I wrote last week that one of the things we in the UK need to build in ‘someone’s back yard’ is a Nuclear Waste Repository.
Olkiluoto Island houses two working nuclear reactors, each generating approximately 400 MW of electricity for more than 95% of the time. It is also home to the first construction of a new type of reactor which may (or may not) be built at Hinkley Point in the UK. When completed this third reactor should generate approximately 1600 MW of electricity.
But more important than nuclear generation, Olkiluoto is home to Onkalo (meaning ‘Cave’ or ‘Cavern’) the world’s first final disposal site for high-level waste.
The lower levels of Onkalo are still under construction and so sadly we were not able to visit the tunnels 400 m below the surface. But we did visit the 60 m deep repositories for low-level and intermediate-level radioactive waste .
Importantly, these are not ‘storage’ facilities, but represent sites for the final disposal of this waste. When they are full, they will be sealed off and left.
After three briefings on Olkiluoto in general and Onkalo in particular, we boarded a bus for a tour of the site, ending up at the entrance to the so-called VLJ repository.
We were asked not to take pictures of the site, but once inside the repository we were told that we could ‘fill up our memory cards’.
We put on obligatory hard hats, and after a large roller-door was raised, we descended on a sloping roadway mined from solid granite.
After 15 minutes or so we reached a large chamber containing two gigantic silos, each about 20 metres in diameter and about 40 metres deep.
Above ground, waste is packed into concrete crates about 2 m x 2 m which are then driven along the ‘road to nowhere’ aka the repository. And then lowered by crane into the silo where they are carefully stacked.
Most of this waste is ‘operating waste’ from the two existing nuclear reactors on site: typically single-use garments used by maintenance workers and operators, and ion-exchange resin used in maintaining water purity.
The current plan calls for three similar silos to be built to accommodate the decommissioned remains of the two existing reactors at the end of their lives.
By the time that Olkiluoto 1 and 2 reactors are being decommissioned, the Onkalo deep repository will be ready to take all the high-level waste that the reactors have produced over their lifetime.
The fuel rods from the reactors will be removed and placed in water storage for about 10 years – a backlog of fuel awaits the availability of the repository. Bundles of fuel rods are then placed inside a strong cast-iron frame and sealed inside a 4 metre long copper cylinder.
Significantly, no attempt is made to reprocess to the fuel. This is somewhat wasteful since useful nuclear material remains unburnt in the fuel rods. But this choice dramatically simplifies the disposal.
Comparison with the UK
The contrast between the rational Finnish approach and the UK’s ‘let’s put this off and make it someone else’s problem’ approach could not be greater.
Admittedly, Finland’s ‘back yard’ is bigger than the UK’s: they have one tenth our population and twice our land area. And additionally they require a much smaller repository than the UK will require.
However, Finland has begun preparing for disposal of waste before their first generation of reactors have reached the end of their life.
In contrast the UK has been generating about 20% of our electricity from nuclear power for around 50 years, so we have benefited profoundly from nuclear power. Our first generation reactors are now being decommissioned and we have lots of spent fuel and other types of radioactive waste.
But despite spending hundreds of millions of pounds planning, in practical terms, we have done absolutely nothing about safely disposing of nuclear waste – including high level waste.
Some is stored in warehouses, but shamefully a great deal is stored in filthy outdoor pools.
My visit filled me with a sense of national shame. But overall I feel pleased to have seen this site with my own eyes. Finland has shown the world that safe disposal of nuclear waste is possible, and not at an extravagant cost.
And if they can do it, then why can’t we?