2012/12/06

How to Dismantle an Atomic Bomb



The members of U2 never answered the question posed in the title of their 2004 CD, but it turns out the answer to this seemingly intractable problem is pretty simple: do nothing. The plutonium pits and tritium initiators in hydrogen bombs go through natural deterioration that would render them useless if they were not constantly given very expensive upgrades. We could walk away from them and leave them in their silos and soon they wouldn't be bombs anymore. They would still be nuclear waste, and potential bomb material, but doing nothing would lead to effective disarmament within a short time.
We hear a lot of news about the need to continue with the reduction of nuclear stockpiles, and we imagine this means the danger of their detonation can be removed only by actively dismantling them and verifying that other nuclear powers are doing likewise. However, the public is largely unaware that atomic weapons need constant maintenance and refreshment in order to be usable. This has led to an impression that the remaining stockpile (admirably reduced since 1990 down to just a few thousand) is just an unfortunate legacy of the Cold War that we might as well keep as long as some countries want to keep theirs and others want to become nuclear powers. Yet it’s not so simple. The maintenance of a nuclear deterrent requires the high cost and risks involved in maintaining plutonium and tritium production lines.
This point becomes obvious if we think about the name of the most fearsome weapon: the hydrogen bomb (this discussion doesn't apply so much to the less coveted bombs made with enriched uranium). If the fissionable dreaded core of the weapon is made of plutonium, what has simple hydrogen got to do with it? Hydrogen became the moniker of the bomb because the radioactive isotope of hydrogen, tritium, is the initiator and booster of the fusion-fission explosion that allows a greater yield to be had from a given quantity of plutonium. But tritium has a relatively short half-life of twelve years, so it requires constant replenishment. The plutonium pits have a much longer half-life, but they quickly lose their effectiveness as well.
For American weapons, tritium was produced during the Cold War at the Savannah River Site in South Carolina, but in the 1990s it was deemed that existing supplies of tritium would be enough to maintain the reduced stockpile of weapons negotiated under the START treaty. But then in 2003 supplies were running low and the Watts Bar Nuclear Generating station, in Tennessee - a commercial nuclear power plant - supplied tritium for nuclear weapons. A new tritium extraction facility came on line in 2006 at Savannah River.
For 19 years, after the environmental catastrophe caused by the Rocky Flats plutonium production facility, the US had no capacity to produce new plutonium pits for its reduced but aging stockpile. It seems that in the early days, none of the nuclear powers, as they were building tens of thousands of weapons, stopped to wonder how they could afford to keep these arsenals fresh in the coming decades and centuries. A cynic (not I, of course) might say that the real reason both the US and the USSR wanted a reduction in stockpiles was that they were waking up to the astounding cost of maintenance. Even with the reduced numbers, all nuclear powers are faced with the same dilemma: how to finance being a nuclear power in perpetuity. How to maintain all the required civilian and military reactors supplying the tritium and the plutonium. How to maintain the technical skills and the art of crafting the perfect plutonium pit.
In 1993 the Los Alamos National Laboratory (LANL) was tasked with re-establishing the nation’s ability to produce plutonium pits, and it wasn't until 2007 that the first pit was completed. The laboratory’s website reported the process this way:

“Practice makes perfect pits,” says Putnam [former director of the Plutonium Sustainment Program]. Significant interruptions to the production cycle increase the risks of introducing deviations into the manufacturing process, which can lead to production errors, resulting in a considerable increase in the scrap rate, that is, a higher number of unusable pits. In addition, efficiency is lost. Pit manufacturing is a “use it or lose it” endeavor precisely because it requires constant production to maintain quality and increase efficiency. “Making pits is a process and an exercise in capability. If that capability is not used, it atrophies - becomes ‘rusty.’” says Tim George, deputy associate director for Plutonium Science and Manufacturing. Over the next few years, the program plans to build or assemble four to six pits a year for various scaled experiments and later disassemble them to practice production and to maintain a capability for the future. “Pit manufacturing is an art,” Putnam asserts.

To hear it described this way, one has to wonder why developed nations worry so much about smaller, impoverished states becoming a nuclear threat. The Los Alamos staff makes it clear that even for a nation the size of the USA, it is not certain the resources will always be available for maintaining a nuclear deterrent.
How much to spend is not an easy question in these days of global financial crisis, and neither party wanted to talk about it during the recent presidential election, even though the House of Representatives passed a defense authorization bill that devoted $160 million to a new plutonium plant in New Mexico that will make 450 or more plutonium pits per year.
Barack Obama began his presidency with a lofty goal of eliminating nuclear weapons, and he won the Nobel Peace Prize just for talking about this and saying a bunch of other fine words about the aspirations of the developing world. The new president’s stated intent contradicted the direction that the US was moving in with the resumption of production of plutonium pits at LANL. Thus, utter confusion reigns. No one knows if the future holds hope of disarmament or a resumption of Cold War weapons production. How much should a super power spend now to maintain a fleet of weapons created in the madness of the early Cold War years?

Molly at nucleardiner.com sums up the conundrum:

All federal tax revenue in 2011 was $2.2 trillion — less than one sixth of the total national debt. The $15 trillion debt amounts to $133,000 per taxpayer. A decision not to build the CMRR-Nuclear Facility could save around $6 billion over the next 10 years. Not expanding plutonium pit production could save tens of billions of dollars over the next half-century.

The choices are no different for other nuclear states that have to question the stupendous environmental and social costs of maintaining both nuclear weapons and the required fleet of civilian nuclear reactors that make weapons production economically feasible.

UPDATE:
About a week after I posted, this article appeared in The Washington Post:
Walter Pincus. "How many nukes does it take to be safe?" The Washington Post. December 18, 2012.

Further Reading:

Pavel Podvig. "The Fallacy of the Megatons to Megawatts Program." Bulletin of the Atomic Scientists. July 23, 2008.

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