Bulgaria loses “tens of millions” due to technical problem at Kozloduy Nuclear Power Plant

Bulgaria is losing “tens of millions” due to the use of poor-quality membranes in the non-nuclear part of Unit 6 at Kozloduy NPP. This was stated by acting Minister of Energy Traicho Traikov during a briefing for journalists at the Council of Ministers. He confirmed that inaccurate material was used for the membranes in question, as they were not supplied by the Russian equipment manufacturer.

The problem is clear to everyone. What is not clear is how it got to this point. And that is what I will clarify,” Traikov said.

He will visit the plant in the coming days to familiarize himself with the situation.

“It is true that the delivery must comply with the sanctions regime (against Russia) but in my opinion steps could have been taken to overcome this and use original parts. The clear fact is that the plant is losing €tens of millions because of this unfortunate technical decision.”

Whoever allowed this to happen will take responsibility,” said the minister, without specifying whether he was referring to the plant’s director, Ivan Andreev.

What are the problems at the Kozloduy NPP?

The problems with the membrane of Unit 6 began in mid-December 2025, immediately after the completion of the scheduled annual maintenance, which lasted more than a month. On December 15, 2025 the unit was shut down for several days to replace a defective safety membrane device (rupture disc) on a separator-steam superheater in the machine room. On December 21, 2025 it was shut down again after a defect reappeared in the turbine’s protective membrane device.

Around the middle of this month the plant announced that on February 15 the unit would be shut down again to replace a defective safety diaphragm device, but this has not happened yet and it is simply operating at reduced capacity.

For three weeks Unit 6 has been operating at about 100 MW below its nominal capacity, which affects both public finances and business costs. When cheap energy from the nuclear power plant decreases another, more expensive source must be found for the regulated market. This means that the state has to pay extra from the Electricity System Security Fund (ESSF). Companies, for their part, also suffer, as the lack of megawatts in the system means an increase in exchange prices, from where they source their energy.

On February 17, Georgi Kaschiev, a nuclear physicist with nearly 20 years of experience at the Kozloduy Nuclear Power Plant and several years at the helm of the Nuclear Regulatory Agency (NRA), calculated that the direct losses to the state from the shutdowns of the unit during the year amounted to €60 million. He made this calculation based on a conservative electricity price on the exchange of €100 per MWh.

This means that for the 10 days since then, according to very rough estimates, the state has lost another €2.5 million.

Translated with DeepL.