Bulgarian nuclear reactor after breakdown from the grid

Bulgarian nuclear reactor after breakdown from the grid

Emergency shutdown after breakdown in Bulgarian nuclear power plant

A nuclear accident occurred in Bulgaria at the weekend. After a warning message in the control center of the Kosloduj nuclear power plant on the Danube, a reactor block had to be taken off the grid. According to the authorities, no radioactivity was released into the environment.

In the Bulgarian Kosloduj nuclear power plant, one of two reactors has been shut down following a fault message. A spokesman for the operator announced that the "thousand-megawatt reactor was automatically disconnected from the power grid on Saturday evening after a warning message". However, no further details were given on the exact circumstances of the disturbance. There was a “technical problem with a turbogenerator”, as it was said, but “had already been solved in the meantime”.

No increased radiation exposure in the surrounding area
The nuclear power plant operator denies the occurrence of radioactivity. Measurements in the vicinity would not have shown increased radiation exposure. The defective generator was located outside the reactor cycle, so it can be assumed that no radioactivity got into the surrounding area, the power plant management said. The health of the population and employees is not at risk.

The district of Kozloduy is located directly on the Danube in the northwest of Bulgaria. The capital Sofia is only about 200 kilometers from the nuclear power plant. If there were a super meltdown, the city would have to be evacuated. Bulgaria was hit by a 5.8 magnitude earthquake last Tuesday. The operator denies any connection between the earthquake and the accident that occurred.

Emergency shutdown of the reactor block
An installed protective device prevented a major incident in which an emergency shutdown was automatically initiated. The other reactor block was only restarted after maintenance work on Thursday. As the Bulgarian government recently announced, the terms of both blocks have been extended by 20 years. Out of a total of six blocks, only two are fully operational after some modernization work.

Already several breakdown series
As early as 2003, the state nuclear agency reported a leak in a weld seam in the primary circuit of the now decommissioned third reactor. An emergency cooling then occurred. An accident also occurred in 2006. Because the loss of coolant could have occurred, an acute meltdown was imminent. The reactor was shut down using boric acid. The operator originally classified the incident as level 0 according to the "International Nuclear Event Rating Scale". In retrospect, the national supervisory authority classified the incident as level 2. The accident only became public months later. Due to safety concerns, four out of six reactors were shut down in 2007 before joining the EU.

The core kiln comes from the old Soviet design and was built in 1969 with the help of the then USSR. The nuclear power plant is identical in construction to the former Greifswald nuclear power plant. After the reunification, the Greifswald nuclear power plant was shut down immediately due to massive security risks.

Another nuclear reactor planned
The member state of the European Union (EU) plans to build another 1000 megawatt block in Kozloduy in the near future. It was only in March of this year that the Bulgarian government announced that it would no longer implement a joint building planned with Russia near Belene an der Donau. Another block of Russian design is to be built in Kozloduy. Bulgaria covers a third of its electricity needs with the help of nuclear power plants. (sb)

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Author and source information

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