Nuclear update: Leak stopped. Why is Japan injecting nitrogen into reactor?
Workers plugged a leak of highly radioactive water into the ocean from Japan's Fukushima Daiichi nuclear power plant Wednesday, even as they tried to prevent another hydrogen explosion in reactor No. 1 by injecting nitrogen gas.
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The irony of the situation is that while stemming one source of water radioactivity, TEPCO was actively opening the spigot on another. With the approval of Japan’s government, TEPCO is pumping into the ocean about 10,000 tons of water from Fukushima’s radioactive waste treatment plant and 1,500 tons of water from the drain pits of reactors No. 5 and No. 6, according to a report from the International Atomic Energy Agency.Skip to next paragraph
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The water being released has about 100 times the legal limit of radiation. Since the legal limit is quite low, the released water would be a health concern for local residents only if they ate seaweed and seafood from the affected area every day for a year, said the IAEA.
Conflicting radiation reports cause confusion
In past weeks, there have been so many reports of different radiation readings in different places from the sea and in the air around Fukushima that many Japanese – and Americans – are confused about whether the surrounding environment is safe.
“At this time, this event has not become a national health disaster for Japan,” said Michael Corradini, chairman of the engineering physics department at the University of Wisconsin in Madison, at a House hearing in Washington on Wednesday.
Airborne radiation doses outside of a 60-kilometer (35-mile) radius from Fukushima now are close to normal, Dr. Corradini testified before the House Energy and Commerce Committee, on behalf of the American Nuclear Society.
However, at the same hearing Dr. Edwin Lyman, senior scientist in the Global Security Program at the Union of Concerned Scientists, said that the Austrian Central Institute for Meteorology has estimated that the Fukushima complex has released 80 percent as much of the long-lived radioactive isotope cesium-137 as was emitted by the devastating Chernobyl nuclear accident.
Yet the amount that has escaped so far is only about one-tenth of the total amount of cesium-137 contained in the three most damaged Fukushima reactor cores, said Dr. Lyman.
“Further damage to the fuel, reactor vessel, and containment could result in far greater releases,” he said.