In a nightmare scenario, fuel will melt at the Fukushima No. 1 nuclear power plant and large amounts of radioactive materials will be released if the water supply to the crippled reactors is halted for 38 hours, according to plant operator Tokyo Electric Power Co.
In a nightmare scenario, fuel will melt at the Fukushima No. 1 nuclear power plant and large amounts of radioactive materials will be released if the water supply to the crippled reactors is halted for 38 hours, according to plant operator Tokyo Electric Power Co.
But TEPCO officials said on Oct. 1 that it is only a simulated worst-case scenario, saying that it is unlikely that water being pumped into the No. 1 to No. 3 reactors would be suspended for many hours.
The officials said TEPCO will be able to restart the water supply within 30 minutes if it is stopped for any problem.
"Even if multiple problems occur, we will probably be able to begin pumping in water in about three hours," an official said.
The water supply may stop when pumps break down, the power supply is disrupted, tanks and other water sources are lost or water supply routes are damaged, according to TEPCO.
Water temperatures in the No. 1 to No. 3 reactors, which have fallen below 100 degrees, will rise by 48-51 degrees if the water supply stops for one hour, according to TEPCO.
In 18 to 19 hours, the water temperatures will reach 1,200 degrees, at which time hydrogen will be generated and could trigger an explosion, as occurred in some reactors in the early stages of the crisis following the March 11 Great East Japan Earthquake and tsunami.
In 38 to 50 hours, nuclear fuel will melt again, as it did in three reactors at the crippled plant, and fuel accumulated at the bottom of the pressure vessels will leak into the outer containment vessels.
But TEPCO officials said it is unlikely that the water supply would be suspended for many hours because there are backup pumps and water can also be pumped in through many routes.