According to the Russian Ministry of Emergency Situations, no radioactivity was released when a malfunctioning turbogenerator forced an emergency shutdown at Novovoronezh Nuclear Power plant on May 12^th.

The affected reactor was back on grid the following day, although only able to operate at half capacity. An investigation of the failure began late Wednesday afternoon.

Novovoronezh nuclear power plant operates three reactors, among them the oldest VVER reactor in Russia. It was first fired up in 1971. The May 12^th emergency shut down was not Novovoronezh’s first. Four incidents labelled "safety significant" by power authorities have occurred in a decade of trouble for Novovoronezh’s reactors Number 3 and 4; both of the old VVER 440-230 type. Seven separate events, considered "safety relevant" by the International Atomic Energy Agency, further taint the plant’s safety record.

Both European Union and the U.S. have provided technical assistance to Novovoronezh Nuclear Power Plant to help with safety: technical training for employees and technical up-grades for reactors. The EU has given the plant €3,5 million from the TACIS-program, while €55 million has come from the European Bank for Reconstruction and Development for improvements to the VVER-440 reactors at Novovoronezh and Kola nuclear power plants.

Other incidents at Novovoronezh NPP:

• 20. December 1990: control element discovered damage.
• 25. October 1991: failure of shutdown system during refuelling.
• 3. March 1992: technical failure.
• 7. March 1992: failure of automatic shutdown system.
• 30. April 1992: breakdown of cooling system.
• 14. July 1992: reactor shutdown due to failure of cooling system.
• 22. August 1992: failure of shutdown system.
• 12. August 1997: leakage from a collector containing radioactive water.