The following text is an excerpt of a recent New York Times article.

Next week President Obama will join 57 world leaders in The Hague for the third biannual Nuclear Security Summit. The first two summits played a critical role in phasing out the use of highly enriched uranium as fuel in research reactors to prevent its misuse by states or terrorists to make nuclear weapons.
But the previous conclaves have failed to address the single largest use of such fuel: in nuclear-powered submarines and aircraft carriers. At this summit, world powers must take an important first step toward ending that dangerous and unnecessary practice.
Naval use of H.E.U. also opens the door for other countries to demand the same right. In Iran, the last administration, and more recently 100 members of Parliament, have called for nuclear-powered submarines fueled by H.E.U., which would give it an excuse to produce and possess weapons-usable