| Abstract: | The possible causes of the destruction of the Chernobyl reactor core were examined by making use of the Nuclear Safety Research Reactor (NSRR) experimental results concerning the destructive forces generated by a fuel failure. A complementary experiment with Chernobyl reactor conditions was performed in order to observe the fuel failure behavior and the resultant vessel pressure rise, etc. Also, generation of hydrogen from the fuel rod cladding and the consequent system pressure rise were estimated based on the experiments.These examinations led to the conclusion that the most probable cause of the core pressure tube rupture in the accident was a static pressure rise due to rapid energy release from fragmented fuel. Other phenomena such as the hydrogen generation and molten fuel contact to the tube wall might have contributed to the tube rupture. The water hammer force is also estimated to have been large enough to break tubes even using conservative assumptions. |
