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Sayano–Shushenskaya hydroelectric power station (Russian: Сая́но-Шу́шенская гидроэлектроста́нция, Sayano-Shushenskaya Gidroelektrostantsiya) is located on the Yenisei River, near Sayanogorsk in Khakassia, Russia. It is the largest power plant in Russia and the sixth-largest hydroelectric plant in the world, by average power generation. The full legal name of the power plant, OJSC [Open Joint-Stock Society] P. S. Neporozhny Sayano-Shushenskaya HPP [hydro power plant], refers to the Soviet-time Minister of Energy and Electrification Pyotr Neporozhny. The head of the power plant is Valery Kyari.
Previous Accidents
1979 accident - On 23 May 1979, spring flood water entered into the machine hall and flooded the first working turbine unit. The turbine was restarted on 4 July 1979. The dam had not yet been completed.
1985 accident - A powerful spring flood destroyed 80% of the concrete spillway bottom plate, tearing apart 50-millimetre (2.0 in)-thick anchor bolts and carving seven meters deep into the bed rock.
1988 accident - A powerful spring flood destroyed the spillway well. As a result, working headway for the future was reduced by five meters.
The 2009 Accident
On 17 August 2009, the station suffered a catastrophic accident that caused flooding of the engine and turbine rooms and a transformer explosion. As of 4 September 2009, 74 people were confirmed dead while one person is listed as missing.
Power generation from the station ceased completely following the incident, with the resulting blackout in residential areas being alleviated by diverting power from other plants. Aluminium smelters in Sayanogorsk and Khakassia were completely cut off from the grid before power supplies were replaced using alternate power sources. Russia warned that in the longer term it might lose up to 500,000 tons of aluminum output due to the power shortage, and called for accelerating the construction of the Boguchanskaya hydroelectric power station to replace lost generating capacity.
The accident caused an oil spill with at least 40 tonnes of transformer oil released, spreading over 80 km (50 mi) downstream of Yenisei.
The plant is expected to restart its operations within 1 to 1½ months, while the complete repair of the power station may take up to four years. According to Russian Energy Minister Sergei Shmatko the rebuilding of the engine room alone would cost $1.2 billion.
Dam subcontractor Gidroelectroremont's chief accountant has been accused by the Khakassia police of embezzling 24 million rubles from the funds allocated by RusHydro for repairing the dam.
Official Report Summary
On 3 October 2009 the official report about Sayano-Shushenskaya hydro accident was published.
In summary, it states that the accident was primarily caused by vibrations of turbine № 2 which led to fatigue damage of the mountings of the turbine, including its cover. The report found that at the moment of the accident, the nuts on at least 6 bolts keeping the turbine cover in place were absent. After the accident, 49 found bolts were investigated: 41 had fatigue cracks. On 8 bolts, the fatigue-damaged area exceeded 90% of the total cross-sectional area.
On the day of the accident, turbine № 2 worked as the plant's power output regulator. At 8:12 the turbine № 2 output power was reduced by an automatic turbine regulator, and it entered into a powerband unrecommended for the head pressure that day. Shortly afterwards the bolts keeping the turbine № 2 cover in place were broken. Under water pressure (about 20 atmospheres) the spinning turbine with its cover, rotor and upper parts jumped out of the casing, destroying the machinery hall equipment and building.
Pressurised water immediately flooded the rooms and continued damage to the plant. At the same time, an alarm was received at the power station's main control panel, and the power output fell to zero, resulting in a local blackout. But it took 25 minutes to manually close the water gates to the other turbines; during that time they continued to spin — without load.
A rescuer and dog look for victims in the debris of the damaged Sayano-Shushenskaya hydroelectric power station, August 20, 2009.
Relatives of victims in the accident at Sayano-Shushenskaya hydroelectric power station read information at the Siberian village of Cheryomushki, August 19, 2009.
Russian Emergency Situations Minister Sergei Shoigu explains the nature of the accident at the Sayano-Shushenskaya hydroelectric power station in Cheryomushky on August 19, 2009.
Medical personnel comfort a relative of a victim of the accident at Sayano-Shushenskaya dam on August 19, 2009.
People grieve as they attend funeral for victims of an accident at the Sayano-Shushenskaya power station, in a settlement of Cheryomushki, August 20, 2009.
Pallbearers carry the coffin of a man who died in the Sayano-Shushenskaya hydroelectric power dam accident at a funeral in Cheryomushky on August 20, 2009.
Buildings sit on the bank of the oil-polluted waters of the Yenisei River, downstream from the Sayano-Shushenskaya hydroelectric power dam in Cheryomushky on August 20, 2009. Oil from the dam's turbines was released into the water as a result of the accident.
A boat motors through oil-slicked water in the Yenisei River, downstream from the Sayano-Shushenskaya dam on August 20, 2009.
Workers collect an oil spill in the Yenisei River, which occurred after the accident at the Sayano-Shushenskaya dam, near the settlement of Mayna, August 19, 2009.
Workers contain an oil spill in the Yenisei River, near the settlement of Mayna, Russia on August 19, 2009.
Russian Prime Minister Vladimir Putin visits the accident site at the Sayano-Shushenskaya hydroelectric power station in Cheryomushky on August 21, 2009. At right is Emergency Situations Minister Sergei Shoigu.
