부산대학교 도서관

Flow blockage of the fuel assembly in the lead-based fast reactor (LFR) may produce critical local spots,which will result in cladding failure and threaten reactor safety. In this study, the flow blockage characteristics were analyzed with the sub-channel analysis method, and the circumferentially-variedmethod was employed for considering the non-uniform distribution of circumferential temperature. The developed sub-channel analysis code SACOS-PB was validated by a heat transfer experiment in ablocked 19-rod bundle cooled by lead-bismuth eutectic. The deviations between the predicted coolanttemperature and experimental values are within ±5%, including small and large flow blockage scenarios. And the temperature distributions of the fuel rod could be better simulated by the circumferentiallyvaried method for the small blockage scenario. Based on the validated code, the analysis of blockagecharacteristics was conducted. It could be seen from the temperature and flow distributions that a largeblockage accident is more destructive compared with a small one. The sensitivity analysis shows that thecloser the blockage location is to the exit, the more dangerous the accident is. Similarly, a larger blockagelength will lead to a more serious case. And a higher exit temperature will be generated resulting from ahigher peak coolant temperature of the blocked region. This work could provide a reference for thefuture design and development of the LFR