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Chernobyl - 20 Years Later: Murderous Atoms    [

    Activists March Against France's Plans to Build New Generation of Nuclear Reactors
    By Sylvie Corbet
    The Associated Press

    Monday 17 April 2006

    Cherbourg, France - More than 10,000 French activists marched in silence to honor victims of the Chernobyl disaster 20 years ago, part of a larger protest denouncing France's plans to build more nuclear reactors.

    Environmentalists gathered Saturday in the rain in the northern port city of Cherbourg, near the site where nuclear-dependent France plans to build the first in a new generation of nuclear power plants. Several protesters held up a sign that read simply "non."

    The new type of plant is billed as more efficient, safer and environmentally friendly than current models. However, French environmental activists argue that nuclear power is inherently dangerous, and say the development of a new generation of plants will slow the search for alternative energy sources.

    France is the only European country that continued making new nuclear plants after the April 26, 1986, Chernobyl disaster.

    It is also the most nuclear-dependent country in the world, with 59 reactors churning out nearly 80 percent of its electricity. About 30 of the aging reactors will be in need of replacement starting around 2020 - which is where the new generation of plants comes in.

    Activists in Cherbourg observed 15 minutes of silence at the start of the march, organized by the group Sortir du Nucleaire. Later, they lay down on the ground as sirens blared to simulate a nuclear accident.

    In front of the local office of power utility Electricite de France, demonstrators piled up hundreds of cans, symbolizing nuclear waste.

    Police said 10,000 people marched, while organizers put the figure at 30,000. Protesters came from Germany, Belgium and the Netherlands. Prominent French figures included anti-globalization activist Jose Bove, Green Party lawmaker Noel Mamere and two former environment ministers, Dominique Voynet and Corinne Lepage.

    "Twenty years after Chernobyl, it's time to remember that we are not protected from a catastrophe, that the French nuclear infrastructure is aging, and that today we are going to stretch out its life expectancy, which is dangerous," Mamere said.

    The new plant in Flamanville, near Cherbourg, is expected to enter service around 2012. If it is acceptable, a series of similar plants could be built and put into service by 2020.

 

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    Chernobyl - 20 Years Later: Murderous Atoms
    Spiegel Online

    Friday 14 April 2006

The Geiger counters continued to tick away for days as much as 2,000 kilometers (1,243 miles) away from the disaster zone, as air masses contaminated with radiation pushed across Europe. Many fears are justified. The major disaster at the Chernobyl nuclear power plant proved the prophets wrong who underestimated the "residual risk" of nuclear energy. A look back from the archives of Der Spiegel.

    The staff at Sweden's Forsmark nuclear power plant, located on the Baltic coast north of Stockholm, was just changing shifts. It was 7:00 a.m. last Monday when workers passing through a routine check in the security sluice at the entrance to the plant's reactor building set off warning signals.

    Radiation testing personnel were alerted. Using a piece of equipment that looks like a handheld vacuum cleaner, they scanned the plant employees and took radioactivity readings on the walls, on the plant grounds and in rainwater cisterns. The results were astonishing. The Geiger counters were ticking like crazy - but outside, not in the reactor buildings.

    "It was crazy," says measuring technician Bengt Wellman. According to Wellman, where the normal reading would be four radioactive decay units per second, "we measured 100 per second," even four kilometers (2.5 miles) from the reactor. Plant manager Karl Erik Sehlstedt issued a level 2 alarm, which meant that the local population was notified by radio. At 11:00 a.m., 800 employees left the power plant and gathered on a nearby athletic field, where they were all scanned for radiation and where many had to leave their shoes behind for decontamination and walk home with their feet covered in plastic bags. An hour and a half later, officials were still unable to rule out the possibility that something had gone wrong at Forsmark.

    But then similar reports about elevated radioactivity levels began coming in from almost every other Swedish testing station and from neighboring Finland. In some places, the radiation was 10 times as high as natural environmental radioactivity. By then, Swedish experts knew that the invisible radiation and silent danger had blown across the Baltic Sea on a southeasterly air current. Meteorologists simulated the wind patterns of the preceding few days and physicists analyzed the spectrum of radioactive particles. Finally, everything pointed to the presumed source of the heightened radioactivity, a nuclear power plant near Kiev, the capital of the Ukraine.

