Considerations on long-term safety

Building upon the results of comprehensive investigations, the Federal Office for Radiation Protection (BfS) has developed its decommissioning concept for the Morsleben repository. In 2005, the BfS submitted the documents to the licensing authority, the Ministry of Agriculture and Environment of the Federal State of Saxony-Anhalt (MLU) and presented them to the general public. According to this concept, the decommissioning will consist of widely backfilling the mine, sealing the emplacement areas and the shafts. An important component of the nuclear licensing procedure required for decommissioning are considerations on long-term safety. Morsleben is the first radioactive waste repository that is intended to be decommissioned under nuclear law.

Public presentation of the plan documents 2009

With the consent of the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU), the BfS submitted the documents to the licensing authority in 2005 for public participation. Following several expert talks and comprehensive references, recommendations, and requirements by the licensing authority, part of which already referred to further, more detailed testing and licensing documents, the documents required for public participation were completely revised and again submitted in January 2009 with the consent of the BMU. The licensing authority concluded the examination of these documents in September 2009 and confirmed that they were suitable for being displayed in the public participation procedure. Once the documents were displayed to the public at the end of 2009, affected citizens could raise objections against the project. The objections were discussed in a public hearing that took place in October 2011.

Statement on the long-term safety assessment

After the public hearing, the BMU asked the federal Nuclear Waste Management Commission (ESK) in 2011 to examine as to whether the long-term safety considerations carried out by the BfS were in correspondence with the state of the art of science and technology in terms of methodology. Following comprehensive consultations, the ESK presented its statement "Long-term safety assessment for the Morsleben repository for radioactive waste (ERAM)" on 31 January 2013. Apart from the BfS documents, it was based on the BMU safety requirements on the disposal of heat-generating radioactive waste and the SSK statement on the radiological requirements for the long-term safety of the ERAM, which had not been available at the time the BfS carried out its long-term safety considerations.

Adaptation to the state of the art of science and technology

In its statement, the ESK comes to the conclusion that the long-term safety considerations carried out by the BfS should be adapted to the current state of the art of science and technology which has further developed since the licensing procedure on decommissioning began. The BMU has fully adopted the recommendations of the ESK and has tasked the BfS with their implementation.

Implications for the duration of decommissioning

In its recommendations, the ESK stated that "the proof of long-term safety was feasible with reasonable effort". By way of derogation, it had been the BfS position right from the outset that a processing time of several years was required for the implementation of the ESK recommendations, which would affect the overall duration of the project. The reason for this is that the safety considerations are carried out on the basis of interim evaluations and basic data. If these basic data or interim evaluations are changed, this results in major impacts on the safety considerations built on them. Furthermore, there are numerous cross connections among the individual documents, so that many documents must be revised to secure the required consistency.

On 25/26 June 2014, the BfS invited to an extended project status discussion which was attended by the Ministry of Agriculture and Environment (MLU) Saxony-Anhalt as licensing authority, the Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (BMUB) as functional and legal control body, and the planners and experts involved. In the project status discussion, the different points of view between licensing authority and operator regarding the content and the duration of the necessary revision of the procedural documents were exchanged.

Current work on the implementation of the ESK recommendations

Based on this stocktaking of June 2014, the parties involved have since been working to develop an effective form of the plan-approval procedure. First aspects covered by the ESK recommendation have meanwhile been processed. For example, the recommendation regarding the period of long-term proof has been dealt with and co-ordinated with the ESK. Likewise, the plausibility of the results from the calculation on long-term safety based on randomly selected data sets has been examined (recommendation 2).

As to whether the long-term safety considerations required for the decommissioning of the Morsleben repository are in full compliance with the advanced state of the art of science and technology once the ESK recommendations have been implemented, must be re-examined when the revision has concluded. With good reason, the requirements for the planning documents for the decommissioning of the Morsleben repository are high. The safe decommissioning of the repository to protect man and environment and in compliance with the state of the art of science and technology is of top priority. At the same time, the ongoing development of the state of the art of science and technology is a challenge for the preparation, revision and period of validity of planning documents. For several years, the BfS has therefore been promoting a reorganisation of the licensing procedure.