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Budget cuts and environmental concerns put UK depleted uranium upgrade out of the picture

Military periodical Jane’s International Defence Review has reported that the UK is unlikely to replace or upgrade its depleted uranium ammunition in the foreseeable future.
18 January 2011 - ICBUW

During discussion of an upgrade of the new 120mm L23 tank round, Jane’s reports that the controversial status of DU, and cuts to the UK’s defence budget, are limiting the UK’s options for upgrading its L27 ammunition (also known as CHARM 3), which contains a DU penetrator.

Computer generated schematic of proposed L23A2 round.
Computer generated image of the latest version of the L23

The latest version of the L23 round (designated the L23A2) is at the design stage, and a decision on the penetrator material is expected in the next few months. The L23 is being developed primarily as an export round for use by Oman. The tungsten alloy that was originally under consideration for the L23 is said “like DU, to potentially have unlooked-for side-effects”, so alternative alloys of tungsten are being considered.

Concerns over tungsten-nickel-cobalt alloys stem from a 2005 study, which found that embedded pellets of the alloy triggered aggressive cancers in rats. However data on the toxicity of tungsten heavy alloys is limited and further research is needed. What is significant is that concerns over the toxicity of penetrator materials – euphemistically termed environmental effects have become a significant issue and that perhaps lessons have been learned from DU.

Environmental effects
Environmental effects appears to be the preferred term used by the arms industry when discussing the effects of DU and it has been given as a reason for discontinuing the use of DU as a penetrator material. BAE Systems (who are also running the current L23 project) cited environmental reasons when it ceased production of the L27 DU round in the early 2000s, although the real reason was more likely the lack of customers as its export market was limited by political and strategic factors. Similarly, when ICBUW discovered that the US was moving away from DU as a penetrator material in medium calibre ammunition, environmental reasons were cited as one of the factors in that decision. It is a straightforward matter that DU introduced into the environment is an environmental contaminant. As such, citing environmental reasons allows those in the weapons industry an uncontroversial reason not to use DU, without making any concessions on the question of whether DU is harmful to human health.

This is not to diminish the environmental effects of DU contamination. The considerable costs and effort involved in the comprehensive decontamination of sites in the Balkans are documented in the 2010 ICBUW report A Question of Responsibility. Similarly, it is known that environmental clean-up of the range used to test the 25mm M919 round used in the M2 Bradley Fighting Vehicle cost US$2 million.

Naturally, ICBUW welcomes any developments that highlight the irresponsibility of using a material like DU in weapons. These latest developments serve to further de-legitimise its use, and that is all to the good. However, it would be foolish to expect a company like BAE Systems, with its history of corrupt practices and sales to repressive regimes, to stick to a supposedly ethical position if it became expedient to abandon it. More fundamentally, restricting the debate to questions of environmental damage and economic cost obscures the potential human cost and the ongoing need for proper research on the effects of uranium weapons on civilians.

UK procurement cul de sac
Unlike other large NATO countries, such as the US, France and Germany, the UK’s 120mm tank ammunition fires from a rifled, rather than a smooth barrel, and the round is comprised of a separate charge and projectile, rather than being incorporated into a single assembly. The Challenger tank has not proved appealing to the export market, and only Jordan, Oman and the UK currently field tanks of this type. Jordan was supplied with the UK’s old fleet of Challenger 1 tanks when the UK upgraded to Challenger 2 in the early 1990s, while Oman bought 38 Challenger 2s. Greece considered purchasing the Challenger 2 in the early 2000s, but eventually opted for the German Leopard 2 instead.

Challenger 2 fires outside Basra, Iraq
Challenger 2 tank firing near Basrah, Iraq

The choice of a rifled barrel means that both Challenger tanks are not able to use NATO standard ammunition, and must have bespoke rounds manufactured for them. The UK does not supply Oman or Jordan with the L27 DU round, and the contract with Oman stipulates that their L23 stockpile must be kept up-to-date. As such, the UK is essentially committed to maintaining both L23 and L27 rounds for the lifetime of the Challenger tank, with few customers to share the cost of development and production. When completed, the new L23 rounds are expected to cost around £2,500 each.

