David Cameron is to announce plans for the largest ever shipment of nuclear waste from the UK to the United States.
In return, the US will send highly enriched uranium to Europe where it will be used to help diagnose cancer.
The prime minister will make the announcement in Washington at a summit on civil nuclear security.
The BBC’s James Landale said the PM’s aim was to show that it is possible to think differently about how to dispose of nuclear waste.
One British official, he added, described the agreement as a landmark win-win deal.
Mr Cameron will tell world leaders in Washington that Britain will transport 700 kilograms of highly enriched uranium to the US.
Officials said this would be the largest ever such movement of nuclear waste, which the US has more capacity to store and process.
In return, a different form of used uranium will be transported from America to the European Atomic Energy agency (Euratom) where it will be turned into radio isotopes that are used to detect and diagnose cancer.
At the fourth Nuclear Security summit, to be chaired by US President Barack Obama, Mr Cameron will also announce Britain and the US are to hold a joint exercise to test both countries’ ability to prevent cyber attacks on their nuclear stations and waste facilities.
The prime minister will offer British expertise to countries like Japan, Turkey, South Korea and Argentina which have all asked for advice on how best to protect their own nuclear plants.
And he will commit £10m to be spent on civil nuclear security world wide.
During the biennial summit, first held in 2010, heads of government will also consider their response to the nightmare scenario of terrorists creating and using a dirty bomb.