When I used to work on turbo generators, the kind you find at power plants I saw carnage of what happens when those blow up. The retaining rings on the ends, typically a few thousand pounds were prone to breaking on older generators because of the alloy used. When that would happen it would send the projectiles through steel and concrete walls.

The balance bunker for load testing and balancing these at the shop I worked in was a pit 40 feet underground with 50 ton caps placed over top.