Eliminating plutonium stockpiles

LONDON: The vast stockpiles of weapons-grade plutonium building up from the dismantlement of tens of thousands of nuclear weapons are one of the most difficult legacies of the Cold War. Few efforts could be more central to international security than ensuring that this material does not fall into the wrong hands, and that it is never returned to the arsenals from whence it came.

On Jan. 14, 1997, the U.S. announced some initial proposals for achieving these objectives with its own excess plutonium. A plan for taking similar measures in Russia needs to be urgently worked out to guarantee that Moscow moves in parallel with Washington to complete this essential disarmament task.

Unlike highly-enriched uranium (HEU), plutonium cannot be transformed into proliferation-resistant fuel. The U.S. and Russia agreed in August 1992 that Washington would buy 500 tonnes of HEU from Russian weapons, blended to proliferation-resistant, low-enriched reactor fuel over the next 20 years and that the U.S. would blend down its own excess HEU stockpile in a similar way.

In contrast to HEU, nearly all plutonium isotopes can be used to make nuclear explosives. Blending the plutonium with other isotopes, therefore, does not solve the proliferation problem. While the plutonium produced as a by-product in commercial reactors is often referred to as 'reactor-grade' rather than 'weapons-grade', bombs can be made from 'reactor-grade' material as well. Plutonium oxide can be blended with uranium oxide to make mixed-oxide (MOX) fuel - as used in civilian reactors in Belgium, France, Germany, Japan and Switzerland - but weapons- usable plutonium can be separated back out of the MOX fuel by simple chemical steps using readily available technology.

For the foreseeable future, plutonium poses no prospect of profit, except perhaps on a nuclear black market. Making fuel from plutonium is more expensive than buying uranium fuel on the open market, even if the plutonium is 'free'. This is because plutonium's toxicity requires stringent safety precautions, and its proliferation potential requires extensive safeguards.

This profitability issue is at the center of a long-running debate. The U.S. argues that it will be decades, if ever, before uranium becomes expensive enough to give plutonium a market value that outweighs its proliferation risk. This view is not shared by Russia, Japan and West European countries, who argue that plutonium recycling will soon be profitable, and that the proliferation issues can be, and are being, addressed through effective safeguards.

The first step towards better control is to determine how much excess plutonium there is, and ensure it is secure and not being used for new bombs. The U.S. has declared that over 225 tonnes of fissile material -- including more than 52 tonnes of plutonium, around half the total U.S. stockpile -- is excess to its military requirements, and that this material will never again be used in nuclear weapons.

Washington intends to put its excess material under International Atomic Energy Agency (IAEA) monitoring structures in order to verify that commitment. This approach was strongly endorsed at the Nuclear Safety and Security Summit in Moscow in April 1996. Implementing the process has been slow, however, with only about 12 tonnes of material (of which only two are plutonium) under safeguards so far.

Moscow has indicated that it also expects to have a substantial excess stockpile. Its total stockpile of separated plutonium is considerably greater than that of the U.S., but it has not yet made a specific declaration or given international inspectors access to any of it. At the Moscow summit, Russian President Boris Yeltsin endorsed placing excess materials under international monitoring, and offered inspectors access to the storage facility being built with U.S. assistance at Mayak in Russia. However, the secrecy-bound nuclear bureaucracy and the KGB's successors remain powerful sources of resistance. Nevertheless, in September 1996, the U.S., Russia and the IAEA established a trilateral forum to decide how to proceed on the issue.

There are no easy or cheap solutions to the problem of excess weapons-grade plutonium stockpiles. Despite safeguard arrangements, simply placing this material in storage leaves it far too vulnerable to theft in the event of a security breakdown, or to reincorporation into a massive nuclear arsenal after a political change. Hence, it was agreed at the Moscow summit that this material should be transformed into spent nuclear fuel or other forms 'equally unusable in nuclear weapons' as soon as practicable. The question is: how is this to be done?

In January 1997, the U.S. confirmed that it plans to pursue a dual-track approach to dispose of its own excess weapons-grade plutonium. It intends to move forward as quickly as practicable with both the option of converting some to MOX fuel in currently operating commercial reactors, and immobilizing some of it with highly radioactive fission products for disposal as waste. The most promising immobilization approach appears to be the process known as 'vitrification'. This is being used to dispose of liquid high-level radioactive wastes, which are mixed with molten glass and then cooled in enormous canisters to stabilize them for disposal. If incorporated into these canisters, the plutonium would be almost as difficult to recover and make weapons from as plutonium in spent fuel.