Although the L23 is not a DU round, information about the programme and the other 120mm Challenger programmes can tell us a good deal about the future prospects for the UK’s DU ammunition. Firstly, it is clear that the UK prefers to spend money redeveloping "second class" tungsten rounds for Oman and Jordan, rather than exporting the most up-to-date ammunition such as the L27, or the L28 its tungsten-based equivalent. This means that proliferation of uranium weapons from the UK is unlikely while the Challenger 2 remains in service.

Cross section of a UK kinetic energy round As for the UK’s own uranium weapons capability, it is clear that earlier choices in ammunition and tank design have sent development of 120mm armour piercing rounds into a cul-de-sac. The US, periodically re-designs its DU penetrator with an increased length to diameter ratio (thereby increasing its ability to penetrate armour). Because the UK round is made up of a separate penetrator assembly and charge, this is not a possibility for the UK, as there is no space left for the penetrator to expand into (see picture of current L23 round, right).

Short of a major re-design of the Challenger gun, ammunition storage and autoloader, there are few innovations that could improve the penetrating power of the L27 DU round and there are currently no plans to update it. Since BAE Systems finished manufacturing the L27 there have been no facilities in the UK that could manufacture penetrators for an updated round. Jane’s speculates that an updated version of the L28 tungsten round is a more likely possibility, given the controversy over using DU, although it is by no means certain that this would offer greater penetrating power. The alternative would simply be to replace the propellant in the penetrator assembly when it reaches the end of its shelf life at around 2015, and just retain the current penetrator stock. This would almost certainly entail more controversial testing of the re-manufactured stock at the Dundrennan range in Dumfries and Galloway in southern Scotland.

Until recently, it was expected that the existing Challenger fleet would be re-fitted with the German smoothbore L55 gun, which is used on the Leopard 2 tank, and is compatible with both German tungsten and US 120mm DU rounds. This project – entitled the Challenger Lethality Improvement Programme (CLIP) – conducted test firings in 2005 and 2006 with German DM-53 tungsten ammunition, which was apparently better at penetrating armour than the L27 DU round fired from a standard Challenger 2. However budget considerations have now meant the cancellation of the project.

Current cuts in the UK defence budget have meant that the Challenger fleet is being cut by about 40% to around 230 vehicles. While defence is not facing the same extreme cuts as some other branches of government, defence spending is being re-aligned to the kind of warfare being fought in Afghanistan, where heavy armour has not played a major role. It is clear that tank improvements are unlikely to be a procurement priority for the foreseeable future. For the time being it must be expected that Challenger will not see the kind of investment which will be necessary for it to keep pace with the most advanced armour piercing rounds fielded by other major military powers. Whether this will be the case for the remaining lifetime of the Challenger 2, which may remain in service until 2035, remains to be seen.

Diminishing capabilities
This is a striking development as the use of DU, as opposed to alternative materials, is justified by the UK, US and France by what they claim is an overwhelming military need to use the most powerful armour piercing rounds available. This imperative is really a relic of Cold War military doctrine, in which the ability of one tank to destroy another would have been the major determining factor in tank battles which, in turn, could have been decisive in any conflict between superpowers. Fortunately such scenarios are now less likely, and the need for tanks to field the most advanced armour piercing ammunition is less relevant to the kind of wars now being fought by the major military powers. That the UK is content to retain the 11 year-old L27 for the foreseeable future in spite of its diminishing capability, is a tacit admission of that fact.

Although ongoing financial pressures mean that a replacement is unlikely in the near future, these latest developments considerably undermine both the claim that DU is a material uniquely suited to armour piercing, and the whole basis for believing that its penetrating power should outweigh humanitarian and environmental considerations. While this may not have any immediate effect, it will mean that when the time comes to finally replace the L27, the UK will find it extremely hard to justify the development of a new DU round.


Penetrator material decision awaited for new Challenger 2 tank round, International Defence Review, 11-Jan-2011.

Embedded Weapons-Grade Tungsten Alloy Shrapnel Rapidly Induces Metastatic High-Grade Rhabdomysarcomas in F344 Rats.