Olkiluoto 3 annual outage completed
Olkiluoto 3 (OL3) returned to electricity production today, Thursday, May 16, after the plant unit’s first annual service outage. The plant was synchronized to the national grid on Thursday, May 16th, at 1:15 PM. After this, the plant unit will be technically ready for a power increase. The power increase will be carried out according to the production plan.
It was anticipated that the service outage after the first operating cycle would be very laborious. As OL3 is the largest nuclear power plant unit in Europe, the amount of equipment and components is extremely high. All in all, about 7,500 work phases were carried out during the OL3 outage.
In addition to refuelling, the most important activities carried out at OL3 during the annual outage included preventive maintenance on the protection system, washing of steam generators, generator maintenance, pressure equipment inspections, leak-tightness tests on containment isolation valves, and servicing of pressuriser safety relief valves.
The first EPR plant in Europe also underwent a significant number of different periodic tests and maintenance activities during the service outage.
The annual outage at OL3 took longer than originally planned. The outage was meant to take 37 days, but in the end lasted for about 74 days and 9 hours. Additional days were required due to the shutdown process and the preparations for refuelling taking longer than expected and as a result of technical problems identified during maintenance activities. Indications of a risk of foreign material in the fuel elements were also detected during the outage, and the inspections of the elements were therefore significantly more time-consuming than expected.
According to Marjo Mustonen, Senior Vice President, Electricity Production, many valuable lessons were learned for the future from the service outage that has now been completed.
-The first annual outage at OL3 provided valuable knowledge about the duration of the various maintenance activities. We also gained a significant amount of data and maintenance experience which will benefit us in both the planning and the execution of future service outages. Cooperation with equipment manufacturers was another field where we gained experience, Mustonen sums up.
Despite the extension of the estimated duration, Marjo Mustonen says she is pleased with the outcome.
- Although the pressures were high, this has also proven how well our organization was able to respond to unexpected situations. All planned works were completed, and most importantly, safely. The main objective in every annual outage is its safe execution, Mustonen says.
Olkiluoto 3 is by far the most efficient electricity production plant in Finland. It produces about 14 per cent of all electricity produced in Finland.
Two of the three nuclear power plant units in Olkiluoto have now undergone their annual outage. In addition to OL3, the refuelling outage at OL2 was also completed on 9 May. There is still one more plant unit to go. The annual outage of OL1 started on Friday, 12 May. The duration of the OL1 outage is about 15 days.
For more information, and requests for interviews, please contact:
Johanna Aho, Head of Communications, tel. +358 40 729 0822
Teollisuuden Voima Oyj has produced electricity for its shareholders, Finnish industrial and energy companies, safely and reliably for over 40 years. The island of Olkiluoto produces about 30 percent of Finland's electricity needs. Climate-friendly nuclear electricity not only benefits society but also reduces the environmental impact of energy production. Moreover, the world's first final disposal facility for spent nuclear fuel is under construction in Olkiluoto.
