japan nuclear power plant meltdown spreading

The task force's July 2011 report concluded U.S. The task force then reviewed NRC regulations to determine whether any actions were needed to ensure the safety of U.S. In April 2011, the Commission named a formal task force of senior NRC experts to examine information from the accident. The inspections covered procedures to compensate for extensive onsite damage, loss of all alternating current power, and seismic and flooding issues, as well as procedures for dealing with a damaged reactor. The NRC told its inspectors to independently assess each plant's level of preparedness. nuclear power plants took action to prepare for a Fukushima-like event. The 50-mile recommendation expired in October 2011. Embassy's advisory for American citizens to avoid the area within 50 miles of Fukushima Dai-ichi. government agencies, provided technical information supporting the U.S. On March 16, the NRC, along with other U. The NRC maintained its presence at the U.S. By March 14, the agency had sent additional staff to provide technical support to the U.S. The NRC sent two experts that weekend to assist the U.S. By the afternoon of March 11, the agency had fully staffed the Operations Center and begun interactions with Japanese regulators. The NRC's first focus was potential tsunami effects on California's nuclear power plants and other nuclear materials users on the West Coast and in Hawaii, Alaska, and U.S. The NRC's 24-hour Operations Center in Rockville, Md., began monitoring the situation shortly after the earthquake and tsunami occurred. Work continues to isolate the damaged reactors and radioactive contamination from the environment. Japanese authorities eventually stabilized the damaged reactors with alternate water sources. The Japanese government has reopened limited areas for residents to return to, but many communities remain off-limits. Radioactive contamination spread over a large area of Japan, requiring the relocation of tens of thousands of people. The hydrogen exploded inside the reactor buildings of Units 1, 3 and 4, damaging the buildings and releasing more radioactive material from Units 1 and 3. The conditions in the reactors generated extreme pressure, causing leaks of radioactive gas as well as hydrogen. Those systems eventually failed and all three reactors overheated, melting their cores to some degree. Steam-driven and battery-powered safety systems at Units 1, 2 and 3 worked for several hours (and more than a day in some cases). One of Unit 6's diesel generators continued working, providing power to keep both Units 5 and 6 (at right in the photo) safely shut down.

Units 4, 5 and 6 were shut down for routine refueling and maintenance. Units 1, 2 and 3 at Fukushima Dai-ichi were operating when the earthquake hit. The tsunami also damaged some of the site's battery backup systems. Four of six Fukushima Dai-ichi reactors lost all power from the generators. At that point, an estimated 45-foot-high (14 meter) tsunami hit the site, damaging many of the generators. Fukushima Dai-ichi lost all power from the electric grid, with diesel generators providing power for about 40 minutes. Eleven reactors at four sites (Fukushima Dai-ichi, Fukushima Dai-ni, Onagawa, and Tokai) along the northeast coast automatically shut down after the quake. On March 11, 2011, a 9.0-magnitude earthquake struck Japan about 231 miles (372 kilometers) northeast of Tokyo off the Honshu Island coast. plants for information on comprehensive earthquake and flooding hazard analyses. The NRC's March 2012 actions also asked all U.S. nuclear power plants to meet specific deadlines for: 1) maintaining key safety functions even if installed electricity sources fail 2) installing additional equipment to monitor spent fuel pool water levels and 3) installing/improving systems to safely vent pressure during an accident (for designs similar to Fukushima Dai-ichi). The Fukushima Dai-ichi Nuclear Accident.Backgrounder on NRC Response to Lessons Learned from Fukushima

Japan nuclear power plant meltdown spreading