Fuel for nuclear bomb in hands of unknown Russian black marketeer, officials say • Hacker News Board

Re: Fuel for nuclear bomb in hands of unknown Russian black marketeer, officials say

#131

Post by mikeash » Sun, Nov 15, 2015, 1:52 AM UTC

jessriedel wrote: post #124

mikeash wrote: post #117

Earlier quoted context omitted.

That's fair, but I see two big problems with this. First, to what degree can we say Ukraine is threatened by nuclear weapons, when we know (not because of empty promises, but just the realities of nuclear weapons) that nukes are not on the table? Would we say that Iraq or Afghanistan were threatened by nuclear weapons? I certainly wouldn't. Second, let's say the mere possession of nukes by the attacking party does qu…

I think there is easily a greater than 5% chance of Russia using nukes in the case of an all out war between Russia and Ukraine. (Remember how realistic it was for the US to develop small bunker-buster weapons just a few years ago? What sorts of tactical nukes do you think Russia has stored away somewhere?) Any that's plenty of risk to dramatically influence the conflict, whether diplomatic or violent. So now you're…

I think there's a 0% chance of Russia using nukes against Ukraine. The Russians aren't stupid, and they know how that would end. They also have no reason to do so, since they would have no trouble winning conventionally. Russia has been going out of their way to keep that war low-key to avoid provoking outside intervention, which is the only reason they don't already own the place completely.

Re: Fuel for nuclear bomb in hands of unknown Russian black marketeer, officials say

#132

Post by gh02t » Sun, Nov 15, 2015, 2:21 AM UTC

rbanffy wrote: post #113

excuse-me-sir wrote: post #69

Earlier quoted context omitted.

Welcome to the list .

There is enough information floating around for almost any reasonably competent engineer with a knack for physics (or vice versa) to build an implosion device. The list is long.

I'm going to have to dispute that one... an implosion weapon is very complicated. Even if you had detailed plans, you simply can't build them without access to very high precision tools. The tolerances necessary to make them work are extremely severe, especially in the construction of the initiator (the thing that initially injects neutrons to kick off the reaction) and in the triggering for the explosives. The basic concept is really easy to grasp, but the nitty-gritty engineering details are much harder than is readily apparent.

Gun-assembled weapons are simpler, but still complicated. The big issue with them is that they tend to go critical as the target and projectile are coming together and blow themselves apart before the bang really gets going. Getting them to come fully together and stay confined long enough to get good yield is not as easy.

Re: Fuel for nuclear bomb in hands of unknown Russian black marketeer, officials say

#133

Post by JupiterMoon » Mon, Nov 16, 2015, 10:37 AM UTC

mikeash wrote: post #130

JupiterMoon wrote: post #120

Earlier quoted context omitted.

Your numbers are meaningless. The German weapons were modern. The French were not and the UK's were virtually non-existent. The UK had no reason to declare war in 1939 other than their promise to defend Poland. We went into a global war that lasted 6 years, took half a million of our lives, bankrupted us and caused us to lose a global empire (well that was a good side effect). Bear in mind that this was ~20 years aft…

What's the point of declaring war on the basis of their promise to defend Poland, if they never actually did anything to help Poland? It's not nearly so simple as that. For example, the French had better tanks, as well as more tank. There were plusses and minuses on both sides, but the result is far from clear and certainly not an overwhelming advantage in either direction. Combine this with the German army being bus…

The hope was that declaring war would be enough to cause Hitler to not actually invade. The reality was that the UK (who are the ones we were talking about) really didn't have much in the way of army or air force at that time.

As for the French tanks. In 1939-1941 tanks were fairly useless. The German dive bombers were the dominant weapon system -- it was only when the allies had decent air forces that the dive bombers became irrelevant.

Re: Fuel for nuclear bomb in hands of unknown Russian black marketeer, officials say

#134

Post by ethbro » Mon, Nov 16, 2015, 3:03 PM UTC

mikeash wrote: post #131

jessriedel wrote: post #124

Earlier quoted context omitted.

I think there is easily a greater than 5% chance of Russia using nukes in the case of an all out war between Russia and Ukraine. (Remember how realistic it was for the US to develop small bunker-buster weapons just a few years ago? What sorts of tactical nukes do you think Russia has stored away somewhere?) Any that's plenty of risk to dramatically influence the conflict, whether diplomatic or violent. So now you're…

I think there's a 0% chance of Russia using nukes against Ukraine. The Russians aren't stupid, and they know how that would end. They also have no reason to do so, since they would have no trouble winning conventionally. Russia has been going out of their way to keep that war low-key to avoid provoking outside intervention, which is the only reason they don't already own the place completely.

Agree that they would have no trouble winning conventionally, but are you sure they know how that would end?

A few years ago, I think consensus would have been that Russia wouldn't annex a sovereign state or deploy military assets in support of a separatist movement.

... I think reality is a lot more complicated.

If they decided to go for a big push, and realized they could hasten victory substantially by deploying a few low-yield tactical devices? The international community has proved nothing other than "It's easier to ask forgiveness than permission."

Besides, in a hypothetical case of annexing all of Ukraine, does "Russia used some tactical nuclear devices" really look that much worse than the also-present "Russia invaded and annexed a sovereign state"?

Re: Fuel for nuclear bomb in hands of unknown Russian black marketeer, officials say

#135

Post by jhayward » Wed, Nov 25, 2015, 6:19 PM UTC

gh02t wrote: post #79

jhayward wrote: post #39

Earlier quoted context omitted.

I believe the 20% threshold was chosen because that represents the largest plant and processing cost step in enrichment. In other words once it is at 20% you can use a much smaller enrichment plant to take it to weapons level due to the nature of the cascade. My back of the envelope calcu-guess is that 20% enriched represents about 95% of the work on the way to weapons grade. [edit: guess based on only isotope ratios…

The calculations for it are a little weird and involve a rather strange unit called the SWU (separative work unit) and which is actually independent of the separation process, but it works out to be more like ~75% of the effort to go from natural -> 20% enriched as it is to go from 20% -> 95%. You still need the raw mass though. To get enough weapons-grade uranium for a bomb (~15kg) from 20% enriched feed stock and d…

This is a late reply but for posterity readers I was able to learn a lot from this article [1]. I'm still not certain how to interpret the 3rd graph in terms of relative work or cost for the 20% vs 90% enrichment levels.

[1] http://www.world-nuclear.org/info/nuclear-fuel-cycle/convers...