    At this point, the people of Kiev were unaware that a nuclear inferno had erupted two days earlier less than 100 kilometers (62 miles) north of their city. They continued to buy fruit and vegetable in local markets and decorate the city's houses and streets for the annual May Day celebration. Horrified, US Chairman of the Joint Chiefs of Staff William J. Crowe told US members of Congress that satellite images revealed that only hours after the accident, Soviet authorities had allowed a soccer match to continue in the vicinity of the reactor meltdown. The players and onlookers had no idea of the hazards to which they were being exposed.

    It was with this silence, inwardly and outwardly, that the Soviets would have preferred to gloss over what had happened in their reactor No. 4 at one of their biggest nuclear power plant complexes. As it turned out, it was the most serious catastrophe in the history of the peaceful use of nuclear energy, an event experts in both the East and the West had declared practically impossible - the "super maximum credible accident."

    It was only in response to pressure from the global public and because they believed, for some time, that they would need foreign help in containing the reactor fire that the Soviets first admitted that an "accident" had occurred, later upgrading their assessment of the event to a "catastrophe." The government was no longer denying what Soviet news agency Tass called "a certain amount of leakage of radioactive substances" until finally, last Wednesday, Soviet state television even showed a photo of the half-destroyed nuclear power plant, of the ruin of what was once Chernobyl, reduced to little more than charred iron beams and blackened walls - a monument to technical hubris.

    The speculation over the immediate consequences of the catastrophe continued through the end of last week. According to Western intelligence agencies, there were "several hundred dead" and thousands still likely to die as a result of the accident. But the Soviets continued to insist on their numbers: 2 dead, 197 wounded, including 18 with life-threatening injuries. According to Soviet officials, 50 patients had already been released from hospitals.

    Even before the details became known, politicians and nuclear power lobbyists in the West embarked on a true campaign of appeasement. At the annual meeting of the "Working Group of Regional Energy Supply Companies" in Munich on Tuesday evening, politicians from were quick to point out that these types of "mishaps cannot occur in Germany." Later on, unofficial sources revealed a more alarming position: that such disasters just happen to be "the price of technological progress."

    Officials wanted to avoid a revival of the debate over the purpose and blessings of nuclear power at all costs, to ward off the kinds of public misgivings over nuclear energy that thwarted the construction of nuclear power plants in the German towns of Wyhl and Gorleben and led to violent civil protests over plants at Grohnde and Brokdorf in the 1970s.

    But the attempts of nuclear power proponents to quell the growing fears of citizens by containing their arguments failed. Fear of the invisible danger grew as shifting winds blew contaminated air back and forth across the heart of Europe during the course of the week, and as instruments measuring radioactivity levels from Davos to Monaco produced printouts showing sharp peaks.

    It was a danger that couldn't be felt, seen or heard. In fact, human beings have no inherent means of perceiving radiation - which was all the more reason to be concerned about reports on television and the radio. First the Polish stations, and later stations in the German states of Bavaria and Hesse, cautioned citizens to avoid drinking milk from cows that graze outside, and to carefully wash fresh produce.

    Radiation doses up to 500 times higher than normal were measured in some parts of Poland, especially in the eastern portion of the Masurian Lakes region. At a press conference, officials said that a "certain number" of cases of thyroid cases could be expected. Medical experts estimate that 10,000 Poles will contract radiation-induced cancer in the next 30 years.

    Large numbers of trucks and cars coming from Eastern Europe were checked at border crossings. Whenever Geiger counters registered higher levels of radiation, vehicles had to be decontaminated and, in some cases, air filters had to be removed and were then classified as "low-level radioactive waste."

    The German Ministry of Health issued an order imposing special inspections on Polish geese and other food products from Eastern Europe. Non-essential travel to the Soviet Union was cancelled. Western companies ordered their employees to return home. Overly anxious citizens in Germany and Scandinavia bought up the inventories of iodine tablets at pharmacies, and the University of Mainz Hospital reported the first cases of poisoning caused by the ingestion of iodine tablets.

    On Friday, the Hamburger Abendblatt ran a cover story titled "Today and Tomorrow: Wind from the East." Suddenly every weather report was focusing on the wind direction and all but ignoring sunshine and rain. Concerned pregnant women overloaded telephone lines at the German Weather Service in Offenbach with questions of where they should go to avoid the risks posed by radiation. Officials recommended giving dry milk to young children, and called for excessively contaminated fresh milk to be processed into cheese.

