A leaked letter from the Finnish safety inspectorate to Areva, the French nuclear company which is building a new reactor in Finland, has been seized upon by green campaigners opposing the operation.
The letter expresses concerns about the control and protection systems at the site, and holds out the prospect that construction will have to be halted.
The letter, from Jukka Laaksonen, director general of STUK, the Finnish nuclear watchdog, to Anne Lauvergeon, the chief executive of Areva, does raise serious issues, however.
In it, Mr Laaksonen writes: “The construction of Olkiluoto 3 plant seems to proceed generally well but I cannot see real progress being made in the design of the control and protection systems. Without a proper design that meets the basic principles of nuclear safety, and is consistently and transparently derived from the concept presented as an annex to the construction license application, I see no possibility to approve these important systems for installation. This would mean that the construction will come to a halt and it is not possible to start commissioning tests.”
Areva has not yet replied.