The Olkiluoto Nuclear Power Plant (Olkiluodon ydinvoimalaitos) is on Olkiluoto Island, which is on the shore of the Gulf of Bothnia in the municipality of Eurajoki in western Finland. It is one of Finland's two nuclear power plants, the other being the two-unit VVER Loviisa Nuclear Power Plant. The plant is operated by Teollisuuden Voima, a subsidiary of Pohjolan Voima.

The Olkiluoto Nuclear Power Plant consists of two BWRs with 860 MWe each. Unit 3, the first EPR (European Pressurized water Reactor) is under construction, but various problems with workmanship and supervision have created costly delays which have been the subject of an inquiry by the Finnish nuclear regulator Säteilyturvakeskus (STUK). A license for a fourth reactor to be built at the site was granted by the Finnish parliament in July 2010.

Olkiluato Nuclear Power Plant Units 1 and 2

Units 1 and 2 consists of two BWRs with 860 MWe each. These were supplied by ASEA-Atom, now a part of Westinghouse Electric Sweden AB. Steam generators were supplied by Stal-Laval. The units' architecture was designed by ASEA-Atom. Reactor pressure vessels were construct by Uddcomb Sweden AB, and reactor internal parts, mechanical components by Finnatom. Electrical equipment was supplied by Oy Strömberg Ab. Unit 1 was constructed by Atomirakennus and unit 2 by Jukola and Työyhtymä. Unit 1 achieved its initial criticality in July 1978 and it started commercial operations in October 1979. Unit 2 achieved its initial criticality in October 1979 and it started commercial operations in July 1982.

Olkiluato Nuclear Power Plant Unit 3

The first license application for the third reactor (EPR) was made in December 2000 and the original commissioning date of the third reactor was set to May 2009. However, in May 2009 the plant was "at least three and a half years behind schedule and more than 50 percent over-budget". The commissioning deadline has been postponed several times and as of June 2010 operation is set to start in 2013 at a fixed price of €3 billion ($4.1 billion). The reactor pressure vessel was installed on 21 June 2010.

The project was started by Areva NP, a joint venture of AREVA and Siemens, but Siemens withdrew and sold its share to AREVA. Work began on the Olkiluoto EPR in 2005, but various problems with workmanship have created delays:

First to come to light were irregularities in foundation concrete, which caused work to slow on site for months. Later it was found that subcontractors had provided heavy forgings that were not up to project standards and which had to be re-cast. An apparent problem constructing the reactor's unique double-containment structure has also caused delays.

According to Professor Stephen Thomas, "Olkiluoto has become an example of all that can go wrong in economic terms with new reactors". Areva and the utility involved "are in bitter dispute over who will bear the cost overruns and there is a real risk now that the utility will default". The project has also been criticized by the Finnish nuclear safety regulator, STUK, because "instructions have not been observed in the welding of pipes and the supervision of welding." STUK has also noted that there have been delays in submitting proper paperwork. Olkiluoto 3 was supposed to be the first "third generation" reactor which would pave the way for a new wave of identikit reactors - safe, affordable, and delivered on time - across Europe. The delays and cost overruns have had knock-on effects in other countries.

Olkiluato Nuclear Power Plant Unit 4

On 14 February 2008, Teollisuuden Voima submitted an environmental impact assessment of the unit four to the Ministry of Employment and Economy. On 21 April 2010, the Government of Finland decided to grant a permit to Teollisuuden Voima for construction of the fourth reactor in Olkiluoto. The decision was approved by the Parliament on 1 July 2010. If constructed, the fourth unit would be a PWR or BWR with a power output of 1,000 to 1,800 MWe.

Onkalo waste repository

After the Finnish Nuclear Energy Act was amended in 1994 so that all nuclear waste produced in Finland must be disposed of in Finland, Olkiluoto was selected in 2000 to become the site of disposal of all of Finland's spent nuclear fuel.

A nuclear waste repository research tunnel known as Onkalo (lit. "cavern") is being constructed in the granite bedrock just miles from Olkiluoto power plants. The municipality of Eurajoki issued a building permit for the facility in August 2003 and excavation began in 2004. The Onkalo project will be developed in phases:

• Phase 1 (2004–09) will focus on excavation of the large access tunnel, spiraling down to a depth of 420 metres (1,380 ft)
• Phase 2 (2009–11) will include continued excavation to a final depth of 520 metres (1,710 ft) and research on the characteristics of the bedrock, to adapt the layout of the repository
• About 2012, Posiva Oy (the agency responsible for construction of Onkalo) plans to submit an application for a construction license for the final disposal facility: approval and final planning is expected to take several years
• Phase 3 is expected to begin about 2015, construction of the final disposal facility to begin
• Phase 4, the facility is expected to begin encapsulation and burial in 2020.

The Onkalo repository is expected to be large enough to accept canisters of spent fuel for one hundred years before it is full about 2120, at which point the tunnel will be backfilled and sealed.

Critics state that fractured bedrock in this area may lead to problems with increased flow of ground water. Also, the very large amount of copper used in nuclear waste canisters could tempt criminals to retrieve copper from the containers in the future.

Into Eternity, directed by Danish director Michael Madsen, is a feature-length documentary film about the Onkalo Waste Repository.

Olkiluoto Nuclear Power Plant
Country	Finland
Locale	Eurajoki
Status	operational
Construction began	1973
Commission date	10 October 1979
Owner(s)	Teollisuuden Voima Oy
Reactor information
Reactors operational	2 x 860 MWe
Reactors under construction	1 x 1,600 MWe
Reactors planned	1 x 1,000–1,800 MWe
Reactor supplier(s)	ASEA-Atom (units 1 and 2) Areva (unit 3)
Turbine manufacturer(s)	Stal-Laval (units 1 and 2) Siemens (unit 3)
Power generation information
Installed capacity	1,720 MWe
Annual generation	14,268 GW·h
Net generation	323,760 GW·h