For those trying to keep up with my fabulous rate of writing progress… the project that has been keeping me busiest of late is a particular chapter in my “Nuclear Pulse Propulsion” book… specifically, the chapter on the design of the Orion pulse units. Of course the most interesting part of the design of the pulse unit – the atom bomb at its core – is safely classified, with just about every meaningful diagram, dimension, mass or detail redacted from the available documentation. However, enough data is available to piece together outlines of several of the designs. And I’ve been dealving into the declassified literature on atomic bomb design to try to re-create what the pulse unit A-Bombs may have been. And you know what?
Atom bomb design is neato.
There’s enough info out there that a trained chimp like me could produce a fairly decent preliminary design for a basic A-Bomb. I suspect it might only blast itself to flinders and scatter fallout over a few city blocks, but the *next* design might work just fine. The only thing keeping Jihadist jackasses from building their own bombs is… uranium 235 and plutonium 239 are damned hard to come by. Probably easier to simply buy one from North Korea or some drunken Russian military commander with gambling debts.
This chapter should prove to be pretty interesting.
12 Responses to “Build Your Own Pulse Unit And Wake Up The Neighborhood”
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239 actually…
I don’t know.
Sure getting the actual fissile to begin with is a big first step, but if any jackass could put together a nuclear weapon if given a supply of the materials then the same jackass could also build am air-cooled graphite pile reactor, start pushing little aluminum-canned slugs of natural uranium through it on a two month irradiation cycle and extract all of the yummy pu-239 on the other side with solvents.
Every case I’ve seen of a place going nuclear has been a nation-level effort requiring years of R&D, a substantial industrial and beau-coup bucks being spent.
Could someplace like Saudi Arabia build nuclear weapons an go all ‘Sea of Fire!’ jihad on our asses? With sufficient expenditure of time and capital, yes. Case in point: Iran
Could a bunch of bumblefucks in a cave if handed a bunch of pure u-235 or pu-239 build a nuclear weapon? Maybe, but I see it being more likely they’d poison themselves or kill themselves in a prompt-critical accident than anything else.
The fact that countries build nuclear weapons and the sociopaths do not strongly hints that it takes more than having the materials, a machine shop and good(bad?) intentions to pull it off.
The reason why small-scale actors have not built nukes is, as I said, the difficulty in obtaining the proper fissile materials. Building an effective isotope seperator is something that requires a pretty massive industrial base.
Uranium 238 can be had by virtually anybody. But you cannot make a nuclear explosive using U238. And processing the small amount of U235 out of naturally occuring uranium is a non-trivial task. And if you are able tol *steal* weapons grade U235 or Pu239… you’ve probably just stolen an entire nuclear bomb, and don’t need to bother with designing and building the bomb yourself
Scott, I thought the real “secret” about Orion was the way that the blast was focused (~80% of the blast within a ~20deg cone), which led to Casaba-Howitzer?
Also, although it may not be relevant in the US, beware that in the UK you can break the official secrets act by merely “assembling” information that’s already in the public domain (i.e. de-classified, non-secret). I remember an article in New Scientist (13th July 1978) entitled ‘Can a secret be SECRET if it isn’t actually secret?’, to which the answer was YES!
Being on a watch list just means that you always have somebody watching over you like a brother.
> I thought the real “secret” about Orion was the way that the blast was focused
Actually, no. The Orion pulse units that were baselines for the 10-meter and 4,000-ton versions used off the shelf nuclear technology, married to ideas on how to focus the momentum impulse. But focussing the momentum was a relatively small task compared to getting the nuke in the first place.
Casaba Howitzer remains a bit of a mystery. The Orion pulse units used nukes that produced essentially spherical blasts; the *casing* aroudn the nukes helped focus some of the energy of the nuke into a plate of propellant which exploded in a somewhat coherent “beam.” But Casaba Howitzer *may* have actually used some form of shaped charge nuke. It’s so vaguely described, and so deeply classifed, that it’s really hard to say.
> beware that in the UK you can break the official secrets act by merely “assembling” information that’s already in the public domain
Well, I guess this might put the kybosh on my plans for running for President of the UK someday.
Well, you have the endorsment of no other than Theodore B. Taylor on both the items: easiness in building a very rough fission bomb (he suggested to steal spent nuclear fuel from a commercial reactor pool, separate the plutonium chemically and build an inefficient implosion bomb, say one tenth of a kiloton due to the excess Pu-140), and Casaba Howitzer existence. It is all in the McPhee’s masterpiece, “The Curve of Binding Energy”.
Read up on the South African nuclear weapons effort. They did in a backyard shed with half a dozen machinists. Admitedly, they had an advantage ’cause they had access to encriched Uranium which as, was noted the biggest hurdle but once over that, they built it fairly easily and tested it. Of course, America wasn’t exactly strenuous in it’s efforts to stop this.
“The reason why small-scale actors have not built nukes is, as I said, the difficulty in obtaining the proper fissile materials. Building an effective isotope seperator is something that requires a pretty massive industrial base.
Uranium 238 can be had by virtually anybody. But you cannot make a nuclear explosive using U238.”
I understand that, which is why I specifically said a natural uranium fueled graphite reactor.
Natural uranium, straight out of the ground, is .7 percent u-235. This is too low of a fissile content to allow a chain reaction with water as a moderator due to light waters tendency to parasitically absorb neutrons, but better moderators such as heavy water and graphite can sustain a chain reaction on natural uranium.
So you take your uranium, put it through the reactor on about a two month schedule so your bred pu-239 doesn’t have time to absorb more neutrons and work up the chain to pu-240 and 241 and so forth which would make building a working weapon extremely difficult if not impossible, and separate the pu out with the PUREX process.
This is how the US produced all of the plutonium that was used it’s nuclear weapons.
See:
http://en.wikipedia.org/wiki/B_Reactor
http://en.wikipedia.org/wiki/X-10_Graphite_Reactor
I’m also not really to worried about some nefarious group getting a hold on spent LWR fuel as it’s next to useless for building weapons and /VERY RADIOACTIVE/ to boot.
http://depletedcranium.com/why-you-cant-build-a-bomb-from-spent-fuel/
In The Curve of Binding Energy by John McPhee, Theodore Taylor gives details about how easy it is to make a crude nuclear device in your basement. He mentions there are all sorts of tricks of the trade that will improve the device, but he can’t tell you about them because they are still classified.
Implosion is the gold standard, more so than gun style bombs. Something I saw in the old movie Fantastic Voyage. There was this cart they rolled about called a “precision handling device.” Now it was more than likely a movie prop, same as everything else–and yet I can see something like that being used to assemble nuclear shapes. Maybe someone saw some lab equipment and said “that would look nice in a movie.” If so, Jamie from Mythbusters might like a look at any gears inside for use in robotics…
The “Precision Handling Device” was actually built on the base of a McAllister camera dolly.