IAEA'S International Working Group on Integrated Transport and Storage Safety case for Dual Purpose Casks

Spent nuclear fuel is generated from the operation of nuclear reactors and it is imperative that it is safely managed following its removal from reactor cores. Reactor pools are usually designed based on the assumption that the fuel will be removed after a short period of time either for reprocessing, disposal, or further storage. As a result of storing higher burn-up fuel, significantly increased time-frame till disposal solutions are prepared, and delays in decisions on strategies for spent fuel management, the volume of spent fuel discharged from reactors which needs to be managed and stored is on the increase. Consequently, additional storage capacity is needed following the initial storage in reactor pools. Options for additional storage include wet storage or dry storage in a dedicated facility or in storage casks. One of these options is the use of a Dual Purpose Cask (DPC), which is a specially designed cask for both storage and transport. The management of spent fuel using a DPC generally involves on-site and off-site transportation before and after storage. Most countries require package design approval for the DPC to be transported. In addition, it is required in many countries to have a licence for storage of the spent fuel in the DPC or a licence for a storage facility that contains DPCs. Therefore, demonstration of compliance of the DPC with national and international transport regulations as well as with the storage requirements is necessary. In order to address this increasing need among Member States, the IAEA established an international working group in 2010 to develop a guidance for integrating safety cases for both storage and transport in a holistic manner. The working group consists of experts from regulatory bodies, Technical Support Organizations, operators for both transportation and storage, and research institutes. This activity is planned to be completed by 2013. Currently, a technical report has been drafted and is expected to be finalized in the near future. In this paper, the IAEA's activity on demonstration of the safety of DPCs in a holistic manner is described, and then an overview of the draft document is provided. The difference between the conventional storage cask concept and the DPC concept is also highlighted. (authors)