The most spectacular examples of the inherent danger of nuclear reactors are the accidents at Three Mile Island and Chernobyl. There have been other near catastrophes, however, the most recent of which occurred at the Davis-Besse reactor in Ohio, USA. A leak allowed coolant water to eat a softball size cavity in the pressure vessel that typically operates at about 150 times normal atmospheric pressure (2165 psi). Only the 9.53 millimetre stainless steel cladding on the inner side of the pressure vessel prevent a catastrophic loss of coolant. The cladding itself had significant stress-corrosion cracks; US Nuclear Regulatory Commission (NRC) sponsored research concluded that, at normal operating temperature and pressure, the vessel could have operated between two and thirteen months before it failed.
This is stunning!! This failure was caught by chance just in time.
The NRC has not said what the consequences of such a failure might have been. I am in the process of trying to find out. But it would, at the very least, have severely damaged the reactor and forced a shutdown of all similar reactors.
One consequence of this near disaster was that all similar reactors have had both their heads examined. Several upper heads have been replaced. The public needs to know of the dangers inherent in nuclear power. It should be a part of the informed debate on the issue. Pro-nuclear forces should not be able to set the terms of the debate and ignore the very real threat that reactors pose to the public.