Nuclear power station reactor fuel needs to be topped up every 18-24 months. Many may not realize that after this fuel is changed it is stored openly in containers that can prevent radiation leakage and can last for 100 years. Therefore, a permanent storage facility is needed because safe levels of radiation will only be reached after more than 1000 years.
This year, the Onkala (Finnish for cave) spent nuclear fuel storage facility will finally open in Eurajoki, Finland after construction began in 2004. It is built in bedrock 437 meters deep to ensure that spent nuclear fuel will be safely stored for more than 100,000 years. This is the longest-lived underground nuclear storage facility ever built by humans and has cost over €1 billion (~RM 4.65 billion).
STUK, Finland's nuclear safety authority, is expected to issue a final assessment of the storage site by the end of June. If approved, Onkalo will be the first commercially operating deep geological repository for spent nuclear fuel. Operations are expected to begin late this year or early 2027. It will remain in operation until 2100.
The process of transferring the spent fuel into the repository will be carried out entirely by elevators and remotely operated vehicles. The tunnel will then be closed with concrete for permanent burial.
Onkala has the capacity to store up to 6,500 tonnes of spent nuclear fuel from five Finnish reactors. The spent fuel is stored in corrosion-resistant copper containers that are then inserted into an 8-metre-deep hole dug into the Onkalo bedrock. It is then covered with bentonite clay to prevent leakage of fluids and radiation.
