Washington state Health Department 
 
 The reactors on all the plants scrammed, shut off immediately as they were designed to do. 
 
 Control rods were properly lowered into the uranium-filled pools to stop the nuclear reaction that generates the heat and steam that move huge turbines that generate the power. 
 
 Enormous, high-volume pumps kicked in to send cooling water through the intricately designed, uranium-235-filled fuel rods, to prevent them from melting. 
 
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 Radiation is terrifying to most people. And the less you actually know about it, the more frightening it can be.Watching what looked like an endless Hollywood production of carnage in the coastal communities of northeastern Japan as they were inundated by earthquakes and 30-foot-tall, tsunami-driven waves was bad enough. But then the fires of disbelief were stoked anew as panting cable news crews ticked off details of six separate nuclear reactors that had completely or partially melted down or were soon expected to.Older TV viewers might recall being terrified, along with the rest of the world, as they watched the nuclear-disaster-that-could-never-happen at Three Mile Island unit 2 along the Susquehanna River near Harrisburg, Pa., in 1979. Or the even more disastrous explosion seven years later at Chernobyl Reactor No. 4 in the Ukraine.These earth-shaking events involved a single reactor, not the six that are now focusing the world's attention on the Fukushima I and Fukushima II nuclear complexes 150 miles north of Tokyo.Nuclear event and emergency-response experts huddled over the weekend in command centers from the White House to the Nuclear Regulatory Commission to state governments in California, Oregon and Washington. They watched the latest news unfold half a world away on big screens and shared information on dedicated, confidential government hot lines.They saw Japan's multiple-redundant nuclear safeguards work, at first.All worked according to much-practiced plans. But then, suddenly, a flood of information from the Japanese government described a cascade of almost unbelievable reports.The power running the pumps died. The locomotive-sized diesel backup generators were destroyed by the flooding from the tsunamis. Neutron-absorbing boron and seawater -- a combination so corrosive that it was a death sentence for the reactors -- was pumped in, in a final effort to avoid a nuclear meltdown.Then, like scenes from "The China Syndrome" or from the pages of "The Night We Almost Lost Detroit," an explosion ripped off the outer wall and roof of the building holding the 41-year-old General Electric reactor. Late Sunday night, a second building blew into pieces. In both explosions, the reactors were not yet breached.But several of the reactors were spewing a deadly cocktail of assorted radioisotopes, including iodine-131, cesium-137, xenon and krypton carried aloft with the radioactive steam.Almost instantly, postings on thousands of websites and blogs pontificated on the importance of every shred of information, real or imagined.Some presumed experts talked of curies, rads, becquerels, sieverts, mrems and other terms describing the escaping radiation, using measurement terms that haven't been used in years or had absolutely no relevance to a leaking reactor. Rarely did they explain what these numbers meant.Some postings were criminally absurd and flat-out wrong.One map that went viral showed color-coded plumes of radiation moving eastward across the Pacific and the prediction that radiation levels measuring 3,000 rads would reach the Aleutian Island chain in three days. Levels of 1,500 rads will hit the northern coast of British Columbia within a week and western North American "from Alaska to the Baja tip in 10 days, with radiation levels of 750 rads,'' the posting warned.These numbers, which would kill or sicken quickly, have absolutely no basis in fact at all. And, according to a radiation expert at the Federal Emergency Management Agency, they are more typical of the levels that might occur after a nuclear attack.In fact, Japanese nuclear officials have said repeatedly that they're dealing with "a minimal level of radiation that does not harm human health."It is good to sometimes be skeptical of government claims. During Three Mile Island, a hydrogen bubble in the damaged reactor was poised to destroy the unit, yet power company and state and federal officials denied the existence of the destructive bubble for days.Some companies were quick to take advantage of such skepticism