If you're interested in a visual of how different welds interact with the metal, I watched this video on SpaceX's Starship welding that was helpful [1].
Something I try to remember is that most non-organic materials gain their properties from a precise lattice structure. This often doesn't come across when looking straight at the chemistry equations. Welding both disrupts and rebuilds this lattice structure, which is why it requires so much skill to do at volume.
Why does it take 12 months to weld these things in the first place? The article doesn't say anything about that, and I can't intuit why it would take that long in the first place.
The heavy forged sections of a pressure vessel are really thick and there is a limit to how thick a single weld can be using conventional techniques. So you have to do many passes. Each one of those requires bringing the temperature of the massive forged sections that are being welded up to temperature, cooling it, and then x-raying the partial weld before proceeding with the next cycle. The actual time spent doing the weld is cumulatively not more than a week.
My (albeit short and 30+ years ago) experience in the nuclear industry as an apprentice would lead me to believe that it's about quality control and inspection as well as it probably being a long-winded task if the pressure vessel is 8 inches thick. I'd think it would need to be entirely welded at that depth, with each weld pass being X-ray inspected.
Everything I did when briefly working in a reactor (3 months of my 4 years) took a LOT of time because of safety checks and routine.
And then all the meetings are about how you make time for resolving all the bugs introduced by copilot. But you can't cancel any meetings, so you need to create a new meeting because it is a new issue. And copilot is cheap so why not just buy more compute time? Surely that's cheaper because humans and machine solve problems in the amount of time and to the same degree of satisfaction, right? We should probably schedule a meeting so we can make a project to find out. We can probably find out if we measure the number of lines of code each can write. It'll be easy.
You call that luxury! When I was a lad we were put into a cardboard box on the middle of t’motorway, made to code an entire distributed database in our lunch hour, and if we had less than 100% coverage the project manager would cut us into little pieces and dance on our graves.
you had graves?! in my day management would sell our organs on the black market and feed the rest of our corpses to the HQ lobby piranha aquarium, though they'd still charge our estates for the tombstone retainer of course.
You had piranha tanks? Back in my day our managers just threw us in a empty concrete room with no windows and no outlets, tossed a computer at us and said "fix it". If we were lucky they'd say what "it" was. If we were extra lucky, they'd throw us a keyboard. Not that that mattered anyways.
You had keyboards? Luxury, back in my day we had to stamp punch cards with the tips of our fingers. If we made a mistake, the head operator would cut one of our fingers off with a bread knife. We didn't mind though, it made us tough, that and sleeping in the car park wrapped in tape from old backups just t'stay warm.
You had concrete car parks? When I were a lad, we had to inherit from car park and implement parking spaces ourselves. And if you had an overflow you had to walk -2147483648 miles to work.
Welding stuff at this scale/depth takes time. It isn't just inspections either. There is lots of prep work. Sometimes the material itself has to be pre-heated/cooled in order to prevent warps/cracks in huge blocks of metal. But, for the same reasons, that preheating itself cannot be done too quickly. Multiply this by hundreds or thousands of weld lines and 12 months doesn't sound so long.
Typical welding can only safely deposit a certain volume of metal at a time due to physics constraints.
Either the puddle gets too large and sags, or flux needs to be removed between passes, or the work piece needs to be moved with a certain speed/force that doesn’t scale, or the heat can only be deposited on a single surface at a limited rate, which causes problematic distortion and limits penetration.
Welding a 6” thick piece of anything with stick/tig/mig may take dozens or even hundreds of passes depending on geometry, material, available welding positions, etc.
Welding the same thing with stir welding may take 100+ or even 1000+ tons of pressure in a moving weld fixture.
And because of that, will also cause major distortion to the part unless done very carefully.
Electron beam welding doesn’t have many of these issues because the electron beam doesn’t get absorbed in a point at the surface (and the beam can be very narrow), allowing very deep penetration compared to something like an electrical arc, also allowing a lot less total heat input to get the welded spots to fuse, and that also means weld joint shapes can be used that won’t need filler metal being added, or movement, it doesn’t have puddle size issues or flux removal problems (necessarily). Due to the lower total heat input, it also wouldn’t have as significant distortion effects.
The internal tension/distortion created from welding heat can be really mind blowing - we’re talking enough to twist automobile frames into pretzels if not done correctly, or rip apart armor plating and heavy machinery joints just from the act of cooling.
It also doesn’t have force scaling issues like stir welding (generally).
It would require completely, perfectly clean surfaces and a non-reactive environment, and clearance for the beam emission equipment though.
If it was homogenous steel plate, definitely. My understanding is that modern tank armor is actually a composite with many layers of materials like hardened steel, rubber, ceramic, etc. Those allow disruption of kinetic penetrators and shaped charges more effectively than a homogenous piece of steel, so effectively more armor 'thickness' for a given weight/thickness.
No idea how they weld those things together!
There are some neat videos on youtube showing some pretty cool simulations of the how and why.
Yup good points. I now rememeber "dorchester" and "chobham" armours. I must say that I too am at a loss to imagine how they are fabricated into solid hulls!
That's my issue with articles like this. It sounds pretty great, but it provides barely any context. The quote at the end is a quote from the company's project lead, which sounds like it was taken from a company press release. So, yay?
Yeah, I'm wondering about that as well. Did this exact design take 12 months previously? Or did a 30ft-wide BWR vessel take 12 months? That would be a pretty significant difference.
I did a small amount of nuclear-grade welding myself and it was always one hour of welding, one or more days of testing. So if they could replace many small passes with one all-the-way-through pass, that would vastly decrease production time. But even then, testing a weld that spans the length or circumference of a vessel is still going to take a very long time. Since they don't mention any massive, profound, fundamental improvements in post-weld testing methods, I'm guessing they just left that out of their "24hr" claim, which makes it very misleading.
I once worked with a guy who had his nuclear ticket, on a team of welders working on high pressure steam and pressure vessels. Even many of the steam welds had to be x-rayed and he said the nuclear process was more intense, not just testing but technology and performance.
Means he had a certificate that showed he was considered (by the US navy in this case) competent in making welds suitable for building or repairing a nuclear reactor or related devices.
We didn't need that, of course, but because high pressure steam is so dangerous we used only union welders who were rated master and who already had experience in steam plumbing. I don't remember if there was a special ticket for that, but everybody we hired was interviewed and had to do some welding as a part of it (the equivalent of a leetcode test on the whiteboard I suppose). If it isn't obvious: I was not qualified to usefully interview any of them.
