This Week in Engineering explores the latest in engineering from academia, government and industry.
Episode Summary:
The Finnish power utility TVO has open the first new European nuclear plant in 15 years. The pressurized light water reactor is the product of a French/German design team and promises to deliver as much as 15 percent of the nation’s total electricity needs. Although it is a decade behind schedule and billions of Euros over the original cost estimates, the plant promises to deliver clean power for decades—along with ground-breaking deep storage of nuclear waste, and an interesting experiment in the use of waste heat for agriculture.
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Transcript of this week’s show:
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Something just happened in Europe, and it is something that has not happened in 15 years: a new nuclear power plant has just been commissioned.
The new reactor, Unit Three of the Olkiluoto nuclear power complex in Finland, was grid connected on March 12th, 2022, and has started supplying current to the national grid. Initial power output is 103 MW electrical, and the power plant operator, TVO, expects the 1,600 MW electrical unit to operate at full capacity in July.
First criticality was attained on December 21st, 2022, and during the test phase TVO generated between 3 – 4 TW hours of power, representing about 10 percent of Finland’s demand. By summer, the OL Three unit is expected to produce about 14 percent of the nation’s entire electrical power needs.
The Olkiluoto Three project is complex and controversial. The original reactor design by Framatome and EDF of France and Siemens of Germany, called EPR, is a third-generation pressurized water design. Construction in Finland began in August 2005, with the project managed by Areva and Siemens. Siemens left the nuclear industry in 2011, and construction delays were common as early as a year into the project due to quality problems with subcontractors.
Areva NP claimed that Finnish regulatory delays in approvals for design and documentation were responsible for an 18-month schedule slip, and by 2008 the delays and cost overruns pushed the expected online date to 2012. By May 2009, the operation was almost four years behind schedule and more than 50 percent over budget, with Areva and TVO in a legal dispute over responsibility for cost overruns.
In 2010 and again in December 2011, TVO announced project delays, and in October 2017 completion was predicted for 2019.
Part of the delays were traced to the nature of the plant, which has a reactor larger than previous designs, and the use of new welding techniques in the reactor pressure vessel, as well as very large critical pressurizer forgings that required several attempts to produce approved parts.
Cost overruns were considerable, rising from the original estimate of €3 billion, to a final cost of €11 billion, split between TVO and Areva.
What did TVO get for their money? A third-generation pressurized water reactor, with a compact core and—due to the light water moderator—a negative temperature coefficient of reactivity, increasing safety and making the reactor easier to control.
From an engineering perspective, a major difference in PWRs compared to other reactor designs is a much higher system pressure in the primary coolant loop, typically 150 atmospheres, which is around 2,000 psi. Steam for the turbine hall is supplied by a secondary loop.
The Finnish plant has two other notable features. The site is the location for the Onkalo deep geological repository for spent nuclear fuel, the first in the world. In addition, waste heat which is typically rejected to ambient in all types of thermal power plants, is instead being used for a small-scale agricultural experiment before cooling water is pumped back to the sea. The experiment currently grows wine grapes, as well as whitefish and sturgeon for caviar.
With an increased emphasis on both clean energy and on the reduction of reliance on Russian fossil fuel supplies in Europe, nuclear power is back on the table—especially in France, which has a long history of power generation with fission.
But with the high costs associated with large-scale reactor designs, can large-scale projects be brought online fast enough to matter, even if they are affordable? Small modular reactors and fourth-generation designs may be the answer, but as the cost of renewables such as photovoltaics fall, the competition will be fierce.
