Proposed faciltiies at Forsmark (Credit: SKB)Swedish engineering consultancy company Sweco has been commissioned by waste and fuel management company Svensk Kärnbränslehantering (SKB) to design the planned used nuclear fuel repository at Forsmark, as well as the planned expansion of the final repository for short-lived radioactive waste at the site.

The contract is valued at SEK10 million ($1 million). SKB has applied to build a final repository for used nuclear fuel in Forsmark and to expand the already existing final repository for short-lived waste.

“The assignment is unique with high requirements," said Ann-Louise Lökholm Klasson, CEO of Sweco Sweden. "Our expertise in rock engineering and plant design, as well as [our] experience in the specific conditions that apply to projects in nuclear fuel management, is well suited," she added.

A final repository for approximately 12,000 tonnes of used nuclear fuel is planned some 500 metres underground involving a system of tunnels where 6,000 copper canisters with used nuclear fuel are placed.

The existing final repository for short-lived radioactive waste, SFR, will also be expanded.  “This is an extensive assignment that we are now embarking on in Forsmark to prepare for our upcoming major construction projects. About 40-50 people will work on detailed planning [in addition to] SKB's own staff," said SKB CEO Eva Halldén.

Sweco's assignments include the preparation of tender documentation for contracts for tunnels, shafts and rock spaces in the two projects.

Design work will begin immediately and last for about two years. The detailed design will include drawings and designs for tunnels and rock spaces in preparation for blasting and excavation work. Licensing tests according to the Nuclear Technology Act and the Environmental Code are ongoing for both plants, and only preparatory work can be started.

The nuclear power companies in Sweden merged in the 1970s to form  SKB, which is responsible for handling all radioactive waste from the Swedish nuclear power plants.  

SKB submitted applications to build Sweden's first repository for used fuel, together with a plant to encapsulate the fuel, to the Radiation Safety Authority (SSM) in 2011.

SKB also applied to extend the storage capacity of the Clab interim fuel storage facility from the current 8000 tonnes of fuel to 11,000 tonnes.

The applications have been reviewed by the SSM and the Land and Environment Court, but a final decision to authorise the project will be made by the government. The final decision will follow consultations with the municipalities of Oskarshamn and Östhammars, which have the power to veto the application.

The SFR repository, in the municipality of Östhammars, which began operations in 1988, is situated 60m below the bottom of the Baltic Sea. It comprises four 160-metre-long rock vaults and a chamber in the bedrock, with a 50-metre-high concrete silo for the most radioactive waste. Two parallel one-kilometre-long access tunnels link the facility to the surface.

Most of the short-lived waste deposited in the SFR comes from Swedish reactors as well as from hospitals, veterinary medicine, research and industry. The facility currently holds about 63,000 cubic metres of waste and is 60% full. SKB applied in December 2014 to treble the size of the SFR facility. The extended part of the repository will comprise six new rock chambers, each 240-275m in length.

Photo: Proposed facilities at Forsmark (Credit: SKB)