These guys were great to hang around with. go have a beer, horse around, etc with but wow, when they were on the clock all of them (machinists, etc too) were deadly serious. No fucking around.
Hah, an old family friend related a welding interview story on the other end of the spectrum.
He had been working as a machinist and welder for BART, on a mixture of road and rail car maintenance as well as other fixed infrastructure work. He interviewed for a job at Lawrence Berkeley Laboratory, but was intimidated when they asked him to "weld some gold tissue paper".
"when they were on the clock all of them (machinists, etc too) were deadly serious. No fucking around."
Sounds like true professionals. There is no fucking around with serious work, when real lifes depend on it. I wish, more people had that attitude, then there would be less mess everywhere.
I used to work at a shipyard as a welder. The zero-bullshit professionalism when it was go time was genuinely satisfying to be working in: there was no way someone could fake their skill- literally everyone I worked with was competent.
If it weren't for the literal toxic working environment, I'd be tempted to quit tech and return!
In America, they're all based on the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC). It covers all the different types of nuclear certifications for organizations, because normal welding certs don't cover the nuclear industry.
The "nuclear ticket" for most is probably:
> NPT - Fabrication of parts, appurtenances, welded tubular products and piping subassemblies
From ToughNickel [2]:
> BPVC Section IX outlines the brazing and welding qualification procedures for nuclear pressure vessels. Section IX also gives the welding and brazing qualifications required to work on equipment for use around nuclear reactors. Welders must be qualified per the procedures listed in paragraph NCA-5250.
Also, appurtenances up above, not actually a typo.
Not sure if this applies, but IIRC some welds are embedded in complex structures that require only very skilled workers... and sometimes only a left handed guy can access the surface.
The materials they are welding can have lead times of months/years from the forgeries and the quality requirements are insane because of the safety/enviromental/economic considerations.
So therefore the work has to be inspected[0] regularly and everything has to pass before work continues.
>"Using conventional techniques, this can take over a year, but Sheffield Forgemasters have reduced this to under a day using what is called Local Electron-Beam Welding (LEBW) to complete four thick, nuclear-grade welds.
LEBW is a revolutionary method to weld two pieces of metal together using a high-energy density fusion process centered on a high-powered electron gun operating in a local vacuum. This melts and fuses components to one another and allows for an efficiency of 95%, deep penetration, and a high depth-to-width ratio."
Never heard about this before... let's learn more about it!:
Apparently you first need a vaccuum chamber to prevent energy dissipation... that sounds about right...
But then we find this interesting quote:
>"Magnetic lenses can shape the beam into a narrow cone and focus to a small diameter. This allows for a high power density on the surface to be welded."
Now that's super-cool!
(Or, well, super-hot -- as the case may be! :-) )
Then there's this:
>"The beam can then be redirected to meet the needs of applications beyond welding such as surface hardening, annealing, exact beam positioning, imaging, and engraving. Resolution of 0.1 mm can be achieved."
Now that is truly useful!
It seems like this would be an excellent technology for creating future space stations, spaceships and other deep-space vehicles, of one form or another...
The one thing I still wonder is whether SMRs could create a security nightmare.
Every nuclear power plant is a fantastic target for terrorists. Transports of nuclear waste are a fantastic target, too.
I read once that the UK has many nuclear waste trains driving all the time, most of them empty, just to make it hard to guess which one to hit. (I assume other western countries have the same system). That kind of security doesn’t scale well.
My issue with thinking like this is that there are plenty of targets for terrorists: packed trains, stealing a big truck, etc. The fact that these events are pretty rare suggests that there aren't nearly as many terrorists as people seem to be worried about.
Every power generation method has its plusses and negatives. I don't know if the risk from an SMR incident outweighs other methods, but it sounds promising. We certainly need an alternative to sources we know are bad (coal, oil, etc).
Western society in general is a bunch of future cancer and heart disease victims all freaking out that they're going to die in a nuclear meltdown, or by the hand of a terrorist, or by a lone gunman "mass shooter," or in a plane crash, or any number of other threats that are scary but statistically highly unlikely.
Human beings are just utter crap at intuitively estimating risk.
> Western society in general is a bunch of future cancer and heart disease victims all freaking out that they're going to die in a nuclear meltdown […]
Also, COVID (to round out the top three in many places).
The difference is you can trivially avoid death by airliner crash. You can't practically reduce your chance of death by COVID unless you simply never go outdoors or have visitors
Compare the relative probability of dying of cancer as a result of a nuclear meltdown to dying of cancer as a result of cigarettes or chemical carcinogens.
True overall (regarding overall alpha emitter load), the issue with fallout is radioactive Iodine, Stronium, Cesium, etc. Those elements have short half lives and won't be as present in significant quantities in flue emissions because of the age of coal (just as daughter products in much lower concentrations than the Uranium). Notably, they're also present in 'hot' reactor fuel, albeit in different ratios/qtys (usually) than fallout.
Notably, Stronium-90 levels in deciduous teeth of kids born in the 80's.
"Strontium-90 concentrations in deciduous (baby) teeth of 515 children born mainly after the end of worldwide atmospheric nuclear bomb tests in 1980 are found to equal the concentrations in children born during atmospheric tests in the late 1950s. Recent Sr-90 concentrations in the New York-New Jersey-Long Island metropolitan area have exceeded the expected downward trend seen in both baby teeth and adult bone after the 1963 ban on atmospheric testing. Sharp rises and declines are also seen in Miami, Florida. In Suffolk County, Long Island, Sr-90 concentrations in baby teeth were significantly correlated with cancer incidence for children 0 to 4 years of age. "
Stronium in teeth is a proxy for Stronium in bones too, and those don't fall out.
I think it just reinforces the point. It isn't even a significant proportion of a person's cancer risk.
It's like worrying about the KGB covertly planting listening devices in your house while tech companies are openly planting listening devices in your house. It's not at all unreasonable to be concerned about invasion of privacy, but the people who think they're at significant risk of being individually targeted by the security service of the former Soviet Union because of what they saw on TV have got a screw loose.
I agree that people are bad at estimating risk, but I would also argue that the reason many people live long enough to become cancer victims is because of this freaking out.
The reason people live so long is because we went all-in on fossil fuels through the 1800s, 1900s and early 2000s. Our long lives and high living standards are pretty much all flow-ons from cheap energy.
