INVESTIGATION OF SPENT FUEL INTEGRITY IN DRY STORAGE AT JAPANESE NUCLEAR POWER PLANTS - Presentation

 In Japan, the first spent fuel interim storage facility away-from-reactor will start its operation in 2012. This facility stores BWR / PWR spent fuel assemblies using dual purpose (storage / transport) metallic dry casks which will be transported to their destinations after the interim storage for decades. This facility is not equipped with a hot-cell for opening the primary lid of the cask because one of the basic concepts of the facility is a simple operation not to handle a radioactive material directly, that reduces radiation exposure of workers and a risk of contamination troubles. On the other hand, a visual inspection of spent fuel assemblies is usually carried out before spent fuel transportation in Japan. Although a visual inspection of spent fuel assemblies is not carried out in the interim storage facility as has been discussed, we consider that it is necessary to confirm spent fuel integrity by the same level of confirmation as visual inspection before transportation after the interim storage. For this purpose, we will establish a quality control system of metallic dry casks from manufacturing to the end of storage, and for more conservatism, we are continuously investigating spent fuel integrity in dry storage at the nuclear power plants. This paper introduces results and future plans of our investigation of spent fuel integrity in dry storage in Japan. (The investigation was also aimed at the integrity of metal gasket.)