Does nuclear energy have a future, in light of the events at Fukushima? Fukushima Daiichi is the six-unit nuclear-power station on the northeast coast of Japan that was hit by a powerful tsunami, preceded by one of the strongest earthquakes on record. The extent of the damage is considerable: The three reactors that were operating at the time of the earthquake were destroyed by the high-pressure steam produced by heat from radioactive decay and the explosive reaction of hydrogen inside the structures. The hydrogen was produced by chemical reactions between water and the protective, corrosion-resistant layer of zirconium alloy that normally seals radioactive material in a controlled location.

Those who design, build, and operate nuclear-energy facilities know that bad things can happen. They understand energy, shock absorption, chemistry, physics, and radiation, and they invest a great deal of time and effort to build facilities with layers of defense that can undergo a number of failures while still succeeding in protecting against public harm.

In a nuclear plant, the core contains the fuel materials that generate the heat that produces the steam that turns the turbines and creates massive quantities of electricity from tiny quantities of uranium. A single fuel pellet the size of the tip of my pinkie produces as much heat, when it fissions in a conventional nuclear-energy facility, as a ton of high-quality coal does when it is burned in a modern plant. When things are going right, nuclear-fuel pellets do not produce any atmospheric pollution at all, while burning a ton of coal releases between two and four tons of waste into the environment. In the U. S., we consume about a billion tons of coal each year to produce about 45 percent of our electricity.

 
Nuclear facilities have occasionally suffered core damage. Sometimes core damage is a result of design mistakes, sometimes it is due to actions taken or not taken by human operators, and sometimes it is caused by external forces that were not considered sufficiently probable to be factored into the design requirements. The Fukushima disaster resulted from that last risk....