Word: reactors
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...nuclear reactors work by splitting large atoms into smaller pieces, producing heat. The danger is that the nuclear fuel, unless properly cooled, can overheat and melt through containment walls, releasing radioactivity into the environment. Most commercial reactors guard against meltdown by ensuring that the fuel is always surrounded by circulating coolant, usually ordinary / water. But what if a pipe bursts and the water is lost? Or if the water boils off? To prevent such mishaps, today's reactors have backup systems and backups to the backups. But no matter how many layers of redundancy are built into a conventional reactor...
Enter the new generation of nukes. Virtually every manufacturer has drawn up plans for power stations that are simpler to make, easier to run and demonstrably safer than the nuclear piles now in operation. While Westinghouse and General Electric are concentrating on improving their water-cooled reactors, many nuclear scientists are taking a different approach. One design, the so-called modular high-temperature gas-cooled reactor (MHTGR), has even won grudging support from the Union of Concerned Scientists (UCS), the most technically competent of the major antinuclear groups...
Proponents claim that the MHTGR (one type of which is shown here) is nearly idiot-proof. The key is to load a new form of nuclear fuel capable of withstanding very high temperatures -- up to 3,300 degrees F (1,800 degrees C) -- into reactor vessels so small that they cannot hold enough fuel to produce such temperatures. The fuel consists of tiny grains of enriched uranium that are coated in ceramic and embedded in billiard ball-size "pebbles" of graphite. The reactor needs no safety cooling system; helium gas flowing through the core simply carries away heat to power...
Critics are quick to point out that no reactor is really inherently safe; even the safest have their weak points. An analysis by the UCS last year concluded that a gas-cooled reactor designed by San Diego-based General Atomics was particularly susceptible to fires in the graphite that holds the fuel. And because the reactor had no containment structure, it was vulnerable to terrorists. Perhaps that is why the nuclear-power industry is quietly backing away from the "inherently safe" label. If anything disastrous happened to a reactor advertised as totally fail-safe, confidence in the technology might never...
...people of Pripyat had no way of knowing that their small Ukrainian town was dying that morning as they gazed at the ruddy glow over Chernobyl reactor No. 4 some 2 1/2 miles away. It was a bright spring Saturday, April 26, 1986. A townsman came in from sunning himself on a roof, exclaiming that he had never seen anything like it, he had turned brown in no time at all. He had what would later be known as a nuclear tan. A few hours afterward, the man was taken away in an ambulance, convulsed with uncontrollable vomiting. Soon many...