The most obvious cause of the disaster at Japan's Fukushima Daiichi nuclear power station was the massive wall of tsunami water, but would a newer reactor have fared better?
Have decisions made half a century ago have left the world with basic designs that are inherently less safe? In other words, have we been guilty of rejecting the nuclear Betamax in favor of an inferior quality VHS?
When the United Nations convened its Conference on Peaceful Uses of the Atom in 1955, more than 100 ideas were on the table. Now, the nuclear world is dominated by light water reactors, BWRs and PWRs, originally chosen for their functionality in naval submarines. Only Canada manufactures anything different on a commercial scale—the heavy water-moderated Candu reactors.
But are they the best?
Back in the 1950s, engineers believed they were not, with research indicating gas-cooled designs would be more efficient.
At Idaho National Laboratory, Don Wiley argues that sodium-cooled reactors perform under stress much better than the water-cooled variety at Fukushima.
Other reactor concepts that offer major theoretical advantages have fallen by the wayside, or remain stuck in the research stage. These include designs that use thorium rather than uranium as fuel, resulting in less long-lived waste and a lower weapons proliferation risk, and travelling wave reactors that burn their waste as they operate.
Would any of these have proven superior to light water designs?
"With technologies that do the same thing, very often one of them comes to dominate," says Robin Cowan, an economist from the University of Maastricht in the Netherlands. "It's very hard to undo that."
But it is a question governments should contemplate as they consider whether to embark on reactor building programs that would entrench current designs for decades to come.