Newly disclosed manuals for workers at Tokyo Electric Power Co.’s Fukushima No. 1 nuclear plant highlight the utility’s lack of preparedness for an emergency, a major factor leading to the meltdowns after the March 11 quake-tsunami, a review by The Japan Times showed Tuesday.
Instructions in the manuals were all based on the assumption that two backup direct current batteries at reactor 1 would keep working throughout any emergency. In fact, the batteries were knocked out by water when the monster tsunami struck and crippled the Fukushima plant.
The manuals also failed to instruct workers to open by hand critical valves normally powered by electricity to vent steam and thus reduce pressure in the containment vessel.
The containment vessel is the last line of defense to prevent radioactive materials from escaping the reactors. Tepco tried to open the valves to keep the vessel from breaking apart on March 12. Pressure also needed to be reduced to allow coolant water to be injected to prevent a meltdown of the reactor core.
But it took hours for Tepco workers, who apparently had no training in how to open the valves manually, to vent the steam and relieve the pressure, and many experts say the delay may be a key factor that led to the meltdown at unit 1.
Asked at a news conference Monday if the conditions assumed in the manuals were unrealistic, Tepco spokesman Junichi Matsumoto responded, “It may be an open question.
“(But) we don’t believe that we failed to do something that should have been done” to prevent the crisis from escalating, Matsumoto said.