April 8, 2011
The 7.1-magnitude aftershock on April 7 caused blackouts in nearly one million homes in northeast Japan. Officials reported that two people were killed.
April 7, 2011
A magnitude 7.1 earthquake hit off the northeast coast of Japan, near the city of Honshu. TEPCO officials say there is no additional damage to the plant at the time and all workers have been accounted for.
April 5, 2011
The Japanese government set its first radiation safety standards for fish today after thed istressed nuclear power plant reported radioactive contamination in nearby seawater measuring at several million times the legal limit. The Tokyo Electric Power Co., which operates the plant, insisted that the radiation will rapidly disperse and that it poses no immediate danger.
April 4, 2011
TEPCO plans to release 10,000 tons of radioactive water into the ocean in a move to clear space in a waste storage building for water that is even more highly contaminated than the dumped water. Chief Cabinet Secretary Yukio Edano called it an "unavoidable" step. Officials say the water must be disposed of before the normal cooling systems can be brought back on line, and intentionally draining some of it into the ocean is the best option.
March 31, 2011
Radiation levels continue to rise in the ocean, offshore from the nuclear power plant. Officials are also evaluating whether to expand the mandatory evacuation area after the report of high levels of radiation in the village of Iitate, 25 miles from the plant. Workers also continue to struggle with pooling radioactive water; they must keep pumping water to cool the reactors, but storage of contaminated water is becoming problematic.
March 23, 2011
Smoke is seen again at Unit 3. Tokyo water officials say they've found elevated radiation levels in the city's water supply. Testing found the amount of radioactive iodine was at twice the recommended limit for infants.
March 19, 2011
Water spraying resumes at Unit 3. Elevated radiation levels are detected in milk and spinach from areas around power plant. Emergency power is restored to the cooling systems for the spent fuel ponds in Units 5 and 6.
March 17, 2011
Water levels at Unit 4's spent fuel pool run low and radiation levels at the plant are high. Workers attempt to spray the spent fuel pool at Unit 3 with helicopters, fire trucks and water cannons. Little water reaches the pool. The Tokyo Electric Power Corp. reports that 23 of its workers sustained injuries and 18 were contaminated with radiation from the events at the plant following the tsunami.
March 16, 2011
Another fire at Unit 4 hinders efforts to get the reactors and spent fuel pools under control. Steam and smoke rise from Unit 3, due to evaporation of water in the spent fuel pool. Radiation levels surge. The U.S. government advises its citizens within 50 miles of the plant to evacuate.
March 14, 2011
Crisis depeens at Fukushima Dai-ichi. The pressure and heat continue to build in Unit 3, resulting in a hydrogen explosion that destroys the outer containment building. Fuel rods at Unit 2 are fully exposed to air twice, worrying officials. Workers pump seawater into the cores of Units 1, 2 and 3.
March 13, 2011
New problems appear at Unit 3, where workers vent steam to try to avoid another hydrogen explosion. Seawater pumped to Units 1 and 3.
March 12, 2011
Engineers scramble to prevent a nuclear meltdown. Some of the reactors begin to grow hotter with their cooling systems disabled. A hydrogen explosion rocks Unit 1, causing a radiation leak. Workers furiously pump seawater into the reactor's core.