about the Japanese reports.The Web was bristling with links from stories on the disaster taking readers to sites selling "Five Person Deluxe Survival Kits," "life-saving" potassium iodide pills, Swiss Army knifes, tools to turn off leaking gas lines and Geiger counters of all sizes. One site promised, "Your order can be overnighted to you before the lethal cloud arrives."These are ads that are automatically placed by computers and are not set there by the writers or editors.Leading the silliness parade were bloggers who were linking to Cold War civil defense ads from the 1950s showing Tommy the Turtle hiding from a nuclear blast and children being taught to "duck and cover" under their school desks.As real facts flowing from Japan fell to a trickle, the vacuum was filled with speculation.For example, meteorologists and their websites argued over the prevailing-wind currents and surface currents from Japan. Some said the winds would quickly carry the radioactive debris to the West Coast in days. Other forecasters, using the same charts, said the wind patterns would widely distribute and dilute any plume of radioactive material before it reached the U.S.Bad information was coming from even trusted sites. The respected Incident and Emergency Center of the International Atomic Energy Agency says it incorrectly reported that four of the damaged reactors were venting.The U.S. government's watchdog of nuclear power plants isn't doing all it can to keep the public calm.At a White House briefing this morning, Gregory Jaczko, the head of the NRC, said power plants in the U.S. are designed to handle all " significant phenomena," including tsunamis, floods and earthquakes. He was asked several times what size quakes U.S. plants are designed to withstand. But each time he flipped the question back to the Japanese crisis, avoiding answering what he was asked.AOL News called the NRC press office and was told that each site is built to a different seismic activity standard. But when we requested a list of the earthquake design limits for each plant under NRC control, that information isn't available, was the official reply.Asked what the range of protective limits was, he said he didn't think that information was available.What makes this information important is that the Japanese plants that are in crisis were designed to withstand a 7.9 quake, not the 8.9 monster that hit them. Government officials in the U.S. were doing their best to downplay the imminent danger on this side of the Pacific.Rumors spread wildly on the availability and shipments of potassium iodide tablets, which is pretty much the only preventive medication to neutralize the effect of radioactive poisoning that targets the thyroid gland and could eventually cause cancer.When AOL News questioned the Departments of Energy and Homeland Security on Saturday, spokesmen said that none of the medication -- also called KI -- has been shipped anywhere because there is "no apparent need." Officials questioned on the West Coast said the same.Oregon and Washington state health officials told AOL News that if it were needed, the radiation-blocking agent could quickly be shipped in from strategic stockpiles maintained by the Centers for Disease Control and Prevention.An official in California echoed the comments but added that there were already quantities of KI in the state because there are four operating power stations at two sites.The federal agencies said that they "continue to work to assess what is a very serious and fluid situation" but insisted that no one expected any "meaningful effects on the U.S. homeland.''Oregon and Washington say they continue to use continuous-reading Environmental Protection Agency radiation detectors to monitor levels. This is the same EPA system that first detected radiation from the Chernobyl accident at ground level on the West Coast one week after the meltdown in Ukraine.State officials said risks to residents of both states are minimal given the current size of the release from the Japanese reactors and the distance from the West Coast. But they will continue to closely watch the radiation detectors until the Japanese reactors are shut down. ||||| After a once-in-300-years earthquake, the Japanese have been keeping cool amid the chaos, organizing an enormous relief and rescue operation, and generally earning the world's admiration. We wish we could say the same for the reaction in the U.S., where the troubles at Japan's nuclear reactors have produced an overreaction about the risks of modern life and technology. 
 
