ETD

• accidents
• advanced
• analysis
• ATF
• cladding
• code
• FeCrAl
• hydrogen
• KIT
• MELCOR
• nodalization
• quantification
• QUENCH
• sensitivity
• severe
• technology
• uncertainty
• validation

Among several Advanced Technology Fuel (ATF) cladding candidates proposed for enhanced high-temperature performance in Light Water Reactors (LWRs), FeCrAl alloys have been identified as a promising option due to their improved oxidation resistance and their potential to reduce hydrogen generation during high-temperature transients when compared with conventional Zr-based claddings.
In this work, attention is focused on the analysis of the QUENCH-19 bundle test conducted at the Karlsruhe Institute of Technology (KIT), in which a 24-rod bundle was subjected to heat-up, steam oxidation and subsequent water quenching. The experiment was simulated using the MELCOR v2.2 integral code for which a detailed model of the experimental configuration was developed. The simulation results show good agreement with the experimental values for the key performance indicators of the QUENCH-19 test, namely the cladding temperatures and the hydrogen production. Therefore, the results indicate that MELCOR V2.2 can adequately represent the main thermal and oxidation phenomena of FeCrAl claddings under the evaluated conditions.
Furthermore, an uncertainty and sensitivity analysis (U&SA) of the MELCOR results has been performed. The uncertainty of key parameters affecting the cladding oxidation has been evaluated and its effect on selected Figure-of-Merits has been quantified. The results of the U&SA provide insight into the parameters governing the modelling response.