New problems emerge in Japan's nuclear power emergency
Sampling of ocean water 30 km off Japan's coast found radioactive "iodine concentrations at or above Japanese regulatory limits," as well as amounts of cesium-137 below regulatory limits. Some of the contamination may be due to recycled sea water used to cool down the reactors and spent fuel ponds. Still, the volume of water thus contaminated suggests that the damaged Fukushima nuclear power plant complex has already released massive quantities of radionuclides over the past two weeks. More massive releases are a disturbing possibility, experts say.
Technical Update Experts now suspect a breach in Unit 3's containment vessel, based on an incident yesterday in which two workers stepped into pools of water found to be 10,000 times more radioactive than expected). [The] prime minister called the country's ongoing fight to stabilize the plant "very grave and serious."
Previous radioactive emissions have come from intentional efforts to vent small amounts of steam through valves to prevent the core from bursting. However, releases from a breach could allow uncontrolled quantities of radioactive contaminants to escape into the surrounding ground or air. (AP/Seattle Times, March 25)
Water samples revealed the presence of radioactive cobalt and molybdenum, suggesting the possibility of "routine corrosion in a reactor and its associated piping over the course of many years of use," said Michael Friedlander, a former nuclear power plant operator. (New York Times, March 25) Protective Actions Update Japanese authorities have issued a public request for voluntary evacuation of residents within the 12-18 mile zone where sheltering has been recommended. Sheltering is still the official recommendation for that area, but Chief Cabinet Secretary Yukio Edano said that, "It has become increasingly difficult for goods to arrive, and life has become harder." That is essentially what I suggested in a diary two days ago (although I recommended evacuating farther out). The change in policy demonstrates that radiation levels should not be the only consideration in deciding protective actions. The complications of Japan's emergency response prompted the head of the International Atomic Energy Agency to comment that current emergency management practice is outdated and "reflects the realities of the 1980s, not of the 21st century." That observation is hardly new, but possibly this time authorities will be prompted to take action. Food Contamination Singapore officials say they have found low levels of radioactivity in parsley, mustard, rapeseed and perilla imported from Japan. China, South Korea and Taiwan are the latest countries to suspend food and agriculture impacts from affected areas of Japan. On Wednesday, Japan's prime minister urged people to stop eating leafy vegetables from the contaminated area. A total of 11 vegetables were found to have contamination above regulatory limits. Samples of kukitatena had "more than 160 times the safety standard of radioactive cesium." Farmers are dumping contaminated milk, and officials are distributing bottled water after tap water in Tokyo was found to have radiation levels more than twice the level permitted for infants. AsiaOne has published pictures of some of the contaminated vegetables on its website for accurate identification. (This is an excellent idea, as many visitors and residents may not be familiar with local produce.) The Japanese government is ordering farmers to destroy some crops, promising to compensate them for their losses. Japan has been playing a dangerous game of catch-up as it attempts to interdict contaminated milk and produce. It failed to immediately establish a precautionary embargo on agricultural products originating in the contaminated areas, and to enforce it through access control points around the food control zone. Photo by Ian Sane, at Flickr