VIENNA—Iran and the U.N. nuclear watchdog on Saturday agreed to a three-month process that the watchdog hopes will resolve the long-stalled issue of Iran obfuscating its independent safeguard probes, after uranium particles were found several years ago at apparently old but undeclared sites in the country. The issue is seen as one of the obstacles to any potential revival of the Iran nuclear deal, which limits Iran’s uranium enrichment because the byproducts can be used to make the core of a nuclear bomb. The prospects of securing a deal is currently in question as any agreement will soon be redundant. Observers estimate that based on Iran’s known nuclear activities, the country will soon have enough material to fuel a nuclear bomb if the ruling regime decides it wants one. Meanwhile in parallel to the International Atomic Energy Agency’s investigations, 11 months after indirect talks between Iran and the United States on salvaging …