    Officials in the states of Bavaria and Hesse issued ominous-sounding warnings dubbed "preventive measures," advising parents not to allow children to sleep near open windows and to wash children after they had been playing outdoors. Radiation levels measured throughout the southern portion of West Germany, in the far north and in Berlin initially remained within ranges corresponding to normal fluctuations in nature - including the kinds of peaks vacationers might experience while hiking at higher altitudes in the Black Forest.

    West German testing stations did register worrisome peak values at times, including up to 120 times the normal level of radioactive isotope iodine 131 in Berlin and even up to 400 times normal values in the western city of Darmstadt.

    Suddenly Germans found themselves facing a wild, confusing rise and fall of test data, of readings denominated in unfamiliar units, such as Becquerel and Curie, Sievert, Millirem and rad. Information on the locations and intensity of radiation in various parts of the country was suddenly as uncertain as the weather.

    But at no time did radiation doses measured in Sweden and Germany pose an acute health risk. Nevertheless, the range of particle measurements provided experts with the irrefutable evidence that what happened at Chernobyl was not (as the Russians had claimed) merely an "incident" involving the release of radiation amounts that were completely safe for the Soviet Union's Western neighbors. There was no doubt that what had happened at Chernobyl was the kind of catastrophic case statisticians predicted could only happen once every 10,000 or even 100,000 years, an incident known as a core meltdown.

    When this occurs in a power plant such as Chernobyl, up to 180 tons of white-hot uranium, combined with the melted special steel of the fuel sleeves, eats through the reactor's concrete wall. At this point, the radioactive inventory of the reactor core corresponds to that of about 1,500 Hiroshima bombs - except that in this case the nuclear horror doesn't explode in the air in the form of a bomb, but instead, as a glowing, constantly radioactive lump of material, slowly eats its way through the concrete walls and into the ground.

    To date, there is no reliable scientific data and there are no simulations or computer models on what exactly happens in a meltdown - that is, whether the nuclear lava breaks down into many smaller balls or collects into a single aggregate, how long it takes to burn its way through concrete foundations, how deeply it penetrates into the earth and how much radiation it releases. The term "China syndrome" - the fictional idea that a blazing hot plug of uranium in the United States could eat its way through the earth and pop back out on the other side - has even served as the title for a popular nuclear thriller.

    Scientists, including those from the Karlsruhe Nuclear Research Center, believe it is quite possible that even concrete foundations five to seven meters (16-23 feet) thick may not be capable of containing melted chunks of uranium. But five to seven meters would be several times as thick as the concrete floor under the reactor core in Chernobyl.

    The unleashing of such massive amounts of nuclear energy even goes beyond the "Maximum Credible Accident," or MCA, for which power plant engineers design their structures, and is fittingly described as a "Super MCA." Late last week, there were two equally plausible versions as to how this could have happened at the 1,000-megawatt Chernobyl nuclear power plant. According to the first theory - the one making the rounds in Moscow - an explosion in the reactor's computerized control room caused the accident, disabling the plant's automatic shutdown systems and interrupting the flow of cooling water. Under the second hypothesis, a sudden, as yet inexplicable power outage disabled important systems in the plant, including the central cooling pump, and the emergency backup, which was activated immediately, somehow failed. This series of events led to a detonating gas explosion.

    Western experts are already convinced that the accident contaminated more than just the groundwater in the reactor's immediate vicinity, also affecting open bodies of water. There have been indications in Moscow that radioactive material flowing down the Dnieper River and its tributary, the Prypiat, where the Chernobyl plant is located, has reached the Black Sea. In fact, it's been rumored the capital that Black Sea beaches will be closed this season.

    Chernobyl, the scene of a disaster even more serious than the accident at the Three Mile Island facility near Harrisburg, Pennsylvania, will undoubtedly remain a radioactive ruin for many decades to come. Experts estimate that radioactivity at the site measures at least 1000 rem per hour, a radiation level that is immediately and completely fatal to human beings. The question is whether the remaining three reactor units at Chernobyl, which presumably remained intact, can ever be used again. For the time being, the Soviets have shut down the 16 other nuclear reactors of the same type that they currently own.

