SKB must safely take care of all the spent nuclear fuel and radioactive waste that arises during the operation of Swedish nuclear power plants. Included in this assignment is to build and operate a final repository for spent nuclear fuel – the Spent Fuel Repository. The repository must fulfil the authorities' requirements on long-term safety. The requirement can be converted into an average dose for human beings of about one per cent of the natural background radiation.
In order to achieve this, SKB has developed a method where the spent nuclear fuel is protected by three barriers – the canister, the buffer and the rock. The primary task of the barriers is to seal the spent fuel; a second task involves delaying transport of radioactive substances
to the surface.
The technology that will be used has been tested in a real environment, in the Äspö Hard Rock Laboratory and the Canister Laboratory in Oskarshamn. The practical technology solutions exist. There is also a site where the safety conditions are excellent – in Forsmark.
A safety analysis is conducted in order to ascertain that the authorities' requirements have been fulfilled. The analysis is carried out according to a well-proven method that takes into account a time period of up to one million years.
We work with various scenarios in order to cover everything that could possibly happen in the future. We consider how an earthquake could affect the Spent Fuel Repository. We calculate what effect a thick ice cover would have during a future ice age. We conduct research on possible climate changes. Furthermore, we analyse what the consequences would be if anyone were to drill through one of the canisters by mistake or if the barriers were to stop functioning at an
Long time perspective
For most people, 100,000 years is an enormously long time. However, the Spent Fuel Repository is to be placed in an environment that has been stable for billions of years: the Swedish crystalline basement rock. With such an environment, it is possible to make predictions on development in the very long-term.
The results of our safety analyses demonstrate that we meet the requirements on long-term safety with a good margin. This is despite the fact that we made pessimistic assumptions about how the barriers work. After 100,000 years, the dose will be approximately one per cent of the threshold limit value decided on by the authorities.