After several years of study, the U.S. concluded that the two approaches were roughly comparable in cost, timing, environmental impact and non-proliferation and arms-reduction benefits. Washington expects the total program to use or dispose of more than 50 tonnes of excess plutonium to take between 25 and 30 years, with a net discounted present cost of over US$1 billion.

The U.S. has been at pains to clarify that its willingness to contemplate using reactors to dispose of weapons-grade plutonium did not represent any change in its long-standing policy against civilian reprocessing and recycling of plutonium. This is despite claims to the contrary from both critics and advocates of plutonium recycling.

Washington has long held that the fuel cycles being pursued in Europe and Japan, which involve the routine processing and shipment of many tonnes of weapons-grade plutonium, have significant proliferation risks. The plutonium is already separated and posing dangers to international security. Consequently, the U.S. argues that it is planning to use both available options to get rid of its stockpile as quickly and reliably as it can. U.S. officials have made clear that MOX facilities built for this purpose in the U.S. will be licensed and used only for this excess plutonium. Furthermore, they will be dismantled once that mission is complete, and the resulting spent fuel will not be reprocessed.

In contrast, Russia's nuclear establishment strongly favors using both civilian and excess weapons-grade plutonium as reactor fuel. Moscow, however, must deal with the daunting challenges of dismantlement and disposal in the midst of continuing political, social and economic turmoil. Realistically, tackling the problem of Russia's excess plutonium is unlikely to happen soon unless the international community helps finance the effort. However, U.S. plutonium will not be eliminated while Russia's plutonium remains in a directly weapons-usable form. Financing the disposal of Russia's plutonium is thus fundamental to the entire enterprise.

Russia's Ministry of Atomic Energy would like to take advantage of international concern to acquire financial aid for a new generation of plutonium-burning reactors. However, the many billions of dollars needed to fund this are not likely to be forthcoming, given continued disagreements over the commercial value of plutonium and uranium fuels. Using existing reactors could significantly reduce initial capital investment to hundreds of millions (rather than billions) of dollars, and avoid unnecessary delays. Reactors in both Russia and Ukraine could potentially be used. A senior group of U.S. and Russian scientists -- set up to advise the White House and the Kremlin -- recommended that Russia also pursue both the MOX and the vitrification options on parallel tracks.

France, Germany and Russia have proposed establishing pilot plants to convert weapons components to oxide and fabricate MOX fuel. The U.S. has indicated that it could support this trilateral initiative if appropriate non-proliferation conditions are met. The U.S. wants stringent security and accounting measures in place to ensure against theft, and international safeguards over the entire conversion and fabrication process. Washington argues that any MOX plant built with international financing should be used only for weapons-grade plutonium, and the resulting spent fuel should not be reprocessed.

Resources needed to finance such pilot facilities would be better spent if they were designed with scope for expansion; otherwise, larger, new facilities would have to be constructed. Russia is balking at these proposals, and some European countries are also raising questions. Furthermore, the key finance issue still needs to be resolved. Some officials and analysts argue that Russia and the Group of Seven (G-7) industrial nations should share the cost of disposing of Russia's excess plutonium. Others, however, suggest a barter arrangement in which G-7 governments would open their markets to an additional increment of Russian low-cost uranium and enrichment services. Money raised from this arrangement would then be used to pay for construction of the necessary facilities.

The proliferation risk of excess weapons-grade plutonium should be treated as a threat to international security, not as an opportunity to score points in the long-running fuel-cycle debate. Disposal is important to the security of the international community, particularly the G-7 nations. These countries may have to agree to help finance the effort by opening their markets or cheque books. At the same time, if a MOX reactor plant is to be internationally financed, it makes sense for Europe and Russia to agree that it will be focused on 'once- through' use of weapons-grade plutonium. In future decades, when the task is completed, there will be ample time to determine the fate of these facilities.

Window A: The proliferation risk of excess weapons-grade plutonium should be treated as a threat to international security, not as an opportunity to score points in the long-running fuel-cycle debate.