Since General Electric supplied the design four decades ago for all six nuclear reactors at the Fukushima Daiichi power plant, some regulators and critics have questioned whether the system can withstand a nightmare scenario.
Their concerns focused on the reactor's containment system that is the final line of defense against a wide release of radiation. Now GE's technology is facing the ultimate test: Can the structure enclosing the reactor keep the hot, radioactive stew bottled up inside? And can the spent fuel pools withstand a combination of explosions and equipment failure?
There is no sign so far that GE's design is to blame for any of the plant's problems, which mainly have been the result of power failures after the massive earthquake and tsunami that slammed the area Friday. The containment structure is holding up.
Some experts said that if the situation deteriorates at the nuclear plant, GE's design - known as the Boiling Water Reactor Mark 1 - may not withstand the massive amount of hydrogen gas that could be released.
"We're not at that point yet," said Paul Gunter, director of the Reactor Oversight Project at Beyond Nuclear. "They were going to retire Fukushima Daiichi in just a few more months, and so this particular Mark 1 with its substandard design was reaching its endlife, and so it raises a lot of concerns."
GE defended its technology on Monday while it offered engineers to help Japanese officials contain the crisis.
GE's Mark 1 containment system was designed to withstand discrete problems known as design basis accidents, such as a broken pipe releasing hot steam, said Ken Bergeron, a physicist.
But now there are fresh concerns about the fuel rods, which are above the reactors. Officials are concerned that structural damage to the plant may have exposed some of the rods to the air, which would spread radiation.
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