***Well, the alternator housing is not a pressure vessel that’s true,****
Actually it is. There is approximately 50 lb of pure hydrogen in the generator to cool it. If it went there would have been a massive explosion followed by the sealing oil fire. Very nasty!
This does not sound like a hydrogen gas explosion but more like the relief diaphrams on the LP turbines went, signifying a loss of condenser cooling water.
If it did, it would trip the unit and the main steam valves would slam shut, the reheat relief valve would open and dump reheat steam through the Intermediate turbine into the condenser.
The main Pop valves also went due to the sudden buildup of pressure when the main steam valves closed.
The “smoke” mentioned in the article looks more like water vapor leaking out of the various openings caused by the trip off and diaphram openings.
Other than that, I don’t know much about it. ;-)
Well, yeah, I didn't know they used that much, but I knew they kept positive pressure to keep air out.
But compared to the turbine housing... inlet steam at ~3000 psi (at least for fossil fuel plants) it's almost negligible.
There is approximately 50 lb of pure hydrogen in the generator to cool it.
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Thanks for this info. Do you mean 50 lb of hydrogen or 50 psi of hydrogen?
Air and H2 in the generator during a purge procedure blew up. There is never, ever supposed to be a mixture of H2 and air during the purge procedure. H2 is purged with CO2 to 95%+ CO2, then the CO2 is purged with air. When regassing the generator the air is purged with CO2 to 95%+ CO2, then the CO2 is “purged” with H2.