The Swedish "Stipulation Law" of 1977 states that new nuclear power units may not be commissioned until the owner has shown that the waste problem can be solved in an absolutely safe manner. In response to the Bill proposing the Stipulation Law, the nuclear power industry decided in December of 1976 to attack these problems immediately, for which purpose it formed the Nuclear Fuel Safety Project (Projekt Karnbranslesakerhet, KBS).
Following is a summary of the first report from KBS entitled "Handling of spent nuclear fuel and final storage of vitrified high level reprocessing waste".
After some months of storage in pools in the power stations the spent fuel is transferred either to the reprocessing plant or to a central storage facility, CLAB, which will be built in Sweden in the next few years. CLAB is described in another paper to this conference.
If possible the spent fuel is transported directly from the power stations to a reprocessing plant abroad. Currently the Swedish nuclear power utilities have reprocessing contracts with French Cogema and British BNFL. The high level waste, in the form of glass cylinders from reprocessing is foreseen to be returned to Sweden about 10 years after the fuel has been taken out from the reactor.
When the waste cylinders arrive in Sweden, they are first transported to an intermediate storage facility. The main purpose of the intermediate storage is to allow the heat flux from the waste to diminish. This simplifies final storage. During an intermediate storage period of 30 years the heat generation decreases to approximately one-half.
Most of the intermediate storage facility will be situated underground with a rock cover about 30 m thick. This provides good protection against external forces such as acts of war and sabotage. An entrance building with administration and service facilities as well as ventilation inlets and outlets will be built above the ground.
Before final storage the waste cylinders are encapsulated in canisters of 10 cm lead and 6 mm titanium, in a special facility.
In the final repository, the encapsulated waste is received for final disposal. The repository is situated in crystalline rock at a depth of about 500 meters. The repository consist of a system of parallel storage tunnels with appurtenant transport and service tunnel. A number of shafts lead from the surface down to the repository. When fully complete, the repository serving 13 reactors will cover an area of approximately 1 km2. The geometric layout of the tunnel system will be adapted to the geological conditions prevailing on the.elected site. Vertical holes drilled in the floor of the storage tunnels will constitute the final storage compartment. for the waste canisters.