Onkalo spent nuclear fuel repository

Deep geological repository for radioactive waste in Finland

Onkalo (song).

class=notpageimage|

Location in Finland

After the Finnish Nuclear Energy Act^[7] was amended in 1994 to specify that all nuclear waste produced in Finland must be disposed of in Finland, Olkiluoto was selected in 2000 as the site for a long-term underground storage facility for Finland's spent nuclear fuel. The facility, named "Onkalo" (meaning "small cave" or "cavity")^[8] is being built in the granite bedrock at the Olkiluoto site, about five kilometers from the power plants. The municipality of Eurajoki issued a building permit for the facility in August 2003 and excavation began in 2004.^[9]

The site was selected after a long process, which started in 1983 with a screening of the whole Finnish territory. From 1993 until 2000, four prospective sites were examined: Romuvaara in Kuhmo, Kivetty in Äänekoski, Olkiluoto in Eurajoki and Hästholmen in Loviisa. Besides geological and environmental considerations, the opinions of local residents were also taken into account. Eurajoki and Loviisa were singled out for being the locations with the highest local support. The former also had more favorable geographic conditions, thus in 1999 Posiva proposed it to the Finnish government as the selected location. The municipality of Eurajoki confirmed its approval of the site, and the national government ratified the decision in May 2001.^[10]

Posiva started construction of the site in 2004.^[11] The Finnish government issued the company a licence for constructing the final disposal facility on 12 November 2015.^[12] As of June 2019^[update] Posiva expects operations to begin in 2023.^[13]

Construction

The facility was constructed by and will be operated by Posiva, a company owned by the two existing producers of nuclear power in Finland, Fortum and TVO. (Fennovoima, a company which was planning its first nuclear reactor, is not a stockholder of Posiva.)

The facility's constructions plans are divided into four phases:^{[citation needed]}

• Phase 1 (2004–09) focused on excavation of the large access tunnel to the facility, spiraling downward to a depth of 420 metres (1,380 ft).^[14]
• Phase 2 (2009–11) continued the excavation to a final depth of 520 metres (1,710 ft). The characteristics of the bedrock were studied in order to adapt the layout of the repository.
  • In 2012, Posiva submitted an application for a license to construct the repository. The license was granted in November 2015.^[15]
• Phase 3 (2015–17) construction of the repository
• Phase 4, the encapsulation and burial of areas filled with spent fuel, is projected to begin around 2023.

Once in operation, the disposal process will involve placing twelve fuel assemblies into a

The Onkalo repository is expected to be large enough to accept canisters of spent fuel for around one hundred years. At this point, the final encapsulation and burial will take place, and the access tunnel will be backfilled and sealed.

Criticism

In 2012, a research group at the

The spent nuclear fuel has 94% of the original energy content.^[20] Spent nuclear fuel is a valuable resource that can be utilized in breeder reactors, and several other components also have useful applications. The fissile Pu content can contribute to humanity's conversion to clean and reliable energy, and burying it in permanent sealed storage will limit that potential.^[21] As such, if the need would arise to utilize that energy, it will be relatively inexpensive to excavate the canisters back.

Treatment in media

Danish director Michael Madsen has co-written and directed a feature-length documentary