The Olkiluoto Nuclear Power Plant (, ) is one of Finland's two nuclear power plants, the other being the two-unit Loviisa Nuclear Power Plant. The plant is owned and operated by Teollisuuden Voima (TVO), and is located on Olkiluoto Island, on the shore of the Gulf of Bothnia, in the municipality of Eurajoki in western Finland, about from the town of Rauma and about from the city of Pori.
The Olkiluoto plant consists of two boiling water reactors (BWRs), each with a capacity of 890 MW, and one EPR type reactor (unit 3) with a capacity of 1,600 MW. This makes unit 3 currently the most powerful nuclear power plant unit in Europe and the third most powerful globally. Construction of unit 3 began in 2005. Commercial operation, originally scheduled for May 2009,EPR development. An evolutionary design process began on 1 May 2023.
A decision-in-principle for a fourth reactor to be built at the site was granted by the Finnish parliament in July 2010, but in June 2015 TVO decided that it would not apply for a construction license for Olkiluoto 4.
Units 1 and 2 Units 1 and 2 consists of two BWRs, each producing 890 MW of electricity. The main contractor was ASEA-Atom, now a part of Westinghouse Electric Sweden AB. Turbine generators were supplied by Stal-Laval. The units' architecture was designed by ASEA-Atom. The reactor pressure vessels were constructed by Uddcomb Sweden AB, and reactor internal parts, mechanical components by Finnatom. The electrical equipment was supplied by Strömberg. 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.
The original power of the reactors was 660 MW. They were uprated to 710 MW in 1983–1984, to 840 MW in 1995–1998, and further to 860 MW in 2005–2006. Major upgrades were carried out to the units in 2010 and 2011, including replacement of turbines and generators, isolation valves, electrical switchgear and seawater pumps. The upgrades increased the net electrical output by 20 MW to 880 MW each.
In 2017, unit 2 was upgraded and modernized, increasing the output further to 890 MW from the beginning of 2018. A similar upgrade to unit 1 was performed in 2018. The extended maintenance was also made to prepare for a license renewal application. The license extension was granted in September 2018 and allows the reactors to operate until 2038.
In 2023, TVO announced it is considering seeking another license extension of at least 10 years and a power uprate of 80 MW to 970 MW. The environmental impact assessment program, published in January 2024, investigates options to extend the lifetime by 10 or 20 years at the current power or uprating to 970 MW (in 2028 at the earliest) in addition to the 10 or 20-year extension.
Unit 3
Unit 3 is a EPR, a type of third generation pressurized water reactor. It has a nameplate capacity of 1600 MW. Japan Steel Works and Mitsubishi Heavy Industries manufactured the unit's 526-ton reactor pressure vessel.
Construction started in 2005, and the start of commercial operation was planned for 2010. This was pushed back several times only starting regular production in 2023, 18 years after the start of construction.
History In February 2005, the Finnish government gave its permission to TVO to construct a new nuclear reactor, making Finland the first Western European country in 15 years to order one. The construction of the unit began in 2005. Olkiluoto 3 was the first EPR to have begun construction. At the start of construction, the main contractor was Areva NP (now Framatome), a joint venture of Areva and Siemens. However, in 2009, Siemens sold its one-third share of Areva NP to Areva, which became the main contractor. Siemens remained on the project as the subcontractor with the main responsibility for constructing the turbine hall. Areva later sold its majority stake in Framatome, its nuclear reactor and fuel business, to Électricité de France.
According to TVO, the construction phase of the project would create a total of about 30,000 person-years of employment directly and indirectly; that the highest number of on-site employees has been almost 4,400; and that the operation phase would create 150 to 200 permanent jobs. A 90 MW battery storage was scheduled for 2022.
On 8 December 2021, the company submitted its application to Finland's Radiation and Nuclear Safety Authority asking permission to start up Unit 3 and to move forward with initial testing of the unit. This was granted on 16 December 2021. First criticality of the OL3 EPR plant unit was reached on 21 December 2021. An unplanned SCRAM occurred on 14 January 2022, delaying connection to the national grid to February 2022. Electricity production of Olkiluoto's third nuclear power plant unit started on 12 March 2022 at 12.01 p.m. In May 2022, foreign material detached from the steam guide plates was found in the turbine steam reheater, and the plant was shut down for about three months of repair work.
