Naval Surface Warfare Center particle beam weapon development

Post-1992 pivot: Navy particle-beam weapons program (originally anti-missile) was repurposed to consider 3D printing of capital-ship spares — propellers, tail shafts, sea-water valves. Tom's proposal: 500 lb/hr deposition rate with Grüneisen-effect shock-wave stress relief. Never funded — would have required 10 billion dollars and a four-story-deep x-ray-shielded pit.

So that's why now, 25 years later, they're asking me the question: why don't they do this? Well, I had a project back in the mid-1990s to try to make some parts by 3D printing of metals. [Tom passes samples around.] This is nickel-aluminum-vanadium superalloy, electron-beam 3D-printed. We laid down strips. This other one is aluminum-bronze. The Navy was paying for this — they'd like to make propellers and things. We came up with a way to do it, but the equipment would have cost on the order of ten million dollars to make big parts. That's what we were focusing on.

Quarter-billion-dollar Star Wars-era program for relativistic electron beam anti-missile weapon.

During the Star Wars buildup in the mid 80s, there was lots of money for lots of things. The US Navy at White Oak, Maryland, was developing — spent a quarter billion dollars developing — a particle beam weapon. This was to be a relativistic electron beam, millions of electron volts, that if there was a cruise missile or an Exocet missile coming in to attack the ship, this was to take it out. This was after the Falklands War, when the French Exocet missile hit the British destroyer HMS Sheffield and destroyed the ship. The reason it destroyed the ship had nothing to do with the explosive charge of the Exocet or setting off the charges. It was the fact that the ship had an aluminum superstructure, and the superstructure caught on fire. You can't put out the fire, and the whole thing burned.

Cited in the arc-welding origin-of-heat-sources thread. After peace broke out with the Soviet Union, the Navy convened a workshop at White Oak asking whether the $250M particle-beam technology could weld submarines. Tom's answer: at megawatts you could melt a submarine, not weld it (10–50 kW suffices for HY-80). Includes the "hose instability" anecdote — beam wandered in atmosphere, could shoot down a 30-inch-away missile or a cooperative 30-mile-away missile but couldn't aim.

He found this was a pretty interesting heat source — it would melt the tips of the steels with the materials he had. One of the first things — you'll get this in my fusion welding lecture — one of the first things anyone does with a new heat source is they try to weld with it, whether it's a laser, whatever. The Navy developed particle beam weapons in the mid 80s to try to shoot down incoming missiles, and they couldn't do anything with it. In the early 90s they had a workshop at White Oak to figure out — with peace breaking out with the former Soviet Union — we spent a quarter billion dollars developing these high-energy electron beams that would go through the air, and they're supposed to shoot down an incoming missile. And we don't need it anymore. What are we going to do with this quarter-billion-dollar technology? They asked me to come down and talk about whether they could weld submarines. And I said, well, maybe you could melt a submarine, but you can't weld with that much energy. You only need about 10 to 50 kilowatts to make a weld in that piece of HY80 that's going around, and they had megawatts.

Quarter-billion-dollar Navy investment up to 1992 in relativistic electron beam weapons to replace the Phalanx system. Tom uses it to introduce both the magnitude of EB-related Navy R&D and the subsequent search for peacetime applications (deposition welding on propellers). Returns at §2.p5 to discuss 45 MeV Lawrence Livermore machines and the activation limit / radiation shielding problem.

As soon as someone gets a new heat source, they tend to try to use it for welding or something. I told you about this situation where the Navy had spent a quarter billion dollars up to 1992 trying to develop relativistic electron beam weapons to replace the Phalanx system. You'd have this relativistic pulsed electron beam, and if someone was firing a missile at you, you'd shoot it through the air 30 miles away, hit the target, and blow it out of the air before it hits your ship. Well, peace broke out with the former Soviet Union. They were trying to figure out what to do with the technology. They had a little workshop and they asked me, could you weld submarines? I said, well, you could melt a submarine with 5 megawatts of power but you can't weld — you only need at most typically 100 kilowatts of power.

Post-Cold-War repurposing question — could relativistic electron beams weld submarines? Tom's answer: too much power, too much shielding, not practical. Used to illustrate the upper end of the heat-intensity scale and the limits of "just throw more energy at it."

I taught a class a few years ago in the early '90s, '92 or '93. The Naval Surface Warfare Center had spent about a quarter billion dollars trying to develop a particle beam weapon. This was going to be the new Phalanx system: you shoot down an incoming missile from a surface ship using relativistic electron beams that go thirty miles at close to the speed of light. They built these units up at White Oak and some of the National Labs. Then peace broke out with the former Soviet Union, and all of a sudden they had this technology — what do we do with these pulsed-power relativistic electron beams? So they had a three-day workshop and invited me down to help them understand whether they could weld nuclear submarines. They saw Navy work — let's apply it to welding submarines. I got down there, I looked at what they had — megawatts of power — and I said, well, you might be able to melt a submarine but I'm not sure you could weld. You only need about ten to a hundred kilowatts to weld, and you've got so much more energy. Plus it gives off x-rays to beat the band; you have to have two feet of radiation protection, and you can't just clear out the whole shipyard because you're going to start welding a joint. So I had to explain some practical things to the scientists.