In the beginning, nuclear scientists identified two fuel sources for the atomic age: uranium and thorium. They went with uranium. Why? It wasn't because uranium was the better fuel. Thorium is more abundant. It is simpler. It is safer. (Although slightly radioactive, it can't sustain a chain reaction in a nuclear reactor and, hence, can't "melt down.")
But thorium had one strategic disadvantage: You couldn't make plutonium from it. You could make plutonium from uranium. And plutonium was super-energetic, super-destructive. Man-made, the deadliest source of radioactive nuclear energy, plutonium is essentially forever.
In the Cold War, the science goal was synonymous with the military goal: nuclear weapons. Plutonium delivered the deadliest mushroom cloud. Tonnes of it still swirl around in the biosphere, a legacy of atmospheric nuclear tests in the 1960s. Thorium couldn't compete. Regarding it as useless, the U.S. buried thousands of tonnes of it in the Nevada desert.
A Swedish chemist named Jons Jakob Berzelius discovered thorium in 1828 and named it after Thor, the god of thunder in Norse mythology - and incidentally, for our purposes (as suggested in Sir Kenneth Branagh's 3-D film Thor), guardian of mankind.
American physicists Edwin McMillan and Glenn Seaborg, working at the University of California at Berkeley, invented ("synthesized") plutonium in 1940-1941 and named it after Pluto, the god of hell in Greek mythology. Plutonium-239 found its way into the atomic bomb that fell on Nagasaki in 1945, killing 70,000 people. As a metaphor of moral choice in the dawning of the atomic age, the opposing fuels - Thor versus Pluto - could not have been more exquisitely named.
Oddly enough, Ottawa made the same choice as the other nuclear nations in the 1950s and 1960s. Canada didn't need nuclear bombs. For 20 years, more or less, that was the single purpose of nuclear power.
In fact, Atomic Energy of Canada Ltd., the government monopoly, studied thorium as an alternative nuclear fuel for decades. AECL made Canada's objective explicit in 1977 when it held a closed-session strategic retreat in Ottawa with relevant government decision-makers. Canada had abundant water resources, AECL Chairman Ross Campbell said. It had huge coal deposits. It had the tar sands. And it had its own nuclear reactors - with enough uranium to last beyond the turn of the century. Sooner or later, though, Canada would need thorium: "This is a job that must begin soon."
In the meantime, plutonium would remain AECL's top priority. The country couldn't afford to switch to thorium earlier, he said - couldn't afford to "throw away" the plutonium dividend that fission creates when enriched uranium burns inside a nuclear reactor. Yet Mr. Campbell waxed eloquent in his description of the advantages of thorium. It was three or four times more abundant than uranium. By weight, it required only 2 per cent as much fuel (compared to uranium) to produce the same power. It required only minor modification of Candu reactors.
Mr. Campbell then disclosed AECL's highest strategic objective: When Canada finally converted to thorium, he said, Canada's entire uranium supply could be sold abroad: "totally exported." He added: "This is the prize that we are working toward." S.R. Hatcher, an AECL vice-president, asserted: "It is with the thorium cycle that the Candu reactor will realize its full potential."
If so, alas, Candu will realize its full potential first in China, which announced 18 months ago that Canada's reactors provide the ideal technology for China's "full-scale use of thorium" as an alternative nuclear fuel. China noted especially "the enhanced safety" and "the good economics" of thorium over uranium. As it happens, China has abundant reserves - as does India and many other countries. China expects its first thorium-fuelled reactors to go into operation in 2015.
Ironic, isn't it? Canada experimented with safer, simpler thorium for decades. Yet, in the end, confronted with an elemental choice, Canada chose plutonium, hell itself, to fuel its nuclear reactors. Remnant plutonium will persist, embedded in all the spent uranium, for a very long time. As investigative writer author Paul McKay ( Atomic Accomplice) puts it, an immortal hazard to human life through ages to come.
"A fissioned mass of plutonium the size of a stick of chewing gum," Mr. McKay notes, "can destroy a city." Diabolical, really.