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1.0 INTRODUCTION

The SayanoShushenskaya Dam which is located on the Yenisei River, Russia is the largest

power plant in Russia and the sixth-largest hydroelectric plant in the world, by average power

generation.

The decision to build the power station was taken in 1960. On November 4, 1961,

geologists reached the area, and an exact location was chosen. Construction started in 1968

and the plant was opened in 1978. It was partially reconstructed in 1987. The plant was

designed by the Saint Petersburg branch of the Hydroproject.

In 1993, the power plant was privatized and RAO UES became the main shareholder. InApril 2003, the Government of Khakassia by the initiative of the governor Alexei Lebed filed a

suit to invalidate the deal. In April 2004, the East Siberian Arbitration invalidated the deal;

however, it was overruled by the Supreme Arbitration Court.

The plant was closed after accident which caused an oil spill with at least 40 tonnes

oftransformer oil released, spreading over 80 km (50 mi) downstream of Yenisei on 17th

August 2009. Turbine number 6 was restarted on 24th February 2010. The plant is expected to

restart its operations within 1 to 1 months, while the complete repair of the power station

may take up to four years.
http://en.wikipedia.org/wiki/Oil_spillhttp://en.wikipedia.org/wiki/Transformer_oilhttp://en.wikipedia.org/wiki/Transformer_oilhttp://en.wikipedia.org/wiki/Oil_spill


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2.0 WHEN AND WHERE IT HAPPENED?

Russias biggest hydroelectric is Sayano-Shushenskaya dam. The SayanoShushenskaya Dam is

located on the Yenisei River, near Sayanogorskin 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 which is 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.

Figure 1: Sayano-Shushenskaya Dam

Figure 2: Location of Sayano-Shushenskaya Dam
http://en.wikipedia.org/wiki/Yenisei_Riverhttp://en.wikipedia.org/wiki/Sayanogorskhttp://en.wikipedia.org/wiki/Khakassiahttp://en.wikipedia.org/wiki/Russiahttp://en.wikipedia.org/wiki/Hydroelectricityhttp://en.wikipedia.org/w/index.php?title=Pyotr_Neporozhny&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Pyotr_Neporozhny&action=edit&redlink=1http://en.wikipedia.org/wiki/Hydroelectricityhttp://en.wikipedia.org/wiki/Russiahttp://en.wikipedia.org/wiki/Khakassiahttp://en.wikipedia.org/wiki/Sayanogorskhttp://en.wikipedia.org/wiki/Yenisei_River


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The plant is operated by RusHydro. It provides more than a quarter of RusHydros

generation capacity. The plant operated ten types of PO-230/833-0-677 hydro turbines

manufactured at the Leningradsky Metallichesky Zavod, each with a capacity of 640 MW at 194-

metre (636 ft) head (Euler Cruz, 2009). The total installed capacity of the plant is 6,400 MW; its

average annual production is 23.5 TWh, which peaked in 2006 at 26.8 TWh.

The 2009 SayanoShushenskaya hydroelectric power station accident occurred at 00:13

GMT on 17 August 2009, (08:13 AM local time) when turbine 2 of the SayanoShushenskaya

hydroelectric power station broke apart violently. The turbine hall and engine room were

flooded, the ceiling of the turbine hall collapsed, 9 of 10 turbines were damaged or destroyed,

and 75 people were killed. The entire plant output, totalling 6,400 MW and a significant portion

of the supply to the local grid, was lost, leading to widespread power failure in the local area,

and forcing all major users such as aluminium smelters to switch to diesel generators

(wikipedia, 2011). An official report on the accident was issued on 4 October 2009.
http://en.wikipedia.org/wiki/Sayano%E2%80%93Shushenskaya_hydroelectric_power_stationhttp://en.wikipedia.org/wiki/Sayano%E2%80%93Shushenskaya_hydroelectric_power_stationhttp://en.wikipedia.org/wiki/Sayano%E2%80%93Shushenskaya_hydroelectric_power_stationhttp://en.wikipedia.org/wiki/Sayano%E2%80%93Shushenskaya_hydroelectric_power_stationhttp://en.wikipedia.org/wiki/Sayano%E2%80%93Shushenskaya_hydroelectric_power_stationhttp://en.wikipedia.org/wiki/Sayano%E2%80%93Shushenskaya_hydroelectric_power_station


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3.0 WHAT HAPPEN AND HOW IT HAPPENED (INITIATION)

What happened?

