Olkiluoto 3 is expected to come online one year late following quality control problems across the construction. Teollisuuden Voima Oy (TVO), the unit’s owner, admitted the slip in schedule ahead of a report from Finnish regulators that criticised it and vendor Areva NP for failing to guide subcontractors sufficiently.

Stuk, the Finnish Radiation and Nuclear Safety Authority, conducted a four-month investigation into problems on the flagship project and concluded that the amount of work needed for detailed design had been underestimated. The first-of-a-kind EPR was expected to enter commercial operation in May 2009, but now that will probably happen a year later.

A TVO statement said that the production, review and approval of the detailed design, as well as its manufacturing and construction solutions, had taken longer than expected.

The company’s project manager Martin Landtman told Nucleonics Week: “The detailed design is a new thing. This job has been underestimated by our supplier.”

In addition, Stuk investigators contend that turnkey reactor vendor Areva NP often chose the lowest tenders from subcontractors, and that those bids often came from companies inexperienced in nuclear construction. In such a situation, extensive oversight of the work would be expected, but this was not the case. So far, about 1100 subcontracts have been concluded so far, about half of them with Finnish companies.

Landtman said that it has taken “quite some time” for subcontractors to reach the “enhanced performance level required for the new generation of nuclear plants.” He hoped that his company’s suppliers “would take all the needed action and overcome these delays.”

An example of the delays is that of the concrete base slab: Work on site had to stop when the water content of some concrete lots was found to be too high. Although there was no question that the concrete would not meet standards, the investigation into the cause of the anomaly caused an eight-week stoppage and the requirement for an extra layer of concrete.

Four of the five forgings that would comprise the unit’s pressuriser had to be recast – the pieces had not been properly cooled after casting because a propeller meant to circulate water in a cooling pond was not operating. TVO, Areva NP and Stuk had all surveyed the factory but failed to notice the problem.

The Stuk report claims that the chain of command from TVO to the supplier to the subcontractor is too long and that intermediate managers do not have the authority to immediately intervene to maintain quality. It states that a responsible manager should be assigned for every work unit, with the power to give binding orders to subcontractors.

However, the report also admits problems inside the regulator: “Stuk doesn’t have a systematic way to analyse these findings and the root causes of these problems,” said Seija Suksi, chief of the investigation group.

There will be time to train a new generation of operators and it should be an attractive career choice, given that new reactors will likely run for 40-60 years.