In May 1994, the world received a shock when 6 grams of highly purified (99.7 %) weapons-grade plutonium-239 was found in the house of a German businessman. It originated from one of Russia’s plutonium plants. This was the first of several such cases. In one raid, 310 grams of weapons grade ptutonium-239 was uncovered, a third of what is needed to make a massive kiloton nuclear bomb. It is believed that these ‘incidents’ are just the tip of the iceberg. The world is justifiably alarmed at the prospect of uncontrolled plutonium proliferation.
Plutonium is one of the most dangerous materials on earth. Five kilograms is enough to make a crude nuclear weapon. Some experts even believe that only one kg will suffice. Of course this is not the only reason that makes it one of the most dangerous of materials. Less than one thousandth of a gram is enough to cause cancer if inhaled. Plutonium is the second of the transuranium elements with an atomic number 94. It is a silvery looking and highly reactive material. It is so reactive that it is processed in special chambers filled with inert gases to prevent it from reacting with atmospheric gases and the moisture in the air, but it is not the reactivity of plutonium that attracts attention: it is its radioactivity. All transuranium elements are highly radioactive, but only plutonium and neptunium occur naturally, both in very minute amounts. The others are manufactured. The fact that plutonium occurs naturally means that it is stable enough to last if it can be produced by some means. Actually, it is very stable; its most prevalent form has a half-life of 24,131 years. Therefore; if manufactured, it is not easy to get rid of. Nearly all the plutonium that exists on earth today is produced this way.
The road to plutonium production
Of all radioactive materials, three are extremely important for nuclear energy generation by fission: plutonium-239, uranium- 233 and uranium-235. These are the only 3 radioactive materials which can provide a self-sustaining nuclear fission reaction. This means that by bringing together a critical amount of any of these three, a chain reaction can be initiated. This is the principle behind nuclear energy and nuclear weaponry.
Since the 1950’s, scientists have believed that plutonium and not uranium may be the ultimate solution to the world’s energy problem. Although uranium can be found naturally in several minerals, the fissile isotope U-235 is extremely low. With plutonium and uranium are both rare, one may ask ‘why has plutonium become so important?’. The answer is simple: in fast breeder reactors, more plutonium is produced than burnt. This process uses an isotope of uranium U-238, which is not fissile itself but more common than the fissile isotope U- 235. If you irradiate U-238-which we have plenty of-with highly energetic neutrons, it will capture them and eventually decompose into the most dangerous form of plutonium, Pu- 239 , by two successive 13-decays. After that step, plutonium is chemically separated from other material by means of remote controlled facilities. So if you have unusable U-238 you can turn it into highly desirable Pu-239 by using some U-235 or Pu-239. Once you have bred enough plutonium, you can start feeding in the new plutonium without the need for more U- 235 as fuel. The only drawback is that reprocessing and purifying it to use as nuclear fuel is not easy.
Today, things have changed. Countries determined to stay with commercial nuclear energy production need not use plutonium, fuels made of low-enriched uranium will suffice and unlike the past, reserves are enough to sustain nuclear energy production commercially. These fuels are not weapons-usable and are much cheaper and easier to handle. Reprocessing plutonium for reintroduction as nuclear-fuel is a very complex, dangerous and expensive process.
Given these facts, we may wonder why nations want to possess plutonium for nuclear energy generation. Another phenomenon differentiates plutonium from uranium: unlike uranium, all forms of plutonium can be made into weapons (although some mixtures of isotopes are less desirable to a weapons designer). If a nation insists on using costly plutonium rather than cheaper low-enriched uranium for energy generation, one may suspect that the country has other intentions.
Politics of plutonium
Plutonium has proliferated since 1942. Twenty-two countries possess or control separated plutonium in various forms and amounts, either for military or commercial use. As the nuclear warheads are decommissioned according to the Nuclear Nonproliferation Treaty, stockpiles are growing sharply in the world. Although long-standing governmental and commercial secrecy make estimates highly uncertain, roughly 1,100 metric tons of the material exist today. Approximately 260 tons of that stockpile are deployed in the form of surplus nuclear weapons. Of the roughly 650 tons of plutonium in commercial programs, approximately 530 tons are contained in untreated spent reactor fuel, while roughly 120 tons are stored in weapons-usable form or recycled as fuel awaiting potential future use. Every year, the world’s reactors collectively generate 60 or 70 extra tonnes of plutonium and at the moment there is no law against reprocessing it. By the turn of the century, this is estimated to reach around 1700 tonnes. It is calculated that by the year 2003, Russia will have accumulated enough plutonium to make 21,700 crude weapons, whereas US will have accumulated enough for 18,100 weapons.
Nuclear policies are among the most sensitive and closely guarded secrets of any nation. States are unwilling to disclose data related to plutonium stockpiles. International non-proliferation movements are pressurizing governments. Japan has a special attachment to plutonium since their nuclear energy generation policy was originally based on plutonium. It is now the only country to rely on plutonium for nuclear energy and is said to be reviewing its policy. A few months ago, US had declared that it would stop the transfer of plutonium handling technology to Japan because there was the risk that Japan may be using this technology to make nuclear weapons. After months of pressure from the international community and internal non-proliferation groups, last month Japan declared that at the end of 1993 it had 4684 kgs of plutonium inside the country and 6197 kgs in France and Britain waiting to be shipped to Japan, and became the first nation to give the exact figures about its stockpiles. Previously, US had started to declassify some documents about its plutonium stockpiles and reported that it has produced 89 tonnes of weapons-grade plutonium since 1945 and it has 33.5 tonnes of it now stored in Texas. Russians can’t even decide how much plutonium they have. There are discrepancies between the accounting systems of their military and the ministry of atomic energy.
