe 10th European Review Meeting on Severe Accident Research (ERMSAR2022), Akademiehotel, Karlsruhe, Germany, May 16-19, 2022Slide 3/9KONVOI NPP ASTEC model• ASTEC 2.2b is used• All ASTEC modules are activated• Model is based on generic input deck from EU CESAM project [EC. “D40 .42 – 1st set ofreference NPP ASTEC input decks”, CESAM FP7-GA-323264, (2015).]• Fuel inventories calculated with ORIGEN-ARP code• Containment leakage to the annulus• No filtering• Simulation up to basemat rupture[Gómez-García-Toraño, I., 2017. Further development of Severe AccidentManagement Strategies for a German PWR Konvoi plant based on theEuropean Severe Accident Code ASTEC (PhD Thesis). Fakultät fürMaschinenbau, Karlsruhe Institute für Technologie, Karlsruhe, Germany.][Gabrielli F., Stakhanova A., Sanchez-Espinoza V.H., Pauli E., Hoefer A., Feldmann H., "Impact of realistic fuelinventories on the radiological consequences of a severe accident scenario in a generic KONVOI plant by means ofthe ASTEC code", Kerntechnik 2022, 21. - 22. Juni 2022, Hyperion Hotel, Leipzig, Germany]The 10th European Review Meeting on Severe Accident Research (ERMSAR2022), Akademiehotel, Karlsruhe, Germany, May 16-19, 2022Slide 4/9Uncertain input parametersParameter Meaningpar1 Correction factor for the ratio S/V of the fuel pellets due to roughnesspar2 Correction factor for the ratio S/V of the fuel pellets for the limitedsteam accesspar5 Geometrical diameter of the grainpar5a Standard deviation of geometrical diameter of the grainpar14 Threshold Temperature of the cladding Dislocation [K]par15 Threshold Temperature of the oxide layer Dislocation [K]par16 Threshold thickness of the oxide layer [mm]par31 Particle mean thermal conductivity (J/m/K)par32 Average specific heat (J/kg K) of the aerosolpar33 Particle mean density (kg/m3)par34 Particle minimum geometrical radius (m)par35 Particle maximum geometrical radius (m)par36 Shape factor relative to particle coagulationpar37 Shape factor relative to Stokes velocitypar41 Coefficient for the leakage rateparBU Effective full power days• Normal distribution – 6 parameters;• Triangular – 5; • Uniform – 4; • Beta - 1 Iman-Conover method is usedto correlate input parametersThe 10th European Review Meeting on Severe Accident Research (ERMSAR2022), Akademiehotel, Karlsruhe, Germany, May 16-19, 2022Slide 5/9Uncertainty and sensitivity analysis[Time of start of FP release and end of calculation for 200 simulations] [Example of simple statistics] [Median amount for 4 elements released in environment and containment] The 10th European Review Meeting on Severe Accident Research (ERMSAR2022), Akademiehotel, Karlsruhe, Germany, May 16-19, 2022Slide 6/9Uncertainty and sensitivity analysisUncertainty and sensitivity analysisThe 10th European Review Meeting on Severe Accident Research (ERMSAR2022), Akademiehotel, Karlsruhe, Germany, May 16-19, 2022Slide 7/9- For most of the uncertain input parameters Pearson andSpearman correlations are lying in the range [-0.1; 0.1]both for release in containment and environment- Slight effect from some input parameters could be seenat the beginning of the process on the release of low-volatile elements into the containment- In the middle of the process: effect from aerosol modelparameters on Cs and I aerosols in containmentThe 10th European Review Meeting on Severe Accident Research (ERMSAR2022), Akademiehotel, Karlsruhe, Germany, May 16-19, 2022Slide 8/9Conclusions Fast Source Term Calculation (FSTC) tool developed in KIT in the frame of theWAME project Tool has capabilities for U&S analysis and source term predictions (for thatpurpose, MOCABA algorithm developed by Framatome was implemented in thetool) U&S analysis of MBLOCA scenario on KONVOI NPP was performed usingFSTC tool and ASTEC SA code Among 16 selected uncertain input parameters the most important areparameters related to the leakage rate (between containment and annulus) andburnup Effect from parameters related to aerosols could be seen at the later stages ofthe accident – after lower head vessel failureAcknowledgementsThe project was funded by the Federal Ministry of Economics Affairs andClimate Action (BMWi), funding code FZK 1501582 (WAME project).The 10th European Review Meeting on Severe Accident Research (ERMSAR2022), Akademiehotel, Karlsruhe, Germany, May 16-19, 2022Slide 9/9Thank you for your attention!Contacts: KIT, INR; Stakhanova Anastasia, anastasia.stakhanova@kit.edu

Preliminary Uncertainty and Sensitivity Analysis of the ASTEC simulations results of a MBLOCA scenario at a Generic KONVOI Plant using FSTC tool

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Preliminary Uncertainty and Sensitivity Analysis of the ASTEC simulations results of a MBLOCA scenario at a Generic KONVOI Plant using FSTC tool

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