Excavation has finished on a 438m-deep access tunnel at the Onkalo project. Two demonstration tunnels should be completed before 2012. From these, final disposal canister testing holes 8m-deep and 1.8m in diameter will be drilled.
The central access tunnel, 70m long x 8.5m wide x 6m high, was completed last week, and will allow workers and researchers to reach the 50m-long demonstration tunnel one and the 120m-long demonstration tunnel two when they are completed.
Kimmo Lehtola, building supervisor for Finland-based nuclear fuel final disposal organisation Posiva said, “Although the excavation of Onkalo has now reached the research level at the depth of 438 metres, the underground research facility still requires a lot of work.
“Considerable excavation will be carried out in the next few years. The schedule of the upcoming excavation tasks will be further specified during the summer.
Lehtola added, “All three Onkalo shafts: exhaust air, intake air and personnel will be raise-bored in the summer and early autumn from the depth of 438 metres upwards to a depth of 290 metres.
“The raise boring will be performed by the Sweden-based Bergteamet.”
