A Secret Race for Abandoned Nuclear Material
nytimes.com
nytimes.com
An actual bomb is beyond the capability of anybody but a nation-state. Al-qaeda, et al don't have a chance of anything more than a dirty bomb. While dirty bombs suck too, they are limited to contamination of a couple of city blocks - not actual kinetic destruction of those blocks and the contaminated have a high survivability level given the kind of treatment immediately available in a city.
Also, in this day and age of the NSA and supporters using weasel words, I have to wonder if (a) this info was declassified to support justifications for the NSA and (b) if the line about a "nuclear device" is more weasel wording to sound scary without literally claiming they could build a bomb.
Read "The curve of binding energy", and you will learn from Ted Taylor, one of the worlds best nuclear warhead designers, that you can make the simplest atomic bomb by dropping one piece of fissile material on another, provided they are big enough to become a critical mass.
It won't be tens of megatons, but it will be a perfect terror weapon, spreading panic, making a large-ish area uninhabitable and costing a fortune and many years to clean up.
If the terrorists are smart enough bring a couple of sacks of salt, it makes the mess much worse.
There are damn good reasons to go out of the way to prevent access to the funny end of the periodic table.
My understanding of Ted Taylor's claims about compact fission bombs is that, absent high-grade manufacturing processes to properly shape the fissile material, we are looking at a couple of hundred kilograms to achieve critical mass.
Actual "suitcase nukes" in the 10-20 kilogram range require perfectly shaped components and are also very high maintenance due to their electronics degrading rapidly from such close proximity to radiation sources.
Then there is the question of testing. They say you can recognize veteran bomb makers by their missing fingers because they don't get things right the first time. Any testing of a fission bomb anywhere in the world is going to be noticed by seismographs at the very least.
An unsuccessful nuclear explosion would just be a dirty bomb, which would still have the desired effects from a terrorist attack perspective. So there's no real reason to test before hand.
The gun-type nuclear device which was dropped on Hiroshima was never tested at all (not enough HEU to build a test bomb and a bomb for the attack). It's fundamentally an easy machine to build if a terrorist has the nuclear material, it's easy for them to unit test the gun bits and so on, and if the nuclear material is good the final product is as sure to work as any other sophisticated bomb.
All very depressing, but the point is that controlling the material is what's important. The idea that it takes a government to build the gadget itself is just plain silly, unless you're talking about a fusion device.
Israel is a nation-state with a lot more resources available to it like the ability to measure purity and to conduct simulations. In fact a key part of nuclear politics for the last 20 or so years has been super-computer based simulations in lieu of testing. In the US the programs have been responsible for the construction of some of the largest super-computers of their time(s). https://en.wikipedia.org/wiki/Accelerated_Strategic_Computin...
Simple either way should be the take away. The hard part is getting the uranium. That is really hard.
Actually, you can get a nuclear "fizzle" and if you had enough nuclear material to build a reasonable bomb that just didn't quite come off quite right, you will still get everyone's undivided attention: http://en.wikipedia.org/wiki/Fizzle_(nuclear_test)
But also slightly amusing, I'd like to see a parody done.
As far as I know there have been several examples of accidents were scientists did actually drop a fissile blob over another, and the material did go critical, but thankfully the scientist(s) involved were fast enough to separate the pieces so that no catastrophes ensued. They themselves died as a result of exposure to radiation. As I said, more qualified people will be able to fill in the details and citations.
“With modern weapons-grade uranium, the background neutron rate is so low that terrorists, if they have such material, would have a good chance of setting off a high-yield explosion simply by dropping one half of the material onto the other half. Most people seem unaware that if separated HEU [Highly Enriched Uranium] is at hand it’s a trivial job to set off a nuclear explosion … even a high school kid could make a bomb in short order.” - Luis Alvarez, Nobel Laureate in Physics, 1988
The key being, as I understand it, actually getting weapons-grade material of sufficient purity. Though the actual design of a practical, controlled and efficient, weapon would doubtless be more somewhat more complex. For which the n-th country project is well worth reading about:
Theft and diversion is a big deal with Pu and HEU for this very reason. Which is why access to either has a two man rule. And because you can safely handle Pu and HEU,(its just an alpha and criticality hazard so unless you inhale or eat them, or you have bad geometry it's no big deal), that makes it vital that you carefully account for all of it. It won't kill the thief, and you don't need much Pu for a bomb.
https://en.wikipedia.org/wiki/Louis_Slotin#Criticality_accid...
