Plutonium has had quite a history in the 20th century. It was the core of the atom bomb dropped on Nagasaki, Japan in August 1945. That bomb killed 74,000 people and wounded another 75,000.
Richard Garwin hopes plutonium doesn't have a future in the 21st century. He helped build America's first hydrogen bomb in the early 1950s and says that terrorists would need just 10 pounds of plutonium to make a bomb like the one that hit Nagasaki. “I have held in my hands two hemispheres like those which constituted the bomb that destroyed Nagasaki. It's typically coated with a thin coat of nickel metal, and the radioactivity is almost entirely alpha particles that don't penetrate human skin. Plutonium can be carried, it can be stolen and it can be handled without hazard to the person carrying it away.”
Mr. Garwin no longer makes nuclear bombs. Instead, as director of science and technology at the Council on Foreign Relations in New York, he spends a good deal of time warning about the dangers of plutonium falling into the wrong hands. “A single nuclear weapon even of one kiloton could kill a couple of hundred thousand to a half a million Americans if detonated at ground level in an American city. And that's how it would be done: it would be smuggled in and detonated in the middle of a city at the worst time of day. What we need to do is to get rid of this city-destroying bomb potential of the extra plutonium.”
That's not an easy task. Unlike uranium, another nuclear bomb ingredient, which can be blended down to a form not usable for nuclear weapons, plutonium cannot be made less lethal. In all its forms, plutonium can be fashioned for use in nuclear weapons, and it lasts practically forever.
Matthew Bunn, who served as an adviser to the Clinton White House on how to dispose of excess plutonium, says there are no perfect solutions. “You are dealing with a material that has a half-life of 24,000 years, and it's just hard to get rid of. But there are less bad solutions.”
Mr. Bunn, a researcher on nuclear issues at Harvard University, says the ultimate goal is to render plutonium unusable for nuclear weapons. But the complication is that plutonium, the most destructive element invented by man, can also be used to produce electricity.
These dual uses of plutonium figure in the two leading ways to dispose of it. Those who fear plutonium's destructive potential want to immobilize it by combining it with highly radioactive waste and encasing it in glass logs.
Those who see its energy potential want to make it into nuclear fuel and then transport it to reactors to produce electricity. Supporters of this approach contend that burning plutonium has the additional advantage of leaving a waste that is far less usable for nuclear weapons.
The debate over how to dispose of plutonium goes beyond the danger of military plutonium, which can be used immediately in weapons. It also involves huge amounts of plutonium in the spent fuel of nuclear reactors around the world. This diluted plutonium is a step removed from being weapons-ready.
Countries like France, Japan and Russia covet the energy value of plutonium. For them, spent fuel is a potential gold mine. They built plutonium-based nuclear industries in the belief that plutonium would replace uranium as it became depleted. They believe investment in plutonium fuels and plutonium-powered nuclear reactors will pay off in the future by making them less dependent on foreign sources of energy.
But critics say using plutonium as fuel is unprofitable and dangerous. It's not economical because new reserves of uranium have been found, and plutonium-centered technology is still too expensive. They also contend that extensive reprocessing would create large and tempting amounts of weapons-ready plutonium for terrorists and rogue nations.
Paul Leventhal is president emeritus of the Nuclear Control Institute in Washington. “Right now, there are thousands of tons of plutonium locked up in highly radioactive spent fuel, and if reprocessing continues on a large scale, the amount of plutonium in the civilian sector will dwarf what is now in the military sector.”
Since the 1970s, the United States has prohibited reprocessing of plutonium from spent fuel because of the risk of theft or misuse. But some analysts worry that America may be on the way to reversing that policy. They point to a pilot project signed this year with Russia in which the United States has decided to burn as nuclear fuel 34 metric tons of excess military plutonium. The Russians will do the same.
The decision has alarmed some analysts. First of all, they say the burning option is more expensive than burying an estimated four billion dollars, most of which will be paid by the United States and industrialized nations. More worrisome, it will give nuclear thieves greater opportunities to steal. Richard Garwin of the Council on Foreign Relations says “it adds additional proliferation or terrorist hazards as this fresh fuel with its weapons plutonium is shipped around and stored before use.”
Why did the United States choose the "burn" option over "burying"?
Mr. Bunn of Harvard says the Americans had little choice. Originally, the United States wanted to bury a portion of both America and Russia's plutonium. But the Russians refused to consider immobilization. For Russians, plutonium is a national treasure. They remember the resources and efforts that have gone into producing the element. In line with plans to generate revenue, the Russians insisted on burning their plutonium. And in order to maintain some control over plutonium in Russia, which has a spotty record on nuclear security, Mr. Bunn says the United States had to agree. The alternative was to have Russia store the material in its dangerous weapons-grade form for an indefinite time period.
Mr. Leventhal fears that American support of a fuel approach with the military plutonium could indicate a push for larger commercial use of the element. And that increases the risk that terrorists or unfriendly nations might acquire plutonium.
Mr. Leventhal says the solution is clear: don't use plutonium as fuel. Instead, bury it in glass logs under the ground. He says “the only way you are really going to get the world's arms around this problem is for there to be a consensus among the major industrial nations that plutonium is too dangerous to use and that this become an international accord that applies to all nations.”
The US and Russian nuclear fuel program is a first step toward disposing of plutonium. For now, it appears its energy value has won out over the need to remove it from circulation by burying it. It's not clear yet what will happen with other stocks of plutonium: will they be buried, burned or find their way into the hands of terrorists. Plutonium's history in the 21st century is still an open book.