A catastrophic accident took place in the turbine and transformer rooms of the hydroelectric

plant of the Sayano-Shushenskaya dam. Tremendous amount of water from the Yenisei River

flooded the turbine room. Additionally, 40 tons of transformer oil was spilled into the river.

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.

How it happened? (initiation)

It states that the accident was primarily caused by vibrations of turbine number 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 Unit 2 worked as the plant's power output regulator.

At 8:12 the turbine Unit 2 output power was reduced by an automatic turbine regulator, and it

entered into a powerband unrecommended for the head pressure that day.

The explosion of Unit 2 and the destruction of Units 7 and 9 were very probably caused

by water column separation in the turbine draft tubes during unit load rejection. This hydraulic

transient phenomenon was probably caused by turbine governors that had been speeded up

(probably unknowingly) to an unsafe level in an attempt to improve frequency stability under

changing electrical loads.


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Units 7 and 9 apparently had sudden load rejection conditions imposed on them as a

result of the Unit 2 failure. It appears that both Units 7 and 9 experienced draft tube water

column separation followed by powerful uplift.

A rapid load rejection from a heavily loaded condition may have elicited water columnseparation in the draft tube, followed by an extremely violent pressure rise as the water column

rejoined under the head cover. Each draft tube is long enough (about 35m) to trigger a rapid

load rejection. The loaded condition can be up to 475MW or 74% of rated maximum.

The Unit 2 turbine was known to have suffered from extensive cavitation damage to its

runner. This suggests that the local pressure in the vicinity of the draft tube throat was fairly

near vapor pressure during steady state operation. This is to be expected in a region where the

velocity profile is extremely non-uniform, and there is a substantial whirl component of velocity.

A sudden load rejection would have caused a drop in pressure at the draft tube throat as the

draft tube water column was decelerated by the action of the closing wicket gates. If the gate

closure were fast enough, the draft tube pressure would have been reduced to vapor pressure,

leading to the formation of a vapor cavity in the draft tube throat.


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4.0 HOW THE EVENT WAS MAINTAINED OR EXPANDED (PROPAGATION)

The expansion of sequence of the event

As a result of the same gate closure, a simultaneous waterhammer pressure rise in the

penstock and spiral case would have been produced. This pressure rise, however, would have

been simultaneous with the pressure drop to vapor in the draft tube, and would have preceded

the collapse of the vapor cavity by an interval.

The propagation sequence of the event

The penstock round-trip pressure wave travel time of about 0.4 seconds was substantially

shorter than the draft tube mass surge time. A simplified mass surge analysis of the draft tube

flow during this postulated column separation indicates that the time between opening and

reclosing of the vapor cavity would have been of the order of 2 seconds. It further indicates

that the upward water velocity at vapor cavity closure would have been approximately 2.4%

greater than the initial downward velocity when the separation began. This simplified analysis

assumed instantaneous draft tube inflow interruption at the time of column separation, so the

results must be viewed as indicative only.

This is a credible sequence of events, as indicated by an approximate analysis of this

condition for various assumed governor gate closure times. This analysis indicates that column

separation may be expected for governor times faster than full stroke in about six seconds. The

analysis was based on mass surge assumptions and draft tube geometry reflecting uniform area

increase from the throat to the exit. It does not account for the whirl component of velocity and

related low pressure in the draft tube associated with operation well off the machine design

point, and it is, therefore, probably not conservative in this instance.

