I have a lot of dumb thoughts on laser #uranium enrichment, so before I unleash a 3,000-word essay on non-proliferation, SWU for U, and the mountain of US defense stockpiles/wastes, I'll lay out the basic argument here because @Grainjones asked so nicely.

Okay - laser enrichment. While gaseous diffusion and centrifuge enrichment relies on the small (3 AMU) mass difference between U-235,F6 and U-238,F6 to achieve separation, laser enrichment uses atomic/molecular/electronic differences to selectively ionize one uranium isotope.

Once ionized, you can use a magnet to capture the ionized uranium while the rest of the uranium floats on by. Lasers have really come a long way in the last few decades, mainly driven by the field of semiconductor manufacturing and the need to etch smaller features into chips.

SILEX (separation of isotopes by laser excitation) is just one iteration of laser technology, not *the* implementation. But it is perhaps the most advanced of the bunch, and the company has a deal with the US DOE to reclaim residual U-235 in depleted uranium stockpiles.

What's the tails thing about?

There is U-235 (AKA the good stuff) remaining in depleted uranium produced by the US' nuclear weapons program. And by (gently) enriching this stockpile, laser enrichment can extract economically-useful uranium from a (for now) useless waste product.

It bears mentioning that you can use centrifuges for the same purpose. The Russians are masters at this - deploying centrifuges to re-enrich high-assay uranium tails, turning excess SWU into a virtual uranium mine. They don't get ALL the residual U-235...but you get the picture.

SILEX would have a capital/operating expense to produce uranium via tails re-enrichment, but maybe with significant risk of cost overruns, production issues, etc. Right now, uranium ain't that expensive.

How expensive does it need to get for SILEX to pay off? Ask someone else.

As @royatoms has pointed out, there is (1) a need for the US government to produce enriched uranium for defense purposes and (2) not a lot of political willpower for new uranium mining on US soil. Broadly, laser enrichment (or even centrifuges!) offers a way out of this pickle.

Laser enrichment is the non-proliferation boogeyman, as it is capable of producing nearly pure U-235 (AKA bombs). The SILEX implementation is neutered to depleted U to avoid this for the same reason that you don't deploy the Incredible Hulk on civilians. But it bears mentioning.

So yeah - laser enrichment is an unproven but promising & potentially revolutionary technology. Deployed in one specific way, it's a uranium mine. But with mature centrifuge technology in the wings everywhere *but* the United States, not sure when we'll see it. Just me two cents.