    Late last week, American reactor experts concluded that the soil within a 10-kilometer zone (about six miles) surrounding the destroyed power plant suffered "extreme radioactive contamination" and is "likely to be uninhabitable for generations."

    The Soviets evacuated the region within a 30-kilometer perimeter (about 18 miles) of Chernobyl. The largest settlement within the emptied zone is Prypiat, a city of about 50,000 inhabitants specifically designed for operation of the plant, as well as three smaller villages. The region is generally a relatively thinly populated agricultural district, poor by Ukrainian standards, where rye is the principal crop.

    The number of people killed directly as a result of radiation may in fact be relatively small, and could even be limited to reactor personnel. But the number of those who will die from the effects of radiation from the killer reactor in the coming weeks, months or perhaps even decades is impossible to predict.

    Just how seriously people will fall ill, and whether they succumb to radiation-induced illnesses depends on the amount of time for which, at what distance and in what kind of environment they were exposed to radiation, whether they were outdoors or in a building and whether they were on the windward or lee side of the disaster's epicenter. Because a super MCA - unlike the detonation of a nuclear bomb - lacks such salient features as a major explosion, a mushroom cloud rising into the air and a blast of heat racing across the countryside, victims could very well feel spared.

    But despite efforts by the nuclear lobby - in the East and the West - to convince us otherwise, there is no such thing as a dose of radiation harmless to human beings. Even the smallest doses of radioactive radiation can cause damage.

    The standard measure of the effect of radioactive radiation on human beings is a unit known as "rem" ("Roentgen equivalent man"). It refers to the biologically effective dose of energy emitted by different types of radiation (mainly gamma radiation, in the case of a super MCA).

    The West German Interior Ministry in Bonn has developed its own nomenclature for what it calls "catastrophic events." Under this system, 25 rem is a "dangerous dose," 100 rem a "critical dose" and 400 rem a "mid-lethal dose" causing death in 50 percent of those exposed. A person whose entire body is exposed to a "lethal dose" of 700 rem cannot survive and will die of "acute radiation sickness."

    Doctors have a succinct way of putting it: "Radiation sickness is not an illness - it's death." The question is, how quickly does death occur? It's impossible to predict. No method currently exists to determine, after the fact, the precise rem level to which victims were exposed.

    Anyone exposed to the so-called supralethal dose of 1,000 or more rem will begin feeling dizzy in the first few minutes. Vomiting, diarrhea and fever quickly set in, and the whole thing is over within a few hours. Death comes while the victim is in a state of delirium - and as a liberator.

    Those exposed to between 400 and 700 rem spend up to two weeks in agony. The skin and mucous membranes become inflamed and begin to disintegrate. Victims are unable to eat or drink, and fever levels climb to over 40 C (104 F). "Symptom-free intervals" lasting hours or even days can give the doomed the false hope of survival. But survival is only a possibility for those who receive immediate and perfect intensive care in an aseptic "life island" in a specialized clinic, a treatment the German Medical Journal describes as "a balanced supply of fluids and calories, artificial ventilation, pain therapy and bone marrow transplantation."

    The "symptom-free interval" is characteristic of all forms of radiation sickness. Victims believe that they have survived after all, but it's an illusory sensation. At a dose of 400 rem (50 percent lethality), the agonizing symptoms begin after 10 days, and at 200 rem (5-7 percent lethality), symptoms take 20 days to set in. For some Ukrainians, the worst is yet to come.

    A treatment that targets the causes of radiation sickness doesn't exist. Contrary to the kind of talk that tends to gloss things over, medicine - in the East and West alike - is completely powerless when it comes to radiation. And contrary to popular belief, even the use of iodine tablets is only effective in protecting a single organ, the thyroid gland, because taking the pills temporarily blocks the glands' absorption of radioactive iodine. But radioactive iodine is only one of many of the hundreds of dangerous fission products released during a Super MCA. Besides, iodine tablets only protect against thyroid cancer, which may even develop decades later, and by no means against the effects of acute radiation exposure.

    To the best of our knowledge, potential victims in the Ukraine were given no warning whatsoever. German tourists on an Aeroflot flight approaching Kiev saw a tall, black, ominous-looking plume of smoke rising from Chernobyl, but life in the region simply continued - as if nothing had happened.

