London, Sept. 26: A British company claims to have found the ?holy grail? of the nuclear energy industry ? a solution to the problem of radioactive waste disposal.

Amec, the London company that cleaned up Ground Zero in New York and rebuilt the Pentagon after the September 11 attacks, says that its latest process will enable nuclear waste to be stored safely for 200,000 years ? longer than the radioactivity will last.

The company says that the method could transform the nuclear energy industry and offer a viable alternative to fossil fuels.

The technique, called geomelting, has been tested successfully by the American government, which is building a $53-million pilot plant in Washington state. It intends to use the method on 300,000 gallons of liquid waste from atom bomb tests in the 1940s.

Amec has already held talks with British Nuclear Fuels, the nuclear energy company that owns the reprocessing plant at Sellafield in Cumbria and employs 23,000 people in 16 countries. It plans to send a team to America to look at Amec?s site in the next few months.

The department of trade and industry will also study the process. Earlier this month an official said that a huge expansion of the nuclear power industry ? including the construction of 45 new reactors ? was essential if the British government were to meet its Kyoto target of cutting ?greenhouse gases?.

The Amec process involves mixing nuclear waste with soil or other ?glass-formers? in large, lined metal tanks. The mix ? 20 per cent waste and 80 per cent soil ? is heated through two graphite electrodes at temperatures of up to 3,000 degrees centigrade. Gases, mostly carbon dioxide and traces of hydrocarbons, are drawn off and treated separately. The molten substance is then allowed to cool and forms a large glass block that is harder than concrete.

The process, known as vitrification, was devised by the Battelle research institute in Ohio, which also invented the photocopier and the compact disc.

Amec said that its method produced a higher quality and longer-lasting glass than British Nuclear Fuel?s at three-quarters of the cost.