The people who prioritise 0-risk living over energy security are self defeating; but the problem is they keep trying to take the rest of us down with them. Their victory against nuclear energy might technically be one of the biggest catastrophes to ever hit humanity. We have never been hit by something else with so high an opportunity cost in absolute terms. Blind and ignorant fear is no basis for making policy decisions.
Right, but you're describing the process of an open-minded person.
For the fuckwits in any given electorate, your maxim would be better phrased as "default to not having any fucking opinion at all on that of which you know not"
> there are plenty of targets for terrorists: packed trains, stealing a big truck, etc.
The counterargument is that blowing up a train or stealing a truck usually doesn't poison the local area for generations. Higher risks means some consideration is due. If the stakes are higher but the probability is the same, the expected value is still higher.
I for one don't want to live in a hellscape pockmarked by miniature exclusion zones.
> The one thing I still wonder is whether SMRs could create a security nightmare.
People are going to tell you why this isn't a major concern, but the main reason it doesn't matter is that it doesn't matter. There are chemical poisons every bit as nasty as anything in a nuclear reactor which have a half-life of ~forever and aren't that hard to make or obtain. You can't prevent this because they're simple compounds made of common elements.
People are afraid of nuclear because of its association with nuclear weapons, not because there is anything uniquely dangerous inside the reactor worse than things in chemical plants all over the place that nobody pays any attention to.
Nuclear material has the fantastic property that you can precisely measure the danger. Regardless of the specifics of the material, regardless of the geometry, size, surface coating, chemical composition -- a geiger counter will tell you exactly how dangerous the material is.
There is this kind of weird thing that people do where they assume nuclear waste is uniquely dangerous. It isn't! We can just measure it, so the danger is perfectly legible. This is a good thing! The rest of industrial waste is NOT like this. You can see studies of people who live in areas near oil refineries and chemical plants in Texas and Louisiana -- population level cancer and birth defect rates are very high. It's exactly as you say, bog standard "dangerous chemicals" are just as dangerous as nuclear radiation is. Only we can't measure them, so I guess what can ya do if a whole city gets birth defects or cancer?
The double standard is actually wild. I would prefer to live next to a nuclear plant, thank you very much. I can get a geiger counter and know if I'm being poisoned.
The chemical ‘poison’ equivalent to a hot fuel rod (if spread around) is probably roughly equivalent to a couple hundred liters of VX nerve gas or Sarin..
Which, if not near anyone, isn’t very dangerous! It will lose that strength pretty quickly, and the longer lived elements are more like a ton of PCBs, or several tons of organic lead compounds.
Not great, don’t live there, but with proper PPE it wouldn’t kill you anytime soon.
But if moved to a place where people are at and can’t escape from, or smeared on something worth a lot of money, is a really big problem.
If magnified (with say cobalt powder), it could be an even bigger mess.
Hot fuel rods are very strictly controlled for a reason.
It depends on what kind of damage you're trying to cause. Someone would use different chemicals for trying to kill a lot of people in one place immediately than trying to cause a large economic impact by filling the area with something expensive to eliminate that causes health problems. But the same is true of radioisotopes. The most immediately fatal ones have a short half-life and are only effective at that when concentrated rather than dispersed over a large area.
If you have physical access to something with a high monetary value and you want to mess it up, chemical explosives do just fine and can be made from ordinary household substances.
> Hot fuel rods are very strictly controlled for a reason.
The main legitimate reason is that some existing reactors were purposely designed not to poison the fuel with heavier Plutonium isotopes in a way that makes it unsuitable for producing weapons, because the countries wanted to use them for that, but that can be solved in newer designs by doing the opposite. The main political reason is media fear mongering and decades of Russian propaganda designed to keep people buying Russian gas. Which you can kill as many people with as you can with a fuel rod, but half the population has it piped into their homes.
Good point re: non-proliferation. Hot fuel is definitely dangerous in more than one way. Even if the hot fuel could not be refined for weapons, it still wouldn't be something you could just buy or get though eh?
The issue is chemicals tend to be less dense and energy intense. And instill a lot less fear (usually). Many are heavily regulated too though, and some are getting more and more so.
For instance, can you name a chemical that will be any MORE expensive to clean off something you want to keep than a mixed radionucleotide soup? Even HF or FOOF should be way easier. Maybe methyl mercury?
Especially since (as Castle Bravo demonstrated), some of this stuff is essentially impossible to remove due to how chemically reactive it is. Some of the soup is going to want to bond like glue to everything, and is also pretty hot too - but not hot enough to be gone in a year or two.
To your point, there are definitely chemicals that can cause more actual immediate physical harm (probably), like phosgene. Or methyl mercury. Or a number of easily synthesizable chemical explosives.
But I'm not sure they would cause less fear than exploding a bunch of mixed 'hot' radionuclides in a crowded area. Probably because it wouldn't be predictable or immediately obvious who and how many would die. And there would be some pretty nasty looking video/photos of those who did.
To my original point - none of these are Sharks with Lasers on their head improbable, either way. And if someone wanted to instill as much fear and uncertainty as possible (like a terrorist), using the scariest method to the public as possible is going to be on their list.
So, worth making sure there are decent security precautions that actually get monitored/enforced, so someone doesn't just walk off with some hot rods at some point and cause a huge mess.
You won't find me arguing about propaganda and ideology though. Near as I can tell, that's killed more humans than anything else - and will continue to do so.
Also worth burning various media offices to the ground probably, but good luck getting any group of people to agree on whose eh?
> Even if the hot fuel could not be refined for weapons, it still wouldn't be something you could just buy or get though eh?
Eh. Nuclear reactors are expensive because of regulatory requirements, not physics. It's not that hard to get natural uranium. If you're a criminal who just wants fission byproducts and doesn't care about NRC approval, you could make one without too much trouble. If you had some basic knowledge you might not even kill yourself.
> For instance, can you name a chemical that will be any MORE expensive to clean off something you want to keep than a mixed radionucleotide soup? Even HF or FOOF should be way easier.
HF or FOOF might not be that easy to remove now that the thing you're trying to clean it off of has been dissolved by acid or vaporized in the resulting explosion. It is in general hard to clean something after it has ceased to exist.
> But I'm not sure they would cause less fear than exploding a bunch of mixed 'hot' radionuclides in a crowded area.
I hate to quote FDR so maybe we should use the example of the English during The Troubles.
