[philipkglass]

"Liquid solution centrifugation for safe, scalable, and efficient isotope separation"

https://www.science.org/doi/10.1126/sciadv.adg8993

The authors show that a biological type laboratory ultracentrifuge can efficiently function as a near-universal isotope separator. Any element that can be dissolved as a salt in water -- the entire periodic table, excepting the noble gases -- can be enriched according to its relative mass. This can reduce the cost of refining certain isotopes like calcium-48 by orders of magnitude compared to the previous best techniques.

Left unsaid, but implied by its universality: the new technique is also a new approach to producing enriched fissile materials for nuclear reactors and weapons. It requires less chemical engineering sophistication than current processes which require production and handling of gaseous uranium hexafluoride.

[NoMoreNicksLeft]

Surely something about the technique would make it impractical for enriching uranium though... you're not going to be able to produce kilograms of 20% U235 with this are you?

[philipkglass]

Not with off-the-shelf biological centrifuges, no. I don't know enough about centrifuge design to judge how easy/hard it is to build a 60,000 G centrifuge that can handle liters instead of milliliters of liquid per cavity.

The other even more exotic possibility is to use something like this to enrich ordinary reactor grade plutonium to weapons grade plutonium-239. The amount of mass to process with plutonium is orders of magnitude less because spent fuel plutonium is already more than 50% Pu-239, versus 0.7% U-235 in natural uranium, and a bare sphere critical mass of Pu-239 is only 10 kg vs 52 kg for U-235:

https://en.wikipedia.org/wiki/Critical_mass#Critical_mass_of...

The United States considered enriching waste fuel plutonium to weapons grade in the 1980s, when it contemplated another big nuclear weapons buildup against the USSR, but the laser based separation technology to be used was much more complicated than centrifuge separation. The project ended shortly after the USSR dissolved. It was called the Special Isotope Separation Project.

The 1988 environmental impact statement for the project gives some background information:

https://www.energy.gov/sites/prod/files/2015/06/f24/EIS-0136...

[kaba0]

Could someone knowledgeable describe the differences between this new method and “traditional” enrichment of nuclear isotopes? If I’m not mistaken the latter also uses very high RPM rotation, and I believe I have read that the hardest part around managing it is the needed precision/balance of rotating something heavy at such high speed — a tiny imbalance can cause a wobble and make the whole thing break.

What changes?

[nukeman]

Hypothetically, if the technique can enrich U, Pu, or other fissile isotopes in decent quantities, you run into other issues. Stirring an aqueous enriched uranium solution is a great way to have a criticality accident (cf. https://en.wikipedia.org/wiki/Criticality_accident). That’s not to say it’s impossible to manage, just difficult. UF6, the current compound of choice for enrichment, is in the gas phase during the process.

[Iwan-Zotow]

yeah, especially if water ends up enriched in deuterium as well