Top Russian and US nuclear officials are to discuss changes to a deal regulating the recovery of uranium from dismantled Soviet nuclear weapons.
Many Soviet nuclear weapons have been decommissioned
The two countries signed agreements in 1993 and 1994 giving US firm Usec the exclusive right to sell uranium recovered from Russian warheads.
The uranium has been converted into a type that can be used for civilian purposes.
Russia now says it wants to be paid more for the uranium.
Moreover, some Russian officials have controversially demanded the right to sell nuclear fuel directly to customers.
The head of Russia's atomic energy agency, Sergei Kiriyenko, will hold talks with a number of top US nuclear officials on Monday.
He says he wants the US to lift what Russia considers to be discriminatory restrictions on exports of Russian uranium products to US customers.
The two countries have still not signed an inter-governmental treaty on cooperation in civilian nuclear technology.
And Russia says this is hindering progress in modernising agreements signed shortly after the fall of Communism.
In particular, Russian officials complain about the continuation of restrictions on deliveries of their nuclear products to the US.
They are a lucrative export, reportedly valued at half a billion dollars a year.
Under the existing programme - known as Megatons and Megawatts - Russia reprocesses highly-enriched uranium from nuclear weapons decommissioned under disarmament treaties into a form that can be used as fuel for US nuclear power stations.
Nearly 11,000 Soviet-era nuclear warheads have been reprocessed this way.
But Russia increasingly resents the obligation to sell the fuel through Usec - the United States Enrichment Corporation - which is the official agent of the American government.
The Russian government says Usec's pricing policies are designed to protect its commercial interests, rather than Russia's potential earnings.
Uranium prices have tripled over recent years, but this is not reflected in the price Usec pays for Russian imports.
Russian officials have suggested Mr Kiriyenko will lobby the heads of US nuclear corporations to try to bolster Moscow's arguments in favour of scrapping Usec's intermediary role altogether.