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Basically, no. Plans are easy. Any physics graduate student with access to a reasonable technical library is capable of designing a bomb. In fact, about fifteen years ago a physics student actually did design a bomb for his Ph.D thesis, based entirely on unclassified sources. (It was something of a scandal; requests came in from all over the world for copies of it, and the university decided not to issue copies. The government considered classifying it but really couldn't since it was based entirely on declassified information.) There are a lot of ways of doing it. But all of them require a substantial amount of fissionable materials. There are a lot of isotopes which can be used this way, but the most easily used are Uranium-233, Uranium-235 and Plutonium-239, and none of them are easily produced. U-235 is the only one of the three which occurs naturally, since it makes up %0.7 of naturally occuring Uranium. However, at that concentration it cannot create a critical mass. For use in nuclear power plants, it has to be enriched up to a couple percent. For use in a bomb, it has to be nearly pure. But U-235 and U-238 (which makes up the other %99+) are the same element, Uranium. So the U-235 cannot be separated out chemically; it has to be separated out using the fact that it is physically lighter. But it's only about 1% lighter which isn't very much. The way the US does it is to process the Uranium into a hexaflouride, which is gaseous. Then the gas diffuses through filters, with the lighter U-235 being preferentially allowed through because of its slightly lower weight. Each such pass causes a very slight increase in the proportion of U-235; the entire process is extremely slow and very, very expensive, and since UF6 is poisonous and corrosive and generally horrible, and because there's a danger of substantial radiation release when the concentration of U-235 gets higher, the whole process is extremely non-trivial. There's a different approach that involves using that gas in centrifuges and it has its own set of problems. And reducing the metal afterwards is non-trivial. In as much as you may need to process upwards of 2 tons of Uranium to produce enough U-235 to make a single bomb, you can see that this isn't something that gets done in a cave in Afghanistan. U-233 and Pu-239 have different problems. To make U-233 you bombard Thorium-232 with neutrons. Each atom which takes a neutron converts to Th-233, which beta-decays (halflife 22.1 minutes) to Protactinium-233, which in turn beta-decays (halflife 27.4 days) to U-233, which has a half-life of 162,000 years. That will be the only Uranium mixed in with the Thorium, so after a considerable period of bombardment with neutrons and a few months to let the beta decay settle down, it's possible to chemically process the metal by dissolving it with acid, to separate the U-233 from the rest. The separation process is substantially simpler, but neutron activation is non-trivial and requires an operating nuclear reactor or a particle accelerator. And the conversion process is extremely inefficient; there will only be a small fraction of a percent of U-233 in the Thorium afterwards. You might have to process many tons of Thorium this way to create enough U-233 for a bomb. Of the three, Plutonium-239 is the most easily acquired in this day and age, but even it is not that easy to come by. Pu-239 is created the same way as U-233, except that what gets bombarded with neutrons is U-238. That creates U-239, which beta decays (halflife 23.5 minutes) to Neptunium-239 which beta-decays (halflife 2.35 days) to Pu-239, which has a halflife of 24,360 years. Again, it will be the only Plutonium in the metal and since it's a separate element it can be separated out chemically. But the process is very dangerous because it generates a lot of radiation; it's far from trivial. But the reason that it's the easiest one to acquire is that it is present in spent fuel rods from normal civilian reactors. If a sufficient number of those can be stolen, then enough Pu-239 could be extracted to make a bomb. But because the proportion of Pu-239 is very small, it would take a huge number of them, many tons, and someone would notice if they were being collected. (Spent fuel is monitored.) And the extraction process, while easier than for U-235, is far from trivial and is fraught with danger. It takes years to put together the equipment and facilities and experts necessary to create fissionable materials in adequate quantities, and it is extremely expensive. Once that part is done and you have the fissionable materials, making a bomb out of one is relatively easy. And simply creating plans for a bomb is trivial by comparison. Since plans don't explode, and since there is no good reason to believe that al Qaeda has access to a sufficient amount of fissionables to create a weapon, this is really not a concern. The article says Both President Bush and British ministers are convinced that bin Laden has access to nuclear material and Mr Bush said earlier this month t
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