THE question of what to do with the world鈥檚 growing stockpile of plutonium will be complicated rather than answered by the nuclear industry鈥檚 plans to include the metal in reactor fuel, according to German scientists. Their report recommends that plutonium 鈥渟torage rods鈥� should be inserted into spent fuel or combined with nuclear waste and solidified.
Since the demise of the plutonium-fuelled fast reactor programmes in Germany, Britain and France, the nuclear industry has increasingly pursued the idea of fuelling reactors with a mixture of uranium and plutonium oxides, known as MOX. The industry regards MOX as an economic method of 鈥渞ecycling鈥� plutonium that would otherwise have no commercial purpose.
The new report, published in Brussels last month by International Physicians for the Prevention of Nuclear War, estimates that the world stockpile of separated civil plutonium could reach between 200 and 350 tonnes by the turn of the century. This will come mostly from the massive reprocessing programmes planned at Sellafield in Cumbria and Cap La Hague in Normandy. It means that the amount of civil plutonium could for the first time exceed the reserves of military plutonium, which are estimated at 250 tonnes.
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There are commercial-scale MOX fabrication plants at Hanau in Germany and Dessel in Belgium, with new plants planned in both these countries as well as in France and Britain. MOX is burnt in seven reactors in Germany and two in Switzerland. Its use is also planned in a number of Japanese reactors, a further ten plants in Germany, three in Switzerland, 16 in France and two in Belgium.
The German company Siemens, which runs the MOX plant in Hanau, argues that mixing weapons-grade plutonium with other ingredients reduces the possibility of using it to make nuclear bombs. 鈥淢OX technology offers a real industrial possibility for world peace,鈥� says Raener Gend, a spokesman for Siemens MOX operations in Hanau.
But the report, written by Christian K眉ppers and Michael Sailer from the 脰ko Institute in Darmstadt, Germany, argues that weapons-grade plutonium can be 鈥渞eadily鈥� extracted from MOX fuel. If large-scale production begins, they say, MOX fuel will be moved far and wide. 鈥淣ew MOX production facilities should not be started up,鈥� says K眉ppers. 鈥淲e ought to put civil plutonium in international storage for a few years while we work out how best to mix it with waste or spent fuel.鈥�
The report claims that the consequences of a severe accident at a reactor fuelled by MOX would be 鈥渟ubstantially worse鈥� than if it were fuelled only by uranium. The more plutonium there is in fuel, the more of the heavier, longer-lived, radioactive elements known as actinides are created as the fuel is burnt. It points out that MOX fuel greatly increases the burden of nuclear waste disposal because of the large amount of waste produced by reprocessing.