The National Academy of Sciences and the Nuclear Regulatory Commission disagree on how to analyze the safety of nuclear waste storage facilities in case of terrorist attack.

The matter takes on special urgency for Utahns because the NRC is considering a request to license Private Fuel Storage to build a storage facility for the country's nuclear power plant wastes in Skull Valley, Tooele County.

In February, the commission's Atomic Safety and Licensing Board gave preliminary approval to the facility. The NRC itself has not yet acted, and a state appeal of the board decision is set for hearing on April 6.

Meanwhile, the NRC disagrees with the National Academy of Sciences on how to assess danger from terrorist attacks against stored nuclear waste.

The NAS is an organization of distinguished scholars, chartered by Congress in 1863 to advise the federal government on scientific and technical matters. The NRC is the federal agency regulating nuclear matters.

Congress had asked the academy to study "the safety and security of commercial spent nuclear fuel storage," as outlined in a March 14 cover letter from NRC Chairman Nils J. Diaz to Congress.

The academy produced the study, which has not yet been made public, and sent it to Congress. In response, a joint congressional report indicated members of Congress expected the NRC to improve its analysis.

The NRC responded with a document, "U.S. Nuclear Regulatory Commission Report to Congress on the National Academy of Sciences Study on the Safety and Security of Commercial Spent Nuclear Fuel Storage."

Diaz's cover letter and the report are posted on the NRC Web site, www.nrc.gov. Once at the site, click on "Web-based ADAMS" and then "Begin ADAMS Search," then search under the heading "G20050024."

Activists concerned about the safety of nuclear power have complained about the fact that the NAS study has not yet been released. Congress commissioned that study about 18 months ago because lawmakers were not fully confident the NRC was covering all the bases, said David Lochbaum, a nuclear safety engineer with the group Union of Concerned Scientists.

While the report itself is still classified, the NRC has provided a peek at parts of it through its public response.

In 2002, NRC initiated a classified program about withstanding terrorist attacks, says the report.