b'Figure 2. Pulverization thresholdof 75 GWd/MTU. Several sensitivityon cladding balloon and burst was developed by Turnbull et al.studies were performed to gain aevaluated. For both scenarios, time validated to all publicly availabledeeper understanding of the mecha- to failure decreased as rod internal integral LOCA test performed on high burnup fuel. nisms that could lead to or reduce thepressure increased, and the size of the amount of fuel susceptible to HBFF.balloon was relatively consistent. It The first study evaluated the impactwas noted that large changes in time of peak cladding temperature (PCT).to failure of ~10 seconds resulted The results indicate that (1) increasingin a significant decrease in balloon PCT drastically decreased time tosize. Lastly, fuel susceptibility to HBFF failure, and (2) calculated balloonwas calculated for two cases: 800C size was consistent with the literature.and 1,000C. The lower temperature Secondly, the effect of pre-transientcase resulted in significantly less fuel and transient rod internal pressurebeing susceptible to HBFF, and both 96 2020|AFC ACCOMPLISHMENTS'