It’s been fifteen years since I last wrote a blog post in this series about separative work, and although none of the underlying physics have changed, a few things in the market have changed. The most notable of these is the increase in interest around uranium enriched to about 20 percent, which is a legal delimiter between two classes of security associated with enriched uranium. If you’re below 20 percent enriched, your material is considered “Category II” by the IAEA and if you at 20 percent enriched or above, you’re considered “Category I” by the IAEA, along with plutonium and uranium-233, which are also considered Category I materials.

This “enriched-but-not-highly-enriched” uranium is now broadly referred to as “HALEU”, for “high-assay, low-enrichment uranium” and the interest around it since 2015 has been positively meteoric.