As jy die foto’s hieronder kokkenodge sonder om te lees, sou seker skiem dis een of ander powerstation in Japan na daai fokken hectic aardbewings, maar dit is nie. Hierdie is sommer op home soil, pappie! Gelukkig is tax payers daar om vir al hierdie kak te betaal… Nou wonder mens hoekom Eskom elke nou en dan met die hoed in die hand voor die regering se deur staan en bedel vir goodfor…
Hier is wat Wikipedia tune oor die Eksom Duvha Powerstation:
“Construction of Duvha Power Station started in November 1975 and the last unit came into operation in 1984.
In 1993 Duvha became the first power station in the world to be retrofitted with pulse jet fabric filter plants on three of its six units. These plants contribute largely to the reduction of air pollution by removing 99.99% of the fly ash which otherwise would be released into the air through the station’s chimneys.
8 January 2003, Unit 2 generator explodes while being returned to service after a malfunction. On the the 9 February 2011 another unit failed catastrophically while performing over speed testing. The units are over speed rated at 3600rpm and the last recorded speed before failure was 4250rpm.”
En hier is wat ‘n Watkykertjie met ons deel:
Not really intended for the public BUT amazing how pics like these can get out even after Eskom put a blanket of secrecy around the whole incident…
So I found out what happened at Duvha.
They were doing a test of the turbine overspeed protection system, and in short, the protection did not kick in. conventional wisdom tells me that there should be a better way to test a protection system than to try and destroy the turbine and see if it feels like protecting itself, but that’s basically what they did.
The turbine has a governor valve which controls the amount of steam coming into the turbine In order to keep it running at the right speed (3000 rpm for our grid frequency) and then it has a main isolation valve to shut the steam off completely. The protections systems (of which there are 3 independent systems, and a dude with his finger on the emergency button) are supposed to close this main isolation valve in a fraction of a second when the turbine overspeeds.
So they get ready for the test, they dump a helluva lot of steam onto the turbine, speed starts going crazy, it went from 3000 RPM to 4500 RMP in ten seconds (they are generally only designed for 10 to 15% overspeed, all three protection systems should have kicked in by the time you get to 110%). Anyway, I don’t know why, but all three systems failed, and the dude with his finger on the manual trip button wasn’t at his post. So the result was a big bang, some fire and a lot of steam going where it shouldn’t go.
Scary thing is Duvha has a shared turbine hall. All six units are placed in one long straight stripe, with no missile shield between them. And if you look at the third last pic you can see how big that shaft is, if that landed on another turbine it would have destroyed that too. They are very lucky they didn’t lose the entire station.
So anyway, what gets reported in the news? “Unforeseen maintenance” at one of the units at duvha requires it to remain shut down for 18 months. understatement of the century in my book. But you shut off the containment ventilation system at Koeberg for one hour and a radiation alarm goes off, then it’s a front page news national crisis. I give up.