Workers at the Fukushima Dai-ichi nuclear power plant spray a substance to help reduce dust on April 1. Experts say it's likely that workers at the plant could have reduced the severity of the accident if they had made different decisions during the crisis. TEPCO hide caption

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What Went Wrong In Fukushima: The Human Factor
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This March 24 aerial photo shows the extent of damage at the Fukushima Dai-ichi nuclear power plant in Japan. The 40-foot-tall tsunami destroyed the electrical and cooling systems, resulting in meltdowns at some of the reactors. Air Photo Service/AP hide caption

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Reports: Why Things Fell Apart At Fukushima Plant
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Workers at the Fukushima Dai-ichi nuclear power plant spray a substance to help reduce dust on April 1. The cleanup operation at the facility could take more than a decade. TEPCO hide caption

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Cleaning Up Fukushima: A Challenge To The Core
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Manholes poke out from the ground in Urayasu, Japan, due to the liquefaction triggered by the 9.0 magnitude earthquake. The phenomenon, which allows sand and water to rise following ground shaking, was particularly pronounced in this area as a result of the long duration of the March 11 quake. Koki Nagahama/Getty Images hide caption

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In Japan, Shaken Soil Turned Soft After Quake
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TEPCO workers spray synthetic resin over the ground at the plant to prevent radioactive dust from spreading beyond the premises. AP hide caption

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In November 1940, just months after its completion, a large section of the Tacoma Narrows Bridge crashed into Puget Sound in Tacoma, Wash. The bridge collapsed under high winds — a failure that shocked engineers at the time. AP hide caption

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How Safe Is Safe Enough? To Engineers, It Depends
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Japan Self-Defense Force officers in radiation protection suits hold a blue sheet over patients who were exposed to high levels of radiation at the Fukushima Dai-ichi nuclear power plant on March 25. A team of experts at Japan's National Institute of Radiological Sciences have helped treat injured workers. Jiji Press/AFP/Getty Images hide caption

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Rapid Response Radiation Team Tends To Wounded
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Cows that consume feed, grass or water contaminated with radioactive iodine-131 can concentrate the element in their milk. Peter Elvidge/iStockphoto.com hide caption

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The facilities at the Fukushima Dai-ichi nuclear power plant were designed to withstand strong earthquakes and tsunamis, but not to the strength and size experienced on March 11. Air Photo Service/AP hide caption

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Everyday Radiation Exposure Is A Tiny Health Risk
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Japanese Buddhist monk Tanaka Tokuun, who was evacuated from Fukushima prefecture, looks over an instrument measuring radiation levels at a hotel on March 17. Buddhika Weerasinghe/Getty Images hide caption

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A Tokyo Electric Power Co. worker looks at gauges in the control room for Units 1 and 2 at the Fukushima Dai-ichi plant, Wednesday. AP Photo/Nuclear and Industrial Safety Agency hide caption

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Many of the sensors and cameras at the nuclear power plant were disabled by explosions, so plant operators are turning to highly maneuverable robots to get a better idea of what's going on in areas where it's far too radioactive for workers to venture. iRobot hide caption

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First Eyes Inside Nuclear Plant May Be A Robot's
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Japan's Leaked Radiation May Soon Become Harmless
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Reactor Engineers Struggle To Maintain Progress
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Chiyoko Kaizuka, 83-year-old farmer, weeds a spinach field March 20, in Moriya, Ibaraki prefecture. Eugene Hoshiko/AP hide caption

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