A high-level U.S. envoy on Wednesday said Japan's plutonium stockpile poses no concern to the United States, Reuters reports.
"We are not at all concerned that [Japan's] plutonium is either being handled improperly or that there isn't a plan for disposition," said Ambassador Joseph Macmanus, Washington's chief delegate to the International Atomic Energy Agency in Vienna.
The diplomat issued the comment after China said it was "extremely concerned" by a recent media finding that Japan had for decades possessed over 660 pounds of U.S.-origin plutonium, much of which was suited for use as nuclear-bomb fuel. Tokyo reportedly agreed to the material's repatriation after trying for years to retain it in support of domestic scientific research.
In addition to the U.S.-supplied material -- reportedly sufficient to power 50 nuclear bombs -- Japan informed the U.N. nuclear watchdog that it had accumulated 175 tons of plutonium in used atomic waste as of the end of December.
The U.S. diplomat said Washington's political and energy cooperation with Tokyo has placed significant focus on "plutonium and the disposition of plutonium stocks."
"We are satisfied that Japan understands what the conditions are for the use and the maintenance of those stocks and we are not concerned," Macmanus stated.
IAEA Director General Yukiya Amano this week said Japan's plutonium is not at risk of being tapped for use in nuclear arms.