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.


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During the time that the vapor cavity persisted in the draft tube, the transient flow

condition between the throat and the draft tube exit would have approximated a slow mass

surge under the influence of the unbalanced head between vapor cavity and tailwater.

5.0 HOW THE EVENT WAS STOPPED OR DIMINISHES IN SIZE?

It is likely that several seconds passed between column separation and column rejoining at the

collapse of the vapor cavity. The waterhammer pressure rise in the spiral case would have been

relieved quite quickly due to the relatively short penstocks. Apart from that, in order to relief

the pressure, the wicket gates were blown outward after their lower trunnions were pulled out

of their bushings. This in turn gives catastrophe effect when the powerful uplift caused severe

damage to the generators and surrounding structure.

Besides, studs of Units 7 and 9 failed sequentially, causing the rotating parts to tilt as

they were being thrust upwards. This would result in a collision between rotor and stator before

the rotating parts had moved far enough upwards to release penstock pressure into the turbine

pits.

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. One transformer explosion and extensive damage to all ten turbines, destroying at

least three of them.

The time that this force would exist would, of course, be very brief. Based on a 35m

draft tube length, it is estimated that the pressure spike would last about a tenth of a second.

Assuming the parts of the machine that were lifted weighed 1500 tonnes, this pressure spike

could have lifted the machine a meter and a quarter during the tenth of a second duration. This

is about as close to a true explosion as it is possible to get with an incompressible fluid. The

explosion is stopped after all the pressures including water hammer pressure and sudden load

rejection has been ventilated that caused severe and extensive damage to the dam.


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6.0 IMPACT OF ACCIDENT AT SAYANO-SHUSHENKAYA HYDRO-POWERPLANT

As a result of the accident, 75 people were killed. On 19 August 2009, the mourning day was

announced in Khakassia. RusHydro declared 25 August a day of mourning at the company. A

festival in the city of Abakan on 22 August was canceled. According to RusHydro and press

reports, one-third of the plant's capacity (7.6% of RusHydro's total installed capacity) needs to

be replaced, which could take 18 months. The remaining 66% of the plant's capacity will likely

resume operations in about 45 days. The extent of the damage to the plant is not yet clear.

Also, due to the accident, the town of Cheryomushki has banned the sale of strong alcoholic

beverages.

Damage

In addition to turbine 2, turbines 7 and 9 also suffered severe damage and were destroyed,

while the turbine room roof and ceilings fell on and caused additional damage to turbines 1 and

3, with slight damage to turbines 4, 5, 8, and 10. Turbine 6, which was in scheduled repair at

the time of the accident, received only minor damage and was the only one of the station's 10

turbines that did not receive electrical damage due to shorting of transformers. Water

immediately flooded the engine and turbine rooms and caused a transformer explosion.

Transformers 1 and 2 were destroyed, while transformers 3, 4, and 5 were left in satisfactory

condition. Other damage was also severe as the machinery hall was destroyed, including the

roof, ceilings, and floor.

Power supply

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.The power

plant was supplying almost 25% of its power to aluminum industries and smelters. Because of

this accident, it caused a complete blackout in the near-by cities and towns. Replacement of the

turbines completely may take up to four years. Aluminium smelters in Sayanogorsk and

Khakassia were completely cut off from the grid before power supplies were replaced using

alternate power sources. Power to black out areas was fully restored by 19 August 2009.


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Although smelters continue to work at their normal rate, RUSAL warned that in the longer term

it may lose up to 500,000 tonnes of aluminum output due to the power shortage, and called for

accelerating the construction of the Boguchany hydroelectric power station to replace lost

generating capacity.

Environmental impact

The accident caused an oil spill, releasing at least 40 tonnes of transformer oil which spread

over 80 km downstream of Yenisei which flow into the Arctic Ocean according to statements

from the emergency ministry and RusHydro. Local ecosystems were under threat, as do water

intake structures used by several towns and cities located on the river.

