New York Times editorial

March 14, 2011

Japan’s Multiple Calamities

Any comment on the disaster in Japan must begin with the stunning scale of human loss. Thousands dead or missing from the devastating earthquake and tsunami surge. Hundreds of thousands homeless. Whole villages wiped out. And now there is the threat of further harm from badly damaged nuclear reactors. The worst-case accident would be enormous releases of radioactivity.

The unfolding Japanese tragedy also should prompt Americans to closely study our own plans for coping with natural disasters and with potential nuclear plant accidents to make sure they are, indeed, strong enough. We’ve already seen how poor defenses left New Orleans vulnerable to Hurricane Katrina and how industrial folly and hubris led to a devastating blowout and oil spill in the Gulf of Mexico.

It is sobering that such calamities could so badly hurt Japan, a technologically advanced nation that puts great emphasis on disaster mitigation. Japan’s protective seawalls proved no match for the high waves that swept over them and knocked out the safety systems that were supposed to protect nearby nuclear reactors from overheating and melting down.

It is much too early to understand the magnitude of what has happened. But, as of now, this four-day crisis in Japan already amounts to the worst nuclear accident since Chernobyl in 1986.

From early reports, it appears that the troubled reactors survived the earthquake. Control rods shut down the nuclear fission reactions that generate power. But even after shutdown, there is residual heat that needs to be drawn off by cooling water pumped through the reactor core, and that’s where the trouble came.

The nuclear plant lost its main source of electric power to drive the pumps, and the tsunami knocked out the backup diesel generators that were supposed to drive the pumps in an emergency. That left only short-term battery power that is able to provide cooling water on a small scale but can’t drive the large pumps required for full-scale cooling.

Early Tuesday morning, the frightening news came that Japan was facing the full meltdown of crippled reactors at a nuclear power station — with unknown and potentially catastrophic consequences. In a televised address to the nation at 11 a.m. local time, Prime Minister Naoto Kan pleaded for calm as he announced that radiation had spread from the reactors. He added that there was “a very high risk” of further leakages.

With the United States poised to expand nuclear power after decades of stagnation, it will be important to reassess safety standards. Some 30 American reactors have designs similar to the crippled reactors in Japan. Various reactors in this country are situated near geologic faults, in coastal areas reachable by tsunamis or in areas potentially vulnerable to flooding. Regulators will need to evaluate how well operators would cope if they lost both primary power and backup diesel generators for an extended period.

This page has endorsed nuclear power as one tool to head off global warming. We suspect that, when all the evidence is in from Japan, it will remain a valuable tool. But the public needs to know that it is a safe one.