POWER June 2011 - 8

Seven Charged in Siberian
Hydropower Plant
Accident
The Russian Investigative Committee has
completed a probe into the August 2009
accident at the Sayano-Shushenskaya
Hydro Power Plant in Siberia that killed 75
people. The committee has charged seven
people-including the plant's former
head, Nikolai Nevolko, his deputies, and
the plant's former chief engineer, Andrei
Mitrofanov-for violating safety rules. If
found guilty, the officials could face five
years in jail.
On Aug. 17, 2009, an explosion at the
giant 10-turbine hydroelectric station destroyed
Units 2, 7, and 9, and seriously
damaged Units 1 and 3. (For details of
the event, see " Investigating the SayanoShushenskaya
Hydro Power Plant Disaster "
in our December 2010 issue or in the archives
at www.powermag.com.) The plant's
other five units were also damaged.
In an October 2009 report that investigated
what caused the catastrophe
at the 6,400-MW hydroelectric plant,
Russian industrial safety regulator Rostekhnadzor
cited a number of contributing
causes, including design, operation,
and repair shortcomings. It also pointed
a finger at six high-ranking Russian
officials-including former electricity
monopoly chief Anatoly Chubais, Igor
Yusufov (Russia's energy minister until
2004), and Viyacheslav Sinugin (former
deputy energy minister)-saying that
the accident resulted from their " negligence,
laxity, and a lack of engineering
thinking. "
The October 2009 report estimated that
addressing the wreckage to major power
generating assets and environmental damage
would cost up to 7.338 billion rubles
(US$269 million). State-controlled RusHydro,
the Russian Federation's biggest
hydropower producer, recently announced,
however, that it would spend 20.6 billion
rubles over the next two years on restoring
the plant.
RusHydro, which owns power plants
from the Finnish border in the northwest
to the Chinese frontier in the south, has
already restored four 640-MW generating
units. Last year, it connected Unit 6 to
the grid on Feb. 24, Unit 5 on March 22,
Unit 4 on Aug. 2, and Unit 3 on Dec. 22.
Restoration efforts have put the plant's
current capacity at 2,560 MW, and RusHydro
reports that total energy output of the
8
restored generating units exceeds the 10
billion kWh level.
Work has begun on the second phase of
restoration. In 2011, RusHydro is expected
to install six totally new units, manufactured
by Power Machines, and in the final
phase, spanning 2013 to 2014, it will
replace the units restored last year with
new ones. " The service life of new [generating
units] will increase to 40 years [and
the] new turbines will have the maximum
efficiency of 96.6% and improved output
and cavitation performance, " the company
said. The hydraulic units will also reportedly
be equipped with advanced diagnostic
systems to promptly detect status
changes and prevent accidents.
Power Machines said in a statement in
March that the second phase of restoration
was on track. Work to assemble generator
components for Unit 1 was being
carried out in the crater of Unit 9; the
540-metric ton stator will later be moved
to the prepared crater at Unit 1 using a
custom-made lifting beam (Figure 1). Unit
1 is now scheduled to be put into operation
in December 2011.
Recovery Efforts Continue
at Fukushima Daiichi
In April, Japan's Nuclear and Industrial
Safety Agency provisionally raised the
accident rating for three reactors at the
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crippled six-unit Daiichi nuclear plant in
Fukushima Prefecture to Level 7-making
it a " major accident " and putting it on par
with the 1986 Chernobyl accident in the
Ukraine. Recovery efforts continue at the
nuclear plant with workers pumping massive
amounts of freshwater into Units 1, 2,
and 3 and spraying it over the spent fuel
pool of Unit 4.
Plant operator Tokyo Electric Power Co.
(TEPCO) has said that as much as 55%
of Unit 1's reactor core is thought to be
impaired-and the damage may be inhibiting
the flow of coolant water, leading to
higher temperatures and pressures; Unit
2's core is estimated to be 35% damaged,
as is 30% of Unit 3's core. Nitrogen gas
continues to be injected into the containment
vessel in Unit 1 to reduce chances of
hydrogen combustion.
Units 5 and 6, which were not in service
when the devastating 14-meter tsunami
on March 11 took out the power and
debilitated cooling systems for the other
units, remain in cold shutdown. Concerns
continue about the condition of Unit 4,
which also wasn't operating at the time of
the natural disaster but which, on March
15, saw an explosion in the top part of
the building near the spent fuel pond,
subsequent fires, and heightened radiation
levels. TEPCO continues to top up
water levels in the spent fuel pool (Figure
2), which had dropped due to evaporation
POWER | June 2011
1. A massive overhaul. Following the
catastrophic explosion that killed 75 workers
at the 6,400-MW Sayano-Shushenskaya
Hydro Power Plant in Siberia in August 2009,
plant owner RusHydro plans to replace all
the station's damaged units with new ones.
Power Machines, a contractor that will build
and install the 10 new hydraulic turbines,
nine hydraulic generators, and six excitation
systems, has begun work on the Unit 1
stator. RusHydro has to date restored four
less-damaged units and says the plant's capacity
now exceeds 2,560 MW. Courtesy:
Power Machines
2. Pooling resources. This image from
a video taken on April 28 shows Daiichi 4's
spent fuel pool. The unit, which has experienced
fewer problems than Daiichi 1, 2, and
3, has had both a hydrogen explosion and fires
since March 11 even though it was shut down
and all of its 1,331 spent fuel rods and 204 unused
fuel rods were being stored in the spent
fuel pool. A water sample from the pool in
April showed high levels of radioactive iodine
and cesium-indicating that some spent fuel
rods have been damaged. Courtesy: TEPCO
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POWER June 2011

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