If you allow yourself to be terrorized, you let the terrorists win. People are afraid because the media and politicians tell them to be afraid because they're manipulating you just as much as the terrorists are, for their own purposes. Anyone caught doing this should be regarded as committing an act of betrayal and condemned as a coward attempting to capitalize on a tragedy.
> Also worth burning various media offices to the ground probably, but good luck getting any group of people to agree on whose eh?
You don't actually have to burn down their offices. Just stop watching them and at scale they'll fail.
Okay, but at the point you're refining your own Uranium and building your own breeder reactor, you're also at the point you're likely making your own intermediate (or even intercontinental) range ballistic missiles no?
And then you're more visible/have more of a footprint, and it's a lot harder to get under the radar.
And perhaps you'd even have something more useful to do with your life - or at least you'd have something you'd be hesitant to lose in retaliation.
Same as if you're able to build your own airplanes, you don't need to hijack any. But also, if you can hijack an airplane to do what you want to do - why bother going to the effort of building your own?
And as for the other points - I've never been worried about Hamas or personally cared to watch Fox News - and it's been decades. I also stopped reading/watching any general news several years ago.
So why are they not only still there, but have caused a lot of damage since? And made a lot of money?
No man is an island. And no matter how mentally healthy someone in Stalingrad was, they were still in for a world of hurt between '42 and the '60's, eh?
And if you refuse to use a tool against someone who will not hesitate to use it against you, guess what tool they'll eventually end up using all the time?
> Okay, but at the point you're refining your own Uranium and building your own breeder reactor, you're also at the point you're likely making your own intermediate (or even intercontinental) range ballistic missiles no?
Gosh no. Rocket science is legitimately hard to the point that it's a cliche. Getting some elements to do physics together when you don't care about regulatory requirements is pretty much just a matter of putting them near each other and hoping you used enough shielding that it won't kill you.
> So why are they not only still there, but have caused a lot of damage since? And made a lot of money?
Because other people watched them, of course. Everyone has to do their part by turning off the fear-mongering talking heads. You can't stop other people from doing it, but you can stop doing it yourself, and so could they.
> And if you refuse to use a tool against someone who will not hesitate to use it against you, guess what tool they'll eventually end up using all the time?
The one that makes everyone hate them.
It is not possible to defeat evil by doing evil. You only become that which is to be defeated.
Uh huh. Yet, every nuclear power was at exactly at that point right at the same time, and had roughly the same success level (working reactors and rockets).
And the Nazi’s were destroyed by…. Hugs?
And not firebombing, machine gunning, etc. most of Western Europe?
Let me know when you care about reality more than the illusion.
Some things, it's an existential threat - and existential threats like that tend to only be resolvable with by death or complete subjugation of one side or the other.
And then the United States, having won the war using Hugs, disbanded the military industrial complex and threw the One Ring into the volcano, which is why the country is now so beloved in places like Iran and South America.
Notice how we were talking about terrorists and you had to switch to WWII to actually find an existential threat, and yet once you normalize these measures they become routine. Even the term "national security" was meant to imply this -- something critical to the security of the nation, that could cause it to fall to an enemy. How is this applicable to the War on Terror? Was the United States ever at risk of surrendering to bin Laden and disbanding Congress in favor of a Caliphate? It was not, and yet "national security" was the justification for every evil act committed in the name of fighting evil.
If you're weaker than someone else and you can win without fighting dirty, you're clever. If you're stronger than someone else and you can't win without fighting dirty, you deserve to lose.
Impressive way of dodging every point, while maybe agreeing with me while pretending you didn’t, and spinning up a giant strawman?
Bin Laden initiated 9/11 on his own, destroyed a huge center piece of the US financial system and terrorized the entire country.
Were the responses justified, or useful?
What does that have to do with my point that hugs solve none of these actual real world problems?
Do you think that if the US had gone ‘oh, sorry yeah you have a point - our bad’ that things would have worked out better?
And I don’t see how that has anything to do with the risk that someone might also make a dirty bomb - you know, the conversation we’ve actually been having?
Until you actually talk about something related to real world situations here instead of constantly dodging them, I’m out.
> Some things, it's an existential threat - and existential threats like that tend to only be resolvable with by death or complete subjugation of one side or the other.
But a dirty bomb is not an existential threat to the United States. The US military actually evaluated them for their own use and concluded that they're militarily useless and not worth developing.
And since we're not dealing with an existential threat, we don't have to do anything radical to address it. Did some terrorists do a terrorism? Arrest them. They can't keep doing terror plots when they're locked up in prison forever, and if the result of terrorism is "you go to prison and nothing else changes" then there isn't a lot of incentive for anybody to do it.
You're not even reading your own arguments, near as I can tell?
Of course a dirty bomb isn't militarily useful to the US gov't. They have literal nuclear weapons. Hijacking a civilian airliner and using it to attack a target in a suicide attack ALSO isn't militarily useful to the US government. They have cruise missiles.
They also wouldn't stoop to these kinds of tactics, and have overpowering force in other areas, so what else is the enemy going to use (eventually)?
A tiny group (equivalent to a US Army Company in size) being able to attack one of the most prominent financial centers of the United States successfully (and, notably, the Pentagon as well!) on live TV, instilling fear and terror in the populace, and even getting away with it for a decade is of course an existential threat to the United States.
Near as I can tell, no country in the world could pull that off successfully, not even Russia or China.
And how do you propose the gov't was going to 'just arrest' Osama Bin Laden? Or any other terrorist group?
The whole point is that they hide among civilians and go deep underground when hunted, using what we won't do to be successful.
It took a decade to even FIND OBL. And if they put him on trial, it would just give him an audience to push buttons and get his message out even wider and stir up more shit. Look at what is going on with Israel and Palestine/Hamas.
And how would you propose that the gov't not have the populace scared when something like 9/11 happens.
Should the news just not report on someone plowing nearly fully occupied airliners into the iconic and fully occupied World Trade Center towers in downtown Manhattan, or the Pentagon - in broad daylight during a workday, no less.
Towers that were common tourist hotspots and were plainly visible literally from some of the busiest streets in one of the most prominent cities in the entire world?
With no warning, and no effective countermeasures or prevention at the time?
Or that the entire US picks up deep meditation practice to understand the futility of 'holding on' to such things and how they get used against oneself?
Neither of those are realistic, or even a good idea near as I can tell in this situation.
Honestly, this type of attitude is exactly what leads up to these kinds of situations happening. It's sticking one's head in the sand.
