STUK has submitted its report to the ministry: Welding work has been carried out appropriately at OL3


There have been public allegations suggesting that the quality control of welding work at the Olkiluoto 3 nuclear power plant construction site has been deficient. According to an investigation carried out by the Radiation and Nuclear Safety Authority (STUK), these allegations are unfounded. STUK submitted the report requested by the Ministry of Economic Affairs and Employment to the ministry today (Wednesday).

Public concern has focussed on the welds in steel reinforcement for concrete structures. Some of the welds are so-called installation welds, some so-called load bearing welded joints.

Load bearing joints are needed to form the strength in the structure. They play a significant role in the safety of important structures affecting nuclear safety. Load bearing joints have been produced since April 2008. STUK has been systematically overseeing all safety-critical welded joints. No defects in their planning or implementation have been detected. Welding instructions approved by STUK have been used in the work. STUK supervises the construction work and inspects qualification of load bearing joints before allowing concrete casting work to begin.

Typical installation weld. Photo: Lasse Kuosa/STUK.
High resolution photo

Installation welds are used to ensure that the steel concrete reinforcement and the anchoring parts remaining at the surface of the concrete do not move during the casting process. The Radiation and Nuclear Safety Authority does not consider it necessary to carry out detailed regulatory inspections of installation welds. However, even these welds are only produced by welders who have proven their professional competence in practical welding tests. Bouygues Travaux Publics (BTP) (the French company responsible for the construction work), Areva, Teollisuuden Voima inspect the completed installation welds in all structures before permission to begin the concrete casting is given. STUK inspects the completed installation welds in safety-critical structures before permission to begin the concrete casting is given No movement of steel structures has been observed during or after the casting work.

Safety-related deviations must be reported

It has also been alleged in the media that BTP’s employees have been requested to sign an undertaking that they will not divulge any safety problems that they may observe. Should this allegation be true, it would be a serious indication of callous disregard of the safety culture.

According to Teollisuuden Voima, the document shown to them to back up the allegations is a standard attachment to contracts of employment that constitutes an undertaking not to divulge any of the employer’s business secrets. The project manager of BTP has given the Radiation and Nuclear Safety Authority a written statement to the effect that all of the company’s employees are obliged to report any deviations with potential safety implications to their company’s quality and project management. The deviations are recorded and rectified in compliance with the company’s quality system, and the related documentation is made available for inspection by STUK.

The safety culture includes a policy whereby the employees can take the matter further, all the way to STUK, in case they feel that their observations have not been dealt with in an appropriate manner.

STUK´s report (pdf)

Further information:
Assistant Director Petteri Tiippana, tel. +358 9 759 88 654
Section Head Pekka Välikangas, tel. +358 9 759 88 706
Information Officer Risto Isaksson, tel. +358 9 759 88 208

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