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Dual Purpose Casks for Spent Nuclear Fuel

Joint Working Group on Guidance for an Integrated Transport and Storage Safety Case for Dual Purpose Casks for Spent Nuclear Fuel

International Workshop - May 2014

An "International Workshop on the Development and Application of a Safety Case for Dual Purpose Casks for Spent Nuclear Fuel" was held on 19 to 21 May, 2014. Terms of Reference

The purpose of the workshop was to enhance the participants’ understanding of the proposed concept of an integrated safety case for DPCs, to analyze the gap between the current practices within Member States and the proposed concept and to discuss ways of further improving the application of this concept. Fifty-four participants from 19 countries and the European Union were represented at the Workshop.

Presentation materials; meeting summary


Spent nuclear fuel that is generated in the operation of nuclear reactors needs to be safely managed following its removal from the reactor core. Reactor storage pools were designed on the assumption that after a short period of time spent nuclear fuel would be removed for reprocessing, disposal or storage elsewhere. Owing to delays in making decisions on the disposition of spent fuel and in putting decisions into effect, the volume of highly radioactive spent fuel that needs to be stored is growing, and additional storage capacity is required.

In June 2010, the IAEA hosted the International Conference on Management of Spent Fuel from Nuclear Power Reactors. At this conference, strategies were discussed, as well as the framework for the safety of spent fuel management. Several Member States presented their projects for utilizing the concept of a so-called dual purpose cask (DPC) as an attractive option owing to their flexibility and efficiency in the handling of spent fuel. The management of spent fuel using a DPC involves both the storage of spent fuel and its transport before and after storage.

Following the conference, the IAEA initiated a Working Group (WG) in April 2011 to develop guidance for Member States for an integrated safety case for DPCs for the transport and storage of spent fuel, with the support of both the Transport Safety Standards Committee (TRANSSC) and the Waste Safety Standards Committee (WASSC).

At present most Member States in which DPCs are used require a transport licence for the transport of DPCs. In many Member States, a licence for the storage of spent fuel in a DPC or a licence for a storage facility that contains DPCs is also a requirement.

To improve the licensing process, the concept of a ‘holistic approach’ to the licensing process for DPCs was proposed at the conference. This approach allows for the licensing of DPCs to take into consideration the interface issues arising between storage and transport, and to develop an integrated safety case and conduct supporting safety assessments. At the conference, Member States agreed to move forward in developing guidance for integrated safety cases for storage and transport of DPCs. It was suggested that the IAEA explore this issue further.


The objectives of the WG are:

  • To develop guidance for the structure and content of an integrated safety case for a DPC. Such guidance would support the application for approval of the package design for transport and the application for the licensing of the storage facility (as part of the safety case for the storage facility). The document  will include technical considerations for up to 100 years of storage and transport of the casks, irrespective of how the safety case and supporting safety assessment process is addressed within individual national regulatory frameworks. The guidance aims to assist various stakeholders, including operators, regulators and technical support organizations, who are interested in the development or review of the safety case and supporting safety assessments
  • To provide suggestions for revisions to be made to existing IAEA standards relevant to the licensing and use of storage and transport casks

The integrated safety case will consider scientific and technical arguments while demonstrating compliance with the Regulations for the Safe Transport of Radioactive Material (IAEA Safety Standards Series No. SSR-6). Compliance with national regulations for the dry storage of spent fuel as they apply to the DPC during storage will also be addressed.

The guidance will consider various aspects of the demonstration of safety, including acceptance criteria, consideration of the ageing of spent fuel and of materials used for the safety related cask structure, and methods for inspecting casks for transport after storage.

The initial scope of the WG is limited to dual purpose metal storage and transport casks, and to dry storage in casks.

Working Methods and Activities

First Technical Meeting

The first technical meeting of the WG was held in Vienna in April 2011. At this meeting, the WG agreed on a three-year term for completion of its work and prepared the Terms of Reference. It was agreed that the initial structure of the Storage and Transport Cask Safety Case be based on a template provided in the Technical Guide — Package Design Safety Reports for the Transport of Radioactive Material. It was also agreed that the WG would hold its plenary meetings once a year with consultants meetings in between as necessary.

The target date for completion of the work of the WG was set as the end of 2013.

Second Technical Meeting

The second technical meeting of the WG was held in April 2012. At the meeting, the guidance document was further developed. In addition, draft recommendations to WASSC/TRANSSC were discussed. Furthermore, integration and/or expansion of the scope of the WG in the future were discussed, including the concept of multipurpose casks, DPCs for high level waste and a test case for use of the guidance document.

Third and Final Technical Meeting

The third and final meeting was held from 8-12 April 2013, and the draft document was further improved for finalization. On completion of drafting, the document will be processed for publication.

Recommendations to TRANSSC and WASSC were also prepared. Future work plans were discussed and it was agreed to organize a workshop in which to exchange international practice on developing and utilizing a safety case for DPCs as well as associated issues.

The latest version of the draft document, “Preparation of a Safety Case for a Dual Purpose Cask for Storage and Transport of Spent Fuel” was developed by the Joint Working Group.


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| Last update: Friday, 10 February, 2017.