OSAKA - Two ships loaded with plutonium and highly enriched uranium from the Japan Atomic Energy Agency’s Fast Critical Assembly reactor arrived Tuesday at the U.S. Department of Energy’s Savannah River Site near Aiken, South Carolina.
The British-flagged Pacific Egret and Pacific Heron were carrying 331 kg of weapon-usable plutonium. About 236 kg, used for nuclear-reactor testing in Japan, originated in the United Kingdom, while around 93 kg is of U.S. origin and 3 kg is of French origin, according to Savannah River Site Watch, a nongovernmental organization tracking the shipment.
The two ships, which are usually used to transport spent nuclear fuel between Japan and Europe for reprocessing, departed the village of Tokai, Ibaraki Prefecture, in March and were originally expected to reach their destination last month.
Their impending arrival had been the subject of heated debate in South Carolina, with that state’s governor, Nikki Haley, in March demanding in a letter to Energy Secretary Ernest Moniz that the shipment be turned back or sent elsewhere.
In April, the U.S. National Nuclear Security Administration announced that the plutonium, already en route from Japan, will be disposed of at a nuclear waste repository in New Mexico after being processed at the Savannah River Site facility.
Savannah River Site Watch Director Tom Clements said in a statement Tuesday that the arrival of the ships appeared to have been delayed for security reasons.
“The removal of the material from Japan represents a significant accomplishment in our broader global nuclear security efforts to secure highly enriched uranium and plutonium worldwide,” Lt. Gen. Frank G. Klotz, Under Secretary for Nuclear Security and a National Nuclear Security Administration official, said in a statement after the ships had arrived.
“Japan has been one of the United States’ staunchest allies in the global effort to minimize and, when possible, eliminate the use of sensitive nuclear materials at research facilities.”
The plutonium material will first be prepared for disposition at the Savannah River Site and will sent for eventual disposal to a facility near Carlsbad, New Mexico.
The highly enriched uranium from Japan will be sent to separate storage facilities in Oak Ridge, Tennessee, and will be turned into low enriched uranium.
The nuclear material has been returned to the U.S. under a deal struck between Prime Minister Shinzo Abe and U.S. President Barack Obama in 2014, and reaffirmed at the 2016 Nuclear Security Summit.
At the beginning of 2015, Japan’s total stockpile of plutonium generated by its nuclear power plants was estimated at about 47.8 tons, of which about 10.8 tons was in Japan.
The rest was stored in France and the United Kingdom, where it had been sent for reprocessing.
Disposing of plutonium and highly enriched uranium remains one of Japan’s greatest challenges as the government and power companies seek to restart idled nuclear power plants.
Currently, only two reactors, Kyushu Electric Power Co.’s Sendai No. 1 and 2 reactors, are generating electricity. The remaining 43 commercial-use reactors are offline in the wake of the Fukushima crisis.
Estimates show that even if more restarts take place, the spent fuel pools at most reactors will be filled to capacity within about a dozen years.
However, for some, this could be in as little as six years.
Questions also remain over what should happen to the spent nuclear fuel currently sitting in the U.K. and France if it is not returned to Japan.