Nuclear energy is making a comeback, and a new exchange-traded fund from Van Eck Global, the Market Vectors Nuclear Energy ETF ( NLR), provides one of the purest plays on this sector available to U.S. investors. Americans have long been suspicious about the safety of nuclear power plants. In the three decades since the 1979 meltdown at Pennsylvania's Three Mile Island, not one new nuclear power plant has been built in the U.S. But concerns about global warming produced by fossil fuels are fueling demand for cleaner sources of energy. Nuclear power plants emit no greenhouse gases, while coal, the largest source of electric power generation, is a primary offender. Nuclear energy also appeals to those who decry the U.S.'s dependence on foreign oil, since all of our uranium needs are mined here in the U.S. or in Canada, providing a secure supply and a form of energy independence. Soaring demand for electricity and rising natural-gas prices aren't hurting the nuclear industry, either. According to the International Energy Agency, renewable energy sources -- including wind, sun, biomass and geothermal -- will only provide 6% of the world's electricity by 2030. Giving an additional push to the industry is the Energy Policy Act of 2005, which gives generous subsidies, such as tax credits and loan guarantees, to fossil fuel alternatives, including nuclear power. Market Vectors Nuclear Energy debuted on the American Stock Exchange last week. It tracks the DAXglobal Nuclear Energy Index. The ETF fund has an expense ratio of 0.65%.