FACTBOX: U.S. presidential candidates on nuclear energy

(Reuters) - Nuclear energy is part of each of the 2008 presidential candidates' energy platforms.

Republican John McCain supports it wholeheartedly, while Democrats Barack Obama and Hillary Clinton express reservations.

Below are aspects of each candidate's position on nuclear power as outlined in their energy polices.

MCCAIN, an Arizona senator

- believes the United States can use nuclear power more extensively to reduce its reliance on petroleum imported from unstable regions and unfriendly sources.

- believes that fuel sources that are alternatives to oil should be selected by competitive markets but thinks nuclear power has faced an uneven playing field because of political opposition.

- supports the Yucca Mountain storage facility and believes opposition to it is harmful to U.S. interests.

- is open to advances in technology that permit greater safe reprocessing of spent fuel. He believes improvements in reactor design have reduced concerns over safe operation, but that there must be vigilance in all aspects of operation, transportation of waste, and storage of waste.

OBAMA, an Illinois senator

- believes it is unlikely the United States can achieve its goals to fight climate change and reduce greenhouse gas emissions without nuclear power.

- wants four issues to be addressed in order for the nuclear energy industry to expand: the rights of the public to information, security of nuclear fuel and waste, waste storage, and proliferation.

- Obama introduced legislation in the U.S. Senate to establish guidelines for tracking, controlling and accounting for spent fuel at nuclear power plants.

- says he will make safeguarding nuclear material both abroad and in the United States a top anti-terrorism priority.

- aims to lead federal efforts to look for a long-term disposal solution. He opposes using Yucca Mountain in Nevada as the nation's main disposal site.

CLINTON, a New York senator

- believes that energy efficiency and renewable sources such as wind and solar energy are better options for addressing global warming and meeting U.S. power needs because of unresolved concerns about the cost of producing nuclear power, the safety of operating plants, waste disposal and nuclear proliferation.

- opposes new subsidies for nuclear power.

- aims to strengthen the Nuclear Regulatory Commission and improve safety and security at nuclear power plants.

- opposes Yucca Mountain and would halt work there; would convene a panel of scientific experts to explore alternatives for disposing of nuclear waste; and continue research, with a focus on lower costs and improving safety.

(Reporting by Jeff Mason; Editing by Peter Cooney)