Senior Fellow  John R.  Bolton

Your report, "Iran moves ahead with nuclear programme" (May 24), contained the following sentence: "Iran has also declared that it has enriched uranium to a level of 4.8 percent--enough to serve as nuclear fuel, but far short of the levels of about 90 percent needed for atomic weapons."

The plain implication of the sentence is that Iran has a long way to go before it creates the highly enriched uranium (HEU) it needs for weapons purposes--all the way from roughly 5 percent (low enriched uranium or LEU) to HEU's 90 percent.

This implication is false. Enriching a given quantity of natural uranium by centrifuges to LEU levels of the U235 isotope in fact consumes approximately 70 percent of the work and time required to reach HEU concentrations of the isotope. Thus, Iran is not "far short" of HEU levels; it is more than two-thirds of the way there for each kilogram of uranium feedstock it enriches. Your readers should not be misled on this point.

John R. Bolton is a senior fellow at AEI.