The Prime Minister Gordon Brown will talk to his Japanese counterpart, Yasuo Fukuda, at the G8 meeting in Hokkaido next month about a potential £1bn a year deal which would boost the UK's nuclear industry.
Mr Brown and Mr Fukuda will discuss a contract to reprocess fuel at Sellafield in Cumbria to be used in Japan's nuclear reactors, industry sources said.
The deal would provide a welcome new source of revenue for the cash-strapped Treasury and would revive the UK's declining reprocessing industry.
But it would ignite anger among environmentalists alarmed at the potential for nuclear leaks.
If Mr Brown and Mr Fukuda manage to strike a deal, it would end an embarrassing period in relations between Britain and Japan.
A scandal erupted in 1999 when it emerged that Japan, which used to have fuel reprocessed at Sellafield, had been misled.
Sellafield's operator, state-owned British Nuclear Fuels, disclosed that some workers had falsified quality control documents related to a delivery.
The BNFL chief executive at the time, John Taylor, resigned shortly after the UK nuclear safety agency released a critical report.
Since then, Japan has had a contract with France's nuclear giant Areva for reprocessed fuel. But Japan wants to establish a second supplier to strike a better price.
Officials from Japan's trade ministry and several nuclear utilities will visit Sellafield in July.