Some folks are suggesting that we should go easy on Roy Lee Oakley—the inept contract worker attempted to sell sections of a gaseous diffusion barriers to an FBI agent posing as a French embassy employee—on the grounds that gaseous diffusion is “obsolete and [has been] replaced by cheaper and more efficient methods of uranium enrichment.”
Obsolescence is irrelevant from a proliferation stand-point. As one might infer from Iraq’s pre-1991 EMIS program, “obsolete” technologies are still perfectly adequate to make nuclear weapons. Peter Zimmerman nailed this in one of my favorite articles, Proliferation: Bronze Medal Technology is Enough:
To acquire a stockpile of weapons of mass destruction and their delivery missiles, a country does not need to take home the gold medal in the military-technology Olympics. It can strive merely for the bronze medal and obtain an arsenal that can deter its neighbors with the threat of nuclear destruction. Indeed, for a state seeking to acquire nuclear weapons, success with older, tried and proven technologies—whose names can be found in college textbooks, and which are components of commercial products—is preferable to failure in developing the most modern weapons used by the more advanced states. Thus, Iraq’s rediscovery of the electromagnetic isotope separation system (EMIS, or calutrons) as an alternate means of enriching uranium (rather than relying on imported technologies that might have been embargoed) set a precedent that others are likely to follow. The bronze medal earns a developing country a place on the winners’ podium; failure in the pursuit of a high technology does not. (Orbis 38:1, Winter 1994)
In addition to EMIS, Iraq before 1991 also pursued a gaseous diffusion program just as China did to produce fissile material for early Chinese nuclear weapons. GD might not be the preferred route but than again, you can’t always get what you want.
Hell, once you’ve chosen enrichment over plutonium separation, you’re already making big compromises.
Of course, an interesting question is what information a would-be nuclear state would acquire from examining a sample of the classified material.
Given that the composition of the barrier material is the major technological challenge, my guess (and it is a guess) is that the harm might be significant—measured in terms of saving months or more of research—even if the scientists used the barrier for nothing more than confirmation that another method of enrichment (such as EMIS or centrifuges) would be a better investment.