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.
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.
Personally, I'd love to use machine learning to automate the meetings instead.
The old ‘could this meeting be an email?’. Rarely wrong, always controversial.
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.
Pretty neat overall!
Thanks for that fascinating explanation!
The UK has lost it's capability to make tanks from scratch, maybe this approach could be used to substitute in some way?
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.
Edit: The quote actually was taken from a news release. See: https://www.sheffieldforgemasters.com/news-and-insights/news...
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.
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.
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".
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.
If it weren't for the literal toxic working environment, I'd be tempted to quit tech and return!
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.
[1] https://www.asme.org/getmedia/eaacef3f-e8b5-44a4-b0c6-451e1e...
[2] https://toughnickel.com/business/Nuclear-Welding-Certificati...
Presumably its a certification to weld on or around nuclear equipment.
So therefore the work has to be inspected[0] regularly and everything has to pass before work continues.
I imagine half of it is checking the welds are to code and certifying it.