And the world isn't slowing down. Check out this 3D printed surface to air missile project on Youtube.
Getting to the material is mechanically difficult. It's also the type of problem that neatly solves itself.
A fuel rod toting terrorist is a dead terrorist.
> The acceptance criteria in DSRS Section 12.3–12.4 state that accessible portions of the facility that are capable of having radiation levels greater than 1 Gy/h (100 rads/h) should be shielded and clearly marked with a sign stating that potentially lethal radiation fields are possible. DCA Part 2, Tier 2, Revision 3, identifies a number of areas (e.g., resin demineralizers, filters, SRSTs) that may contain quantities of radioactive material resulting in radiation dose rates exceeding 100 rads/h (1 Gy/h).
Now what I'm about to say changes with the fuel being used, but from LLNL's report,
> Even for fuel that has cooled for 15 years, a lethal dose (LD50) of 450 rem can be received at 1m from the fuel assembly after several minutes.
Good luck trying to carry that stuff out. They'll be the walking dead in a few minutes. They'll be unable to walk and will be just dead in ~100 minutes. Give or take 10 to 20 minutes depending on how they're holding the item etc.
And no, they can't just "put it in [a] lead [box]" to run away with it, because then they'll die to bremsstrahlung radiation or braking radiation. It'll take longer, but the end result will be the same.
If it's fuel that hasn't gone into the reactor yet/hasn't undergone neutron activation, then it's not radioactive enough to be a concern unless consumed.
Terrorists are rare and they're usually not that capable. It's easier for them to buy a gun or a lorry and mow down a crowd than it is to plan a fiendishly complicated radiation heist.
I just want to point out that a terrorist that drives a plane into a skyscraper is a dead terrorist too.
You need one terrorist to extract the material and put some quantities in a somewhat shielded container before being incapacitated, and then others to spread it on the subway.
Radiation isn't magic. Several feet/meters of water are used as shielding for the fuel for a good reason.
If you put an activated fuel rod inside of a lead lunch box, you will still die. You will now die from a lethal dose of bremsstrahlung. https://en.wikipedia.org/wiki/Bremsstrahlung
If you interact with this material as an amateur without processes, robotics and safety, you will die. Period. You will also suffer from intense nausea and be unable to move before you die.
Sharks with lasers are more realistic than this concern.
The more plausible scenario is a "dirty bomb" that spreads depleted uranium particles everywhere and gives people cancer long-term. But there's an element of impracticality to this and there's a reason why it hasn't happened yet.
The issue they’re pointing out is that no one seriously considered terrorists flying airplanes into skyscrapers either, for similar reasons.
Until they did it.
After all, it’s very impractical getting a bunch of random terrorists training in flying well enough to do this without being caught.
Let alone co-ordinating everything, getting through multiple layers of airport security, etc.
And everyone ‘successful’ is going to die too. Who would do that?
Historically, terrorists would just hijack a plane for attention and/or money and then let everyone go except for those stupid enough to fight them.
Which is why the reaction onboard to the terrorists taking the planes was so muted, until a passenger on one of the planes heard the news of the first impact, and they realized they were in a very different situation than a hijacking for money.
Not considering dirty bomb type issues a threat would likely be a mistake.
Having a bunch of disposable idiots throw hot fuel rods into a water tanker truck, then driving to manhattan, seeding the water with cobalt-59, and letting the mess ‘sort itself out’ (or blowing the the truck up) certainly wouldn’t be hard compared to 9/11 in these scenarios, or likely kill more than a handful of terrorists. Depending on how well secured the fuel was anyway.
It would create an absolutely terrific mess though.
The only hard part here would be getting the hot fuel (and the idiots), everything else would be ‘COTS’.
Which, like 9/11, would not be seen as ‘expensive’.
>The issue they’re pointing out is that no one seriously considered terrorists flying airplanes into skyscrapers either, for similar reasons. Until they did it.
In the pilot episode, which aired March 4, 2001 (exactly six months and one week prior to the September 11 attacks[5]), rogue members of the U.S. government remotely hijack an airliner flying to Boston, planning to crash it into the World Trade Center, and let anti-American terrorist groups take credit, to gain support for a profitable new war following the Cold War. The heroes ultimately override the controls, foiling the plot.
Episode 6 - "A man contacts the Lone Gunmen, believing his life has been stolen after being abducted by aliens. They end up getting caught in a love triangle involving a one-eyed stereo salesman, brainwashing, and a wrestling dwarf."
Episode 10 - "Yves and Frohike go undercover as tango dancers to stop a man from selling government secrets."
Or, the real 'telling the truth in the form of a lie'?
Their last episode #13 - "The Lone Gunmen team up with Man in Black agent Morris Fletcher to find Yves. What they uncover is Romeo-61, a secret government organization responsible for decades of major incidents."
Was Vince picking up top-secret communications in his fillings (maybe even subconsciously) and ended up telling too much? Or a SG-1 style 'early disclosure'/'disinfo' campaign? Or false-false flag? Or coincidence? Or reaction to some actual gov't preparatory 'conspiracy theory' poisoning the well?
SMRs don't mean they would be scattered around carelessly. They still need the whole steam boiler turbine toybox. And with security requirements they will most likely be put on a site like current NPPs.
yes, and it might make sense, and we will see ... but.
the real economics low-hanging fruit is to build those regular NPPs in increments, basically cheaper AND faster (which also means even cheaper). get real economies of scale, apply all of the last century's industrialization benefits on nuclear energy. (because current cost overruns are insane and mostly because of too-slow AND super-duper-artisanal (which means even slower) plant construction.
But even if the guy will die to steal it that doesn't mean he will live long enough to accomplish anything. And note that he's trying to tote around a gamma source--that's something that can be detected from some distance away. As soon as said terrorist gets it out from behind whatever shields it normally lives behind the alarms start blaring. I remember reading about one, anti-nuke guy kept showing up at meetings at a nuclear facility. Then one day the alarms go off--traced to the old radium-dial watch he was wearing. Rather silenced him.
the words "some" and "somewhat" are doing an impractical degree of heavy lifting. Pre-activation material is just not very radioactive and is thus not a terrorist risk. Post-activation material is basically impossible for a non-nation state actor to store and transport. If you just want to dirty up an area by, e.g., spreading radioactive material on a subway, just buy a lot of smoke detectors or do a midnight raid on a hospital or factory radiation source (not advice!). The point is, these are not going to be practical targets.
