Uncertainty quantification for severe-accident reactor modelling: Set-up and first results of the Horizon-2020 project MUSA

The current Horizon-2020 project on “Management and Uncertainties of Severe Accidents (MUSA)” aims at applying Uncertainty Quantification (UQ) in the modelling (SA), particularly predicting radiological source term mitigated unmitigated accident reactor scenarios. A selected number severe sequences different nuclear power plant designs (e.g. PWR, VVER, BWR) are addressed. application Best Estimate Plus (BEPU) methodology to scenarios requires a key steps: (i) selection for each design; (ii) development reference input model specific design SA-code; (iii) definition figures merit UQ-analysis; (iv) list uncertain parameters be investigated; (v) choice statistical tool propagate deck uncertainties; (vi) feasible approach (i.e., Monte Carlo versus order statistics) address UQ by using software UQ-tools DAKOTA, SUSA, URANIE, etc.); (vii) running phase achieve high successful realizations with SA codes; and, (viii) evaluation results sensitivity analysis). This paper describes these steps such as settled applications work package EU MUSA pays particular attention choices made partners. It presents preliminary also an emphasis major challenges posed BEPU field analysis.