Americans' concerns over nuclear power have spiked in the wake of Japan's ongoing nuclear crisis, but how the events will affect the long-term discussion over sources of energy is still unclear.

In a USA Today/Gallup poll conducted with 1,004 adults last week, about 70 percent of American's said that they are now more concerned with a nuclear disaster occurring in the U.S. In that same poll, 47 percent of respondents said they oppose construction of nuclear power plants in the U.S, compared to 44 percent who favor it.

Sources of electricity in U.S. in 2009

A survey done before the Japanese earthquake and tsunami found that 57 percent either strongly or somewhat supported "the use of nuclear energy as one of the ways to provide electricity for the U.S.," with 38 percent strongly or somewhat opposed. Support for nuclear energy peaked last year, with 62 percent voicing support. Overall, support has been over 50 percent for most of the last decade and is higher now than it was a decade ago.

In its analysis, Gallup said that short-term worries over nuclear disasters may not affect Americans' support for nuclear energy over the long term.

Still, a look at the media coverage and discussion during the crisis shows that the incidents have served as an unhappy reminder of the risks of nuclear energy, which will likely cause regulatory reviews of nuclear safety at a number of U.S. plants. The nuclear crisis also appears to have rekindled people's awareness of radiation and the sources of the country's energy, all of which have trade-offs.

Few options Not surprisingly, the future of nuclear power in the U.S. was one of the top topics for Sunday morning talk shows, with Energy Secretary Steven Chu, Sen. Jeff Bingaman (D-N.M.), and Rep. Ed Markey (D-Mass.) all scheduled. Chu is a strong supporter of expanded nuclear power, particularly smaller, modular reactors that could get built quicker and for lower overall investment.

He said that existing plants, including the Indian Point power plant near New York City, will be reviewed and that the location of future sites will be influenced by the Japanese crisis, according to an Associated Press report. "Any time there is a serious accident, we have to learn from those accidents going forward," he said.

Nuclear opposition groups, such as Physicians for Social Responsibility, echoed previous arguments against nuclear energy, including the health risks, costs, and security concerns from terrorist attack. But even groups that have envisioned some role for nuclear in the country's future energy mix have pushed for greater scrutiny.

Frances Beinecke, the president of environmental advocacy group the National Resources Defense Council, said that the problems in Japan demonstrate that U.S. plants need to reconsider contingency plans in blackouts and other safety mechanisms. "As we learn hard lessons from the crisis in Japan, we must move, in this country, to a complete review and reassessment of the nuclear safeguards we rely on to protect us from the risk of catastrophe," she wrote.

Some people have started to speculate that nuclear power growth in the U.S. could be slowed or stopped. Nuclear power now supplies about 20 percent of the U.S. electricity and a number of existing plants are seeking to extend their licenses to operate. In terms of construction of new nuclear power plants, which will require loan guarantees from the federal government, Sen. Bingaman said Japan's crisis could be a "significant impediment," according to E2 Wire.

Cutting back on nuclear energy, even as demand for electricity continues to rise, would mean an increase in fossil fuels and potentially more solar and wind energy. Solar and wind are growing rapidly but are still a small fraction of the overall energy production in the U.S. and do not supply the steady "baseload power" that nuclear or fossil fuel plants do. Even before the Japan disaster, the use of natural gas, which burns cleaner than coal and is a domestic source of energy, was expected to grow in the coming years.

Moving away from nuclear power, which has no emissions during operations, would have a negative impact from an environmental point of view, according to one analysis. The Breakthrough Institute found that if the U.S. greenhouse gas emissions would increase with a complete phase-out nuclear power, even with a sharp increase in solar and wind, and increases in fossil fuels. It found the same is true in Germany, which shut seven of its 17 nuclear plants indefinitely.

On Sunday, there were reports that Japanese engineers at the Fukushima plant were making progress in averting larger radiation leaks by containing the heat from the damaged reactors and spent fuel containment pools.

If the situation becomes under control in the coming weeks as everyone hopes, media attention will likely move to the devastation in the country from the earthquake and other events. Without a doubt, this incident will have a significant impact on nuclear regulators and, most likely, plant operators. Now, we'll see how attitudes change toward nuclear over time and whether people will maintain attention on the pros and cons of different energy sources.