Overall this looks like someone asked a physics undergraduate to spend an hour imagining roughly how the well-known schematic might be fitted inside a real warhead case. It probably is exactly that. I can't imagine that showing it to the North Koreans advanced their nuclear programme by any more than fifteen minutes.
In two decades of crawling through most of the declassified public nuclear material from the US nuclear weapons program, some exposure to classified material, and numerous hours of interviews with working and retired nuclear scientists he believes it's the single most detailed schematic of an actual specific type of warhead he's seen so far.
https://blog.nuclearsecrecy.com/about-me/
https://en.wikipedia.org/wiki/Alex_Wellerstein
As he's blogging about this it's almost certain he has had real current working nuclear weapons experts from his contact list read the advances and not disagree.
Correct or not, it's not a casual random thought from someone with no exposure to such diagrams.
I'm not a nuclear scientist, but I did study nuclear physics to master's level. To my eye, there's nothing at all interesting about this image. It looks like informed speculation. Without any confirmation that this is a real weapons design (and I see no reason at all to believe it is) then it tells us absolutely nothing which hasn't been in the public domains for decades.
> As he's blogging about this it's almost certain he has had real current working nuclear weapons experts from his contact list read the advances and not disagree.
That seems extremely unlikely to me. People who have held the appropriate clearance to verify whether this is or is not representative of a real weapon, do not tend to casually liaise with someone who has spent their career attempting to prise open that veil of secrecy. In fact, their own careers and liberty depend on not making such personal connections.
Figure 13.9, “Unclassified Illustration of a Staged Weapon (Source: TCG-NAS-2, March 1997),” from the Nuclear Matters Handbook 2020 (Revised), published by Deputy Assistant Secretary of Defense for Nuclear Matters.
Two circles in a box, maybe inside of a reentry vehicle. That’s it. Nothing that gives any actual sense of size, location, materials, physicality.”
> The “obvious” answer, if my above assertions are true, is that it must not actually represent a thermonuclear secondary. [...] It could be some kind of pre-approved “unclassified shape” which is used for diagnostics and model verification, for example. There are other examples of this kind of thing that the labs have used over time. That is entirely a possibility.
However, he then goes on to immediately reject this "obvious" answer, because he thinks the well-known schematics of fission-fusion bombs give the appearance of a classified shape, and because he feels it is "provocative" for a government weapons lab to show a mock up of a well-known schematic in one of their publications. Those positions seem very weak to me.
I also doubt it's useful, but Ted Taylor could supposedly walk around a room full of nukes and guess based on the shape of the casing what was unique about a design
The next paragraph details what the author would have expected to be published by comparison.
And then figure 13.9 is what the DoD expects to see published at all.
Read the article and look at the "officially sanctioned" diagram. This looks like the tl;dr of what he things about this:
> Anyway, I’m just surprised the DOE would release any image that gave really any implied graphical structure of a thermonuclear secondary, even if it is clearly schematic and meant to be only somewhat representative. It’s more than they usually allow!
This linked post of his about an earlier redaction mistake also makes it clear (https://blog.nuclearsecrecy.com/2021/05/17/how-not-to-redact...):
> ...but we’re given a rare glimpse inside of modern thermonuclear warheads. Now, there isn’t a whole lot of information that one can make out from these images. The main bit of “data” are the roughly “peanut-shaped” warheads, which goes along with what has been discussed in the open literature for decades about how these sorts of highly-efficient warheads are designed. But the Department of Energy doesn’t like to confirm such accounts, and certainly has never before let us glimpse anything quite as provocative about these warheads. The traditional bomb silhouettes for these warheads are just the dunce-cap re-entry vehicles, not the warheads inside of them.
Presumably there are uses that need old steel but they are probably smaller amounts.
> Presumably there are uses that need old steel but they are probably smaller amounts.
This comment seems out of place? It would have made sense as a reply to a different comment thread in a different article a couple weeks ago: https://news.ycombinator.com/item?id=41323780 but I don't get how/why it ended up here. No one was talking about steel at all, as far as I can see?
edit: oh, there's another article today where folks are talking about low-background steel. I assume this comment was just supposed to go there. https://news.ycombinator.com/item?id=41436009
Any further use isn't very surprising. Once it is approved and in the wild, re-using it is not really a problem (especially if being run through the same office for approval again).
