Hot functional testing of the reactor systems has begun at the EPR unit under construction at Olkiluoto 3 (OL3) in Finland. Plant operator Teollisuuden Voima Oyj (TVO) said on 18 December that the tests would take several months. TVO will then be able to obtain an operating licence for the unit and continue towards commissioning.

Hot functional testing involves all the systems of the 1600MWe unit, but without the fuel. The temperature and pressure of the water in the primary circuit are gradually increased to operational levels. Hot functional testing is the first plant-level test where the nuclear island and the turbine island are operated together. Several different tests at different pressure levels will be carried out. Cold functional tests to ensure that components and systems important to safety are properly installed took place over four weeks beginning in June. The main purpose was to verify the leak-tightness of the primary circuit.

Power production is expected to begin at Olkiluoto 3 in May 2019, according to plant supplier Areva-Siemens, some ten years behind schedule. The consortium of Areva GmbH, Areva NP SAS and Siemens AG began construction of Olkiluoto 3 in 2005 under a turnkey contract signed with TVO in late 2003. Completion was originally scheduled for 2009.

The Finnish Radiation and Nuclear Safety Authority (Stuk) has said no parts had been used at OL3 that "could endanger the safety of the plant due to uncertainties about their manufacturing history.

Concerns were raised in May 2016, when France’s Nuclear Safety Authority (ASN) said an ongoing quality audit at Areva's Le Creusot forge had identified "irregularities" in paperwork on some 400 plant components produced there since 1965. Areva bought the facility in 2006. Stuk requested utilities Fortum and TVO to investigate whether the forge had supplied equipment whose material quality cannot be fully guaranteed to their nuclear power units. TVO submitted its final report on the investigation into parts used in OL3 to Stuk on 16 November.

Photo: Olkiluoto 3 (Credit: TVO)