 Part of the problem is the lack of media proportion about the disaster itself. The quake and tsunami have killed hundreds, and probably thousands, with tens of billions of dollars in damage. The energy released by the quake off Sendei is equivalent to about 336 megatons of TNT, or 100 more megatons than last year's quake in Chile and thousands of times the yield of the nuclear explosion at Hiroshima. The scale of the tragedy is epic. 
 
 Yet the bulk of U.S. media coverage has focused on a nuclear accident whose damage has so far been limited and contained to the plant sites. In simple human terms, the natural destruction of Earth and sea have far surpassed any errors committed by man. 
 
 Editorial Board Member Mary Kissel explains the Japanese response to the quake. 
 
 Given the incomplete news reports, it is impossible to say how much worse the nuclear damage will be. Unlike the Soviets at Chernobyl, the Japanese have been taking sensible precautions like evacuating people near the plants and handing out iodine pills even if they may never be needed. These precautions increase public worry, but better to take them even if they prove to be unnecessary. 
 
 We will have plenty of time to dissect events at the reactors and the safety lessons going forward. William Tucker provides some useful context nearby, and one crucial point is that the containment walls seem to have held. These walls are designed to withstand quakes and explosions, and it is good news if they have done so. The crisis seems to have been triggered by the failure of diesel generators that provided electricity to cool the reactors once they were shut down. Mr. Tucker explains that this weakness has been corrected in new nuclear plant designs. 
 
 We have no special brief for nuclear power over any other energy source. Our view is that it should compete with other sources on a market basis, without subsidies or government loan guarantees. Every energy source has risks and economic externalities, whether they are noise and bird kills (wind), huge land requirements (solar), rig explosions and tanker spills (oil), or mining accidents (coal). 
 
 But more than other energy sources, nuclear plants have had their costs increased by artificial political obstacles and delay. The U.S. hasn't built a new nuclear plant since 1979, after the Three Mile Island meltdown, even as older nuclear plants continue to provide 20% of the nation's electricity. 
 
 Enlarge Image Close JIJI PRESS/AFP/Getty Images An aerial photo shows the quake-damaged Fukushima Dai-Ni nuclear power plant. 
 
 The Tennessee Valley Authority is a couple of years away from completing a reactor at Watts Bar after years of effort. Proposals for 20 new reactors to be built over the next 15 to 20 years are in various stages of review in the multiyear approval process at the Nuclear Regulatory Commission, with two each in Georgia and South Carolina at the front of the line. But the much-ballyhooed "nuclear renaissance" is a long way off, and it will be longer after events in Japan. 
 
 Our larger point is less about nuclear power than how we react as a society to inevitable disasters, both natural and man-made. Because a plane crashes, we don't stop flying. Because an oil rig explodes in the Gulf, we don't (or at least we shouldn't) stop drilling for oil. And because the Challenger space shuttle blew up, we didn't stop shuttle flights—though we do seem to have lost much of our national will for further manned space exploration. We should learn from the Japanese nuclear crisis, not let it feed a political panic over nuclear power in general. 
 
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 The paradox of material and technological progress is that we seem to become more risk-averse the safer it makes us. The more comfortable we become, the less eager we are to take the risks that are the only route to future progress. The irony is that one reason Japan has survived this catastrophic event as well as it has is its great material development and wealth. 
 
 Modern civilization is in the daily business of measuring and mitigating risk, but its advance requires that we continue to take risk. It would compound Japan's tragedy if the lesson America learns is that we should pursue the illusory and counterproductive goal of eliminating all risk. ||||| Even while thousands of people are reported dead or missing, whole neighborhoods lie in ruins, and gas and oil fires rage out of control, press coverage of the Japanese earthquake has quickly settled on the troubles at two nuclear reactors as the center of the catastrophe. 
 
 Rep. Ed Markey (D., Mass.), a longtime opponent of nuclear power, has warned of "another Chernobyl" and predicted "the same thing could happen here." In response, he has called for an immediate suspension of licensing procedures for the Westinghouse AP1000, a "Generation III" reactor that has been laboring through design review at the Nuclear Regulatory Commission for seven years. 
 
 Author William Tucker explains why the danger is limited at Japan's nuclear reactors. 
 
 Before we respond with such panic, though, it would be useful to review exactly what is happening in Japan and what we have to fear from it. 
 
 The core of a nuclear reactor operates at about 550 degrees Fahrenheit, well below the temperature of a coal furnace and only slightly hotter than a kitchen oven. If anything unusual occurs, the control rods immediately drop, shutting off the nuclear reaction. You can't have a "runaway reactor," nor can a reactor explode like a nuclear bomb. A commercial reactor is to a bomb what Vaseline is to napalm. Although both are made from petroleum jelly, only one of them has potentially explosive material. 
 
