Talk:Enriched uranium

Untitled

I'm making an artical stub for the United States Enrichment Corpoation ( USEC ) that will link here.

Quinobi 20:14, 26 Sep 2004 (UTC)

Dead Link

It appears that the "Uranium enrichment (PDF, 651 KB)" link is dead. Can someone fix or remove this? ~Anon

Confused by the enrichment diagram

(Bringing this to the attention of the image's author, Garzforth) I'm a bit confused by the legend on the Uranium enrichment proportions graphic. For Highly enriched uranium, it presents:

Highly enriched uranium (HEU)
(weapons grade)
20-85% U-235
(≥85% U-235)

I think that the '>=85%' is the saturation for weapons grade, as I don't think 21% would be considered weapons grade, regardless of being classified as highly enriched. So wouldn't that suggest the correct formatting be:

Highly enriched uranium (HEU)
20-85% U-235
(weapons grade)
≥85% U-235

Or something along those lines? I realize I could be completely off in the weeds on this, so apologies if I have my head up my arse. cheers. anastrophe, an editor he is. 20:26, 27 June 2025 (UTC)

I agree, the captions are confusing. Unfortunately they're part of a graphic, which I don't know how to edit without making a new graphic. My suggested fixes:

Highly enriched uranium (HEU)
above 20% U-235
weapon grade
typically above 85% U-235

The description of LEU is similarly confusing and inaccurate. NPguy (talk) 12:12, 29 June 2025 (UTC)

@Anastrophe: The image was a hastily reworked recreation of the original one authored by fastfission to patch over and correct a number of major errors in the original version. I tried to minimize the number of changes while preserving as much of the graphical style (and overall dimensions) of the original as possible. It isn't perfect by any means.

One major weakness is that it does not sufficiently make it clear that it's attempting to describe two different attributes for each range/definition – typical enrichment levels in common use, and all enrichment levels within the strict definition.

For example, LEU is anything below 20% enrichment, but reactor grade LEU is 3–5% enrichment, and when talking about LEU, 99% of the time you are talking about reactor grade LEU.

Similarly, HEU is anything at or above 20% enrichment (customarily ~20–97%), but weapons grade HEU is typically >= 85% enrichment (actually most uses of HEU even beyond weapons are usually in the same range), and when talking about HEU, 99% of the time you are talking about weapons grade HEU (or the equivalent for a non-weapons use).

I suppose it could be reworked to make this more clear. The current version is certainly more confusing than it could be in some ways. It's still a major improvement over the original though. I think part of why I didn't end up making the text captions more verbose was because I couldn't do that without making the image format/size/dimensions diverge overly radically from the original image. Remember, I created this as a drop-in replacement for fastfission's original work, not as a brand-new alternative option. It was a quick and dirty effort in the first place to address the most egregious issues with the original image without changing too much from the original in terms of style, size/dimensions, or format.

I should still have my original files for the current version somewhere. I recall it needed a great deal of special post processing work done to figure out how to get the exported svg file to render text correctly within Wikipedia due to problems with Wikipedia's svg rendering engine. I also had to recreate the entire original image from scratch, which was a non-trivial exercise. Figuring out how to rework it without overly changing it was also problematic.

If you have suggestions on how to modify the existing version to improve its clarity without requiring major changes in image dimensions/format, I'm willing to consider them. Perhaps inserting "typically" on the HEU entry? Rearranging the ordering of lines (pretty sure I had done this originally but rejected using it for the final version because of some problem)? Something else?

Please let me know. Hope this helps answer your questions and clarify things. Garzfoth (talk) 11:45, 1 July 2025 (UTC)

Thanks very much for the clear description/explanation of what's at work here, @Garzfoth:. As it stands, the text of the article does a reasonably good job of describing these various grades in the necessary detail. While the graphic does have the shortcomings described, they're hardly catastrophic, so I'm not sure it's worth the effort to rework them - and I'm reluctant to just drop the labor in someone else's lap (I've zero skills in that domain). So, unless you've got gobs of time to revisit the graphic (and the desire to do so), I think the article will survive with it as is. And thanks for your previous efforts in improving it from where it started. cheers. anastrophe, an editor he is. 18:01, 1 July 2025 (UTC)

Let me be specific about the proposed text edits to the captions. Hopefully these are relatively simple. The first line is the term, the second is the definition, the third gives typical values. It's the intertwining of the parentheticals that makes it hard to read.

• For natural uranium, no change
• For LEU, mostly rearrange to read
  • Low-Enriched Uranium (LEU)
  • <20% U-235
  • reactor grade typically 3-5%
• For HEU similarly
  • Highly enriched uranium (HEU)
  • ≥20% U-235
  • weapon grade typically ≥90%
    

Note that 90% is a more common threshold for weapon-grade. The citations don't support for the figure 85% in the text of the article, so I propose changing that to 90% as well. NPguy (talk) 20:21, 1 July 2025 (UTC)

I agree with the above improvements. For the short term/easier fix than changing the captions WITHIN the graphic, we could add to the current caption a clarification like "HEU is >20%, and weapon-grade is >90%". ---Avatar317^(talk) 20:49, 3 July 2025 (UTC)

HALEU

"low enrichment" is defined but "high-assay" is not. A knowledgeable person (which I am not) ought to provide a definition for the other half of this acronym. Drcampbell (talk) 14:26, 18 January 2026 (UTC)

The article says "High-assay LEU (HALEU) is enriched between 5% and 20%." NPguy (talk) 20:16, 19 January 2026 (UTC)

I also don't get why they call it this, when a more clear name would be "medium enriched". I think "high assay" simply means "high concentration" or "high purity" but I really don't know why they use that term. ---Avatar317^(talk) 01:50, 20 January 2026 (UTC)

An "assay" is something commonly done for material to determine if it is suitable for use in a process or to build something. It is used to describe the purity of ore or the composition of a metal alloy, for example. The enrichment level is a form of assay in that sense. For international cooperation and safeguards, the terms HEU and LEU have longstanding definitions that are used in many legal documents. No one wants to tinker with those by adding MEU into the mix. HALEU is a way of making a distinction without creating a new category. NPguy (talk) 21:07, 20 January 2026 (UTC)