By KEITH BRADSHER, HIROKO TABUCHI, and MATTHEW L. WALD
TOKYO — Emergency vents that American officials have said would prevent devastating hydrogen explosions at nuclear plants in the United States were put to the test in Japan and not success to work, according to experts and officials with the company that operates the crippled Fukushima Daiichi plant.
The failure of the vents calls into question the safety of similar nuclear power plants in the United States and Japan. After the venting failed at the Fukushima plant, the hydrogen gas fueled explosions that spewed radioactive materials into the atmosphere, reaching levels about 10 percent of estimated emissions at Chernobyl, according to Japan’s nuclear regulatory agency.
American officials had said early on that reactors in the United States would be safe from such disasters because they were equipped with new, stronger venting systems. But Tokyo Electric Power Company, which runs the plant, now says that Fukushima Daiichi had installed the same vents years ago.
Government officials have also suggested that one of the primary causes of the explosions was a several-hour delay in a decision to use the vents, as Tokyo Electric managers agonized over whether to resort to emergency measures that would allow a substantial amount of radioactive materials to escape into the air.
“Japan is going to teach us lessons,” said David Lochbaum at the Union of Concerned Scientists. “If we’re in a situation where we can’t vent where we need to, we need to fix that.”Officials from General Electric did not comment on Tuesday.
The seriousness of the crisis at the Fukushima plant became evident within hours of the quake and the tsunami that rushed over the plant’s sea wall.
Just 12 hours after the quake, the pressure inside Reactor No. 1 had reached roughly twice the maximum pressure the unit had been designed to withstand, raising fears that the vessels that house fuel rods would rupture, setting a possible meltdown in motion. With the pressure high, pumping in additional cooling water also was not possible.
