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Il nucleare non è la risposta



The troubles of the Fukushima nuclear-power plant – and other reactors – in earthquake-hit Japan have dealt a severe blow to the global nuclear industry, a powerful cartel of less than a dozen major state-owned or state-guided firms that have been trumpeting a nuclear-power renaissance.

But the risks that seaside reactors like Fukushima face from natural disasters are well-known. Indeed, they became evident six years ago, when the Indian Ocean tsunami in December 2004 inundated India's second-largest nuclear complex, shutting down the Madras power station.

Many nuclear-power plants are located along coastlines, because they are highly water-intensive. Yet natural disasters such as storms, hurricanes, and tsunamis are becoming more common, owing to climate change, which will also cause a rise in ocean levels, making seaside reactors even more vulnerable.

For example, many nuclear-power plants located along the British coast are just a few metres above sea level. In 1992, Hurricane Andrew caused significant damage at the Turkey Point nuclear-power plant on Biscayne Bay, Florida, but, fortunately, not to any critical systems.

All energy generators, including coal- and gas-fired plants, make major demands on water resources. But nuclear power requires even more. Light-water reactors (LWRs) like those at Fukushima, which use water as a primary coolant, produce most of the world's nuclear power. The huge quantities of local water that LWRs consume for their operations become hot-water outflows, which are pumped back into rivers, lakes, and oceans.

Because reactors located inland put serious strain on local freshwater resources – including greater damage to plant life and fish – water-stressed countries that are not landlocked try to find suitable seashore sites. But, whether located inland or on a coast, nuclear power is vulnerable to the likely effects of climate change.

As global warming brings about a rise in average temperatures and ocean levels, inland reactors will increasingly contribute to, and be affected by, water shortages. During the record-breaking 2003 heatwave in France, operations at 17 commercial nuclear reactors had to be scaled back or stopped because of rapidly rising temperatures in rivers and lakes. Spain's reactor at Santa María de Garoña was shut for a week in July 2006 after high temperatures were recorded in the Ebro river.

Paradoxically, then, the very conditions that made it impossible for the nuclear industry to deliver full power in Europe in 2003 and 2006 created peak demand for electricity, as use of air-conditioning increased.

During the 2003 heat wave, Électricité de France, which operates 58 reactors – the majority on ecologically sensitive rivers such as the Loire – was compelled to buy power from neighboring countries on the European spot market. The state-owned EDF, which normally exports power, ended up paying 10 times the price of domestic power, incurring a financial cost of €300m.

Similarly, although the 2006 European heatwave was less intense, water and heat problems forced Germany, Spain, and France to take some nuclear power plants offline and reduce operations at others. Highlighting the vulnerability of nuclear power to environmental change or extreme-weather patterns, in 2006 plant operators in western Europe also secured exemptions from regulations that would have prevented them from discharging overheated water into natural ecosystems, affecting fisheries.

France likes to showcase its nuclear power industry, which supplies 78% of the country's electricity. But such is the nuclear industry's water intensity that EDF withdraws up to 19bn cubic metres of water per year from rivers and lakes, or roughly half of France's total freshwater consumption. Freshwater scarcity is a growing international challenge, and the vast majority of countries are in no position to approve of such highly water-intensive inland-based energy systems.

Nuclear plants located by the sea do not face similar problems in hot conditions, because ocean waters do not heat up anywhere near as rapidly as rivers or lakes. And, because they rely on seawater, they cause no freshwater scarcity. But as Japan's reactors have shown, coastal nuclear-power plants confront more serious dangers.

When the Indian Ocean tsunami struck, the Madras reactor's core could be kept in safe shutdown condition because the electrical systems had been ingeniously installed on higher ground than the plant itself. And, unlike Fukushima, which bore a direct impact, Madras was far away from the epicenter of the earthquake that unleashed the tsunami.

The central dilemma of nuclear power in an increasingly water-stressed world is that it is a water-guzzler, yet vulnerable to water. And, decades after Lewis L Strauss, chairman of the United States Atomic Energy Agency, claimed that nuclear power would become "too cheap to meter", the nuclear industry everywhere still subsists on government subsidies.

While the appeal of nuclear power has declined considerably in the west, it has grown among the so-called "nuclear newcomers", which brings with it new challenges, including concerns about proliferation of nuclear weapons. Moreover, with nearly two-fifths of the world's population living within 100km of a coastline, finding suitable seaside sites for initiation or expansion of a nuclear-power programme is no longer easy.

Fukushima is likely to stunt the appeal of nuclear power in a way similar to the accident at the Three Mile Island plant in Pennsylvania in 1979 did, not to mention the far more severe meltdown of the Chernobyl reactor in 1986. If the fallout from those incidents is a reliable guide, however, nuclear power's advocates will eventually be back.

Brahma Chellaney is Professor of Strategic Studies at the Center for Policy Research in New Delhi

Copyright: Project Syndicate, 2011.


Tratto da www.guardian.co.uk