I like the idea of siting them underground, which completely addresses the aircraft strike vulnerability. Physical security is also easy when they're underground.
Thorcon was pursuing this, but has switched to a ship-based approach.
Searching today, I found a new (to me at least) company that's working on a truly small reactor, 3-15 MW electricity, and is planning on underground siting: https://www.usnc.com/mmr/
It also supplies 10-45 MW of thermal, so great for poleward climes.
Fission will be a critical technology going forward, until fusion generation can compete on power to size/weight ratio...and cost. And until aneutronic fusion power is practical, there's no large benefit to fusion regarding waste.
It's a good thing to call out. The short version of this is that nuclear proponents are a bit hand wavy on this topic and that there is no good plan for this; nor any economical modeling worth talking about.
But there's no such thing as nuclear power deployed on an insecure location. At best you have nuclear plants on very remote or hard to reach sites where the security is a bit minimal. But essentially all existing nuclear is the subject of intense and costly security. Under current non proliferation treaties, that's neither optional nor likely to change any time soon.
Logically that means co-locating small nuclear plants on larger sites is the most cost effective way to secure them. That's something people have speculated about. The most suitable locations for that would be existing nuclear plants and decommissioned coal plants. Of course if you do that, you need to compare the efficiency of having lots of small reactors in one place and compare it to having 1 big reactor in the same place. Big reactors tend to be more efficient.
The notion that you can just fedex these things to wherever, plop them down and then check back in 30 years is a bit naive. That's not how it works in the real world. People deploying these things are going to be on the spot for securing them at a non zero cost. 24x7 for life time of the reactor and the waste.
Total cost of ownership is not limited to production and shipping (also needs security) but also has to include inspections, day to day operations, site security, waste disposal, handling, and security. (though that is commonly excluded and off-loaded on future generations of course), etc.
If you exclude all those things the cost per kwh looks more rosy than it is. The real cost is something most nuclear proponents avoid talking about simply because it generally looks pretty bad. But somebody still has to pay for that.
A Nuclear power plant as a target for terrorists sounds nice as a movie plot, but in practice it sound as a lot of work for much less results.
If they wanted to go after the power infrastructure, a hydrpower dam are generally just guarded with fences and cameras, has built in weak points, and the destruction they bring causes whole nation to shut down. As a side effect they also bring down down stream transmission lines, shutdowns roads transportation on water, rail and road. A dam is basically a large number of nuclear bombs suspended above all the city that is down stream.
Going down in scale, natural gas deliveries, especially train and trucks, are rolling bombs. 22 tank cars has the equivalent energy of the Hiroshima bomb. Both trains and trucks goes through city centers. Those things are dangerous even without terrorist plots. Laws against this however has generally gone the other direction, with more freedom for train and trucks to transport this with less security.
Somebody repurposing the plutonium? No. Plutonium is not plutonium. For a bomb you need Pu-239. The more Pu-240 in your material the harder it is to slam the pieces together fast enough to avoid a premature chain reaction from robbing your bomb of most of it's power.
For both bomb-making and fuel breeding the desired reaction is U-238 + n => U-239, decays to Np-239, decays to Pu-239. There is also the reaction Pu-239 + n => Pu-240. The power guys don't care, Pu-240 works fine. The bomb guys do care. Thus the power guys leave the fuel in the reactor until too much neutron poison builds up. The bomb guys leave the fuel in the reactor only a short time.
Somehow, Thorium has been the future of nuclear reactors about as long as fusion has been. It's almost a running gag.
(And yes, I know that there are concrete plans for commercial Thorium fission reactors, in a way that aren't for fusion, but still no fully-operating, commercial reactor, afaict).
That's not really saying much given the number of new nuclear reactors of any fuel source the west has built in the current century. You have to build something in order to build something that runs on Thorium.
SMRs feel like a much worse target from what I understand.
I'm no expert, but my understanding
1) SMRs are typically designed to be walk-away safe. Their smaller capacity means its harder for them to go critical in a spectacular way. [0]
2) Distributed targets are hard to respond to, but they're also hard to hit in an impactful way. Instead of having to hit one giant nuclear plant which supplies an entire regions energy, you have to hit many much smaller targets which supply much less energy.
Getting it critical is a long way from the worst thing you can do with access to one or more SMR.
However, nobody is going to be using these things individually. You still need a steam turbine, and cooling tower etc. So the general assumption is people will be using 10+ of these things and the added complexity would be offset by economies of scale.
Ideally, the reactor is designed in such a way that a catastrophic failure is not possible.
Something along the lines of the salt plug in a molten salt reactor, that melts when cooling fails and dumps the liquid into a boron bath, halting fission.
You can still put them on a small few sites, with heavy security. You will still reap the yet-to-be-demonstrated benefit of cheaper per-MW power (personally I'm hopeful).
> Every nuclear power plant is a fantastic target for terrorists.
It is not. Let's say you are a terrorist, and you and your team have taken hold of a nuclear power plant. Then what? It's a problem for the world, but not different from you taking over a hotel or a city hall. You might threaten or even kill hostages, but there's no way you can create a significant nuclear threat. Let's say you force an operator, at gunpoint, to remove some rods from the reactor, or otherwise you get possession of some nuclear material. So what? How are you going to get away? You will be surrounded by hundreds or thousands of SWAT officers. What is the scenario where it will make a difference if they take over the nuclear power plant vs a different building?
Well, this actually happened. A guy with a death wish decided to commit suicide by blowing up a nuclear reactor, and he succeeded [1].
Well, actually we don't know this for sure, because the guy (obviously) did not survive to tell the story. It may have been intentional suicide, or simply an unintentional operator error.
But it does not matter. Since then the design of nuclear reactors evolved in such a way as to make it very difficult for an operator to be able to intentionally or unintentionally trigger a blow-up or a melt-down.
It’s good to hear that it’s risk that is already mitigated.
Personally the thing that turns me off nuclear the most is that if things do go wrong sections of land basically become uninhabitable for thousands of years. I probably shouldn’t care but it seams like a major downside.
Terrorists don't need to take over, they just need to plant a big enough bomb or hit it with a big enough plane that it causes a radioactive disaster. Not only do they not necessarily care about their survival, they might actively crave death.
> In the United States, the design and thickness of the containment and the missile shield are governed by federal regulations (10 CFR 50.55a), and must be strong enough to withstand the impact of a fully loaded passenger airliner without rupture.
