Finland’s nuclear safety and radiation authority has approved the EPR Teleperm XS digital instrumentation and control system. The approval of the overall system design for utility TVO’s Olkiluoto 3 reactor is a key hurdle for the power plant, which is over time and over budget.The approval of the overall system design for utility TVO’s Olkiluoto 3 reactor means that the authority can now move on to investigate system-level automation plans.

STUK said that its main aim has been to verify the independence of the safety system from the operation system. "Automation systems, which are responsible for the safety of the plant, should not depend on the systems that are in use when the plant is operating normally, when something goes wrong," it said.

STUK said that AREVA’s initial plans presented some links between the two systems that it could not accept, but it was willing to accept them after independence between the two systems was improved.

TVO and AREVA will now submit a fault analysis of the system, a prerequisite for final approval, to confirm that all possible automation faults are taken into account, TVO said.

TVO went on to say that despite this milestone, and AREVA’s start of I&C testing in Erlangen, Germany, and a successful pressure test earlier this year, it is still not satisfied by AREVA’s operations.

"We have called for the plant supplier to make a plan for the remaining work and supply an updated schedule for the total completion of the plant. The supplier has not supplied them. In addition, [suppliers’] installation at Olkiluoto are not moving because the technical design is not yet complete."

The independence issue has also cropped up in the UK generic design approval (GDA) process of the EPR, and required AREVA to agree to provide an independent, hardwired backup.

Image: Olkiluoto 3 in late March. Image courtesy TVO.