The military uses of DU

As concern grows over the effects on Nato peacekeepers of using depleted uranium (DU) ammunition, BBC News Online's Tarik Kafala considers the military applications of DU.

The main military use of DU is in penetrating armour.

It is a very heavy substance, 1.7 times denser than lead, and has substantial performance advantages over other materials used for the same purposes.

DU use

Balkans operations 99: US Air Force A-10 Thunderbolt II aircraft fired over 31,000 rounds of DU ammunition from their 30mm cannon

Gulf War 91: British military fired 88 DU rounds. Allied forces fired approximately 320 tonnes of DU

When munitions made with DU strike a solid object, like the side of a tank, the round penetrates the armour and metal fragments from it scatter inside the vehicle causing injury, damage and secondary fires.

On impact up to 70% of the round can be aerosolised (turned into a vapour), and particles containing DU oxides are likely to contaminate the surrounding area.

The high temperature fragments created as DU passes through armour can spread to strike everything inside a tank and set fire to its fuel and ammunition.

Defensive use

DU's density and physical properties make it ideal for use as armour plate.

Countries with DU munitions or armour

USA, United Kingdom, France, Russia, Ukraine, Turkey, Israel, Pakistan, China, Saudi Arabia, and Greece

This kind of armour is a big advance. During the 1991 Desert Storm campaign, for example, the armour on US M1A1 Abrams tanks received a number of direct hits from Iraqi shells which did not penetrate.

The combination of DU armour and DU munitions was a key element in improving survivability and giving the US-led coalition the edge.

The high density of DU also makes it useful as a counter-balance for large commercial aircraft, including the Boeing 747, and in yacht keels.

DU is a by-product of the enrichment of natural uranium, either for weapons-making or for reactor fuel.

Alternatives

Britain, France, Russia and the US are the main users DU munitions.

The great majority of armies use tungsten alloys for the same purpose.

The US Department of Defence has argued that DU is the most effective material for piercing armour, because of its high density and the metallic properties that allow it to "self-sharpen" as it penetrates armour.

In contrast, US military officials say, anti-tank munitions made from other materials tend to mushroom and become blunt as they penetrate.

The alternatives to DU do have a 20% lower penetrative performance, and are more expensive.

Tungsten emits no radiation, but, its particles are poisonous.