AHA... right up my alley lol. I work in a steam plant. The fire plug in photo 6 is just that, a fire plug, but there is also a portable extinguisher someone set down next it, and an isolation valve (the tall skinny kind with a window to view an internal indicator), plus the usual collection of stanchions guarding them.
The first shot appears to just be a picture of the plant under fairly normal operation.
In the second shot I am fairly sure that there used to be siding completely across the wall there, sort of an exit wound.
The third shot shows an elbow, which most likely would have been welded at each end and that fact combined with the forces that occur when the rather large volume changes direction make this a likely point for a failure to begin.
Fourth shot, piece of the pipe literally split wide open.
Fifth shot, interior shot in the plant, damage to other lines, and lagging around them.
Sixth shot, fire hydrant and a huge piece of the pipe, notice the person standing in the background? The pipe looks to be about 36-48 inches in diameter.
The rest, you guys understand perfectly well lol. As to what would happen, lines like these at my plant anyway have relay protection, and would most likely immediately trip on phase differential.
The noise and heat would have been incredible, the volume passing through the pipe would have been about 10,000 pounds/minute/megawatt. These units look fairly large, probably in the 125 MW range.
I fervantly hope nobody was close by when it let loose.
