Turbines of the type used in this power plant have a very narrow working band at high efficiency regimes.
 If this band is exceeded the turbines begin to vibrate, caused by the pulsation of water flow and water strokes.
These vibrations and shocks cause the turbines to degrade over time.

Turbine 2 had experienced problems for a long time prior to the 2009 accident.
The first of these appeared after its installation in 1979.
 Throughout 1980-1983, numerous problems with seals, turbine shaft vibrations and bearings surfaced.
From the end of March to the end of November 2000, a complete reconditioning of turbine 2 was performed.
Cavities up to 12 millimetres (0.47 in) deep and cracks up to 130 millimetres (5.1 in) long were found on the turbine runner and repaired.
 Many other defects were found in the turbine bearings and subsequently repaired.
In 2005, further repairs were made to turbine 2.
The problems found were similar in several aspects to the defects observed during the previous repair.

From January to March 2009, turbine 2 was undergoing scheduled repairs and modernization.
It was the first and only turbine in the station which was equipped with a new electro-hydraulic regulator of its rotational speed supplied by the Promavtomatika company.
 During the course of the repair, the turbine blades were welded, because after a long period of operation, cracks and cavities had once again appeared.
The turbine runner was not properly rebalanced after these repairs, following which turbine 2 had increased vibrations, ca 0.15 millimetres (0.0059 in) for the main bearing during the full load of the turbine.
While this did not exceed specifications, the increased vibrations were unacceptable for long term use.
The elevated vibration levels compared to other turbines were apparent for turbine 2 before the repair as well.
The vibrations exceeded the allowed specification in the beginning of July and continued to increase with accelerated speed.

On the night of 16–17 August, the level of vibration increased substantially, and there were several attempts to stop the turbine.
During 16 August up to 20:30, the load of turbine 2 was 600 MW, then it was reduced to 100–200 MW.
On 17 August 2009 at 3:00, the load was increased again to 600 MW; at 3:30, the load was decreased to 200 MW; and at 3:45, it was increased again to 600 MW.
 During this time, the level of vibration was very high, and was also registered by seismic instruments in the plant.
During attempts to shut it down, the rotor inside the turbine was pushed up, which in turn created pressure pushing up on the turbine cover, which was kept in place by 80 bolts, each 8 cm in diameter.

During the morning of 17 August 2009, 50 people were gathered around turbine 2.
As the plant general director, Nikolai Nevolko, was celebrating his anniversary, early in the morning he went to Abakan to greet the arriving guests, and none of the workers present wanted, or had the authority, to make decisions about further actions regarding the turbine.
It seems they were used to the high levels of vibration.

Turbine 2 was started on 16 August 2009 at 23:14 local time.
At 23:44 it was running at a full load of 600 MW.
 During the night, its load varied between 10 and 610 MW.
At the moment of the accident, which was 8:13 local time (00:13 GMT), its load was 475 MW and water consumption was 256 m³/s (9,000 cu ft/s).
Vibration of the bearing was 0.84 millimetres (0.033 in), which far exceeded the values of the other turbines by more than fourfold.
The working life defined by the manufacturer for the turbines was specified as 30 years.
At the moment of the accident, the age of the turbine was 29 years and 10 months.

On 17 August 2009, the turbines were at a working level of 212 metres (696 ft).
At this pressure the recommended power band for the turbines is 570–640 MW (band III) and the allowed band is 0-265 MW also (band I).
Band 265–570 MW (band II) at this pressure is not recommended and output over 640 MW (band IV) is forbidden.
On the day of the accident, turbine 2 worked as the plant's power ou
Turbines of the type used in this power plant have a very narrow working band at high efficiency regimes.  If this band is exceeded the turbines begin to vibrate, caused by the pulsation of water flow and water strokes. These vibrations and shocks cause the turbines to degrade over time.
Turbine 2 had experienced problems for a long time prior to the 2009 accident. The first of these appeared after its installation in 1979.  Throughout 1980-1983, numerous problems with seals, turbine shaft vibrations and bearings surfaced. From the end of March to the end of November 2000, a complete reconditioning of turbine 2 was performed. Cavities up to 12 millimetres (0.47 in) deep and cracks up to 130 millimetres (5.1 in) long were found on the turbine runner and repaired.  Many other defects were found in the turbine bearings and subsequently repaired. In 2005, further repairs were made to turbine 2. The problems found were similar in several aspects to the defects observed during the previous repair.
From January to March 2009, turbine 2 was undergoing scheduled repairs and modernization. It was the first and only turbine in the station which was equipped with a new electro-hydraulic regulator of its rotational speed supplied by the Promavtomatika company.  During the course of the repair, the turbine blades were welded, because after a long period of operation, cracks and cavities had once again appeared. The turbine runner was not properly rebalanced after these repairs, following which turbine 2 had increased vibrations, ca 0.15 millimetres (0.0059 in) for the main bearing during the full load of the turbine. While this did not exceed specifications, the increased vibrations were unacceptable for long term use. The elevated vibration levels compared to other turbines were apparent for turbine 2 before the repair as well. The vibrations exceeded the allowed specification in the beginning of July and continued to increase with accelerated speed.
On the night of 16–17 August, the level of vibration increased substantially, and there were several attempts to stop the turbine. During 16 August up to 20:30, the load of turbine 2 was 600 MW, then it was reduced to 100–200 MW. On 17 August 2009 at 3:00, the load was increased again to 600 MW; at 3:30, the load was decreased to 200 MW; and at 3:45, it was increased again to 600 MW.  During this time, the level of vibration was very high, and was also registered by seismic instruments in the plant. During attempts to shut it down, the rotor inside the turbine was pushed up, which in turn created pressure pushing up on the turbine cover, which was kept in place by 80 bolts, each 8 cm in diameter.
During the morning of 17 August 2009, 50 people were gathered around turbine 2. As the plant general director, Nikolai Nevolko, was celebrating his anniversary, early in the morning he went to Abakan to greet the arriving guests, and none of the workers present wanted, or had the authority, to make decisions about further actions regarding the turbine. It seems they were used to the high levels of vibration.
Turbine 2 was started on 16 August 2009 at 23:14 local time. At 23:44 it was running at a full load of 600 MW.  During the night, its load varied between 10 and 610 MW. At the moment of the accident, which was 8:13 local time (00:13 GMT), its load was 475 MW and water consumption was 256 m³/s (9,000 cu ft/s). Vibration of the bearing was 0.84 millimetres (0.033 in), which far exceeded the values of the other turbines by more than fourfold. The working life defined by the manufacturer for the turbines was specified as 30 years. At the moment of the accident, the age of the turbine was 29 years and 10 months.
On 17 August 2009, the turbines were at a working level of 212 metres (696 ft). At this pressure the recommended power band for the turbines is 570–640 MW (band III) and the allowed band is 0-265 MW also (band I). Band 265–570 MW (band II) at this pressure is not recommended and output over 640 MW (band IV) is forbidden. On the day of the accident, turbine 2 worked as the plant's power ou
2009 Sayano-Shushenskaya power station accident