> ... at least historically, the Atomic Energy Commission and its successor organizations have frowned on disinformation and misinformation for other very practical reasons. If you release a lie, you run the risk of someone noticing it is a lie, which can draw more attention to the reality. And even misinformation/inaccuracy can put “brackets” around the possibilities of truth. The goal of these organizations is to leave a total blank in the areas that they don’t want people to know about, and misinformation/disinformation/inaccuracy is something other than a total blank.
In other words, the author expected to see a previously familiar schematic or nothing. This is clearly not nothing, and also not a familiar schematic, hence the surprise.
But here’s the thing: that internal culture is just as opaque to outsiders as the technology itself! No outsider actually knows how the internal folks think, feel, and decide about little graphics or schematics or whatever. They’ve just inferred some heuristics from incomplete data.
And this is basically just saying “this little graphic seems to violate my heuristics.” Which makes for interesting reading, but there is no real actual objectively verifiable content in this article.
Betteridge’s Law tells us the answer to the headline question is always “no.” And in this case I think common sense agrees: Sandia Lab probably did not give the entire thermonuclear ballgame away with a logo graphic.
As you only require one reference, I will present K.S. Krane, Introductory Nuclear Physics, section 14.5 "Thermonuclear Weapons." The relevant schematic is numbered 14.19. I chose this because it's a textbook that I remember using myself; I'm not sure what is usually used these days.
(Note that nuke warheads fall nose-first, the opposite of space capsules. So the dense material is packed in the nose, with the lighter stuff at the back.)
The nearby disk looks like a represention of airflow around a falling warhead. They, like apollo, likely had an offset center of gravity that allowed them to stear by rotation, creating the asymetrical airflow shown on the disk. Falling in a spiral also probably frustrates interception. So that whole corner of the image is advertising Sandia's ability to do aerodynamic simulations.
You have a technical expertise just close enough to, but firewalled from the actual doe nk physics, where maybe the same image couldn't be released by anyone with doe clearance.
But the guy a few buildings over just doing 'hypothetical' center of gravity modeling? Doesn't necessarily have to live by the exact same rules or go through the same release/declass process as someone with actual weapons schematics.
It leaves a lot still unanswered- but explains away some of the seemingly self- contradictory Sandia policy discussed in the article.
In industrial speak: inside-the-fence vs outside-the-fence regulatory framework, or something similar.
Sometimes the guy outside the fence 'gets away with things' because those things are OK to do outside the fence.
People very quickly figured out that this was the source of the D-T fuel in fusion part of the bomb instead of cryogenic D-T liquid. Lithium Deuteride is nasty stuff, but it's a storable solid. When bombarded with neutrons from the fission primary, the Lithium splits and forms tritium, which then combines with the deuterium that was the other half of the crystal.
The reason the usage was obvious (from the title alone!) is that very few chemists would care about any property of Lithium Hydride, which is dangerous to handle and has few practical uses. Lithium Deuteride is unheard of in analytical chemistry, and its crystallography under high pressure is totally uninteresting to anyone... except physicists working on atomic weapons.
I'm reminded of CGP Gray's videos about flags. https://www.youtube.com/user/cgpgrey/videos Like this one https://www.youtube.com/watch?v=l4w6808wJcU About US state flags
The most frustrating thing about being a designer in those environments is the dunning-krueger cockiness many technical people have in their understanding of design, which they usually believe is purely an aesthetic consideration.*
It's not even like a junior developer trying to 'correct' a senior developer about coding practices in a dev meeting— the better analog is a designer that watched a half hour Coding for Designers talk at a conference trying to correct a senior developer about coding practices in a stand-up, because they'd never have been invited to the dev meeting to begin with. If there were only designers in that meeting— and they likely find the other designer more credible because they jibe with their perspective, don't realize how important the developers input is, and might have watched that same conference talk— that could damage a project. In my experience, designers are way more likely to be solo in meetings with developers and the echo chamber of developer 'expertise' on design drowns out actual professional design expertise. In most FOSS projects, is bleaker than that because designers don't even bother trying.
* though completely out-of-context "rules" born from Tufte quotes aren't uncommon. In art school, we were told that we need to understand the rules in order to know when to break them. Imagine someone who'd never driven before that memorized a few pages of the driving manual calling you an unqualified driver because your actions didn't comply with the letter of one page they memorized even if it was qualified by another, or required for safety.