Though the mayor of Abakan, Nikolai Bulakin, said drinking water was unaffected in

Abakan because it was drawn from the Abakan river, said the BBC, environmental damage had

already been done, in Bulakins words, and he had heard reports that many trout at fish farms

had been poisoned. The oil, which spilled during the approximately 2-3 hour cutoff of river flow

when all the gates of the dam were closed, killed 400 tonnes of cultivated trout in two riverside

fisheries, with its impact on wildlife as yet unassessed.

In efforts undertaken by local emergency authorities, workers with State Inspection for

Small Vessels, and workers with oil transport company Transsibneft, booms are being deployed

on the river to stop the reported 80-kilometre oil slick. Such booms have already been placed

800 metres upriver and 500 metres downriver from Maina Hydroelectric Power Plant. Reports

say 610 people and 103 various machinery units are involved in the effort, including 273 people

and 36 machinery units provided by the emergency ministry. RusHydro has said in official

statements that the transformer oil spilled into the Yenisei does not contain poisonous additives.

If it did contain toxic admixtures, rescue workers would not have been able to work

removing the oil slick from the Yenisei surface without special protective suits, a press official

at RusHydro was quoted by the web-based Gazeta.ru news agency as saying. And they areworking on the river without such suits.Yet, Gazeta.Ru points out, RusHydro is yet to name the

precise brand of the oil used in the transformer. In environmentalists estimates, this will be

crucial to determine how damaging the chemical pollution really has been or will still prove to

be.


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Of particular concern to environmentalists and public health authorities is that

polychlorinated biphenyl (or PCB), an extremely poisonous and carcinogenic substance is known

to be used in old transformers as an electric insulator. It remains to be seen whether PCB was

spilled into the Yenisei in the alleged transformer explosion at Sayano-Shushenskaya. On 19

August 2009, the 15 km long spill had reached Ust-Abakan, where it was cordoned off with

floating barriers and chemical sorbents. The oil spill was fully removed by 25 August 2009.

Financial impact

Share prices

Trading in RusHydro shares at the Moscow Interbank Currency Exchange was suspended for

two days. After trading resumed on 19 August 2009, the shares dropped 11.4%. On the London

Stock Exchange, the share price dropped more than 15%. It is expected that RusHydro's

business losses will amount to US$523 million by 2013. The power plant was insured for

US$200 million by Russian insurance company ROSNO, part of Allianz group, and re-insured by

Munich Re.

Company management has estimated that the re-building work in the engine room alone

would cost them around $1.2 billion. The government has undertaken great efforts for the

search and rescue operation by engaging divers and special robots. Reports say that as of now,

80% of the wreckage has been cleared from the fifth turbine and 90% from the first turbine.Totally around 4000 cubic meters of structural debris have been removed.

Compensation

The Russian government decided to pay compensation of US$31,600 to each victim's family,

and about US$3,100 to each survivor, while RusHydro decided to pay a further 1 million rubles

in compensation. RusHydro also decided to buy housing for 13 families of killed workers with

underage children. There is also program to support these children in kindergartens and schools

and to provide higher education. In addition, a special program for the reconstruction and

development of Cheryomushki settlement, the main settlement where the power plant workers

live, is planned.


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Personnel

The director of the plant, Nikolai Nevolko, was replaced by ValeriiKjari. Several people were

awarded for their heroic actions during the accident. Russian Prime Minister, Vladimir Putin,

awarded JuriSalnikov and Oleg Melnitchuck with an Official Letter of Commendation each.

