Tokyo Electric Power Company, the main operator of the Fukushima power plant, has announced that there was an accident at the stricken facility last year.
According to Japan's Yomiuri Shimbun Monday, power was cut and water levels dropped by 2-meters at the plant's No. 2 reactor last June due to human error.
TEPCO also says it will set up a seawall in front of reactors 3 and 4 to prevent further damage from possible aftershocks.
Meanwhile, Toshizo Kosako, nuclear adviser to Japanese Prime Minister Naoto Kan, has resigned, citing Tokyo's sloppy handling of the crisis.
Kosako stepped down last Friday.. insisting that the government's radiation exposure limit for children is wrong.
He says the Japanese government ignored his advicewhen he said that exposure to 20-millisiverts of radiation a year for everyone is not acceptable, especially for children.