18 Aug 2009 19:57

Sayano-Shushenskaya accident possibly caused by broken turbine

ABAKAN. Aug 18 (Interfax) - The main theory behind yesterday's Sayano-Shushenskaya Hydroelectric Power Plant accident in Khakasia has not been confirmed, said Alexander Toloshinov, former general director of the plant and a board member of the RusHydro generating company.

"A turbine was broken in the machine hall. Instruments indicated that it was not a hydraulic impact, but a broken turbine cover in the machine hall," Toloshinov told Interfax on Tuesday.

Asked whether any of those inside the flooded turbine house could have survived, Toloshinov said: "If they managed to keep out of the water then yes. But if they were trapped in the water, then hardly any chance as the water temperature was only 4 degrees."

Toloshinov said the water inside the damaged turbine house was up to 20 meters deep.

He said the accident could have been the result of a hidden turbine manufacturer's defect that only surfaced after 30 years of use.

Sensors indicated that the turbine was functional and did not detect any gradual wear. But it will only be possible to establish whether this really was a factory defect once the debris has been cleared, he said.

Also, this is only one version of events that is being considered together with the hydraulic impact theory, Toloshinov said.

The Leningrad Metals Plant, currently part of OJSC Power Machines , made the turbine. The Sayano-Shushenskaya HPP's own specialists last performed maintenance on the turbine a year ago, and outside contractors were not brought in, Toloshinov said.

A spokesman for Power Machines told Interfax that "it is premature to draw conclusions about the causes of the accident until the investigation had been completed." Power Machines will be sending specialists out to Khakasia to join the investigative commission.

Power Machines issued a statement later on Tuesday saying that supplies to the plant began more than 30 years ago. The first two power units were brought on stream in 1978 and 1979. "According to Power Machines technical specialists, the first hydroelectric unit had already used its resources and needs to be replaced," the statement says.

The company also said that the service life of such hydroelectric equipment highly depends on the conditions in which it is used as well as constant control of its technical condition and the carrying out of timely planned and preventive repairs. Power Machines specialists had not been called to the plant for repairs since 1993, the company said.

In addition, Emergency Situations Minister Sergei Shoigu cautioned against government officials giving or thinking up reasons for the accident.

"We'll find out what happened and then report on this," Shoigu told reporters, when asked what caused the accident.

Energy Minister Sergei Shmatko said a commission consisting of the best specialists and professionals had been set up. "They will determine the causes of the accident. Right now it would be irresponsible to talk about any main version," he said.

Power Machines produces and supplies equipment for thermal, nuclear, hydro and gas-turbine power plants.