Safeguards Challenges At The Back-end Of The Fuel Cycle In Sweden And Finland

Finland followed by Sweden are both expected to be the first countries in the world to construct and operate facilities for the final disposal of spent nuclear fuel derived from the respective national nuclear programme. In both countries, the spent nuclear fuel will be deposited in crystalline bedrock in deep repositories. This paper discusses the similarities between the projects, but also describes relevant differences such as facility layout, site location, national legislation and concept for safeguards along with the amount and type of fuel intended for disposal. For safeguards purposes, the last possibility to verify the spent fuel assemblies is prior to the encapsulation into copper canisters, as there are no plans to open or retrieve the canisters once they have been welded and brought into the geological repository. The repository is intended to serve as a mean to safely close the nuclear fuel cycle. After backfilling, the inaccessible nuclear material may be considered as beyond the concept of difficult-to-access, i.e. repository is not a storage. This is why open-minded, even non-traditional concepts may be required in order to optimize the application of safeguards.After encapsulation the safeguards system will rely on C/S measures. The chosen measures must be reliable, robust and carefully pre-evaluated in order to avoid potential failures as it is expected that comprehensive methods would be needed to recover the assurance of correctness of the inventory. The back-end of the fuel cycle presents a unique set of challenges for safeguards, especially the geological repository where many conventional safeguard measures cannot be applied. These challenges have been discussed for decades e.g. in the SAGOR and ASTOR programmes. Each solution poses a unique set of challenges added to the practical and safety limitations that need to be taken into consideration acknowledging the State-level approaches.