    But radiation specialists in Vienna and the German city of Homburg an der Saar did measure what actually happened. A group of 50 workers employed by Austrian steelmaker Voest returned home last week from a stint at the company's Shlobin plant, 160 kilometers (about 100 miles) northeast of Chernobyl. In five of the workers, doctors measured twice the normal concentrations of radioactive iodine in the thyroid gland. In Homburg, officials confiscated the exposed luggage and work clothing of personnel returning from Russia, and doctors said that tests revealed "unsettling levels."

    Experts in Scandinavia found 14 different radioactive trace elements, including radioactive isotopes of zirconium, niobium, molybdenum and cesium, as well as the man-made element neptunium 239, whose presence in Scandinavia experts found especially puzzling. They reasoned that if this element was in fact released into the atmosphere, the already weak shell of the Soviet reactor must have given way at a very early point in the catastrophe.

    The appeasement argument in the West followed the same approach. According to a West German study on reactor safety, the "release of fission products would be ... decisively limited" in the event of a core meltdown in a comparably sized nuclear power plant built with Western engineering and specs. The safety shell, or "containment" - the egg-shaped concrete structure that encloses the "hot" core of the reactor and has become a symbol of nuclear power and - is seen as reliable by nuclear proponents in the West.

    In the past, the Soviets opted to dispense with this reinforced concrete container in all of their nuclear power plants. It was only with the "fifth unit" at the Novoronesh power plant that they installed a protective, domed, reinforced concrete cylinder. But as recently as six years ago, Yury Syvintsev, head of security at the Russian Kurchatov Nuclear Research Center, said that the measure was "a waste of money." But in an interview with the publication Sovietskya Rossiya, the head of the construction team that built the container offered this almost oracle-like commentary: "the split atom, even if we call it peaceful, happens to have its own unpredictable moods."

    The Soviets believed that the egg-shaped containment shells were indispensable for the type of reactor whose core recently melted at Chernobyl, and they were convinced that this type of design was especially beneficial. It also happens to be the oldest type of reactor in the history of civil use of nuclear energy. The first reactor of this type, though significantly less powerful than today's models, was constructed in the Soviet Union back in 1954.

    The Russian reactors, known as graphite-moderated pressure tube reactors (or RBMK in Soviet terminology), are not used in the Western world. The core of this type of reactor consists of a massive graphite slab, seven meters (23 feet) tall and 11.8 meters (39 feet) in diameter, which contains 1,693 pressure tubes made of a special steel-zirconium alloy, with each tube containing two fuel rods. Water pumped upward through the tubes absorbs the heat produced in the fission process and turns into steam, which then runs the reactor's turbines.

    The purpose of the graphite is to slow down ("moderare" in Latin) the neutrons that are released during nuclear decay, in turn triggering the fission of other atoms. The desired chain reaction in the reactor core can only develop if a sufficient number of neutrons come into contact with nuclei. The nuclear reaction can be slowed down or even stopped by inserting the 179 control rods. They contain boron carbide powder, which essentially swallows the neutrons, thereby interrupting the chain reaction. For some as yet unexplained reason, this process failed at the Chernobyl plant.

    The Soviets see this model as advantageous because the entire reactor doesn't have to be shut down to replace individual fuel rods. The pressure tubes in the active channels are individually accessible using an overhead crane, a system that promised safety and, perhaps more importantly to the Soviets, made it possible to use the reactor as a breeder for weapons-grade plutonium. This was clearly one reason the Soviets preferred the RBMK reactor type, never made it accessible to international inspectors and never exported a single one of these reactors.

    According to experts, the drawbacks of the RBMK include its relatively high price tag and the fact that it's equipped with a confusing array of tubes and tube connections - upping the number of potential trouble spots in the system. Most of all, as some Western experts have consistently argued, this reactor type poses an especially high safety risk, at least when compared with the light water reactors commonly used in the West, in which water doesn't just remove heat, but also moderates the flow of neutrons (instead of the graphite).

    When a leak in a light water reactor results in water loss, the reactor's output drops and the nuclear chain reaction automatically comes to a standstill. This leaves engineers with enough time to take steps to prevent what is known as afterheat from cracking the fuel rods and, in a worst-case scenario, melting the reactor core.

    But a leak in an RBMK produces the opposite effect, increasing the moderating effect of the graphite. As cooling decreases, the reactor's output increases even further, quickly bringing the entire system to the brink of catastrophe.

