Pratt & Whitney laser disc / laser glazing

Well, radiation — a nuclear reactor hardens the steel vessel. You have to scrap it after 30 years because it's been embrittled. So yes, radiation will change the crystal — the location of vacancies and interstitials and the atoms in the crystal. But as far as hardening it, I don't know of something specifically hardening with radiation. We have used lasers — in fact, Ben Wilcox, back in the '60s, when he was working at Pratt, used high-powered pulse lasers. If you hit something hard enough you can actually blast it apart. You send stress waves of 300 ksi through the material, and you can stress-relieve. We did some of that in the '90s, trying to use laser stress relief. You blast it, do little pulses, and all you do is leave a little divot on the surface, which you can grind off, but you hit it so fast that you send a shockwave through the metal, and that shockwave is a mechanical stress.