Evaluation of the safety requirements for the Konrad repository

The Bundesgesellschaft für Endlagerung (BGE) is responsible for the construction and operation of the Konrad repository for radioactive waste with negligible heat generation. The Konrad mine is being converted into a repository on the basis of the planning approval (PDF, german only, 2,41 MB) granted by the State of Lower Saxony on 22 May 2002. The planning approval was based on the state of the art of science and technology at the time. As a responsible operator, the BGE is carrying out an evaluation of the safety requirements for the Konrad repository according to the state of the art of science and technology prior to commissioning. The initial results are now available and are presented below.

Evaluation concept

In Phase 1, “Determination of the need for an evaluation”, the state of the art of science and technology at the time of the planning approval in 2002 is compared with an appropriate state of knowledge today. That is not as easy as it sounds, for the underlying documents – the planning approval and its supplementary documents – are of considerable length. With that in mind, the contractors all sought a highly systematic way of processing the source documents. The expert reports then establish whether any changes to the state of the art of science and technology have a relevant impact on the existing safety analyses of the Konrad repository. If this is the case, the affected safety analysis is then adapted in the subsequent phase – Phase 2, “Updating of safety analyses” – and further phases include a check to determine which specific changes may be necessary in relation to construction. This is then taken into account during the conversion work.

In April 2016, an initial workshop on the content, form and sequence of the evaluation was organised by the Federal Office for Radiation Protection (BfS), as the operator at the time. In order to carry out the complex project of evaluating the safety of a repository with planning approval during the construction phase with the necessary technical depth and rigour, the evaluation is being conducted in several phases based on the results of the initial workshop, among other things. In January 2019, the BGE put the preliminary closing reports from the first phase of the evaluation up for discussion at a public event in Braunschweig. The contractors then revised the reports again, incorporating the results of the workshop as well as those of the peer review report – which reviewed the methodology and content of the reports – into their final version.

Current status

The work in Phase 1 of the evaluation was put out to public tender and then carried out by various contractors on behalf of the BGE. This included identifying the aspects of the safety analyses that require more in-depth work as part of Phase 2 of the evaluation. The final reports are now available.

Contractors for safety analysis in the post-operational phase (long-term safety)

Project Konrad – Evaluation of the safety requirements for the Konrad repository according to the state of the art of science and technology.

Evaluation of safety requirements in relation to long-term safety, criticality in the post-operational phase and thermal influence on the host rock. Final report on Phase 1: Determination of the need for an evaluation in relation to the post-operational phase (PDF, German only, 1,99 MB)

• Gesellschaft für Anlagen und Reaktorsicherheit (GRS) gGmbH
• AF-Consult Switzerland Ltd.
• DMT GmbH & Co. KG

Contractors for accident analysis

Evaluation of the safety requirements for the Konrad repository according to the state of the art of science and technology – Lot 1:
Determination of the need for an evaluation in relation to the accident analyses (PDF, German only, 4,07 MB)

• DMT GmbH & Co. KG
• DSR Ingenieurgesellschaft mbH

Contractors for safety analysis of normal operation

Evaluation of the safety requirements for the Konrad repository according to the state of the art of science and technology. Determination of the need for an evaluation of the safety analysis of normal operation:
Determination of the need for an evaluation in relation to normal operation (PDF, German only, 1,23 MB)

• Brenk Systemplanung GmbH

Contractor for safety analysis in relation to ensuring subcriticality in the operational phase

Determination of the need for an evaluation in relation to subcriticality (PDF, German only, 774 KB) (PDF, 0,76MB)

• TÜV Rheinland Industrie Service GmbH

Peer review of Phase 1

In addition, the results of the contractors’ work will be reviewed by an independent peer review team to determine the extent to which they are complete, comprehensible and correct.

Evaluation of the safety requirements for the Konrad repository according to the state of the art of science and technology.
Peer review of Phase 1, “Determination of the need for an evaluation” (PDF, German only, 764 KB) (PDF, 0,75MB)

Members of the peer review team:

• Professor Klaus-Jürgen Röhlig; Institute of Disposal Research; TU Clausthal
• Christian Küppers; Nuclear Engineering & Facility Safety; Öko-Institut e.V., Darmstadt (external link)
• Professor Thorsten Schäfer; Institute of Geosciences/Applied Geology; Friedrich Schiller University, Jena (external link)
• Professor Clemens Walther; Institute of Radioecology and Radiation Protection; Leibniz University Hannover (external link, German only)

On Wednesday, 23 January 2019, the Bundesgesellschaft für Endlagerung (BGE) met with experts to discuss the results of the first phase of the evaluation of the safety requirements for the Konrad repository according to the state of the art of science and technology. The contractors then revised their interim results based on the workshop results and the peer review. The final reports from the first phase of the evaluation are now available and are presented here.

Further procedure

Based on the final reports submitted by the contractors and the peer review team, the BGE is now preparing for Phase 2 of the evaluation. In Phase 2, the safety analyses will be examined in greater depth and updated if necessary. The BGE will take account of all safety-relevant areas in need of an evaluation that were identified in Phase 1 in addition to the information provided by the contractors and peer review team. Tasks identified in the process will be arranged into topics and dealt with systematically and with the necessary care with the help of external and internal experts. The preparation and carrying out of Phase 2 will take an extended period of time. The plan is also to discuss the results of Phase 2 with the specialist community at a workshop. In addition, the results will be subject to independent peer review, as in Phase 1.