Turning nuclear waste into diamond batteries • Hacker News Board

Re: Turning nuclear waste into diamond batteries

#41

Post by natmaka » Mon, Apr 25, 2022, 5:01 AM UTC

sylware wrote: post #40

natmaka wrote: post #33

Earlier quoted context omitted.

Breeder reactors research was quite huge (one of the first breeder was built in the US in 1951). To this day there is no such reactor working industrially satisfactorily. This architecture has been, for all practical purposes, abandoned by nearly all countries that were researching and developing it. See https://en.wikipedia.org/wiki/Breeder_reactor#Future_plants One of the most (if not the most) ambitious project wa…

It seems there is a difference between "fast-neutron" reactors and breeder reactors: the article states that russian BN-600 and BN-800 are "fast-neutron" reactors but not in "breeder" mode. Since I am garbage in nuclear physics, I am wondering if those "fast-neutron" reactors "but not breeders" can reuse a significant part of current nuclear waste?

I'm not a specialist. If I understand correctly "breeder mode" depends upon fuel composition (which actinide/isotope, in which proportion...). Non 'fast-neutron' mode is dubbed 'thermal' and seems less interesting as it obtains less energy (however some fuel, such as thorium, may enhance its performance), however it has benefits (less difficult to design/build/exploit(?)).

https://en.wikipedia.org/wiki/Fast-neutron_reactor https://en.wikipedia.org/wiki/Thermal-neutron_reactor

Re: Turning nuclear waste into diamond batteries

#42

Post by Manuel_D » Mon, Apr 25, 2022, 7:16 AM UTC

natmaka wrote: post #39

Manuel_D wrote: post #35

Earlier quoted context omitted.

The same issues apply to the materials needed to manufacture wind turbines, solar panels, and the batteries needed to mitigate intermittency. Uranium's incredible energy density means increases in raw uranium costs is negligible (enrichment is a much more expensive part of the overall nuclear fuel cost). From the previously linked article: > Over the last twenty years, uranium spot prices have varied between $10 and…

True, however those materials needed to manufacture wind turbines, solar panels... can be recycled, most of them infinitely (at human scale), and it more and more becomes either legally or economically unavoidable. Uranium isn't recyclable: there is no satisfactorily running fast-breeder. My point was not about costs but about emissions. Extraction and immediate post-processing (before enrichment), and therefore ore…

As per my original post, the total emissions from nuclear (including fuel extraction) is lower then wind and hydro: https://en.wikipedia.org/wiki/Life-cycle_greenhouse_gas_emis...

Uranium recycling is not the same thing as breeder reactors. It's essentially the same nuclear enrichment we do to natural uranium to bring it up to concentrations of U235 as usable fuel, just used on spent fuel rather than virgin uranium.

Also, for uranium sea water extraction the plan is to drop buoys with the absorbtion material and let natural currents bring water into contact with it. Pumping all that water out of the ocean would of course be stupid.

Re: Turning nuclear waste into diamond batteries

#43

Post by natmaka » Mon, Apr 25, 2022, 9:46 AM UTC

Manuel_D wrote: post #42

natmaka wrote: post #39

Earlier quoted context omitted.

True, however those materials needed to manufacture wind turbines, solar panels... can be recycled, most of them infinitely (at human scale), and it more and more becomes either legally or economically unavoidable. Uranium isn't recyclable: there is no satisfactorily running fast-breeder. My point was not about costs but about emissions. Extraction and immediate post-processing (before enrichment), and therefore ore…

As per my original post, the total emissions from nuclear (including fuel extraction) is lower then wind and hydro: https://en.wikipedia.org/wiki/Life-cycle_greenhouse_gas_emis... Uranium recycling is not the same thing as breeder reactors. It's essentially the same nuclear enrichment we do to natural uranium to bring it up to concentrations of U235 as usable fuel, just used on spent fuel rather than virgin uranium.…

Emissions: those are present (now) emissions. The paper I quoted (read above) is about future emissions (median up to 110g CO‐eq/kWh by 2050), bumped up by lowering ore grades.

Recycling: however breeders are AFAIK the most efficient way to tackle this (however it is so difficult there is no adequate industrial reactor, after ~70 years of prototypes and research). Other ways don't seem very appealing, for example France ceased to recycle in 2013.

Yes, since the 1980's a fair amount of Grand Plans aimed a extracting uranium from seawater. Nothing industrial yet. I won't hold my breadth.