7.0 HOW THE ACCIDENT CAN BE PREVENTED?

Emergency Plan

Problem: Emergency Planning Failures, failures did not happen in seconds it took 1 hr 7

minutes for consecutive failures to fully launch and news apparently reported 3 hours after the

accident. Safety systems/back up systems planning did not include catastrophic failure. Early

recognition of catastrophic failure and warning could have saved lives. These including failed

closed vs. failed open, plus manual requirements - steel gates to the water intake pipes of

turbines weighed 150 tons each and had to be closed manually (opening valves with hydraulic

jacks to keep them open). This took 25 minutes (record fast time but they knew how to do it,

as the gates frequently had to be closed manually). This showed that risk factors were not a

significant enough part of the planning process. Risks to include consequences for the facility

as well as personnel conducting the manual action - some of these stayed and did their task,

thus losing their lives. There were only oral orders were contemplated in case of emergency.

Sayano-Shushenskaya did not have operational drills. They did have some emergency

drills focused on fires, but not on equipment, operational aspects with series of

actions/consequences to recognize when they had reached full emergency mode.

No good system for how to control/operate immediately following a disaster; very poor

organization which was evident in the news reports. This is the steps between emergency and

recovery planning.


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Prevention: Every place must have emergency plan. A definite plan to deal with major

emergencies is an important element of OH&S programs. Besides the major benefit of

providing guidance during an emergency, developing the plan has other advantages.

Unrecognized hazardous conditions that would aggravate an emergency situation may be

discovered and work can be done to eliminate them. The planning process may bring to light

deficiencies, such as the lack of resources (equipment, trained personnel, supplies), or items

that can be rectified before an emergency occurs. In addition an emergency plan promotes

safety awareness and shows the organization's commitment to the safety of workers.

The lack of an emergency plan could lead to severe losses such as multiple casualties

and possible financial collapse of the organization. Besides, an attitude of "it can't happen here"

may be present. People may not be willing to take the time and effort to examine the problem.

However, emergency planning is an important part of company operation.

Since emergencies will occur, preplanning is necessary to prevent possible disaster. An

urgent need for rapid decisions, shortage of time, and lack of resources and trained personnel

can lead to chaos during an emergency. Time and circumstances in an emergency mean that

normal channels of authority and communication cannot be relied upon to function routinely.

The stress of the situation can lead to poor judgement resulting in severe losses.

Figure 3: Scene-Emergency exit sign must exist to direct people to

safe places.


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The overall objective of the plan

An emergency plan specifies procedures for handling sudden unexpected situations. The

objective is to reduce the possible consequences of the emergency by:

preventing fatalities and injuries;

reducing damage to buildings, stock, and equipment; and

accelerating the resumption of normal operations.

The emergency plan includes

all possible emergencies, consequences, required actions, written procedures, and the

resources available

detailed lists of personnel including their home telephone numbers, their duties and

responsibilities

floor plans, and

large scale maps showing evacuation routes and service conduits (such as gas and water

lines).

Procedures

Many factors determine what procedures are needed in an emergency, such as

the degree of emergency,

the size of organization,

the capabilities of the organization in an emergency situation,

the immediacy of outside aid,

the physical layout of the premises, and

the number of structures determine procedures that are needed.

Common elements to be considered in all emergencies include pre-emergency

preparation and provisions for alerting and evacuating staff, handling casualties, and for

containing of the emergency.


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Natural hazards, such as floods or severe storms, often provide prior warning. The plan

should take advantage of such warnings with, for example, instructions on sand bagging,

removal of equipment to needed locations, providing alternate sources of power, light or water,

extra equipment, and relocation of personnel with special skills. Phased states of alert allow

such measures to be initiated in an orderly manner.

The evacuation order is of greatest importance in alerting staff. To avoid confusion, only

one type of signal should be used for the evacuation order. Commonly used for this purpose are

sirens, fire bells, whistles, flashing lights, paging system announcements, or word-of-mouth in

noisy environments. The all-clear signal is less important since time is not such an urgent

concern.