    To prevent ignition of the graphite, the reactor core in an RBMK is lined with a gastight steel shell. If this lining cracks or melts, oxygen leaks into the system, causing the graphite slab, which is nothing but crystalline carbon, to ignite like an enormous block of charcoal. But instead of bursting into flames, the smoldering graphite slab can glow eerily for days or even weeks. The process generates combustion gases which, like a kilometer-high chimney, transport a portion of the reactor's radioactive substances high into the atmosphere.

    In addition to these graphite reactors, which have now proven to be highly volatile, the Soviets have also built the kinds of pressurized water reactors (PWR) common in the West. But until recently, the Soviets also dispensed with containment for this type of reactor (WWER 440 and 1000) - specifically for reasons of cost.

    In fact, Soviet nuclear engineers even went so far as to malign the West's more sophisticated safety philosophy as a monstrous product of capitalist thought. Nuclear physicist Klaus Fuchs (now 74 and living in East Germany) has called the West's policy of "using more and more steel and concrete to technically control even the most unlikely accident" an "economically unjustifiable concept." Indeed, Soviet bloc engineers have attempted to recast poverty as a virtue. According to Fuchs, "a high level of personnel qualification" and an appropriately deep understanding "of system and process design" are sufficient to eliminate the need for safety precautions made of steel and concrete.

    In an article in Spektrum, the publication of East Germany's Academy of the Sciences, Fuchs wrote that nothing is more detrimental to resolving the problem of safety "than staring, transfixed, at the MCA like some rabbit staring at a snake."

    In a 1982 study on "the Soviet nuclear program," Bremen physicist Jens Scheer wrote that the Russians have not only demonstrated "unprecedented unscrupulousness" in whipping their nuclear program into shape, but also a certain na vet and mystification in working with the atom - not unlike the romantic notion that manned space travel has somehow transported the spirit of Mother Russia into space.

    "The rise of the nuclear sun provides for the good of Soviet people ... it floats, it floats, that white ship against a green shoreline - oh pearl in the constellation of the atom - Leningrad nuclear power plant Number One," wrote Leningradskaya Pravda in 1977, when a reactor of the same type used in Chernobyl went into operation on the banks of the Neva River in Leningrad.

    Non-Russian operators of Soviet nuclear power plants took a more levelheaded approach to the issue and recognized the Soviet concept's weaknesses. Although the Finns, for example, felt coerced into buying two 440-megawatt pressurized water reactors from their Soviet neighbors, they insisted that the systems be protected with additional, Western-designed containments supplied by US manufacturer Westinghouse. Babcock & Wilcox, another US firm, brought the reactors' emergency cooling systems up to Western standards.

    The situation is similar in East Germany, where Soviet-designed nuclear power plants were also equipped with additional safety features, though not to the level of West German safety regulations. East Germany's engineers, who boast of "having combined the advantages of Western and Eastern designs," also believe that they can make do without a protective shell of reinforced concrete.

    Last week, nuclear power expert Bennett Ramberg of the University of California pointed out that there is a clear West-East decline when it comes to nuclear safety. According to Ramberg, the Soviet Union is "at the lowest end of the safety scale, even behind developing countries and other Soviet bloc nations. The Americans, he said, are "about in the middle," whereas the West Germans are "at the very top."

    It is certainly true that safety requirements in West German nuclear power plants, pushed through to a large extent by citizens' initiatives and deemed "completely exaggerated" by power plant operators for years, are now the world's most stringent - a status for which plant operators are now claiming responsibility. But last week Professor Dieter von Ehrenstein, a nuclear physicist at the University of Bremen, expressly warned the Germans against "inappropriate arrogance."

    Although it is correct that an accident like Chernobyl cannot happen here in Germany, simply because the type of reactor installed there doesn't exist in the West, by no means does this mean that the Soviet Union is the only country with unresolved safety problems. Other serious accidents - including an MCA - are possible in Western nuclear power plants. American power plant operators have narrowly averted an MCA at least three times. A partial core meltdown occurred in October 1966 in the Enrico Fermi experimental breeder reactor near Detroit when the sodium cooling system failed. In March 1975, electricians working with an open flame in a cable shaft caused a cable fire that shut down the entire electrical control system at the Browns Ferry reactor in Alabama, causing the main cooling system to fail. The Three Mile Island reactor near Harrisburg, Pennsylvania, narrowly escaped a total core meltdown in March 1979 when a series of operator errors and technical problems led to a partial destruction of the reactor core.

