VIENNA - An explosion on Monday atJapan's disaster-hit nuclear plant may have damaged the primary
containment vessel of one reactor unit, the Vienna-based UNnuclear watchdog said.The International Atomic Energy Agency said the explosion atthe Fukushima Daiichi unit 2 "may have affected the integrity ofits primary containment vessel."The IAEA said primary containment vessels of units 1 and 3appeared intact despite explosions there. It said units at theFukushima Daini, Onagawa, and Tokai nuclear power plants were ina safe and stable condition.