GWEN IFILL: And to new questions about nuclear safety in this country in the aftermath of the Japanese accident.
Ripples from the earthquake and tsunami that devastated the Japanese coast and triggered a nuclear crisis are still being felt more than four months later. Radiation levels at the Fukushima Daiichi plant are down, but thousands of nearby residents, kept away by a 12-mile restriction zone, still haven't returned to their homes.
Japan's prime minister said the disaster has led his nation to reevaluate its heavy dependence on nuclear energy.
NAOTO KAN, Japanese Prime Minister (through translator): We should plan to take gradual steps to wean ourselves off nuclear power and become a country that can live without nuclear energy. I think that's the correct direction for our country to take.
GWEN IFILL: And the accident has triggered similar questions in the United States.
SEN. DIANNE FEINSTEIN, D-Calif.: The lesson is that we need to think carefully about whether our country has properly estimated the threats to our nuclear facilities and designed the facilities to endure them. An independent review of the design basis for all United States plants, I believe, should be a priority.
GWEN IFILL: That challenge has fallen to the Nuclear Regulatory Commission, which today presented a new set of industry safety recommendations.
In the short term, plants would improve backup electricity systems for spent-fuel pools and enhance cooling systems. And emergency guidelines would be updated. Ultimately, plants like the ones in Japan would have better ventilation to prevent hydrogen buildup and gas explosions. And, the task force said, the plants should be able to operate for at least eight hours on backup power, in the event of the sort of outage that crippled the Japanese plants.
In the months since the accident in Japan, a number of news organizations have reported of other shortcomings and potential safety lapses at plants around the U.S. The latest, in today's Wall Street Journal, found staff members at the NRC had long been concerned about seismic risks at two dozen nuclear sites, mostly in the Midwest and along the East Coast.
NRC Chairman Gregory Jaczko wants to move on the latest safety recommendations within 90 days. But representatives of the nuclear industry say that may be too tight a deadline for an agency that typically takes years to change policy.