Global warming poses a profound threat to humanity and the natural world, and is one of the most serious challenges humankind has ever faced. We are obligated by our fundamental responsibility to future generations and our shared role as stewards of this planet to confront climate change in an effective and timely manner.

The atmospheric concentration of carbon dioxide— the heat-trapping gas primarily responsible for global warming—has reached levels the planet has not experienced for hundreds of thousands of years, and as a result the global mean temperature has risen steadily for more than a century. The National Academies...

An operating nuclear power plant contains a large amount of radioactive material, and an accident that results in the release of this material could cause significant harm to people and the environment. People exposed to high levels of radiation will die or suffer other health consequences within days or weeks. Lower radiation levels can cause cell damage that will eventually lead to cancer, which may not appear for years or even decades. People may need to be permanently evacuated from areas contaminated with radiation. The costs of evacuation and environmental remediation, and those of the loss of usable land, could...

The 9/11 attacks highlighted the concern that nuclear plants, their onsite storage pools for spent fuel, and spent nuclear fuel being transferred between facilities for reprocessing or storage may be vulnerable to terrorist attacks that could cause significant radiation releases. Given the growing sophistication and adaptability of terrorist networks and the limited ability of governments to deal with them effectively, this risk will likely persist into the foreseeable future.

Recent independent studies have highlighted the vulnerability of commercial nuclear power plants to terrorist attack, and the possible consequences of such attacks. For example, a 2002 study by the National Academy...

Some of the technologies used for nuclear power are dual-use, meaning that they can also be used to produce the materials needed to make nuclear weapons—highly enriched uranium (HEU) and plutonium.⁸¹ In particular, facilities for enriching uranium for use in power plant fuel can be used to make HEU, while facilities that reprocess spent reactor fuel produce plutonium. Nations that possess those technologies would find it easier to build nuclear weapons, and terrorists could acquire plutonium from reprocessing facilities. An expansion of nuclear energy could well increase these twin threats to U.S. and world security.

However, the expansion of...

Because the spent fuel removed from a nuclear reactor is highly radioactive, it must be disposed of in a way that protects the environment from contamination and living organisms from exposure. Radioactive isotopes can be spread by air or water, and can also become part of the food chain. While the radioactivity of spent fuel drops with time, according to a 1995 National Academy of Sciences study, the “peak risks [from a repository] might occur tens to hundreds of thousands of years or even farther into the future.”⁹⁶ Isolating spent fuel from the environment is therefore a highly demanding task—...

Some argue that new reactor designs on the drawing board will provide much greater levels of safety, security, and proliferation resistance than today’s generation of reactors. It is true that new reactors could be designed to be safer than today’s plants, and much more resistant to sabotage and attack. However, for designs in the early stages of development, enough information is not yet available to judge whether this potential will be realized.

Some of the claims about the benefits of new designs that are fairly well developed have merit, while some are exaggerations. While some design features would correct major...