Sefdan analyses of NRU full-length high-temperature tests

Since the reactor accident occurred at the Three Mile Island Unit-2 Reactor (TMI-2) on March 28, 1979, considerable effort has been devoted worldwidely to experimental and analytical researches in order to shed light on the severe fuel damage process. Despite the extensive effort, the process has not been fully understood even in early stage of accident in which the major relocation of fuel rod material does not start. Especially the phenomena not clearly understood were; the maximum temperature of fuel rod to be reached, and the controlling mechanisms on temperature turnaround and on relocation. In order to more profoundly understand such severe fuel damage phenomena, a computer code SEFDAN with one-dimensional core thermal hydraulics was developed in Japan Atomic Energy Research Institute (JAERI), and SEFDAN was applied to analyses of typical severe fuel damage (SFD) tests and accident