    An accident that in some respects resembled the Chernobyl reactor catastrophe occurred back in 1957 in Britain's Windscale nuclear plant, which the British were using to produce weapons-grade plutonium. Like in the Chernobyl accident, the graphite in the reactor core at Windscale also caught on fire. More than 100 operating channels in the graphite core were affected, and it took officials two days to extinguish the smoldering fire. Radioactive contamination from the accident covered an area of 500 square kilometers (193 square miles). The reactor remained off-limits for 10 years before officials could begin dismantling it. It took the British nuclear power agency a full 25 years to admit that fallout from the accident led to an estimated 40 cancer deaths in England.

    The Windscale accident was contained because plant officials managed to remove a large share of the uranium cartridges from the danger zone before the situation became uncontrollable. But even though the reactor was much smaller than the Chernobyl reactor, extinguishing the fire proved to be difficult. An initial attempt to smother the fire with carbon dioxide gas failed. In the end, the reactor core was flooded with water. The hydrogen explosion some experts feared never materialized, and the containment system remained in place.

    Early last week, Professor Karl Heinz Lindackers, a reactor expert with the Rhineland Technical Inspection Agency (T V), suggested to the Soviets that they extinguish the Chernobyl reactor fire by spraying it from the air with hundreds of thousands of cubic meters of water. But another German reactor expert, Professor Rudolf Schulten, disagreed. According to Schulten, who also works with graphite in the high-temperature reactor at J lich near Cologne that he developed, the only possible way to put out the reactor fire in the Ukraine is by spraying it with wet sand.

    In fact, the Russians are trying to reduce the risk of radiation emanating from the core melt by dropping sandbags, lead and boron onto the reactor. Images taken on Thursday from "Spot," a recently launched French satellite, showed that the amount of smoke over Chernobyl has subsided to a sufficient extent that roads on the plant grounds are visible once again.

    "What kind of nuclear disaster will German citizens have to face before our politicians finally give up nuclear energy?" It was with these words that Huberg Weinzierl, Chairman of the Federal Association for the Environment and the Protection of Nature (BUND), reacted to the news that the radioactive cloud had made it from Chernobyl to Berlin, Bavaria and Austria. For West Germany, which is second only to Japan in per capita use of nuclear power plants, there was more at issue than the possibility of an acute threat posed by radioactive particles from the East.

    Like the Austrians (who don't even have their own nuclear power plants), the Germans face neighboring countries' nuclear power plants lined up along their borders. "I don't have to go very far at all in (the western state of) Saarland," said Jo Leinen, the state's minister of the environment, on a special television broadcast, "we will soon have four nuclear power plants nearby in France that aren't up to current standards of safety."

    In explaining his position later on, Leinen said that safety standards are higher in Germany than in France, and that this difference is already evident in the quality of materials. According to Leinen, the Germans use higher-quality concrete and steel than the French. In addition, he said, the reactor pressure housing in French nuclear power plants is not lined with special steel, but instead is made with simple prestressed concrete. This makes the lining far more susceptible to internal and external pressure, such as the pressure resulting from the impact of a plane crash.

    "No one can guarantee," Saarland Minister of the Environment Leinen continued, "that a different type of accident" cannot happen in Germany. BUND Chairman Weinzierl used a comparison to make his point, saying that when someone is involved in an accident with a Volkswagen, they would never say that "an accident with a Mercedes" is impossible. According to Weinzierl, "the arrogant technology comparisons between East and West are pure cynicism, given the lethal threat posed by any use of nuclear power."

    There is no doubt that the multiple layers of safety systems and the rupture protection shell required for all civil power plants, the multiple-redundancy emergency cooling systems, automatic rapid shutdown features and superior filtration and retention systems in German nuclear power plants offer additional safety compared with Soviet plants. But Bremen nuclear physicist Scheer uses the expression "absolutely unfounded optimism" to describe Science and Technology Minister Riesenhuber's claim that a case such as that currently transpiring in the Kiev region is inconceivable in West Germany.