The following are "musts":

identify evacuation routes, alternate means of escape, make these known to all staff;

keep the routes unobstructed.

specify safe locations for staff to gather for head counts to ensure that everyone has left

the danger zone. Assign individuals to assist handicapped employees in emergencies.

carry out treatment of the injured and search for the missing simultaneously with effortsto contain the emergency.

provide alternate sources of medical aid when normal facilities may be in the danger

zone.

containing the extent of the property loss should begin only when the safety of all staff

and neighbours at risk has been clearly established.

Testing and Revision

Completing a comprehensive plan for handling emergencies is a major step toward preventing

disasters. However, it is difficult to predict all of the problems that may happen unless the plan

is tested. Exercises and drills may be conducted to practice all or critical portions (such as

evacuation) of the plan. A thorough and immediate review after each exercise, drill, or after an


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actual emergency will point out areas that require improvement. Knowledge of individual

responsibilities can be evaluated through paper tests or interviews.

The plan should be revised when shortcomings have become known, and should be

reviewed at least annually. Changes in plant infrastructure, processes, materials used, and key

personnel are occasions for updating the plan.

It should be stressed that provision must be made for the training of both individuals

and teams, if they are expected to perform adequately in an emergency. An annual full-scale

exercise will help in maintaining a high level of proficiency.

Transfer Of Knowledge

Problem: Lack of recognition of hazards including impact of aging equipment and the impacts

of new designs, controls, and grid changes not recognized. For instance needs repair vs.

needs shutdown. Since it was within specifications, even though vibrations were

troublesome, they did not recognize the hazards of continued operation. Within specifications

does not mean they can operate heavy loads long term in those specific ranges.

Transformer failures are not entirely uncommon and most power plants are equipped todeal with these kinds of incidents. However, it appears that the failure of the transformer may

have lead to a mechanical failure of the generators at the plant. A sudden loss of load could

cause the turbines to over-spin, putting them past their design limits. Loss of phase or sudden

loads, such as from a short circuit, can also subject the turbines to enormous mechanical stress.

The effectiveness of strainers and trashracks on water inlets are an obvious item to

check, including regular maintenance. It is also possible from the above anecdotal evidence that

the lack of adherence to maintenance and changeout schedules could have been a factor.Maintenance KPIs (Key Performance Indicators) are often useful process safety metrics.


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Prevention

o Transfer of Experience and Knowledge

Many of current wardens of hydropower projects hydroelectric, pumped storage, pump,

auxiliary, etc. projects having over 50 years of knowledge are approaching their retirement

age. There are concerns that knowledge transfer to the new hydropower generation of experts

appears to be insufficient. This is resulting in inexperienced manufacturers and engineers

attempting to design and operate hydraulic projects and have taken short-cuts in the design

process. These designs often result in large-scale problems that can endanger the projects

long-term feasibility.

So, unless specific action is taken to preserve and improve the transfer of knowledge

pertaining to design, construction and operation of hydroelectric plants, the current and future

worldwide projects will be in jeopardy. It is necessary to teach the design, operation and

maintenance of power stations and the auxiliary systems in hydroelectric as well as nuclear, and

other plants.

o Post Graduate Education

New graduates, particularly Masters or PhD recipients, should have 10 to 15 years of design

and on-site experience to be able to manage or lead a team in charge of the new plant design.

They should also be up-to-date with the new published materials on the subject, such as

journals and textbooks. In addition, since there is insufficient training available, self-learning

time should be increased in order to ensure adequate competence and reduce the number of

accidents and errors. The official education costs millions of dollars; however, the serious

accidents cost billions, and they may endanger lives. The organized university transfer of high

quality experience and knowledge has so far failed; the sufficient financial support is not yet

available. Universities, electricity sector and governments are invited to support this extremely

important action so as to ensure the continuity of expertise.

o Designing and Reviewing

Hydro storages and pumped-storages are of paramount importance as the most reliable and

most affordable storages of clean renewable energy - wind and solar. However, such energy

sources require a large investment of capital. Design, construction and operation of


