(CNN) -- The future of earthquake-ravaged nuclear power plant Fukushima Daiichi is still anyone's guess, but it's already triggered fears of subsequent nuclear disasters elsewhere. As efforts continue to get radiation levels under control in the damaged facilities in Japan, several countries have expressed doubts about their own nuclear programs. And seven in 10 Americans say they're more concerned about a nuclear disaster happening in the United States than they were before, according to a recent USA Today/Gallup poll. Are these fears justified? What are the real risks of nuclear power, both globally and in the United States? And what do we do with all of that nuclear waste?Nuclear and hydropower have lower greenhouse gas releases than coalFukushima Daiichi is further from Los Angeles than Chernobyl is from New YorkCountries have expressed skepticism about nuclear powerYucca Mountain in Nevada is a proposed site to store used nuclear fuel in U.S.
Experts say that while nuclear power has generally proven relatively safe, it is important to question whether nuclear plants everywhere could cope with a two-fold natural disaster combination like the earthquake and tsunami that rocked _ on March 11. At _, these have been big problems because the electricity needed to keep them cool was lost, allowing radiation levels to rise, after the earthquake and tsunami.