    All safety studies conducted by Western power plant operators use the evasive term "residual risk" - as if the risk in question were barely measurable and negligible. But upon closer inspection, it becomes clear just how much these safety scenarios are filled with self-deception and suppression of the truth. These studies ultimately define a "Maximum Credible Accident" as an accident that operators believe they can still control technically.

    This applies, for example, to an assumed scenario in a West German nuclear power plant in which all safety systems fail and a core meltdown occurs. Even in this case, according to a West German safety study, the risk to the population would be low. The study's authors write that the fission products escaping from the melt are, "in most cases," retained in the safety container for at least several days.

    Like in a smoke-filled room in which the air is clear by the next day, despite all windows and doors being kept shut, because the smoke particles have settled on the furniture and walls, this period would allow the worst radioactive particles to remain in the safety container, even if it develops a leak after a few days as a result of increasing pressure.

    But there is certainly the possibility that this pressure container will burst earlier than expected, possibly as a result of a steam explosion in the reactor core. But risk studies downplay this alternative to such an extent that it seems virtually nonexistent.

    According to the German study, although many tests have been conducted in recent years on the "problematic issue of steam explosions," and although such explosions have also been observed during these tests, they are "extremely unlikely" in reality. Karlsruhe safety expert J.P. Hosemann also believes that "core meltdown accidents on the high-pressure path" (the technical description of an accident involving an explosion) have not yet been "analyzed in detail."

    Despite all this uncertainty, German power plant operators have not hesitated to build reactors in close proximity to densely populated regions or even near major cities. In a study commissioned by the city of Schweinfurt, using the Grafenrheinfeld nuclear power plant as an example (the 1,300 Megawatt nuclear power plant is located only three kilometers from Schweinfurt city limits), the Heidelberg-based Institute of Energy and Environmental Research calculated the unthinkable consequences of an accident.

    The study concludes that in the event of a reactor accident with core meltdown, steam explosion and loss of the outer protective shell, up to 46,000 residents of Schweinfurt would be killed within four hours. Evacuation of the 85,000 people normally in the city at lunchtime would be impossible.

    Bavarian Minister of the Environment Alfred Dick's efforts to downplay the horrific results of the study followed what is by now a familiar pattern. According to Dick, accidents of this nature would only be conceivable if the multiple protective precautions in place in the power plant were to fail simultaneously, which, he said, is "practically impossible."

    As nuclear physicist Von Ehrenstein illustrated last week, the Western philosophy of redundant safety features has its own limits. After all, each additional emergency shutdown system or safety valve constitutes another potential source of trouble.

    Safety analysts have also noted that all civil nuclear power plants currently in service carry a hereditary burden. In an effort to acquire nuclear energy as quickly as possible and at the smallest possible cost of development, engineers essentially mounted the new energy potential onto aging steam machine technology. This approach was not necessary.

    In the 1950s, Siegfried Balke, the second German Minister of Atomic Affairs, considered the theoretical possibility of converting "the energy from the radiation directly, and not through the detour of heat," into electrical current, using a method known as direct conversion. This alternative was ultimately abandoned and engineers decided to apply the light water reactor model that had been developed for American submarines to the civilian nuclear power program. Other promising lines of development, though less risky, were discarded and treated cavalierly, often to save costs. As an example, the high-temperature reactor Rudolf Schulten developed in J lich, which was cooled with helium and substantially safer than other models, only made it as far as the prototype stage.

    Instead of increasing operating safety, the decision to combine the atom with the water in James Watt's steam machine ultimately increased susceptibility to problems.

    As of last September, "significant incidents in nuclear power plants" had occurred 151 times, in a total of 14 Western countries, between 1971 and 1984.

    Teams of engineers in the United States and Sweden are currently in the process of developing alternative power plant concepts after all, concepts equipped with greater "inherent" safety - making them superior to today's power plants, with all their added emergency shutdown features and retention containers.

    But these new types of power plants would only gradually diminish the risks, and they could not completely rule out radiation accidents.

    "The completely safe nuclear power plant," former nuclear manager Klaus Traube said last week, "cannot exist."

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    Translated from the German by Christopher Sultan.

    This article appeared in the May 5, 1986, issue of Der Spiegel, just days after the world became aware of the Chernobyl nuclear disaster. During the next few weeks, Spiegel Online will publish a series of reports on the worst accident in the history of civilian nuclear energy and how it changed Europe and the world.