Before the end of the cold war there was the perceived threat of a nuclear war. The threat has now changed. The loose security measures in the underfunded Russian and other former eastern-block nuclear industries are a much greater threat than a nuclear war or the hazards of nuclear waste. A nuclear war is a remote possibility because everybody seems to be aware that it would be a zero-sum game with no winners. Also nuclear waste disposal technology is so powerful that once the waste is disposed, it is nearly impossible for the nuclear waste to return to circulation or effect the human environment again. On the other hand, growing stockpiles of nuclear material that can be made into nuclear weapons is certainty a greater threat, especially when it is in unsafe hands prepared to sell at very low rates. Russia has reported 900 illegal attempts to gain entry to its nuclear facilities and another 700 cases where nuclear workers tried to smuggle out nuclear material. We don’t have any reason to believe that all attempts were stopped. Some material may well have been smuggled secretly. Some experts say that it is possible to make a nuclear bomb equivalent to the one dropped on Nagasaki, out of 7 kilograms of spent nuclear fuel instead of 5 kilograms of weapons grade plutonium and the know how for it is at large now. That technology is now available to everybody who wants to learn it, from the US documents of 1950’s that are no longer classified. Add the international loose measures for the monitoring and reprocessing of nuclear waste to this and the threat we are face to face today is clearly evident.
An institution called the International Atomic Energy Agency is responsible for monitoring the nuclear reactors in countries with no nuclear arms and that have signed the Nuclear Non-proliferation Treaty. It keeps an eye on those countries and makes sure no plutonium is secretly diverted to military use. There are countries like India and Israel that are not signatories and evidence that IAEA can be fooled. Both North Korea and Iraq recently declared that they had secretly produced 3 grams of weapons-grade plutonium. Even if the countries are unable to divert plutonium to the military, this does not prevent them from developing nuclear weapons. A nation can develop other parts of the bomb such as the case and electronics, and when the nation’s leader decides it is time to have a nuclear bomb, plutonium can be directed to the military. The nation would have a nuclear bomb in a few days.
With plutonium, the odds are weighed against the well being of humankind. If nation states persist in the costly production and use of plutonium, they risk weapons proliferation, environmental devastation and damage to human health. In addition to its dangers as a deadly nuclear weapon constituent, the release of plutonium into the environment also poses health and environmental risks. Even if plutonium does not reach and damage the environment and human health via the routes mentioned above, there is always the danger posed by the nuclear powered warships and submarines as a rather easy way to a nuclearly polluted environment. Four sunken nuclear submarines lie in the depths of the Atlantic and there are reports that the reactors and the war-heads they were carrying are leaking plutonium and other nuclear materials into the ocean. This may turn out to be the biggest environmental and health hazard ever encountered, if these nuclear materials enter the food chain. Although there is no risk that at that depth, fish will eat these materials, it is always possible that they can be carried to suitable places by strong ocean currents where fish may feed. A stronger possibility is that it may be eaten by plankton which is in turn eaten by fish. Indeed, the risks are enough to require that plutonium production is judged too dangerous to allow its dangerous continuous production. Building on the international non-proliferation regime and current practices in the nuclear industry, a more comprehensive and specific regime must be constructed to manage plutonium and hasten its elimination. But such an international step is not that easy to take. 161 countries are signatories to the non-proliferation treaty and any change such as the banning of plutonium reprocessing, requires that they all agree on the subject and sign again.
These risks might be more tolerable if plutonium held unquestionable economic value in the foreseeable future. But no proven technology exists to generate electricity from plutonium or highly enriched uranium at economically competitive costs. As noted above, fuels made of low enriched uranium are both cheaper and less dangerous. Also, they do not pose comparable health, environmental or security hazards. The reserves of low-cost, low-enriched uranium accessible world-wide may run out, but not before the late 21st century, and then only if nuclear energy use increases markedly without eliciting increased supplies from either more efficient uranium handling or discovery of new reserves. Such an outcome is unlikely. Plutonium for long-term research and development programs will always be available in the form of spent fuel, even after the large surpluses of separated plutonium are reduced.
Today, the nuclear arms race is not accelerating as it was in the late 1940s and again in the late l970s; rather, it is being reversed, and unlike the 1970s, plutonium is not seen as the millennial solution to the energy needs of the world or as the salvation for the international nuclear power industry. Today, plutonium is increasingly perceived as a global problem that must be solved. Even the research grants for the reprocessing technology of plutonium are coming to a halt. Central to the establishment of an international plutonium regime is giving priority to gaining control of surplus stockpiles of separated plutonium that could be most readily reintroduced into weapons. The difficulties lie not in the mechanics but in the politics of international storage and ultimate disposal. Because it will take time to determine how and where to dispose of plutonium, the issue of safe, secure storage must be addressed at once.
By internationalizing the disposal and safety problem, the plutonium regime could provide a forum for scientists, engineers, environmentalists and others to examine the world’s technical capabilities and geography in order to identify the best possible options for disposing of plutonium and other radioactive materials.