 Once the reactor has shut down, there remains "decay heat" from traces of other radioactive isotopes. This can take more than a week to cool down, and the rods must be continually bathed in cooling waters to keep them from overheating. 
 
 On all Generation II reactors—the ones currently in operation—the cooling water is circulated by electric pumps. The new Generation III reactors such as the AP1000 have a simplified "passive" cooling system where the water circulates by natural convection with no pumping required. 
 
 If the pumps are knocked out in a Generation II reactor—as they were at Fukushima Daiichi by the tsunami—the water in the cooling system can overheat and evaporate. The resulting steam increases internal pressure that must be vented. There was a small release of radioactive steam at Three Mile Island in 1979, and there have also been a few releases at Fukushima Daiichi. These produce radiation at about the level of one dental X-ray in the immediate vicinity and quickly dissipate. 
 
 Editorial Board Member Mary Kissel explains the Japanese response to the quake. 
 
 If the coolant continues to evaporate, the water level can fall below the level of the fuel rods, exposing them. This will cause a meltdown, meaning the fuel rods melt to the bottom of the steel pressure vessel. 
 
 Early speculation was that in a case like this the fuel might continue melting right through the steel and perhaps even through the concrete containment structure—the so-called China syndrome, where the fuel would melt all the way to China. But Three Mile Island proved this doesn't happen. The melted fuel rods simply aren't hot enough to melt steel or concrete. 
 
 The decay heat must still be absorbed, however, and as a last-ditch effort the emergency core cooling system can be activated to flood the entire containment structure with water. This will do considerable damage to the reactor but will prevent any further steam releases. The Japanese have now reportedly done this using seawater in at least two of the troubled reactors. These reactors will never be restarted. 
 
 None of this amounts to "another Chernobyl." The Chernobyl reactor had two crucial design flaws. First, it used graphite (carbon) instead of water to "moderate" the neutrons, which makes possible the nuclear reaction. The graphite caught fire in April 1986 and burned for four days. Water does not catch fire. 
 
 Second, Chernobyl had no containment structure. When the graphite caught fire, it spouted a plume of radioactive smoke that spread across the globe. A containment structure would have both smothered the fire and contained the radioactivity. 
 
 If a meltdown does occur in Japan, it will be a disaster for the Tokyo Electric Power Company but not for the general public. Whatever steam releases occur will have a negligible impact. Researchers have spent 30 years trying to find health effects from the steam releases at Three Mile Island and have come up with nothing. With all the death, devastation and disease now threatening tens of thousands in Japan, it is trivializing and almost obscene to spend so much time worrying about damage to a nuclear reactor. 
 
 What the Japanese earthquake has proved is that even the oldest containment structures can withstand the impact of one of the largest earthquakes in recorded history. The problem has been with the electrical pumps required to operate the cooling system. It would be tragic if the result of the Japanese accident were to prevent development of Generation III reactors, which eliminate this design flaw. 
 
 Mr. Tucker is author of "Terrestrial Energy: How Nuclear Power Will Lead the Green Revolution and End America's Energy Odyssey" (Bartleby Press, 2010).
– America is positively freaking out over the state of Japan’s nuclear reactors, with some calling for a halt to the development of new nuclear plants. But that’s a wild overreaction, opines a Wall Street Journal editorial. The media’s done a poor job of putting the tragedy in Japan in proportion: The quake killed hundreds, and released a thousand times more energy than the nuclear explosion at Hiroshima. “In simple human terms, the natural destruction of Earth and sea have far surpassed any errors committed by man.” In a separate piece, William Tucker breaks down the technical workings of the reactors, and concludes that there’s little danger. “None of this amounts to ‘another Chernobyl,’” he says. Chernobyl had massive design flaws that these Generation II reactors don’t; their containment structures have held. “If a meltdown does occur,” he concludes, “it will be a disaster for the Tokyo Electric Power Company, but not for the general public.” For another (paywall-free) dose of realism, click here.