Finland builds a facility to store nuclear waste for 100,000 years

More than 1,000 feet below sea level.
Ameya Paleja
Nuclear waste stored in barrels on a temporary basisvchal/iStock

At 1,377 feet below sea level, Finland is making a permanent site to store its nuclear waste for centuries to come. The facility will be opened up in 2024, Science Magazine reported last month. 

Many countries in Europe are moving away from nuclear power. At the turn of the new year, Germany shut down three of its six functional nuclear power plants as it turns to renewable forms of energy in the long term. France and Belgium have also announced similar plans to move away from nuclear power. Still, Finland seems to be going the other way, as it is currently building another nuclear power plant. 

Finland's push for nuclear power

Finland is a relatively small country by size, and most of its 5.5 million residents reside in the south of the country. Five nuclear reactors are currently in operation in the country at two power plants located on the country's southern shores. In operation since 1977, these power plants supply 35 percent of the country's energy needs, and at 95 percent operating capacity, the reactors are among the world's most productive.  

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At 1,600 MW, the world's largest nuclear reactor started to produce electricity on 12 March 2022. Regular production is expected to begin on 30 September 2022, after a test production phase.

With another nuclear power plant in the works, Finland needs to secure the nuclear waste that it will produce.

The country had begun the process of identifying potential sites for long-term storage of its nuclear wastes. In the year 2000, an island near the town of Eurajoki off the western coast of the country, was selected. Eurajoki is no stranger to nuclear power with three nuclear reactors operational at the nearby Olkiluoto power plant. Almost everyone in the town has a friend or a relative who has worked at the nuclear power plant.   

Onkalo - the Pit

Storage of nuclear waste needs a watertight site, which the contractor company, Posiva, found under a bedrock. Nearby are two earthquake faults that might become active after the next ice age. Still, since the facility is located precisely between them, it is expected to remain safe from seismic activity. 

In Finland, nuclear power plants cool down spent fuel rods in interim water pools. Prior to their final storage in the pit, the water in the pools will be suctioned off by robots in a stainless steel room, covered by 4.25 feet thick concrete walls, Science Magazine reported. 

The rods will then be put into cast-iron canisters, which will be placed in a copper canister with inert gas argon, filled between them to create a non-reactive atmosphere. The copper casks will be buried in tunnel floors and filled with bentonite clay to absorb water and prevent it from reaching the fuel. The tunnels will be covered with concrete, not to be disturbed for 100,000 years, as the nuclear fuel's final resting site. 

The site that is now known as Onkalo Spent Nuclear Fuel Repository is expected to begin operations by 2024 or 2025 and remain operational till 2120, after which it will be sealed off permanently.   

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