Experimental studies on safety of dry cask storage technology of spent fuel - Allowable temperature of cladding and integrity of cask under accidents

The purpose of this report is to publish results on a comprehensive review of research subjects on safety of the dry cask storage and to publish a part of the research results. (1) A method to calculate the maximum allowable temperature of fuel cladding tvas proposed, based on experiments using irradiated and non-irradiated Zircaloy tube specimens, in order to prevent excessive creep deformation of fuel cladding in dry cask. (2) Under an accidental test of ''Cask drop onto concrete floor'', the cask integrity was demonstrated using full-scale casks (100-t class). (3) Under an accidental test of ''Building collapse and drop of heavy objects onto cask'', the cask integrity was demonstrated using a full-scale cask (100-t class). (4) As to possibility of cask toppling by earthquake, analytical and experimental results using a scale model cask shan ed that the cask will not be toppled by earthquake.