In September 2022, the Radiation and Nuclear Safety Authority (STUK) granted a licence for the Olkiluoto 3 reactor to increase its power output to more than 60 percent to a full 4,300 MW of thermal capacity. On 30 September 2022, the reactor achieved its design output power.Europe's biggest nuclear reactor reaches full power – Arab News In October 2022, damage was discovered in the feedwater pumps and unit 3 was shut down for an investigation, delaying the end of commissioning testing. On 28 October, it was announced that cracks a few centimetres long had been found in all four of the feedwater pump impellers. The feedwater pumps are larger than in other nuclear reactors. In January 2023, it was announced that new more robust impellers will be installed in all four feedwater pumps, and test operation at full power should restart in February.
The plant started regular electricity production on 16 April 2023 after test production and commercial operation on 1 May 2023. Unusual for nuclear reactors in Scandinavia, OL3 reduced production in May 2023 due to negative market prices during the spring thaw when hydropower was unable to absorb surplus.
Construction delays The first licence application for the third unit was made in December 2000 and the date of the unit's entry into service was estimated to be 2010. However, since the start of construction, several delays to the schedule have been announced. In July 2012, TVO announced that the unit would not go into service before 2015, five years after the original estimate. In a statement, the operator said it was "not pleased with the situation" although solutions to various problems were being found and work was "progressing", and that it was waiting for a new launch date from Areva and Siemens.
At the end of 2013, TVO said that the Areva-Siemens consortium plans to reduce workers and subcontractors on the construction site and says that it expects the contractor to provide details about the expected impact on the project's schedule.
In February 2014, TVO said that it could not give an estimate of the plant's startup date because it was still waiting for the Areva-Siemens consortium to provide it with an updated overall schedule for the project." Later the same month it was reported that Areva was shutting down construction due to the dispute over compensations and unfinished automation planning. According to Kauppalehti, the estimated opening was delayed until sometime between 2018 and 2020.
In July 2019, TVO announced that regular electricity generation is expected to start in July 2020. The delay was caused by slower than expected modification works. In August 2020, TVO announced that regular electricity generation was delayed to February 2022 due to slow progress in system testing, technical problems found in the testing, and delivery time of spare parts to replace faulty components.
The delays have been due to various problems with planning, supervision, and workmanship, and have been the subject of an inquiry by STUK, the Finnish nuclear safety regulator. The first problems that surfaced were irregularities in the foundation concrete, and caused a delay of 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 also caused delays, as the welders had not been given proper instructions.
In 2009, Petteri Tiippana, the director of STUK's nuclear power plant division, told the BBC that it was difficult to deliver nuclear power plant projects on schedule because builders were not used to working to the exacting standards required on nuclear construction sites, since so few new reactors had been built in recent years.
In 2010, Jukka Laaksonen, Director General of STUK at that time, analyzed reasons for the delay: Many nuclear power plants were constructed in Europe in the 1970s and 1980s. After that there was a long break in the construction, and experienced experts retired. Areva did not have experience in construction of nuclear power plants. In all the earlier projects in which Areva supplied the reactor, Électricité de France was responsible for the construction management. Many experienced subcontractors had left the business, and Areva had to find new subcontractors and to coach them in nuclear manufacturing. The original schedule, four years from construction start to grid connection, was too ambitious for a first-of-a-kind plant that is larger than any earlier reactor. The project started very slowly because Areva was not adequately prepared. When the construction permit was given in 2005, parts of the detailed design were not yet available. Areva did not recognize how much additional work was needed to complete it. The construction started to proceed in a controlled manner two years later. Areva was not used to STUK's regulatory approach with an early focus on the quality of structures and components. Manufacturing information and a quality control plan must be approved by both the licensee and STUK before manufacturing of the most important components is allowed to start. Inspections with hold points are made during the manufacturing. The large size of the reactor and the application of new technologies brought major challenges. Some manufacturing technologies had not been used before. For instance, new welding techniques were used in the reactor pressure vessel. Many large components, such as pressurizer forgings and some reactor internal parts, had to be re-manufactured once or twice to achieve the specified quality. TVO's key persons did not have experience from management of a large construction project.
Construction of the turbine succeeded better under the responsibility of Siemens. Installations of the main turbine equipment were completed about one year behind the original schedule.
After the construction of the unit started in 2005, Areva began constructing EPRs in Flamanville, France, and in Taishan, China. However, as of 2019, the construction of the EPR in France is ten years behind schedule. Taishan 1 in China became the first EPR to start power generation on 29 June 2018, and the second one (Taishan 2) came online in 2019.
Cost The main contractor, Areva, was expected to build the unit for a fixed price of €3 billion, with any construction costs above that price falling on Areva. In July 2012, those overruns were estimated at more than €2 billion, and in December 2012, Areva estimated that the full cost of building the reactor would be about €8.5 billion, well over the previous estimate of €6.4 billion. Because of the delays, TVO and Areva both sought compensation from each other through the International Court of Arbitration.