A ship carrying 331kg of weapons-grade plutonium left Tokai in Japan on 22 March for the US Savannah River Site in South Carolina aboard an armed British vessel Pacific Egret, operated by Pacific Nuclear Transport. Pacific Egret is being accompanied by another armed vessel, the Pacific Heron.
The shipment is part of a 2014 agreement between Japan and the USA which was intended to alleviate concerns about Japan's stockpile of 47.8t of plutonium - 10.8t held in Japan and 37t that have been reprocessed in the UK and France and are waiting to be returned. The shipments were also part of the US Department of Energy National Nuclear Security Administration's Global Threat Reduction Initiative programme to recover weapons-usable materials of US and other origins. Japan originally purchased the plutonium from Western countries in the 1970s for use at the Japan Atomic Energy Agency's nuclear research facility at Tokai in Ibaraki Prefecture.
Japan began building a major reprocessing plant at Rokkasho in Aomori Prefecture with assistance from France's Areva in the early 1990s. However, the project has been repeatedly delayed, and in November its opening was postponed for the 23rd time, until 2018, to allow for more safety upgrades and inspections. Japan had planned to burn the plutonium in its Monju fast breeder reactor in Fukui Prefecture, but it has been suspended for more than 20 years, following an accident. Monju is now on the verge of being closed due to poor safety records and ongoing technical problems. Plans to burn uranium-plutonium mixtures as mox fuel in conventional reactors have also been delayed since the Fukushima disaster and the closure of most of Japan's NPPs.