A patchwork of state and local mortality reports, inconsistent data on illnesses and pollution combined with an American population that has moved around quite a bit in the past 50 years are just some of the challenges, said John Burris, chairman of the cancer-risk study committee.

Proving scientifically whether long-term exposure to low doses of radiation around the nation's 104 nuclear facilities has meant a higher rate of cancer for those living nearby will be a daunting task, Burris said.

"If you show living near a nuclear facility increases your chances of getting cancer, there will have to be radical changes," Burris said at a public meeting in Tennessee earlier this month. "But that is not up to the committee."

The study, called for by the Nuclear Regulatory Commission, is planned to update a 1991 National Cancer Institute study that found no danger in living near nuclear plants. President Obama has called for $36 billion in federal loan guarantees for nuclear power plant construction.

The first phase, to be wrapped up the first of next year, focuses on developing scientifically sound approaches for carrying out the study. The next phase will be the actual risk analysis, study director Kevin Crowley said.

Similar studies, like those on the populations of Hiroshima and Nagasaki, Japan, have been successful because they focused on a single atomic blast — not decades of population, Burris said.

The committee has held public meetings this year in Chicago, Atlanta, Tennessee, Washington, D.C., and Irvine, Calif.

Many of those who attended the hearings called for a scientific test of what Paul Gunter, director of the Maryland-based Reactor Oversight Project for Beyond, called "he-said-she-said" debate among experts about whether nuclear plants cause cancer in surrounding populations. The group opposes nuclear plants and weapons.

John Keeley, a spokesman for the Washington-based Nuclear Energy Institute, which represents the industry in the USA, said nuclear companies support the study.

He said the industry is not aware of any epidemiological study linking cancer to living near a nuclear plant. Keeley said he does not expect the academy's study will make that link.