3 ms·
Just had to do the calculation. With 3.5% enriched uranium, about 1/8 of that mass on the power supply is fuel. Yeah, it's not impossible. But nuclear reactor
by marcosdumay 2y ago
Just had to do the calculation.
With 3.5% enriched uranium, about 1/8 of that mass on the power supply is fuel.
Yeah, it's not impossible. But nuclear reactors aren't usually anywhere near 7 times heavier than their fuel.
- Tuna-Fish 2y agoI would assume such a high-performance system uses bomb-grade material.
- marcosdumay 2y agoHum... You can make things about 20 times better by enriching the uranium more. But then you'll get into severe storage and control problems. And that thing has to work for 13 years, untouched. There's a maximum somewhere on the middle. Anyway, I don't think reactors on earth are anywhere close to 140 times the mass of the fuel either. And they don't have to use radiative cooling.
- jandrese 2y agoNuclear plants on Earth are way more than 140 times the mass of the fuel, but that's mostly concrete for the radiation shielding. If you're only worrying about the core and cooling infrastructure it's not nearly as bad. But of course as everyone has mentioned cooling things in space is hard and you'll want to minimize the number of moving parts because maintenance is impossible and you can't use convection to move heat around which makes it even more difficult. Remember that on Earth nuclear reactors create electricity by boiling water to turn turbines. Such a system will be far more difficult to design for space.
- perihelions 2y agoAll space nuclear fission reactors use weapons-grade uranium—they'd be impractical otherwise.
- littlestymaar 2y agoIs there anything like a "space nuclear fission reactor" in the first place? My understanding was that all the so called "nuclear reactors" in space where jus powered by radioactive decay of short-lived material, not by fission.
- two_handfuls 2y agoOh yes there is. The soviets launched two 6 kilowatt fission nuclear reactors in space. https://en.m.wikipedia.org/wiki/US-A https://en.m.wikipedia.org/wiki/US-A
- littlestymaar 2y agoAh, I wasn't aware of that, thanks!
- philipkglass 2y agoAlso one American reactor: https://en.wikipedia.org/wiki/SNAP-10A https://en.wikipedia.org/wiki/SNAP-10A
- Iwan-Zotow 2y agoSearch for Topaz space reactor
- deleted 2y ago[deleted]
- littlestymaar 2y ago> But nuclear reactors aren't usually anywhere near 7 times heavier than their fuel. On not on earth, but Soviet spatial reactors[1] weren't too far from that: > The fuel core of the reactor was 0.24 m in diameter, 0.67 m long and weighed, as an assembly, 53 kg,[1][2] and contained 35–50 kg of enriched uranium. The entire reactor, including the radiation shielding, weighed 385 kg. The problem is yield, out of 100kW of thermal power it was only able to generate up to 3kW of electricity due to lack of efficient cooling in space. [1]: https://en.m.wikipedia.org/wiki/BES-5 https://en.m.wikipedia.org/wiki/BES-5