Wonder if this isn't something similar, if the DoE has some sort of "standardized notional warhead" design they can use to give to outside researchers without having to give every post-doc and grad-student a security clearance.
> MACE (Modal Analysis Correlation Exercise) assembly, and was created by the UK Atomic Weapons Research Establishment in the 1990s to serve as a sort of a Utah Teapot of weapons structural modeling: a benign shape that could be used to test aspects of the code that would nonetheless tell you if the code would work for real weapons assemblies.
The Sandia folks may be extra special, it is a pretty famous place. But engineers are people first of course, so lots of variation. And also, some are super serious of course, but there are hacker tendencies, playful tendencies. I bet if some intelligence agency folks wanted to, they could find some engineers out there who’d be receptive to this sort of thing.
If it is a fake, known-stupid design, including it would be a funny prank that wastes the time of people that might want to nuke us, right?
In order to mesh the geometry for finite element analysis, the geometry virtually always needs to be defeatured.
So the cross sectional CAD model here is a nice curiosity but basically useless for any reverse engineering purposes which is the key reason this stuff is kept secret.
I did finite element model preparation for a living many year ago and it did not only involve heavy defeaturing but interestingly also remeshing with quads.
Renderers love triangles, FE solvers love boring quads.
Btw even in Blender (which is pure visual rendering) people prefer quads. The common wisdom is that you should keep your topology quads with nice rectangle-ish aspect ratios if you can at all. It is not that triangles don't work, but they have a tendency to do visually unpleasant silly things when animated or sculpted or subdivided.
That's because, in a mathematical sense, triangular and tetrahedral meshes aren't able to be as accurate as quickly.
This story is probably nothing interesting because this went through all the public use approvals needed for public presentations and being available on osti.gov.
It is probably just a toy test problem used on a capabilities logo for Sierra. Maybe it comes from some sort of integration test that is easier to run than the actual problem.
https://www.amazon.com/Arms-Influence-Preface-Afterword-Lect...
> It’s literally the logo they use for this particular software package.
Which seems to refer to the image of the re-entry vehicle in isolation from the infographic where the author originally found it.
Other than that, I'm not so sure about the particular design pointed out by the author.
> Someone reminded me of something I had seen years ago: the British nuclear program at Aldermaston, when it has published on its own computer modeling in the past, used a sort of “bomb mockup” that looks far more deliberately “fake” than this Sandia one. I offer this up as what I would think is a more “safe” approach than something that looks, even superficially, like a “real” secondary design:
> This is called the MACE (Modal Analysis Correlation Exercise) assembly, and was created by the UK Atomic Weapons Research Establishment in the 1990s to serve as a sort of a Utah Teapot of weapons structural modeling: a benign shape that could be used to test aspects of the code that would nonetheless tell you if the code would work for real weapons assemblies.
I don't know... hit it with an HTCPCP request and see if you get back 418 - I'm a Teapot, or not.
IIRC the story, this was still during WWII. They were testing the flight characteristics of the bomb casing. It did not contain a core. But it was still extremely classified. They had the test casing in the back of a truck, taking it from Sandia to Kirtland AFB. The truck got in an accident, the tailgate fell open, and the bomb casing fell out and went rolling around in the street.
I think the author is omitting the most likely explanation for why it wasn't redacted in future publications.
It took from 2007 to 2024 for someone (him) to publicly notice this.
If your job was to censor documents coming out of Sandia National Laboratories, and you screwed up this massively, what's your incentive to call attention to your screw-up?
Better to just coast along, by the time you retire or move on to another job your ass is off the firing line.
Ditto (but less so) if this was your co-worker or team mate, after all North Korea, Iran etc. already have access to the published document.
What could anyone in your organization possibly gain from the ensuing shitstorm of admitting something like that?
Has this person worked, well, pretty much anywhere, where people have a stronger incentive to cover their own ass and keep out of trouble than not?
Or, that internal report and subsequent shitstorm did happen, but what do you do at that point? Make a big public fuss about it, and confirm to state actors that you accidentally published a genuine weapons design?
No, you just keep cropping that picture a bit more, eventually phase it out, and hope it's forgotten. Maybe they'll just think it's a detailed mockup of a test article. If it wasn't for that meddling blogger...
