Olkiluoto pipe welding 'deficient', says regulator

16 October 2009

The start-up date for Olkiluoto 3 will be pushed back beyond mid-2012, the plant owner has said. At the same time, national safety regulators have found more problems with welding practices.


Olkiluoto 3 dome installation (TVO)
The reactor building dome of Olkiluoto 3 was installed last month (Image: Areva)

In a statement, Teollisuuden Voima Ojy (TVO) said that "based on the latest progress report submitted by the plant supplier, Areva-Siemens, TVO now estimates that the start-up of the plant may be postponed beyond June 2012, which is the current schedule confirmed by the supplier." The company said that it has requested a "re-analysis" by Areva-Siemens of the anticipated start-up date.


TVO's director of the Olkiluoto project, Jouni Silvennoinen, said: "The reactor plant civil construction works are taking longer than previously estimated and the pace of completion continues to be slower than planned. These accumulating delays are now impacting the start of the installation and erection works."


Work began on the 1600 MWe EPR in 2005, but various delays have seen the start-up date pushed back from the original schedule which would have seen it operate this year.


Welding queries


As the first EPR - a design produced by France's Areva, which includes the former nuclear business of Germany's Siemens - it has suffered from first-of-a-kind problems. The Areva-Siemens consortium building the unit for a fixed price of €3 billion ($4.1 billion) has faced many challenges with supply chain and construction practices.


First to come to light were irregularities in foundation concrete, which caused work to slow on site for 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 has also caused delays, while meeting regulators requirements for the instrumentation and control system "may become critical for the plant time schedule," according to Silvennoinen.  


The latest difficulty came when Finland's nuclear safety and radiation regulator, Stuk, noted that "instructions have not been observed in the welding of pipes and the supervision of welding." It said that one welder did not have any welding instructions to hand and was not familiar with the welding requirements. As a result, "an excessive amount of power was being used."


Stuk said that it had also found deviations concerning "the use of shielding gas necessary for welding and the shape of the contact surfaces to be welded." It said, "Pipe welding in accordance with instructions is essential to ensure the integrity of pipes during the operation of the plant."


Stuk has requested a report from TVO, explaining "why the instructions were not observed in the welding work, and why the supervision carried out by the subcontractor, plant supplier and TVO did not result in these deficiencies being observed." Additionally, TVO must explain "the significance of the deficiencies observed from a point of view of weld quality." The subcontractor cannot resume welding operations at the site until the report is approved by Stuk.


In the first half of 2008, TVO submitted a claim to Areva-Siemens for compensation for "losses and costs incurred due to the delay" in completing the construction project. TVO had also rejected a claim presented to it by Areva-Siemens contesting that it had been much slower than agreed in processing and passing on technical documents to Stuk. The Areva-Siemens consortium has filed a request for arbitration with the International Chamber of Commerce.