Washington (CNN) -- Two weeks into Japan's nuclear crisis, a top U.S. Nuclear Regulatory Commission official and an industry critic gave Congress starkly different opinions on whether lessons can already be gleaned from the disaster and applied to U.S. plants.
The commission's executive director, Bill Borchardt, repeated the agency's view that United States' 104 nuclear reactors are safe, and said early information out of Japan does not suggest changes are needed, at least so far.
But a representative from an industry watchdog group strongly disagreed, saying Fukushima Daiichi has exposed vulnerabilities in U.S. plants that deserve immediate attention. Chief among them, he said, is that U.S. plants need more emergency batteries to cope with longer power blackouts, and plants should reduce the amount of fuel stored in spent fuel pools.
"There are lessons, learned at high cost in Japan, that can and should be applied to lessen the vulnerabilities at U.S. reactors," said David Lochbaum, a nuclear engineer with the Union of Concerned Scientists.
The hearing before the Senate Energy Committee brought together representatives of government, industry and the Union of Concerned Scientists, all of whom said radiation from Fukushima Daiichi does not pose a significant health threat to people in the United States. But they differed on whether the Japanese experience demonstrates a need for immediate action in the United States.
Last week, the Nuclear Regulatory Commission launched a 90-day review of the Fukushima disaster and ordered its staff to release "quick reports" in 30 and 60 days.
"I'll knock on wood as I ask this question," said Sen. Bob Corker, R-Tennessee. "Your sense is that you've seen nothing in Japan so far that you haven't already tried to engineer or change in our own existing facilities of that nature?"
"I would say that's true," Borchardt replied. "But that's why we're doing this extensive both short-term and long-term review."
Borchardt said past incidents have led to safety improvements. The 1979 accident at Three Mile Island near Harrisburg, Pennsylvania, led to expansion of a program placing resident inspectors at every nuclear power plant, he noted. The United States also requires inert gas inside containment buildings to protect them from hydrogen explosions, and requires plants to have severe accident mitigation guidelines.
But the Lochbaum criticized the pace of change.
"If the past three decades have demonstrated anything, it's that the NRC will likely come up with a solid action plan to address problems revealed at Fukushima, but will be glacially slow in implementing those identified safety upgrades," he said.
Lochbaum said the agency should require nuclear plants to be able to withstand longer power shortages. Among other things, the United States should upgrade the batteries that are a back-up source of power. Like Fukushima, 11 U.S. nuclear plants have eight hours of battery capacity, Lochbaum said. Ninety-three have only four hours of capacity, he said.
"I think we can do that. I don't think it's difficult. I think Japan showed the price of not doing that," Lochbaum said. "So I think it's cheap insurance for the reactors in the United States to go ahead and do that."
An industry representative agreed with Lochbaum that the industry should develop severe accident mitigation plans for spent fuel pools.
"We have some measures in place, but not to the extent we do for the reactors," said Anthony Pietrangelo of the Nuclear Energy Institute.
Pietrangelo told the committee the Fukushima incident has prompted the industry to review existing measures, and consider staging emergency equipment regionally.
"One thing I can say going forward is that our industry, our hallmark is learning from operating experience," Pietrangelo said. "We will enhance safety as a result of Fukushima, we will get these lessons learned. ... We started that already but it's going to take a long time to get a full understanding of what transpired there. But when we do, I can assure you that we will enhance safety margins across the industry."