A Brief History of: The Sayano Shushenskaya Dam Disaster (Short Documentary)

harnessing the power of water has proven very useful in a generation of electricity acting like natural batteries large bodies of water in conjunction with dams can provide many thousands of megawatts of electrical energy however like all sources of power mishandling can end in disastrous results [Music] usually this channel doesn't tend to look at non-polluting power sources however the disaster we're looking at today took the lives of 74 people and caused millions of rupaul's worth of damage so ticks most of the boxes for a plainly difficult video today we're looking at the catastrophic cyanus power station accident and i'm going to rate it about here on my patented plainly difficult disaster scale the sayanu sushenskaya power station is one of the world's largest hydroelectric sites and is russia's largest the plant has the potential to provide electricity for a city of over three million people situated in saiyan gorsk which is around here on a map in 1960 a need for a hydroelectric plant on a yenisai river was highlighted and surveys were undertaken to find the perfect location in 1961 construction work began in 1963 on what would be the country's largest hydroelectric power station the plant included the dam reservoir and the power plant building the first hydro project designed turbine was installed in 1978 with more turbines being installed in the following years and the whole project going online in 1985. the 242 meter high dam supports the sayano tsuchenski reservoir with an area of 31.34 kilometers cubed with a useful capacity of 15.34 kilometers cubed the plant has 10 640 megawatt 16 blade turbines giving a total output of megawatts seventy percent of the electrical power created on site goes to united company russell's for smelters in siberia the turbines and their generators are housed inside a 950 vast turbine hull the dam used at sayeno shuchensky was of the arch gravity type this design curves upstream in a way that it directs most of the water pressure against the rock walls on each side of the canyon that the dam sits in this provides force to compress the dam improving its strength such is the design of the structure but the dam has a striking curve similar to the hoover dam in the usa the need of a dam is to hold back the weight of the water kept in the reservoir behind it this weight has a potential for electric power generation by harnessing a force that everything on earth encounters gravity electricity is produced by the opening of sluice gates on the reservoir side of the dam once opened the water flows down through the 620 foot long pen stocks inside the structure the water has a high energy caused by the weight of the remaining water inside the reservoir the water is passed through a turbine which in turn rotates turning a generator the fine-tuning of the power produced by the plant wicket gates are used and these surround the turbine more or less power can be generated by these gates regulating the water flow and are vital in keeping control of the desired output as well as varying power these gates can be closed completely essentially bypassing the turbine after all this the water is passed to an outlet gate to resume its flow down the river let's look at the turbine and its attached generator in more detail water flows in radially and exits actually the rotational force from the flowing water through the turbine blades in the runner is transferred via a shaft to the turbine's generator attached to the shaft is a rotor which is made up of electromagnets around its perimeter the electromagnets are made by circulating direct current through loops of wire around stacks of magnetic steel conductors are mounted around the outside inside a fixed stator as the rotor rotates inside the stator an electrical current is created after this the electricity is taken to a transformer then to the power grid the turbines used at the plant had a narrow band of efficient working to reach the recommended megawatts power zone where the turbine is most efficient it has to transition through a not recommended zone at which excessive vibrations are generated if the turbine's output power sits in the not recommended zone for too long damage can be caused to the main bearing these were split into four bands band 1 was the allowed band and was the lower end of the power spectrum next was band 2 also known as the not recommended zone then there was band 3 the recommended zone then band 4 which was the forbidden zone the vibrations were produced by the pulsation of the water flow and over time could wear down the turbine's mountings and bearings to a point that the unit would be unsafe to operate the hydroelectric plant's lifetime has been mired with various issues many of the turbines experience seal vibration and bearing issues as well as several floods turbine 2 had its fair share of issues ever since its installation in 1979 this particular unit had seemed to have taken a lot of the brunt of the extreme forces put upon it during its operating life as such by the early 2000s it was showing its age with cracks in the turbine runner and issues with bearings were also highlighted and replaced between january and march 2009 the plant was undergoing modernization part of this was the installation of a