Moosey. please read the article below on UNF - you clearly have...

Moosey. please read the article below on UNF - you clearly have a mistaken view concerning the ²³⁵U content of UNF (i.e used nuclear fuel)

EMO said about 6GW of new capacity must be added every year, about twice the amount of capacity currently being installed

This article (an other reputable sources) says that RepU has "Reprocessing used fuela to recover uranium (as reprocessed uranium, or RepU) and plutonium (Pu) avoids the wastage of a valuable resource. Most of it – about 96% – is uranium, of which less than 1% is the fissile U-235 (often 0.4-0.8%); and up to 1% is plutonium. Both can be recycled as fresh fuel, saving up to 30% of the natural uranium otherwise required. The RepU is chiefly valuable for its fertile potential, being transformed into plutonium-239 which may be burned in the reactor where it is formed"

Hopefuly you realize that natural uranium contains 0.71% ²³⁵U so RepU doesn't really have that much more ²³⁵U than natural uranium. Also when iUNFcomes out of a reactor it is:

1. In the form of
a) High Level radioactive waste when taken out of the "pool" where it cools for about 5 years looks like



a) The pellets (shown in the photograph above) are the "spent fuel" and are contained in the zirconium alloy tubes in the fuel element and when removed contain fission products (Strontium 90 and Cesium 137 have half lives of about 30 years) but also includes other radioactive elements. The decay profile is:


The spent fuel (UNF) After cooling in the reactor pond they are still very radio-active and have to be handled in a hot cell but are still largely UO₂ but contain many fission products and higher actinides all with different isotopes of to elements: ,
b) the uranium (RepU) within this UNF contains the following isotopes of uranium:



Note that the amount of 235U is not too much different to natural uranium which is 0.71% and can even be less (particularly for "high burnup fuels" which are a new fuel type likely to be adopted for LWR's
c) This separated RepU not only needs to be separated (in a hot cell) buthas to be turned into UF6 (it's still radio active so this needs to be done in a "special" conversion facility) - I call this RepU₆
d) This RepUF₆ then needs to fed into a Silex LIS system with the laser tuned to remove the ²³⁶UF₆ - this will contaminate the LIS system so the LIS system would need to be dedicated to refining RepU
e) The resulting "fuel" would still contain ²³⁴UF₆ which would reduce its quality and the trace amount of ²³²UF₆ would emit gamma rays further reducing its quality and handling

After removing the ²³⁶UF₆ the product would still be of lower quality than NUF₆ with a similar ²³⁵U content. The message I am trying to convey is that processing RepU using LIS is highly unlikely to ever be commercial. From what I can see whilst there is mined uranium around then its cost is likely to much lower than using LIS to remove undesirable isotopes - IMO the best thing to do with RepU is to turn it into RepU₃O₈ and burying it - the only real benefits of re-processing are to reduce the amount of HL waste and possibly extracting the Pu for use in MOX. Likely to still be ample supplies of depleted uranium which can be used in a fast breeder reactor to breed more Pu based fuel.