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Summer 2005 Vol. 5 No. 2

Table of Contents

©Creatas Dousing Danger at Nuclear
Power Plants

Ways to Reduce Risks From Terrorist Attacks

Almost from the day the first U.S. commercial nuclear power reactor went online in 1957, rods containing used -- yet still highly radioactive -- uranium have been accumulating in cooling pools and dry casks at over 100 operating and decommissioned plants. Since Sept. 11, 2001, some independent analysts have worried that these fuel rods could be stolen by terrorists to make "dirty bombs" or that cooling pools at the plants could become new targets for terrorist attacks.

At the request of Congress, a committee of experts was convened by the National Academies to examine the safety and security of spent nuclear fuel stored at commercial nuclear power plants. The committee's consensus report was delivered in classified form in July of last year to Congress, the U.S. Nuclear Regulatory Commission (USNRC), and the U.S. Department of Homeland Security. A public version of the committee's report was released in April 2005.

The committee found that cooling pools at some plants are potentially at risk from a terrorist attack, but given existing plant security measures, the likelihood that terrorists could steal enough spent fuel to use in a nuclear dispersal device is small.

Spent nuclear fuel rod in cooling pool, ©Tim Wright/CorbisThe most significant threat from a terrorist attack is the potential for breaching the cooling pools themselves. The committee said an attack that partially or completely drains a cooling pool could have severe consequences, including the initiation of a high-temperature fire in the fuel's zirconium cladding, which could result in the release of large quantities of radioactive material. The report recommends that two immediate steps be taken to reduce the chances and consequences of such fires: repositioning fuel rods in the pools to more evenly distribute heat loads from radioactive decay and installing water-spray systems to cool the fuel in the event of a coolant loss.

The committee noted that the potential risks depend on plant design. Some cooling pools, for example, are located below ground level or are otherwise protected from external line-of-sight attacks. For this reason, the Nuclear Regulatory Commission should promptly undertake plant-by-plant vulnerability analyses to determine which plants are at highest risk. The committee also found that dry cask storage, which is used to store fuel older than about five years, has security advantages over storage in cooling pools; for example, it divides the inventory of spent fuel among a number of individual containers. Consequently, less fuel is at risk in an attack. Once the recommended plant-by-plant vulnerability analyses are completed, the USNRC may conclude that earlier-than-planned movements of spent fuel from pools to dry casks would be prudent at some plants.

The report also recommends that the USNRC improve the sharing of pertinent information from its analyses with nuclear power plant operators and commercial vendors. During its work, the committee observed that current classification and security practices have impeded the sharing of valuable information that could improve plant security, with a negative effect on feedback, cooperation, and overall confidence in the agency.

The public version of the National Academies' report was prepared with the cooperation of the Nuclear Regulatory Commission. It contains all of the findings and recommendations of the original classified study, although classified security and safeguards information has been removed. "This publicly available version of our report," said Bruce Alberts, president of the National Academy of Sciences, "fulfills our responsibility to inform the public and elected officials about a critical national security issue while also ensuring that we publish nothing that might inadvertently aid a terrorist."   -- William Skane

Safety and Security of Commercial Spent Nuclear Fuel Storage: Public Report. Committee on Safety and Security of Commercial Spent Nuclear Fuel Storage, Board on Radioactive Waste Management, Division on Earth and Life Studies (2005, approx. 125 pp.; ISBN 0-309-09645-6; available from the National Academies Press, tel. 1-800-624-6242; $32.00 plus $4.50 shipping for single copies).

Louis J. Lanzerotti, distinguished research professor, New Jersey Institute of Technology, and consultant, Bell Labs, Lucent Technologies, Murray Hill, N.J., chaired the committee. The study was funded by the U.S. Nuclear Regulatory Commission and the U.S. Department of Homeland Security.

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Copyright 2005 by the National Academy of Sciences