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hydroelectric projects requires very high level of details to be accurate, well conceived and

executed; the hydro-power plant design has to be carefully coordinated to achieve safe and

economical operation, and to be social, technological, and environmental success. Therefore,

any hydroelectric installation, as a rule, should be designed using several stages; at each

milestone, the project should be reviewed and validated by independent reviewers nominated

by official authorities. Omitting this independent analysis and evaluation, or worse yet,

neglecting to follow the proper design procedures puts the project at risk. There is a clear need

to plan, finance and implement various long-term initiatives. All experts face the dilemma where

to draw the line between the effort of achieving a better design and when to call the project

design final. The art of balancing all the components is acquired by experience: premature

implementation often leads to expensive maintenance and operational problems; on the other

hand, seeking perfection leads to costly and delayed projects. The challenge of making such

decisions is further complicated by extensive overlap of technologies, experience, and

knowledge requirements and ever-present social and economic dimension.

Technology And Science

Problem: Various transient conditions (load rejection, emergency closure,) mostly cause water

column separation in the turbine draft tube and subsequent rejoinder, with the potential to

seriously damage both the turbine and water conveyance system. Catastrophic accidents were

experienced. Water induction and accumulation in steam piping and water reentrainment into

the turbine can lead to water hammer and other damage. Three types of instruments can

detect this comdition quickly: gamma gauge, water droplet monitor, and fast response

thermocouples.

Prevention: Water storage (Reservoir) & water conductor system comprising of intake, head

race tunnel, surge shaft, emergency valves & pressure shafts, penstock, main inlet valves are

very vital organ of a hydro power plant. Due to negative and positive water hammer during

sudden changes in water flow, it is essential to attend to these plant & equipment very

carefully. It is very important to regularly test operation of conduit isolation system/equipment

i.e. intake gates, butterfly valves, excess flow device, surge equipment etc.


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Economical Storage And Generator

Problem: When the accident occurred, turbine vibrations were more than five times the

specified vibration limit. This high vibration accelerated bolt fatigue, more than five times the

specified vibration limit., and the functional capacity of the bolts was lost. Nuts on at least 6 ofthe bolts that held the turbine cover in place were missing and, of 49 bolts that investigators

evaluated, 41 had fatigue cracking, with 9 bolts showing fatigue damage that exceeded 90

percent of the total area.

Prevention: Vibrations are very important, and must be analyzed and followed through all the

time. When measured vibrations are close to the limits, operation is only permitted under site

monitoring and supervision; if intensity of vibrations is above permitted limits incident should be

expected; the units must be repaired to prevent accident.

Pump storage systems is the only economical way to store large amounts of clean

electricity besides the long-term promise of other technologies to store large amounts of clean

electricity. Variable speed hydraulic machines operate at the best efficiency and with highly

reduced vibrations all the time. The operating and maintenance cost is reasonable (minimized)

if appropriately managed by experts. Total efficiency of the plant is increased up to 85%.


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8.0 CONCLUSION

As a result of the accident, 75 people were killed. On 19th August 2009, the mourning

day was announced in Khakassia. RusHydro declared 25th August a day of mourning at the

company. Thus, safety precautions are really essential and they should always be practiced by

each of the personnel to avoid any accidents while maintaining the performance of the plant.

9.0 REFERENCES

1. Euler Cruz and Rafael Cesario (2009), Accident at Russias biggest hydroelectric Re-

00, Presentation on disseminate some technical and general aspects of the accident,

Brazil.

2. http://www.boston.com/bigpicture/2009/09/the_sayanoshushenskaya_dam_acc.html

3. http://www.documentingreality.com/forum/f181/sayano-shushenskaya-hydro-

accident-russia-17-august-2009-a-53006/

4. http://www.waterpowermagazine.com/story.asp?storyCode=2058518


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10.0 APPENDICES

Before the accident

After the accident


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Flooding of the powerhouse started

Flooding of transformers


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100 tones of oil had been spilled in the river

Major losses

Documents

Compilation Edited