Edit: Also, I bet there's nobody involved in the day-to-day of redacting documents that's aware of what an actual weapons design looks like. That probably happens at another level of redaction.
So once something like this slips by it's just glazed over as "ah, that's a bit detailed? But I guess it was approved already, as it's already published? Moving on.".
Whereas a censor would have to know what an actual thermonuclear device looks like to think "Holy crap! Who the hell approved this?!". And even then they and the organization still need the incentive to raise a fuss about it.
Updating a logo (especially a bad logo) after a couple of years is not exactly a newsworthy event. If you replaced any other part I would not assume it was to correct an accidental disclosure of classified information.
The fission stage in that warhead has numerous refinements that help miniaturize it, for instance the implosion is probably not spherical so it can fit in the pointy end of the warhead. A really refined modern weapon is packed with details like that.
Besides, real engineering doesn't just need a schematics, it needs details, and some of the missing ones are notorious (FOGBANK) and inherently difficult to figure out with any confidence in the absence of weapons tests (or even more expensive giant buildings crammed to the gills with lasers).
So yeah, not very useful to an aspiring designer. I understand the author's surprise but I suspect they really did just become a few notches less crazy about the redundant protection on information that has been public for 30 years.
It is not even clear if when he speaks about "safe" is he talking about being safe from nuclear proliferation, or safe from clueless bureaucrats causing you legal trouble.
My impression from his book is that his position on nuclear secrecy is that a lot of it is pointless or outright contra-productive, but that isn't really the point of the blog post. The point of the blog post is that if something has changed about what information is considered safe to release, that is interesting to him. He is more interested in the humans and institutions than in the technology, I'd say.
The issue seems to be “Organisations party to classified information have to keep it secret regardless of whether it’s in the public domain”.
As an academic historian the author is intrigued by the diagram - was it a mistake or was it authorised as a declassified representation? Either way, the consequences would be of interest.
> It is not that nobody knows how these weapons are supposed to work.
Optimally small, lightweight, robust, safe, reliable - all sorts of engineering short-cuts or novel techniques … you don’t want to give way accidental insights about the “hows” an enemy hasn’t thought of.
A modern fusion bomb requires much less of that than the initial fission bombs.
So I don't know how much a state actor could infer from an image like that, if we assume it's a schematic of an actual bomb.
But it's just not true that someone in possession of detailed plans for how to construct a bomb isn't put into a much better position. They'll need a much smaller amount of fissionable material than they otherwise would with a cruder design.
That is not how nuclear secrets work. The US Department of Energy holds that restricted data (a special kind of classification that only applies to nuclear secrets) is "born secret". That means, even if you come up with a concept for a nuclear weapon completely independently without ever talking to anyone, it is considered classified information that you are not allowed to redistribute. This doctrine is highly controversial and the one time it has been tried in court the verdict was inconclusive, but to this day it is how the DoE interprets the Atomic Energy Act of 1954.
In general this is very precarious to attempt to enforce, of course. If the DoE sues someone because they published their nuclear weapon designs, that'd be seen as a tacit admission that the design could potentially work. Nevertheless they actually did do this at one point (United States v. Progressive, Inc., 1979).
That’s not really true. If you manage to independently come up with classified info and release it to the public, you will get a visit from an agency.
Overall I think you’re correct.
When @Snowden blew the whistle on the NSA spying operation, all he did was download everybody's powerpoint presentations and send them to @andygreenwald.
Where did he end up? Intentional misinformation? It was definitely not clear but that was the last one he listed…
His lectures are always highly entertaining, a real pleasure to watch.
This is a clip from his lecture explaining the basics of thermonuclear warheads:
And the full “Nuclear 101” lecture, in two parts:
After a couple of decades of internet I was expecting people to realize other timezones exists.
> I happened to look at a slide deck from Sandia National Laboratories from 2007 that someone had posted on Reddit late last night (you know, as one does, instead of sleeping), and one particular slide jumped out at me:
The author is making fun of themselves for being up late reading this deck instead of sleeping. They’re not making fun of the person who posted the slide deck.
A logo is the Sierra stylized text in the lower center.
And the two others in the slide's footer.
That Sandia might use, what was obviously intended as a diagram as a logo is a whole other thing but doesn't make it one.
As long as all representation of that thing are that big and readable one can assume they were not used as logos.
