Leaks in the pressure vessels themselves, where the fuel is. In other words, perhaps three of the reactors are technically in a state of meltdown and breached containment.
This appears to be the conclusion this week, ever since repair of a water gauge has resulted in data showing that the water is disappearing at a faster rate than otherwise expected, and apparently accumulating in the lower levels of the plant, in the turbine buildings. Radiation levels where the water is pooling are said in a Wall Street Journal story to be in the range of 1 to 2 Sieverts per hour. A two hour exposure at such levels would kill you in 30 days.
Scientific American has these details via Reuters:
"There must be a large leak," Junichi Matsumoto, a general manager at the utility [TEPCO] told a news conference.
"The fuel pellets likely melted and fell, and in the process may have damaged...the pressure vessel itself and created a hole," he added.
Since the surface temperature of the pressure vessel has been holding steady between 100 and 120 degrees Celsius, Matsumoto said the effort to cool the melted uranium fuel by pumping in water was working and would continue.
VESSEL HAS A HOLE
Based on the amount of water that is remaining around the partially melted and collapsed fuel, Matsumoto estimated that the pressure vessel had developed a hole of several centimeters in diameter.
Read the full story, here.
