Design Assessment by BAM of a New Package Design for the Transport of SNF from a German Research Reactor

For disposal of the research reactor of the Technical University Munich FRM II a new transport and storage cask design was under approval assessment by the German authorities. This new design has been assessed by BAM in view to the mechanical and thermal safety analyses, the activity release approaches and subjects of quality assurance.The cask body is made of ductile cast iron and closed by two bolted lid Systems. On each end of the cask a wood-filled impact limiter is installed to reduce impact loads to the cask under drop test conditions.For the safety analyses of the package a combination of experimental testing and analytical/numerical calculations were applied. In total, four drop tests were carried out at the BAM large drop test facility. Two tests were carried out as a full IAEA drop test sequence consisting of a 9m drop test and a 1m puncture bar drop test. The other two drop test were performed as single 9m drop tests.The main objectives of the drop tests were the investigation of the integrity of the package and its safety against release of radioactive material as well as the test of the fastening system of the impact limiters. Furthermore, the acceleration and strain signals measured during the tests were used for the verification of FEA used for the safety analysis of the package design.Additional calculations by using the verified numerical model were done by the applicant and assessed by BAM to investigate e.g. the brittle fracture of the cask body made of ductile cask iron within the package design approval procedure.This paper describes the package design assessment from the point of view of the competent authority BAM including the applied assessment strategy, the conducted drop tests and the additional calculations by using numerical and analytical methods.Submitted for oral presentation.