[lightedman]

"SMR make as much sense as space datacenters."

So a whole lot of sense given the entire US Navy uses them and I already have one datacenter operating up in space (small test unit that over 3 months has provided ZERO issues) and a bigger one heading up into orbit next year when it's done being made.

"but you can't gaslight thermodynamics"

No but you can certainly conflate them like you're doing right now.

[Manuel_D]

The Navy uses highly enriched uranium for its reactors, something like 70-80% enrichment. This is a non starter for civilian use, on account of proliferation concerns. That, and the enrichment requirements drive up fuel costs.

[15155]

Naval reactors use HEU specifically so that humans can live and work in close proximity for long periods of time.

Land-based deployments don't have this constraint.

[Manuel_D]

What does the enrichment of uranium have to do with humans working in proximity? In both low-enriched land based plants and in marine nuclear power plants, the radioactive materials are contained in the pressure vessel and inner cooling loop.

[15155]

HEU results in fewer actinide products and a substantially more-compact reactor.

[crote]

So in other words: a non-naval SMR which doesn't use HEU is going to be substantially larger - which would make it substantially more expensive, and therefore not representative of civilian SMRs?

[15155]

Who said anything about expense? Why does "bigger" equal "more expensive?" Lead, concrete, etc. are cheap on land, but volume is a precious resource on a ship. HEU isn't the only reactor fuel out there, either.

And of course, all non-naval reactors are naturally going to be larger: they aren't surrounded by a practically-infinite fluid heatsink.

[Arodex]

>the entire US Navy uses them

Is the business of the US Navy to sell electrity on the market?

You are the one conflating things that have absolutely no connections.

[lightedman]

"Is the business of the US Navy to sell electrity on the market?"

No but they do use those reactors to power areas in times of disaster relief.

[Arodex]

So, when cost is of no importance.

[RealityVoid]

Ok, this is interesting. I am skeptic about DC's in space, but I do appreciate people actually doing stuff. What is it computing up there. How did you get it up? How does one usually talk with their satellite. I guess you don't merely have a dish since it's probably not geostationary.

[lightedman]

"What is it computing up there."

Hyperspectral satellite imagery - think ASTER/LANDSAT/MODIS but more modern, for surficial minerals study.

"How did you get it up?"

How else? Paid a rocket company to launch it into orbit after proving various flightworthiness tests and getting various certifications and permissions from relevant gov't authorities.

"How does one usually talk with their satellite. I guess you don't merely have a dish since it's probably not geostationary."

K-band. Don't need tons of power, just a good LoS from ground on your target. And yea, not Geostat, I'm in LEO.

[crote]

Right, so a regular satellite. That's indeed as relevant to the multi-100kW-scale "space datacenter" idiots like Musk are proposing as naval SMRs are to commercial power plants.

[lightedman]

All satellites are regular satellites, there is literally nothing special about anything in orbit outside of what it carries - it's still just a falling body in space.

100kw is literally nothing to generate in space. At typical silicon efficiencies that's football field in size, and about 70% that if you jump to more expensive multi-junction cells. I can make a folding panel the size of a compact car that'd unfurl out to cover that. That's maybe 4 hours in NX just retooling my current design. The only limitation is the capabilities of the launch vehicle.

I've already got one small (single 4U) datacenter in orbit. It works. It works GREAT. It can scale up to constellation quantity.

And I don't have to waste any water for cooling or constantly pollute the air for power generation or throw extra waste heat into our atmosphere, as a side bonus.

It makes plenty of sense to those with the education. What's hilarious is I'm doing all this on a GED.

[marcosdumay]

Yes, SMRs probably have a small niche market on military-adjacent applications.