PARIS (AFP) – France and Britain will sign Tuesday a treaty that will see the two countries test the safety of their nuclear arsenals in a joint facility in France, the French presidency announced.

A nuclear simulation centre will be built at Valduc in eastern France, about 45 kilometres (30 miles) northwest of the city of Dijon, and start operating from 2014, the presidency said.

It will enable French and British scientists to model the performances of nuclear materials to ensure the "viability, safety and security in the long term of our nuclear arsenals," it said.

British Prime Minister David Cameron and French President Nicolas Sarkozy will sign agreements in London Tuesday for unprecedented defence cooperation that will also include the creation of a joint military force and sharing of aircraft carriers.

The Valduc laboratory will work with a French-British research centre based in Aldermaston in southern England, the French presidency said.

Together the facilities would involve "several dozen" French and British experts and cost both countries several million euros, it said.

The cooperation, described as unprecedented, would be conducted "in total respect of the independence of deterrent powers of the two countries," it said.

A British official said the joint facilities "will combine our scientific and engineering talent, and maximise the mutual economic benefit" while also promising considerable savings as expensive equipment would be shared.

It did not mean however that the countries would share their nuclear secrets, in part because the British and French have different warheads, the official sid.

"We will maintain our independent nuclear deterrent, there won't be dual keys on nukes. This is about experimentation and ensuring the safety and security of our capabilities," the official said.