Increasingly, the nation looks toward nuclear power as an alternative to global-warming fossil fuels. Applications for new and extended reactor licenses are snowballing.

Yet progress on a national nuclear dump site is virtually paralyzed.

Late last month, California and Nevada filed a litany of challenges against a proposed nuclear-waste repository near Las Vegas, delivering another in a series of setbacks to this mega-billion dollar plan.

The state challenges - hundreds of them, mostly focused on environmental risks, corrosion and water-supply concerns - may not kill the Yucca Mountain repository. But they are likely to slow its already glacial pace.

By many measures, nuclear power plants are safer than coal-fired plants, which expose millions of people to life-shortening air pollution. Nuclear energy is low in carbon emissions, and new reactor designs have the potential - though still unproved - to cut the danger of radioactive accidents or misuse.

STORAGE STRATEGY NEEDED

But it is foolhardy to push farther out onto the nuclear limb without a viable strategy to either permanently store or reduce radioactive waste. Much of the spent fuel from U.S. nuclear reactors sits in wet or dry storage at the nation's 100-plus commercial nuke plants, presenting a widespread security challenge.

This month, the Nuclear Regulatory Commission revised rules to better defend plants from physical and cyberattacks. But many of the details are classified, inhibiting public review of the measures.

According to the U.S. Department of Energy, "more than 161 million people reside within 75 miles of temporarily stored nuclear waste."

Some advocates say the U.S. could ease the nuclear-waste problem by following the path of France, which reprocesses a portion of its usedfuel. But that strategy - besides producing plutonium that can lead to weapon proliferation - also leaves significant nuclear waste. And France, like the U.S., has no permanent deep-underground repository.

Research on these issues is ongoing. But until there are signs of a breakthrough, or a genuinely safe storage site, the rush to nuclear power is a stampede to nowhere.