Safety of radioactive waste management is a major driving force of the project. Decommissioning and disposal of spent fuel and the long-term integrity of the barrier system are the most critical safety risks related to nuclear energy. Among Nordic countries, Finland and Sweden have disposal facilities for nuclear waste, with the planned start of the disposal in 2020’s. The date may be further delayed due to uncertainties.
Indeed, more research is still needed to verify the system. In both countries, the waste disposal concept (called KBS-3) is the same: the spent nuclear fuel is first sited in a cast iron container, which is then sealed in a copper canister. The copper canisters are placed in holes drilled into deep bedrock, which are finally filled with bentonite clay. The bentonite clay is expected to provide a favourable environment for the copper canisters to retain their integrity for at least 100 000 years. Safety of facilities for radioactive waste management must be appropriately assured during their lifetime. Despite the extensive research of the concept, there are still areas which need more research effort in order to minimise the safety and environmental risks of nuclear waste disposal.
One of key questions is the behaviour of copper in sulphide containing environments, as recently brought into attention by the statement of The Land and Environment Court in Sweden. Indeed, Fennoscandian bedrock is very sulphidic and it is likely that at some point during the repository time scale the copper canister comes into direct contact with a sulphide containing environment. The topic is timely also in Norway, as Halden nuclear power plant will be permanently closed and the focus will be shifted to nuclear waste management issues. Internationally, also Canada considers nuclear waste disposal concept based on the external copper barrier.
The ultimate goal of this research project is to provide such mechanistic and kinetic information on the behaviour of copper in the expected repository conditions that is of importance for the lifetime prediction of copper canisters and for the design of proper monitoring activities to be applied during the repository, e.g., evaluate the probability of localised corrosion and provide average and instantaneous corrosion rate data during the experiments. The experimental work will involve both short-term and longer-term, up to 12 months, experiments that are supplemented by computational modelling.
In addition to the technical outcome, the proposed project aims to establish and maintain a Nordic network of experts focusing on challenging corrosion issues, which cannot be resolved only by national efforts. The project provides an excellent framework for international visibility through high-quality research articles and presentations. The proposed activity is linked with Finnish Research Program for Nuclear Waste Management (KYT) and with the research funded by Swedish Science Council.