Finnish nuclear waste management organisation Posiva has begun a trial run of its Onkalo spent nuclear fuel repository for final disposal as full operation approaches of what will probably be the world’s first deep geologic repository for spent nuclear fuel.

Posiva said in a statement that equipment and systems are being tested together for the first time during the trial run, which began on Friday (30 August) and is likely to last “several months”.

The disposal of spent nuclear fuel is being tested without using actual spent fuel, Posiva said.

It said: “The purpose of the trial run is to verify safe final disposal before the start of the actual final disposal operation.”

Four dummy fuel cannisters will be deposited in holes which are eight metres deep in a 70-metre-long final disposal tunnel. The tunnel will then be filled with bentonite clay and sealed with a concrete plug. The trial run also covers the retrieval of a “damaged” cannister which will be brought back above ground.