by CKR
I've expressed doubts before about the ability of terrorists to produce a nuclear bomb, but this weekend, as I read the second issue that Foreign Policy has continued to send me after my subscription lapsed, I realized the basis for believing that it's much harder than it seems in a thought experiment.
Specifically, I was reading the letters responding to Peter Zimmerman and Jeffrey Lewis's article, "The Bomb in the Backyard," and something clicked in my mind. My earlier criticism of that article almost touched on the issue that I think is central to developing these scenarios, but it wasn't entirely clear.
As the Manhattan Project constructed the gaseous diffusion plant at Oak Ridge and the plutonium-producing reactors at Hanford, it became clear that a place would be needed to bring everything together for the bomb. J. Robert Oppenheimer, a professor of physics at the University of California at Berkeley, was chosen to lead the effort. He chose Los Alamos, on the Pajarito Plateau of northern New Mexico. He had been leading a calculational effort to determine critical masses and other requirements for the bomb, the dozen or two participants scattered around the country. Now they would take the materials from Oak Ridge and Hanford and form them into those calculated geometries to make their final product. It would take a few more experts, Oppenheimer figured, in metallurgy and electronics, just as Zimmerman and Lewis figure. When the Army asked how many to plan for, Oppenheimer estimated several dozens of men (most scientists were men back then) and their families. The final total was in the thousands.
Back in the 1970s, as lasers were developing, the idea of separating isotopes with lasers instead of gaseous diffusion or even centrifuges became popular. A laser isotope separation plant could be installed in a garage instead of the city-sized buildings at Oak Ridge. A small group at Los Alamos did a few calculations and figured that the dozen or so of them could do a proof of principle over Labor Day. Didn't happen. Not even close. As the project proceeded, it became the next Fourth of July. Easy enough to do over a weekend. Not even close. The project went on for several years without significant successes.
Both had seemed so easy as very capable scientists thought about them. I think the problem in both cases was that the scientists were physicists, and that their background lay more in calculation than in lab work. A chemist who has experience in lab work, in contrast, will tell you that things more often than not don't work right the first time. Sometimes the second, third, and fourth times. You can follow the instructions exactly and it just doesn't work.
It's easy to say you need a capable foundry person and a machinist to form the plutonium for a terrorist bomb. It's much, much harder to do, even for capable people, and things have a way of going wrong: heaters burn out, stuff gets spilled, someone comes in not at the top of their game and messes up.
My conviction on these issues was formed during the isotope separation project. I've had a couple of nice experiments where things went exactly as predicted and even better. But I've also learned not to trumpet my successes until I've got them.