Fukushima 1 Nuclear Accident Day 1: Friday, 11 March 2011

A 9.0 magnitude earthquake strikes off the coast of Honshu Island at a depth of about 24 kilometres (15 mi). Fukushima I power plant's nuclear reactors 1, 2, and 3 are automatically shut down by the shake. Nuclear reactors 4, 5, and 6 were undergoing routine maintenance and were not operating, (reactor 4 was defueled Nov 2010). The tremor has the additional effect of causing the power plant to be cut off from the Japanese electricity grid, however, backup diesel generators kick in to continue cooling. Tokyo Electric Power Company (TEPCO), the plant's operator, finds that units 1 and 2 are not operating correctly and notifies the proper officials.

15:01 (approximate)

The tsunami unleashed by the earthquake strikes the Fukushima facility damaging the backup generators required to cool the reactors. With the loss of power from the grid and the damage to the generators, the plant has become "dark". Later, reports indicate that only the generator for unit number 6 remained working in full operational capacity.

According to a report in the New York Times, "[A]t the start of the crisis Friday, immediately after the shattering earthquake, Fukushima plant officials focused their attention on a damaged storage pool for spent nuclear fuel at the No. 2 reactor at Fukushima I, said a nuclear executive who requested anonymity.... The damage prompted the plant’s management to divert much of the attention and pumping capacity to that pool, the executive added. The shutdown of the other reactors then proceeded badly, and problems began to cascade."

16:00

The Nuclear and Industrial Safety Agency of Japan initiates an emergency headquarters in an attempt to gather information on the 55 nuclear reactors in Japan. There is no report that radiation was detected outside plant borders.

19:03

Prime Minister Naoto Kan declares a nuclear emergency status. This is announced by Yukio Edano, Chief Cabinet officer in Japan. Japanese government officials try to comfort the people of Japan by telling them that the proper procedures are being undertaken. They also announce that no radioactive leaks have been detected.

An evacuation order is issued by the government to persons within a 3 kilometres (1.9 mi) radius of the Fukushima I station. Those within a 10 kilometres (6.2 mi) radius are told that they can remain in their homes and carry on with regular activities until told otherwise.

At Fukushima I, the ongoing lack of electricity is causing the cooling system to fail, and the pressure within the nuclear units build up. This pressure buildup is the result of residual decay heat causing the coolant, which is not being circulated, to evaporate. There is no confirmation of radiation leaking from the reactor. TEPCO announces that pressure inside reactor unit 1 of Fukushima I is more than twice normal levels.