Japan will load weapons-grade plutonium onto a ship as early as this weekend to send to the United States, in what will be largest such shipment of the highly dangerous material since 1992, Greenpeace said on Friday.
The shipment of 331 kilograms of plutonium, enough to make about 50 nuclear weapons, will be loaded in Tokai Mura northeast of Tokyo onto the Pacific Egret, an armed British ship, and transported to the U.S. Department of Energy’s Savannah River Site in South Carolina, the environmental group said.
Shipments of plutonium are highly sensitive because the material can be used in advanced nuclear weapons or as a so-called dirty bomb. In Japan, public sensitivity is also high because the country is the only nation to be bombed with nuclear weapons.
The U.S. embassy in Tokyo declined to comment.
The shipment is a tiny portion of the nearly 50 tonnes of plutonium Japan holds. Most of Japan’s plutonium comes reprocessing spent nuclear fuel burned in the country’s reactors. All but two of Japan’s reactors have been shut down since the Fukushima nuclear disaster of 2011.
The plutonium being shipped this weekend was supplied by the United States, the United Kingdom, and France for the Japan Atomic Energy Agency’s Fast Critical Assembly project in Tokai Mura, according to the International Panel on Fissile Materials.
The agreement to transfer the material to the United States was reached in March 2014, according to the panel’s website.
A spokesman at the Japanese atomic agency declined to comment, citing security reasons.