Very likely. In the US, all civilian nuclear applications are under the oversight of the NRC, and the NRC is a very conservative organization. I don't see them relaxing such any regulation for SMR's, let alone a regulation with such 9/11 vibes.
Sure, but if we're talking about terrorists that a documented history of being willing to blow themselves up, I don't see why they wouldn't do this too. To avoid the painful death, blow yourself up after absconding but before radiation poisoning really takes its toll.
Terrorists willing to blow themselves up at a time of their choosing is the key there. With nuclear waste hot enough to be a menace, the window between getting the material and being painfully incapacitated and/or dead by the material is pretty damn small. Especially since nuclear plants tend to have things like lots of checkpoints and security.
If you receive around 1 Gy in five minutes, you won't abscond very far. And you would likely receive a lot more. Not to mention that you would leave a trail of radioactivity from the reactor to your lair/hiding place.
But it is well possible that some people could still try. The Four Lions, only in the real world.
I’ve personally seen someone get 7 Gy and be relatively functional (in a localized area) - no worse than he went into the OR anyway, to get the stent put in his brain. And he almost certainly lived another decade or so.
The other stuff sure, but it takes a truly mind boggling amount of radiation to incapacitate someone (near) instantly. A lot more than that.
100-150 Gy? The only concrete number I found looking around for ‘instant’ was 1000 Gy to likely kill someone within an hour.
Here's an IAEA report from an incident where a worker walked into an irradiation room of a commercial irradiator with the radioactive source still up - he was only there for about one minute and received a dose of "only" about 10-20Gy total, but realized something was wrong because of intense pain that developed shortly after entering the room, followed by intense neusea and diarrhea 5 minutes later. Despite receiving urgent care immediately he still died a month later.
It's a fascinating(if very morbid) read if you want to have a look:
Localized exposure is a different story, some body parts can take a lot of radiation. IDK if someone, having just burglarized a live reactor, can keep their exposure localized in a favorable place.
I think incapacitation is what matters. The human body will fight death for some time, but it won't be able to running around with a heavy backpack of fission material. Various tissues will scream bloody hell almost immediately from being torn apart by the radiation.
True, though notably the Chernobyl 'firefighters' were picking up hot chunks of core and fuel from the reactor building roof, and reported at most feeling tired at the time. They did die shortly afterwards, but that was weeks to a month after.
We're talking about people with EG civil engineering degrees masterminding these plots. The middle-eastern terrorists of yesteryear are not necessarily uneducated. Osama Bin Laden was educated as an engineer in the US and likely would have thought through the endgame and implications of such a plot well before executing it.
These people are not stupid and would likely know what they are getting in to. I'd be more worried about a single unhinged person, but that's why we have security guards, and the problem would likely solve itself in short order in that case.
IDK how many real-world casuistics we actually have, but Wikipedia says that absorbed dose over 30 Gy results in severe headache, severe fever, nausea, vomiting and seizures, with death taking up to two days.
I linked it in another comment, but I'll put it here as well - here's an IAEA report about an accident where a worker walked into an active irradiation room of a commercial irradiator, he was there only for about a minute total but had to leave because of intense pain which made him realize something is wrong. The total dose is estimated at 10-20Gy but it was still enough to make him very unwell almost immediately and caused death about a month later:
Yeah, we are pretty lacking on high end data but my understanding was somewhere around 50Gy was expected to knock out brain function. And picking up the hot stuff from a reactor is way above that.
I can't speak for the UK but in the US this can't be true. The plan for nuclear waste from the energy industry in the US is to leave political office before it is an issue. There is no way to dispose of it, period. Multiple plans have been put forth, many billions spent and none of it has ever actually been implemented.
I think the military is a little different in that they get to override certain concerns.
"The Civil Nuclear Constabulary (CNC) is the armed police force in charge of protecting civil nuclear sites and nuclear materials in England and Scotland."
I am more concerned about when/if we have millions of small nuclear reactors around, some of them will end up abandoned/lost. Then many years later, they will start to leak (think rain getting in).
Unlikely, that would imply a major breakdown of civilization. They are all connected to power lines, else they would not have been installed in the first place.
And we saw what happens when nuclear installations are caught behind frontlines. In such situations, installations composed of SMRs would have advantages. For example, artillery blowing one up would be quite gnarly still, but less so than if that happened to a much larger monolithic plant!
I mean during cold war many RTGs were deployed in remote regions of the world and subsequently lost. We even know of some cases where random people came across them and opened them up(unknowingly killing themselves in the process).
SMR won't deployed to remote locations and then forgotten though. They will be installed and managed like usual nuclear installations: at dedicated sites, with appropriate security, and close supervision. Their purpose is to make these installations more modular and thus cheaper to maintain, extend, upgrade, and ultimately to decommission.
And yet before this I kept seeing publications about how they can be packed in a few containers/trailers and delivered anywhere to start producing heat/power...
I guess it might have been about a different company, but you can understand my worries ?
Also comes to mind the previous recklessness of some : while the USA has judged the use of "full blown" nuclear reactors in space too dangerous, the USSR launched 33 of them, 3 of which accidentally fell back to Earth, one contaminating a chunk of Canada. They even seemed to have kept launching them after Chernobyl, though that might have been inertia ?
Just because it could be deployed almost anywhere, doesn't mean it will. Just like with rental housing containers that could be ordered to be shipped anywhere a road leads to.
We will likely see more nuclear installations though due to the fact that they don't have to be gargantuan to scale with the engineering costs. But they will be subject to the same regulatory regime that governs the existing installations.
One of the benefits often cited (and it is again in this article) is that SMRs allow for electrical generation to be located extremely close to where it will be consumed, avoiding line losses on the transmission grid. How significant are the line losses for a plant that is 100 miles from where the electricity is being consumed?
At least in a US context, the proximity advantage is often less about line losses than about the political realities of building transmission. We have way less transmission in the US than we're expected to need as we electrify, and the right-of-way acquisition, permitting, etc., to build new high-voltage transmission are really daunting. NIMBYs tend to hate it (somewhat understandably -- it's ugly), and every jurisdiction along the path of the proposed new line typically has its own permitting process which effectively grants it veto power (unlike gas pipelines, interestingly, where the federal government has permitting authority that supersedes local authority).
A big potential advantage of these kinds of solutions is that you can just site the plant such that you can avoid building the transmission at all. Of course, nuclear obviously has its own NIMBY concerns, permitting issues, etc., so it's not a panacea.
