The United Nations nuclear safety agency on Friday welcomed Japan's announcement that it had successfully stabilized the reactors at the Fukushima Daiichi nuclear power plant that was damaged earlier this year and that the release of radioactive materials is under control. A massive earthquake and tsunami on March 11 knocked out water cooling systems at the plant, contaminating air, water, plants and animals with radioactive plumes dozens of kilometers from the site, and threatening a total meltdown of the fuel rods in the worst civilian nuclear crisis since the deadly Chernobyl power plant explosion in the former Soviet Union 25 years ago. Japan said Friday that the reactors have achieved a “cold shutdown condition,” according to a statement issued by the Director General of the International Atomic Energy Agency (IAEA), Yukiya Amano.