new automatic control system meant to slow or speed up the turbine to match output power demands once again turbine 2 had defects along its blades once the work had been completed the runner had not been rebalanced leading to vibrations once again although it was deemed within design specs this vibration would wear down the bearings and mountings of the turbine however over the coming months the vibrations soon began to exceed specifications it was once again shut down for investigation however a strange turn of events would lead the plant down to the path of destruction a fire alarm at the bratz hydroelectric plant on the 16th of august 2009 the fire took the plant offline and in response the saiyan of shushensker plant was ordered to take over the regulating duties in order to pick up the slack the plant had to get as many turbines as possible online including turbine 2 which had been shut down due to the excess vibrations by the 17th of august all but one of the turbines were pressed into action with units one two three four five seven and 9 operating in regulating mode with units 3 8 and 10 generating base load power unit 6 was shut down for maintenance work and as such more personnel than usual were in the turbine hall normally around 12 people staffed the vast building but on that day over a hundred milled around the hall undertaking repair work on the morning of the 17th the output of unit 2 varied widely and because of this it sat for too long in the dangerous band too aka in a not recommended zone the turbine began to vibrate in doing so weaking its internal components at 8 13 am a loud bang ran out in the turbine hall the turbine cover shot up followed by the 920 ton rotor the rotor still spinning flew across the gallery destroying everything in its wake the turbine was ejected from its pit under the 20 atmospheres of water pressure exposing the pen stop essentially there was now no barrier between the force of the reservoir water and the turbine hall the monumental amount of water then began gushing into the turbine hall flowing over the other turbines and their generators shorting them out in the process the control room became aware of the disaster as unit 2's electrical power output dropped to zero causing a local blackout the water soon cut through the structural still and the turbine gallery roof collapsed workers were washed away out of the building down into the river some were later rescued however others were sadly not the still gates to the water intake pipes of the turbines weighing around 150 tons each were closed manually these were held up by hydraulic jacks the process would take at least 25 minutes or whilst this was happening water continued gushing out of the destroyed unit too the emergency diesel generator was started and the spillway gates of the dam was opened units 7 and 6 continued to operate after their safety shutdown systems failed to trip the turbines became submerged causing damage to equipment and structures units 2 7 and 9 were completely destroyed with remaining experiencing serious damage within 24 hours over 1500 rescue workers reached a plant managing to save 14 in total 75 personnel were lost during the event the damage did not end with just the turbines and their generators as over 100 metric tons of oil used on site was released into the river causing severe environmental damage to local wildlife by the 24th of august the water inside the damaged buildings was pumped out and on the 28th of august the search and rescue operation was completed the repair works wouldn't be completed until 2014 costing well over 1 billion dollars but what caused russia's largest hydroelectric dam to self-destruct sadly the answer is unsurprising and has played out many times in industries all over the world post accident and investigation were undertaken during the probe into the calls of the disaster retaining bolts were shown to have broken under stress worryingly some of the bolts showed no sign of nut braking which meant that when they were installed no nut was present the unit was put on regulating mode when restarted on the 16th meaning that the power output of the turbine would pass more times through the not recommended zone as it tried to match power demand the operation of the turbine in a not recommended zone was not altered by the operators at the plant the push to operate the units in such an unsafe band was purely motivated by the fire at brett's hydroelectric plant to make up for the drop in power this coupled with poor maintenance left a disaster inevitable i hope you enjoyed the video if you'd like to support the channel financially you can on patreon from one dollar per creation that gets you access to votes and early access to future videos i have youtube membership as well from 99 pence per month and that also gets you early access to videos check me out on twitter and also if you want to wear my merch you can purchase it at my teespring store and all this have to say is thank you for watching [Music] you

Channel: Plainly Difficult

Views: 744,327

Keywords: Atomic, Nuclear History, Education, Plainly Difficult, dark docs, History, The Sayano Shushenskaya Dam Disaster, Dam Disaster, Russian History, Sayano Dam, Shushenskaya, Hydro electric, disaster dam

Id: vWSleesle-E

Length: 11min 18sec (678 seconds)

Published: Sat Oct 17 2020