The chief of the UN nuclear agency will visit Japan next week to meet with Japanese leaders and see final preparations for the release of treated radioactive wastewater from the damaged Fukushima nuclear plant into the Pacific Ocean, officials said Friday. Japan's government hopes the visit by International Atomic Energy Agency head Rafael Mariano Grossi will add credibility to the discharge plan. It has been strongly opposed by local fishing groups and by neighbouring South Korea, China and some Pacific Island nations over safety concerns.