Neutronic and Thermal hydraulic evaluation of accident tolerant cladding materials in a WWER1000

The concept of Accident Tolerant Fuel (ATF) claddings is developed to improve the safety of light water reactors (LWRs). The main objective of this work is neutronic and Thermal Hydraulic (TH) analysis of potential cladding materials in a WWER1000. In this analysis, the ZrC, TiC, SiC and FeCrAl are evaluated as enhanced alternatives for traditional Zircaloy-4. For neutronic analysis, Monte Carlo particle transport method is used. For thermal hydraulic analysis, the performance of the materials in unmitigated small break LOCA is evaluated by MELCOR. Assessments show that ATFs can delay the failure of reactor pressure vessel (RPV) and core melting by reducing the heat generated from oxidation reaction. The TiC and FeCrAl claddings are more reliable in the accident, but they are not desirable from the perspective of the Neutronics. The calculations demonstrate that ZrC and SiC can be excellent alternatives to the Zircaloy-4. Also, simulations show using TiC and FeCrAl as a 0.1 mm thick covering of the Zircaloy-4 improves the multiplication factor, but it is not sufficient.