Readers of this blog know how to use LFTR technology to avoid making long-lived nuclear waste in the first place, but what about the waste we’ve already got? I posted this on NEI Nuclear Notes some time ago but thought I ought to post it here as well:
But before you read it, this article might serve as a very good introduction to the problem:
My modest proposal:
1. Shut down Yucca Mountain and devote the funding in the waste fund to the development of liquid-chloride and liquid-fluoride reactors. Chloride reactors would be used to destroy transuranics and breed U233 from thorium. Fluoride reactors would start with U233 and thereafter consume only thorium without producing transuranics.
2. Fluorinate spent nuclear fuel currently in storage. Remove uranium through further fluorination (from UF4 to UF6) and either send it for re-enrichment or convert it to UO2 for low-level disposal. Remove transuranics from the fluoride mixture by reduction with aluminum metal, which was recently demonstrated by French research to effectively separate TRU-fluorides from fission product fluorides.
3. Send fission product fluorides to a monitored storage site for ~300 years until they decay to background levels of radiation.
4. Convert metallic TRUs (obtained by reduction) to TRU-chlorides and destroy them through fission in a chloride reactor. Chloride reactors are capable of very hard spectrums and have inherent safety features not found in solid-core fast reactors.
5. Breed U233 from thorium during the destruction of TRUs in the chloride reactor and use them to start thermal-spectrum, fluoride reactors that use thorium as an essentially unlimited energy supply.
Such a scheme would destroy long-lived waste while transitioning to a fuel source (thorium) that does not produce the transuranics in the first place. Plus it would put this “nuclear waste” issue to bed once and for all.