You have a separation as strong as possible says an expert

Two months after the recall order spectacular of the authorities of safety French (ASN), Finnish (STUK) and British (HSE) on the control of the EPR reactor, the dialogue is beginning to bear fruit. According to a source close to the ASN, "it felt a significant increase in the EDF effort" to resolve this problem, and the first technical elements brought by the electrician "seem encouraging." Nothing is acquired, and Constable of nuclear power has before it several months of analysis. He left until end of 2010 to validate the computer program, which allows to drive the Central changes and demonstrations and stop emergency incident. EDF, which is first online as a future operator of the Flamanville, must still provide written by the end of the year, then in January and, finally, next June. On 2 November, the three authorities of security had fired the alarm for the first time in a concerted manner. Today, the ASN recognizes have been surprised by the media flurry that followed. But it has at least achieved something: to be listen by EDF and Areva, who designed the control with the German Siemens. It was not won in advance. If it had not issued a reserve at the beginning of the Flamanville site, in 2007, the Authority started issuing doubts as the work. Last year, its permanent group of experts for nuclear reactors had asked EDF to clarification. In vain, because response elements made June 15 by the electrician had not achieved the reassuring. Hence this common output with HSE and STUK, who expressed the same reservations.

Operation and safety

What are they To function correctly, a nuclear power plant is chock full of sensors, which send information to automata and actuators. For example, they can open or close a valve to obtain the right level of pressure. These facilities are all control-command, knowing that a part is dedicated specifically to the operation of the reactor and the other to its security. If is summarized in the extreme, such that the EPR is designed today the authorities believe that the border between these two parties is not quite tight. "You have a separation as strong as possible", says an expert. Security authorities also believe that the system is not strong enough. They want that in even unlikely an accident situation, the security part could take over and stop the reactor without any concern.

Areva and EDF are clearly committed to assure and to provide the necessary answers. But they can take different forms from one country to another. In France, since the N4 reactors built in the 1990s, experts have no opposition in principle to a fully digital control - as soon as it meets the requirements of security. In Finland, on the other hand, the culture seems to favour the existence of a back-up "wired" for the safety of the architecture part. It is not of electrical cables, but electronic frozen, thus safer. For Designer Areva, the ideal would be to provide a standard solution. But the group must adapt to the wishes of the authorities of local security and its customers. Consultation is not to say harmonisation.