Two separate repositories or a combined repository for radioactive waste?

Nagra is planning a deep geological repository for low- and intermediate-level waste and one for high-level waste – or one so-called combined repository.

Switzerland foresees disposal of radioactive waste in two repositories: one for low- and intermediate-level waste and one for high-level waste. The two repositories could be located in the same siting region as a so-called combined repository provided safety is not compromised and there is sufficient space.

The variants «two separate repositories» and «combined repository» are compared in a new report by Nagra. The focus is on impacts on the environment and on topics such as spatial requirements, waste transports, synergy effects and operational safety. Long-term safety is not addressed in the report and will be considered at a later stage.

The report reveals the following: A combined repository requires only about half (56%) of the space at the surface that two separate repositories would require. The construction volume (82%), the volume of material excavated during construction (90%) and the lower consumption of resources and energy also speak in favour of a combined repository, as do the cost advantages: A combined repository would cost around 1.6 billion Swiss Francs less than two separate repositories.

In the case of a combined repository, the ecological and socio-economic impacts are concentrated in one siting region; they are greater there and last longer than at sites for two separate repositories. The manpower requirements are lower (90%) for a combined repository than for two individual facilities. In the case of a combined repository, personnel can also be employed on site for a longer operating period, which also results in a better build-up of know-how.

Conclusion: The report shows that a combined repository would have significant advantages over two separate repositories. However, a combined repository can only be realised if long-term safety is not compromised in any way.