Curium-247

Whilst I'm (still) figuring Lambert curves, without much luck - here's a piece on primordial Curium. This got me, er, curious. Because I didn't think we had any. Benoit Côté et al. doi 10.1126/science.aba1111

Curium-247 is the isotope in question and is, it turns out, not very radioactive. Half of it will decay to our dear friend ²³⁵U ... after 15.6 million years. This is still a short time from the perspective of a 4567 million year old solar-system so, as noted, I do not expect to see any today. I do expect the Uranium-235 in its grave but Côté's team say more; they've found the traces of the original. Alongside Iridium-129 which decays about the same.

I read that the Curium / Iridium ratio found in meteorites looks a lot like the ratio of their decay-product. So these elements have not been subjected to further baryon irradiation in space. Further, when these elements were created in the first place, the Curium wasn't created in any great quantity. This is telling Côté that the Creator (as it were) was stingy with His neutrons. He concludes: not a neutron-star merger.

I wonder about using any neutron emitter to create some Curium-247 right here today, or at least in some orbital factory. Besides firing it off for the usual Atomic Rockets, it might be good in a power-generating reactor.

Cm-247 stores for a long time, as noted, so isn't a hazard in small doses. And when it decays it decays into something you can still use. As I look around I see that its own critical mass is 7 kg (pdf): compare U-235 at 52 kg or even U-233 "thorium" at 15 kg. (Take that, NuScale!) Out in space every one of these masses decreases if you goose it with a little antimatter.

One issue of course is that whatever hits something with one neutron will likely hit it with a second neutron, especially if the target sticks around... which Curium-247 will do. Cm-248 also sticks around, 348000 years here, and she has some research value; but she is not useful for blowing sh!t up, like fusion rockets. And a third neutron will make californium which will fire more neutrons around the place and really mess you up.

Circling back to the original post, perhaps one reason we don't see Cm-247 in high doses today may well be exactly because wherever it collected into 7 kg packages, it went boom. That might put neutron-stars back on the table.

UPDATE 7/27: considering NuScale. VERY belatedly . . .