N-reactor cooling failed before tsunami (JAPAN)

The Yomiuri Shimbun

An emergency cooling system of the No. 1 reactor at the Fukushima No. 1 nuclear power plant malfunctioned after the March 11 earthquake and before the tsunami hit, data released by plant operator Tokyo Electric Power Co. have revealed.

According to a large cache of data concerning plant operations from March 11 to 14 released Monday by TEPCO, the No. 1 reactor's isolation condenser, which operates on direct-current power, began to malfunction shortly after the Great East Japan Earthquake struck the Tohoku and Kanto regions.

TEPCO on Sunday announced that after the tsunami completely knocked out the cooling system, fuel rods in the No. 1 reactor melted down 16 hours after the earthquake hit at 2:46 p.m. on March 11. If the cooling system had operated normally, the meltdown could have been delayed, according to some nuclear experts.

The Economy, Trade and Industry Ministry's Nuclear and Industrial Safety Agency demanded TEPCO release the data, which include water levels within reactor containment vessels and radiation levels for several days after the earthquake, in addition to operator logs and operation records.

http://www.yomiuri.co.jp/dy/national/T110517005443.htm