‘Ambitious’ goal is for operational readiness at Olkiluoto facility by end of 2026
Posiva has begun drilling the first hole for the final disposal of spent nuclear fuel at the Olkiluoto deep geologic repository in southwest Finland.
Posiva, the company responsible for the final disposal of spent nuclear fuel in Finland, said the drilling began on began on 26 August at a depth of 400 metres in the 1.9-billion-year-old bedrock.
The first test disposal holes at the repository, known as Onkalo, were drilled in the autumn of 2022, Posiva said.
The start of drilling for the first actually disposal hole was accelerated followed drilling readiness checks that were carried out before the summer holiday season. In a kick-off meeting on 25 August, safety issues, technical specifications and more detailed plans for the drilling operation were reviewed.
“The final adjustments to the equipment were made in the morning and by early afternoon the drill was already hitting the rock,” said Kimmo Lehtola, construction manager at Posiva Käytö.
The hole, 8.4 metres deep and 1.75 metres in diameter, is where the final disposal canister containing the spent nuclear fuel will eventually be placed. It is being drilled vertically into the floor of a previously excavated final disposal tunnel.
The Onkalo deep geologic repository is likely to become the first in the world to operate.
In August, Finland’s nuclear regulator, the Radiation and Nuclear Safety Authority of Finland (Stuk), published its safety assessment of the facility.
Posiva said the assessment was a significant milestone in a project that has been systematically developed, researched and assessed for more than 40 years.
It said the facility will be the first industrial-scale final disposal facility for spent nuclear fuel.
Operating Licence Needed
Before final disposal operations can begin, Posiva needs an operating licence from the government. Testing and commissioning activities need to be completed.
“Our ambitious goal is to achieve operational readiness for the start of final disposal by the end of 2026,” said Posiva’s president and chief executive officer Ilkka Poikolainen in August.
At Onkalo, the spent fuel will first be encapsulated before being placed at a depth of approximately 430 metres in the repository, excavated into the bedrock.
Posiva is a private company jointly owned by Finland’s two nuclear power producers: Teollisuuden Voima Oyj (TVO), which owns 60%, and Fortum Power and Heat Oy, which owns 40%. The companies are responsible by law for final disposal.
Onkalo is intended for spent nuclear fuel generated by TVO’s Olkiluoto and Fortum’s Loviisa nuclear power stations, which have five units between them.
Posiva’s final disposal plans use a multi-barrier principle. Spent nuclear fuel that has been cooled for several decades is isolated from the environment deep in the bedrock by means of several complementary engineered and natural barriers.
