Il duce - I disagree with Moosey on this one but would actually...

Il duce - I disagree with Moosey on this one but would actually be very happy if the US does re-cycle UNF but IMO Silex (or GLE would have no role in this one). The reason to re-cycle used fuel is primarily (at least in France) to reduce the volume of HL waste - NOT to produce cheap fuel (MOX) which is actually more expensive (and low quality) than new fuel from mined resources. That's why I would be happy to see recycling since the high costs would imply a higher mined fuel price (~US$200/lb) and our NUF6 tails would also fetch a much higher price than currently.

I have talked about the problem in previous posts but UNF contains 236U (from neutron capture of 235U (only about 80% of 235U fission's with thermal neutrons) and 236U builds up in the UNF. 236U is a nuclear poison and as such UNF is a low quality fuel and to work in a thermal reactor requires more 235U (making it still more expensive). A;so the nitric acid solvents (or salts in the electrolytic process) become contaminated and create a lot of mid level waste. The Russians have REMIX process which up blend UNF with HALEU - it's being tested now but the Russian say that the quality is not great.

Moosey has suggested previously that our process could be used to remove the 236U for the UNF - I don't think this would work due to:

1. The equipment would become contaminated and therefore would need to be dedicated to UNF and would increase handling issues
2. The v3 laser frequency separation between 235U and 236U is only 0.006 microns in RepU - I doubt if we could achieve that accuracy and in any case (even at cryogenic temperatures) the "bell shaped" separation curves for 236U and 235U overlap and separation would (IMO) be poor.

It may be a possibilty for HALEU UNF since the remaining 235U (after it's spent) is about 6% but even there it would probably be better to bland it with high 235U material from pure HALEU (or HEU).

To me the better options are:

1. To bread Pu (in a fast reactor) (or just separate the Pu from UNF and produce MOX (the rationale here is to reduce the HL waste volume rather than produce viable (but poor quality) fuel
2. To use a fast reactor (like the Natrium) which burns the fuel (HALEU) much more efficiently using fast neutrons which fissions the 236U (and also 238U and higher actinides - Pu, Np, Am Ce etc) and just uses the natural fuel much more effectively (UNF from thermal reactors can also be used in fast reactors (called waste burners) to get more energy but this does not involve our type of process to re-enrich it.

Sorry IMO our process is outstanding for
1. Tails (as at Paducah) - there are plenty of them elsewhere
2. Producing more fuel from the same amount of feedstock (10% to 20% more)
3. Producing LEU and LEU+
4. Less so than the above for HALEU - our process is less affective at higher 235U levels
5. Scavenging out high value (or poisonous/problematic) isotopes which have reasonable separation of v3 frequency band - lower atomic weight elements tend to have a larger v3 band separations (hence good for zero spin Si) - will be interesting to see how SLX get on with Yb.

Sorry but I disagree with Moosey on this one and consider UNF a "red herring" from SLX's standpoint