An earthquake with a preliminary magnitude of 6.9 struck deep under the seabed off the coast of Japan south of Tokyo yesterday, the Japan Meteorological Agency said.
The quake's epicentre was near the Ogasawara islands south of the capital, the agency said, adding that a tsunami warning had not been issued. The quake's preliminary depth was put at 480km below the seabed.
There were no immediate reports of damage. Earthquakes are common in Japan, one of the world's most seismically active areas, and a magnitude 8.5 quake struck the area around the chain of islands that run south from Tokyo last month. There were no reports of casualties or serious injuries.
Japan accounts for about 20pc of the world's earthquakes of magnitude 6 or greater, which has made the country's extensive nuclear power infrastructure hugely problematic.
On March 11, 2011, the northeast coast was struck by a magnitude 9 earthquake, the strongest quake in Japan on record, and a massive tsunami. Those events triggered the world's worst nuclear crisis since Chernobyl a quarter of a century earlier.
With the country is still dealing with the huge clean up after Fukushima and debating its future use of atomic energy, Japan now faces another nuclear conundrum - what to do with 16 tonnes of its plutonium sitting in France after being reprocessed there.
With its reactor fleet shut down in the wake of Fukushima, Japan is unable to take fuel made from the plutonium at the moment and could be forced to find other countries to use it.
The matter has taken on greater urgency as Areva, the French nuclear company that owns the La Hague reprocessing facility holding the plutonium in western Normandy, faces billions of dollars of losses.
"In this whole mess (at Areva) we have a huge amount of Japanese plutonium," said Mycle Schneider, an independent energy consultant, adding Japan would need to resolve the problem sooner rather than later.
An Areva spokesman said the company had long-standing contracts with Japanese utilities to take nuclear fuel made from the plutonium.
Schneider said leaving it in France would be one option, but that the cost would likely be high.
"Giving its plutonium away and paying for it would expose the Japanese to the reality of plutonium as a liability rather than an asset," said Schneider.
A precedent for that kind of deal could be set in Britain, where the government has offered to take ownership of 20 tonnes of Japanese plutonium stored at the Sellafield processing plant.
"This is a kind of win-win deal," Tatsujiro Suzuki, a former vice chairman of the Japan Atomic Energy Commission, told Reuters, before he made a presentation on spent fuel at the same meeting as Von Hippel on Thursday.
"The British side would make money and the Japanese would lose less," said Suzuki. (Reuters)