site.btaKozloduy NPP to Shut Down Unit 6 for Refuelling, Maintenance on October 18

Unit 6 of the Kozloduy nuclear power plant will be shut down for refuelling and scheduled repairs on October 18, said Chairman of the Nuclear Regulatory Agency (NRA) Tsanko Bachiyski at a seminar for journalists, which took place near Vratsa.

Regarding the problem with the steam generator, for which the unit was preventively shut down in June for repairs, the NRA has requested that a special programme be drawn up so that the nuclear plant detects the defect before it occurs. According to Bachiyski, a special probe to this end will be tested during the forthcoming planned repair of the unit.

The reason for the preventive shutdown of the unit was due to faults detected in the process of operation of the oil system of the 24/400kV unit transformer (the non-nuclear part of the unit), as well as indications of heat carrier leakage in the steam generator.

The second thing the NRA has asked is for Kozloduy NPP to establish exactly what is influencing the problem. "We are waiting for a programme for systemic monitoring which will keep track of all the factors," Bachiyski said, adding that this will not solve the problem immediately, but some steps are already being taken to resolve it.

It has been established that the defect appears in only one area. That is why the NRA wants to be shown the process by which this problem can be solved. This will be part of the upcoming planned repair. Currently, for some other problems, through this probe, the problems are detected and resolved in a timely manner. The leak that has occurred is within the technological regulation and does not pose any danger to the environment and people, Bachiyski assured. The unit has been shut down preventively to prevent this process from growing.

The NRA Chairman pointed out that the steam generator was not to be replaced. According to him, it has enough resources, and only this problem needs to be solved. He is of the opinion that in one to two years there will be a final solution to the problem and the condition of the tubes will now be assessed before a leak even occurs.