VIENNA—Iran is expanding its enrichment of uranium beyond the highly enriched threshold of 20 percent purity at a Natanz plant where it is already enriching to 60 percent, but the new activity does not involve keeping the product, the U.N nuclear watchdog said on Monday. The move is likely to help Iran refine its knowledge of the enrichment process—something Western powers generally condemn because it is irreversible—but since this time the product is not being collected it will not immediately accelerate Iran’s production of uranium enriched to close to weapons-grade. It has, however, prompted the International Atomic Energy Agency to “increase the frequency and intensity of its safeguards activities” at the above-ground Pilot Fuel Enrichment Plant (PFEP) at Natanz, the IAEA said in a report seen by Reuters. As of around 90 percent uranium is considered weapons-grade. The IAEA said in a statement outlining the report that Iran informed it …