Further documentation will provide clearer answers regarding the copper canister

Almost all parts of the application are approved, but the Land and Environment Court requests more documentation on the copper canister. Allan Hedin is a safety analyst at SKB and leads the work of preparing the supplementary documentation.

– We plan to be ready during this year, he says.

The court lists five different corrosion phenomena that need to be investigated further. It includes pitting corrosion, stress corrosion and hydrogen embrittlement, and the effect of radiation on these forms of corrosion.

Allan Hedin is a safety analyst at SKB. Photo: Gabriel Liljevall.

– These issues are not new and we have been working with them for several years. For some of them, further work is in progress for the safety analysis report that will be submitted to the Swedish Radiation Safety Authority in the next step, says Allan Hedin.

– The material for most of what the court requests in its opinion is ready or planned to be ready in 2018. Some minor studies may be added. It is mostly a question of additional laboratory studies and calculation analyses.

Stepwise licensing process versus here and now

SKB’s application for the Spent Fuel Repository is reviewed under two different legislations with different review procedures. In the licensing under the Environmental Code, the court says yes or no based on the documentation that is available here and now. Under the Nuclear Activities Act, there is a stepwise licensing process, where SKB needs to apply for a licence from the Swedish Radiation Safety Authority to start new steps in the repository programme, for example construction of the repository. In each step, the licensing process is based on an updated safety analysis.

The issues where the court now calls for more documentation were included in the material presented in the main hearing last autumn and SKB then provided their arguments in those parts. SKB’s opinion is that the different corrosion phenomena will not damage the copper canisters in a way that could affect long-term safety.

– We made that assessment before the main hearing in the Land and Environment Court and we stand firm in our opinion also in light of what some of the other parties argued in the hearing.

– When we left the main hearing, we thought that we had presented our arguments in these issues in a way that should have been sufficient for the court, but obviously we were not able to provide full answers in all parts.

Supplementary work

Work is now in progress with the aim to have the supplementary documentation ready during this year. After providing its opinion, the court has handed over the review of the case to the Government, where it is further processed at the Ministry of the Environment and Energy. SKB has not yet received a request from the Government to provide supplementary documentation, but we assume in our planning that we will receive such a request.

– Therefore, we will conclude the studies that we think needs to be included and prepare documentation on the individual issues and their combined significance for long-term safety. Our report will target a hypothetical reviewer with solid expert knowledge of both corrosion and safety analysis. We believe that a thorough factual review of our documentation is necessary to settle the issue credibly.