Under the terms of the nuclear-cooperation agreement between the US and Japan, a transportation plan for any shipment containing plutonium is subject to U.S. approval, when the fissile material was extracted from nuclear fuel originally supplied by the U.S. for use in Japan's power reactors. In 1992, the United States required Japan to use a gunboat to escort a shipment of plutonium from France to Japan, in a ship called the Akatsuki-Maru. Japan is pressing the U.S. not to require an armed-escort vessel for this coming shipment by arguing that the same stringent physical protection standards need not apply, because the plutonium has been converted into MOX fuel.
Plutonium is a key ingredient of nuclear weapons.
There is ample evidence that reactor-grade plutonium can be used to fabricate nuclear weapons. Less than eight kilograms is enough to construct a bomb. The plutonium in fresh MOX fuel can be separated from the uranium by straightforward chemical means. The UK, France, Japan and the US should move immediately to end the proposed trade in plutonium under the guise of MOX, and instead concentrate their efforts on ensuring that the UN talks are a success in the interest of both current and future generations. The transport ships are also expected to collect Mox fuel from the French reprocessing plant at La Hague.