"At 3:20 p.m., the screwdriver slipped and the upper beryllium hemisphere fell, causing a "prompt critical" reaction and a burst of hard radiation. At the time, the scientists in the room observed the blue glow of air ionization and felt a heat wave. In addition Slotin experienced a sour taste in his mouth and an intense burning sensation in his left hand. Slotin jerked his left hand upward, lifting the upper beryllium hemisphere and dropping it to the floor, ending the reaction. However, he had already been exposed to a lethal dose of neutron radiation."
The "very fast" portion could be accomplished with a steel pipe and explosives. The manufacturing would certainly be within the capability of a reasonably skilled group of insurgents/freedom fighters. The big question is where they'd get the fissile material.
No, no it isn't. The theory is well known. More importantly, the theory has been been put into practice before, and the practice is pretty well known too. Actually making the parts would be relatively easy. The hard part, as usual, is getting one's hands on the fissile material.
In a study* from either the late 40s or early 50s, the US put a handful of "normal" physicists (ie, not exceptionally brilliant) in a room without access to any classified nuclear research, and told them to design a bomb based only on what information was publicly available. Their design was handed to the people actually designing and building atomic bombs for evaluation. The result? The design was a viable a-bomb, not the most efficient, but it would have worked.
*I don't have details handy, but the guy who wrote "Dark Sun" covered it in either "Dark Sun" or his first book.
I wonder if a multinational could hide purchases in enough companies to avoid being identified. Even more interesting would be using something like decentralized task markets and subcontracting to have a group of agents/companies/etc. build you a bomb without them knowing they're building a bomb. Things like "provide an HPC cluster" "simulate high-energy physics for a research paper" "high precision timing circuit" "high accuracy 3d machining for arbitrary purposes" etc. could all be contracted fairly blindly.
The trick to keeping nuclear weapons out of the hands of someone is the security of the material, its hard to enrich. Its not hard to build the bomb. Enrichment is really really really hard. And its currently impossible to hide that your enriching. So you basically secure the material, and look out for people trying to make it. Thats how all non-proliferation works.
Nothings hard about the know how, everything you need to know is in the public domain. And dont forget, pure fission bomds are 1940s tech.
It's not a big secret how to build a simple gun type bomb. You don't need much precision for that. You get enough HEU, and it's game on. You get the right shaped Pu and a few other items, and you have an even higher yield bomb than that of the HEU bomb. Again, 1940s technology is all you need.
Fusion bombs, yes much harder. But who needs that when you can build a Nagasaki yield bomb?
With laser enrichment, you can do enrichment in a typical house with typical power consumption, so it seems easy to hide.
But building the tech today is quite complicated, and hopefully that stays that way in the future.
And so one danger is that the material makes its way to such a nation state.
> I have to wonder if (a) this info was declassified to support justifications for the NSA
And there's one of the dangers of running a program that supposedly[0] depends on utter secrecy, requiring the government to outright lie about it: the inevitable leak exposes the government as liers, further eroding trust in government.
[0] I say "supposedly" because I think the main danger to the programs from exposure is knowledge that what they're doing is illegal or reprehensible. The programs are now exposed, and I assume they're going full bore, producing exactly the same results as they did pre-Snowden.
http://lewis.armscontrolwonk.com/archive/4021/tunnel-re-seal...
The same author as the original article here, Ellen Barry, actually wrote about this program back in 2011 too. So it hasn't been suddenly declassified.
For example, suppose it captures a neutron. Copper has two natural isotopes, copper-63 and copper-65. Copper-64 has a half-life of hours, and decays into Nickel-64 or Zinc-64, both of which are stable and occur in nature. Copper-66 has a half-life of minutes, and decays into Zinc-66, which is stable and occurs in nature.
But maybe it didn't capture a neutron. And there might be impurities in the copper that are dangerous when irradiated. Or maybe it was physically contaminated with dangerous isotopes of another element.
Just saying that it was "irradiated" doesn't give us enough information to tell what actually happened.
Nick Middleton travelled there in 'Going to More Extremes' (which is well worth the watch). https://www.youtube.com/watch?v=nAFGx9nU3q4
TL;DR different elements, different concentrations of isotopes.
https://en.wikipedia.org/wiki/MOX_fuel#Fast_reactors
http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Fuel-Re...
http://www.huffingtonpost.com/renee-parsons/mox-fuel_b_27078...
Note that there is a separate program that takes excess weapons HEU from Russian stockpiles and downblends it for sale as nuclear fuel. This is the "Megatons to Megawatts" program, and it has downblended almost 500 tons of HEU since 1995.