I find that NIMBY concerns can be very much connected to cost and profits. Looking at wind farms which has both a lot of noise and visible footprint, people becomes much more acceptable to those costs if the profits from the farm ends up with people who live there.
An other comment here talked about how almost 80% of the energy bill in California are from fixed costs from primarily transmission. That is a lot of space to create economical incentive for people to have a plant located very near where they live. Similar, politicians are much more willing to be permissive with permits when there is an economical benefit for the region, as energy costs are quite significant bit of a regional budget.
Can't address it overall but some while back I did some calculation on shipping power around the world from wherever the sun was shining. I took the real-world numbers for the biggest transmission lines--and found the only question being how many nines on the loss percentage.
You are fighting two separate forces. Some of the energy is lost to heat in the wires, this is minimized by making the voltage as high as possible--but the higher the voltage the more corona loss there will be.
Worse in cold weather? I thought conductors get more efficient the colder they get (or is cold relative to humans insignificant to high voltage lines)?
1 reactor per day would double the number of reactors in the world in less than 18 months. Can we generate enough people qualified to run them without compromising safety?
They're pretty small for a commercial reactor. But on the other hand nobody stops us from building them in parallel. The point is that they break existing rules: we'll stop counting reactors, for one thing, because numbers will mean a different thing. And also, more importantly, we need a lot less qualified operators to run them safely.
that was welding together just one part of a reactor, it would involve a lot more than that one part. You'd have to get all the various steps done in parallel and all stages less than 24 hours to get a "1 a day" pipeline going. I think that is wishful thinking by anyone's standards.
That's one large bottleneck resolved, perhaps one of the most limiting. But it doesn't mean they will actually crank up the assembly line that far to then sit on a large inventory, which would create its own issues.
One thing to note is you won't be able to have a welder just standing there operating this, as it will produce energetic photons from bremsstrahlung, some of which will scatter back out of the metal. There will be little or no induced radioactivity, but the radiation environment during operation will be significant.
Low pressure nuclear systems (like molten salt systems) will not need nearly as thick walls or deep welds, but they have their own problems.
I think one of the issues is just that for thermal power plants in general, there are big economies of scale, one big boiler/turbine/etc is better then multiple small ones)
Much more than from the Canigou Sun Bear project in SW Colorado ($1.5B for 971 MWp, including I think 2 hours of batteries, 1979 GWh/year (23% capacity factor), 35 year life for the PV).
77% of the cost of a kWh in California are fixed costs. So if production cost 19 cents, then your cost would be 19 cents + 77% of your current price + a few more cents for the profit on the production costs. IOW, it would increase your electricity bills.
Last year, North Sea wind parks produced at full capacity for more hours than french nuclear plants.
The advantage of nuclear is of course that to some degree you can schedule the shut-downs.
Solar will make energy production essentially free [1] at the time scales we are looking at. The price of renewable energy systems will be entirely in moving them through time and/or space to when the demand is. We need massive Hydrogen build out anyways to decarbonize industrial processes, so betting on Hydrogen storage for this purpose seems reasonable.
The thing for nuclear economics is this: People will build these solar cells anyways. So during summer/day time you can not sell your nuclear power. So nuclear power plants don't need to be cost competitive with Solar. They need to be cost competitive with hydrogen storage if you only operate them for a fraction of hours per year. Nobody has shown a viable economic path for this. The only benefit is that the technology is more proven than mass hydrogen storage and conversion. However, proponents always point to unproven future hypothetical technologies to bring down prices to make nuclear cost effective.
And nuclear waste disposal remains a problem as well.
> Solar will make energy production essentially free
It may end up being cheaper to just use PV to resistively heat large masses of rock and use that heat to drive turbines, instead of fissioning uranium to make the heat. Not that this would be the best way to do things, but it would be an illustration of nuclear's cost problem.
> Nuclear only has a 90% uptime, whereas the goal for power delivery is 99.99%.
Nuclear in the US has a more than 90% uptime, and the downtime is scheduled maintenance, which is done at times chosen specifically because the load on the grid is known to be lower then, rather than being chosen by nature at random.
Not arguing the earlier points or saying this is relevant - but - here in Kansas, kinda known for it's wind, it usually dies down around sunset. We do get wind at night sometimes but we get a lot more during the day.
Yes, it is well known that the sun shines during the day and the wind blows at night, so together they provide all the baseload we will ever need. Ignore the new coal plants, nothing to see there.
Security against malevolent actors? Having reactors everywhere seems like an invitation for disaster...
edit: i am pro clean power and i believe nuclear waste can be stored safely; I just don't want to put town's at risk via under secured nuclear facilities.
Why wouldn't you locate a bunch in one location and make what is essentially a traditional plant? I don't think anyone with any common sense is talking about dropping 1 for every hundred houses or so in suburban chicago. There won't be any kids being like "yo dawg lets go climb that SMR after school"
It was my understanding that these would still be built more or less like conventional nuclear power plants. You just stick a whole bunch of SMRs in one location.
All the site prep work, concrete, electrical grid connections, steam generators, water etc is in one place.
There are rarely 1 conventional reactors on a site, although there are a few examples to the contrary. The largest sites have 6-8 reactors. Typically there are 2-4, which facilitates load management during outages.
The good news from the security prospective is that SMRs will likely be similarly concentrated, just with greater numbers of reactors. They are highly unlikely to be sprinkled about willy nilly, despite the thinking of some. Siting is a major problem with all power generation and particularly with nuclear: getting a site approved is a major accomplishment involving no end of costly wheeling and dealing over many years.
Although there are use cases, often championed as killer applications for SMR, such as very remote, undeveloped locations, I expect that for every 1 such isolated reactor actually deployed, 100 will be lined up in rows and columns at major reactor sites.
A big consideration is grid structure, it's very expensive to create power distribution from generators into the infrastructure. There already exists grid infrastructure at old reactor sites, so I think it's very likely that they would be ideal candidates for SMR deployment.
Some fraction of existing coal and LNG sites, and their existing infrastructure, are also feasible. Larger sites are often quite distant from populations and have large perimeters.
Someone else might have more detail, but I believe these are “basically” massive metal tubes that are created by building up welds, one on top of the other, to achieve extremely high integrity structures for containing nuclear fission.
https://camvaceng.com/electron-beam/ebflow/
It has a mini-vacuum chamber on the welding head so you can e-beam weld large workpieces without needing a large vacuum chamber.