Test production phase proceeds at Olkiluoto 3 – 10-day uninterrupted operation tests completed in early hours of Monday


The test production phase and electricity production resumed at OL3 in mid-March, after the completion of maintenance activities on the pressuriser valve stations. The ongoing demonstration run trials have been in line with expectations and the finishing line of the test production phase is in sight.

A 24-hour performance test related to commissioning was carried out at the plant unit as soon as electricity production had been restarted. It was followed by a 10-day period of testing the uninterrupted operation of the unit which was completed at 02:00 a.m. on Monday, 27 March.

- The test was designed to demonstrate the reliability of OL3, or its ability for uninterrupted production during a 10-day period at a continuous, constant capacity level. The test period concluded successfully in the early hours of Monday, tells Tommi Lamminpää who works as the Main Engineer in reactor surveillance.

The 24-hour performance test conducted previously has also been approved officially. The acceptance certificate was signed last week.

Finishing line in sight

Regular electricity production at OL3 has been announced to start on 17 April. That means there is still about 3 weeks left of the last test cycle. In practice, only some demonstration run tests remain to be conducted.

Regular calibration activities and other periodic tests as well as regular maintenance work will also be carried out as part of the normal operation of the plant.

- Operational activities during the demonstration run of OL3 are to a large extent the same as during regular electricity production, Lamminpää points out.

The final stage of the demonstration run is reserved for testing the regulation properties of OL3. The power output of the plant will then be tested in three separate power regulation tests at 35-80 percent output levels.

With the start of regular electricity production at OL3, Olkiluoto will produce about 30 percent of Finnish electricity.

Text: Ville Kulmala
Photo: Tapani Karjanlahti