Steam Oxidation, Burst and Critical Heat Flux Testing of FeCrAl Cladding in the Severe Accident Test Station

Steam Oxidation and Burst Testing in the Severe Accident Test Station

“…Initial characterization showed relatively small crack sizes for experiments up to 76 MPa hoop stresses. Additional testing with higher stresses is in progress and will be reported in a future report [28].…”

“…This report summarizes recent work (1) to evaluate FeCrMo compositions as an alternative to FeCrAl and address some of the fundamental issues about protective Cr2O3 scale formation in high temperature steam and (2) report initial LOCA burst testing. Additional SATS integral and steam oxidation testing for FeCrAl is reported elsewhere [26,28].…”

Report Summarizing Boiling Transition (Dryout) Testing of FeCrAl Cladding

“…The C26M tube is much more oxidation resistant than the Zircaloy-2 tube. Previously, a 1-2µm thick oxide was observed to form on Zircaloy-4 after 12 cycles to 650°C, while no oxide was observable on C26M [9]. In addition to oxide formation, internal oxidation (including both O and H ingress) of Zr-based cladding is expected to degrade performance and post-exposure characterization is in progress to determine the depth of ingress.…”

“…In the severe accident test station (SATS) located at Oak Ridge National Laboratory (ORNL), a novel experiment has been developed to gauge accident tolerance of fuel cladding materials under simulated cyclic dryout conditions [9,10] by modifying the parameters of a standard loss of coolant accident (LOCA) experiment [11]. Approximately ~30 cm lengths of cladding material (containing zirconia filler rods meant to imitate the internal volume occupation and thermal mass of fuel) were internally pressurized with Ar and subjected to thermal cycling in a steam environment.…”

“…Zircaloy 2). However, Accident Tolerant Fuel (ATF) cladding materials, such as iron-chromium-aluminum (FeCrAl) alloys, have the potential to withstand much longer dryout durations due to their improved oxidation resistance and enhanced mechanical properties relative to Zr-based claddings [4][5][6][7][8][9]. However, no standard experiment exists to demonstrate this benefit.…”