WASHINGTON—Because of used nuclear fuel’s physical characteristics, the security that protects it and the high level of radioactivity within it, it is not material that terrorists can convert into a “dirty bomb,” the Nuclear Energy Institute (NEI) said today.
“Used nuclear fuel is well protected at nuclear power plants, which are the best defended industrial facilities in the United States,” NEI President and Chief Executive Officer Joe Colvin said. “Notwithstanding the disturbing news about the arrest of an individual allegedly planning to detonate a dirty bomb, Americans can have confidence that used fuel from nuclear power plants would not be the source of the radioactivity.”
Nuclear fuel is a thumbnail-sized uranium pellet with a ceramic and zirconium alloy coating. Thousands of pellets are bundled in fuel rods that typically are 12 feet long, with many rods bundled into fuel assemblies. Once the fuel undergoes fission and is removed from the reactor core, it is highly radioactive. Physical shielding is required to prevent people near it from being exposed to dangerous levels of radiation.
“News reports for the most part have accurately made clear that the radiological effects of a dirty bomb would be extremely localized,” Colvin said. “Even detonating used nuclear fuel where it is stored—either in water-filled vaults or steel- and lead-lined dry storage—is a tactic that would provide little if any assurance to terrorists that they could cause any radiological harm to the public.”
Because used nuclear fuel is highly radioactive, terrorists would have to undertake tremendously complex steps to move it off-site, and the radioactivity would kill them if they tried to do so without undertaking elaborate steps to assure their own safety while handling the material, Colvin said.
“Even if terrorists were able to gain access to used nuclear fuel—a feat that is tremendously improbable given the paramilitary security forces and built-in plant defenses they would encounter—fuel assemblies are large, heavy, inflexible housings built in a way that would prevent terrorists from wrapping it around an explosive charge, as some news reports over the past 24 hours have suggested,” Colvin said.
Used nuclear fuel is transported by the industry in containers designed to protect their contents in severe accident scenarios, which also provides a strong measure of protection against terrorists. Used fuel containers certified by the Nuclear Regulatory Commission have several layers of protection, with steel providing the outer strength and lead functioning as a radiation shield. Typically, for every ton of used fuel, there are four tons of protective shielding.
Before the NRC certifies container designs, they must meet rigorous engineering and safety criteria. In addition, the container designs must be able to pass a sequence of hypothetical accident tests, including:
A 30-foot free fall onto an unyielding surface, which would be equivalent to a head-on crash at 120 miles per hour into a concrete bridge abutment;
A puncture test allowing the container to fall 40 inches onto a steel rod six inches in diameter;
A 30-minute exposure to fire at 1,475 degrees Fahrenheit that engulfs the entire container; and
Submergence of the same container under three feet of water for eight hours.
Containers are also subject to separate testing under 50 feet of water for eight hours.
In addition to the test required for NRC certification, engineers and scientists at Sandia National Laboratories in New Mexico conducted a wide range of tests on used nuclear fuel containers in the 1970s and 1980s. These tests, which verified computer models, included:
Running a flatbed tractor-trailer carrying a container into a concrete wall at 84 miles per hour;
Placing a container on a rail car that was driven into a concrete wall at 81 miles per hour;
Placing a container on a tractor-trailer that was broadsided by a train locomotive traveling at 80 miles per hour.
In all cases, post-crash assessments showed that the containers—although slightly dented and charred—would not have released their contents. Other Sandia tests evaluated a terrorist attack, and showed that the impact of missiles on containers would be minimal, particularly compared to the impact on a host of other hazardous materials.
The Nuclear Energy Institute is the nuclear energy industry’s policy organization. This news release and additional information about nuclear energy are available on NEI’s Internet site at http://www.nei.org.