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Daily News on Nuclear, Biological & Chemical Weapons, Terrorism and Related Issues
U.S. Begins Deploying Portal Radiation Sensors to Airports
WASHINGTON -- The U.S. Homeland Security Department has deployed more than 1,000 cargo-scanning radiation detectors around the country, but until late last year none could be found at the nation's airports (see GSN, Sept. 11, 2008).
That changed in September with installation of a radiation portal monitor at Dulles International Airport near Washington, D.C. Another three machines are due to be deployed at unspecified airports this spring and ultimately 30 sites that handle 99 percent of all U.S. airborne cargo could receive the technology.
The intent is to prevent a nuclear or radiological weapon from being smuggled into the country through an airport. It is part of a larger DHS effort that has placed about 1,120 portal units at U.S. seaports and border crossings since 2001.
"The reason we left the airports for last is because we were fully cognizant of the fact that the airports were going to be the most challenging environment to work in," said Patrick Simmons, head of the Nonintrusive Inspection Division of DHS Customs and Border Protection. "The airport environment is very, very fluid. ... We wanted to have our lessons learned and we really wanted to bring our best practices to bear."
Each monitor costs $450,000 to buy and install. They are capable of detecting any form of radiation but not of identifying the source as a harmless material or potential weapons ingredient.
The technology has been criticized for an excess of "nuisance alarms" -- going off after detecting low-level radiation produced by items such as kitty litter or bananas. Some experts have also questioned the portals' ability to detect weapon-grade material stored inside a shielded container (see GSN, Aug. 17, 2004).
Customs and Border Protection said it could not publicly address which points of entry are considered most likely to be used by smugglers of radioactive material.
The agency began its rollout at Dulles due to the airport's proximity to an obvious terrorist target and to the lawmakers who maintain what Simmons called "extreme congressional oversight" over federal radiation screening activities (sees GSN, Jan. 9, 2008). "It was an easy place to bring visitors," he said.
Dulles also needs only one monitor, as there is a single road leading from the tarmac to warehouses where cargo is temporarily stored before being shipped by truck to a final destination.
All cargo with Dulles as its final airport destination must pass through the portal, which consists largely of two yellow posts that each support two white sensor panels. Ultimately, nearly all containers that leave the Virginia facility by air would be screened at another airport that also possesses the detection technology, Simmons said.
"Eventually at some airport it's got to exit. So we'll catch it wherever it exits," he said.
Air cargo is generally stored in pallet-sized containers rather than the larger metal boxes pulled by trucks or stacked on rail cars. Small tractor-like vehicles take the containers off the tarmac and through a gate, passing through the sensor at the airport speed limit of no more than 5 mph.
If the monitor detects radiation, a flashing light goes off ahead of the driver, indicating that the vehicle must stop at a booth a quarter-mile down the road.
Officers who staff the booth at all times would also receive the alert at a sophisticated work station. Their job is then to interview the driver and to use more-precise hand-held detectors capable of identifying the specific isotope that is producing the radiation.
The alarm rate at Dulles is similar to that seen at other U.S. entry points, Simmons said. More than 95,000 "conveyances" -- a vehicle pulling one or more cargo containers -- passed through the portal between Sept. 8, 2008, and Jan. 4, producing 297 alarms. As has been the case nationwide, none of the alarms led to the discovery of threatening material.
"Sometimes the alarm doesn't go off" at all during a four-hour shift at the booth, said CBP Officer Stanley Peterson. "Sometimes it goes off once or twice."
Items found to set off sensors are much the same at Dulles as elsewhere.
"Although the commodities might be less, it's the same type of commodity," Simmons said. "We get a lot of earthen ware, a lot of porcelain, a lot of tile. ... People are shipping granite via air, which I certainly never would have suspected prior to rolling out this program."
The top alarm trippers are industrial devices and people who have undergone medical procedures involving radiation, according to CBP officers. Any person or item that passes through the monitor multiple times per day would have to undergo the same scrutiny each time they set off an alarm, they said.
"Being out here, you have to be alert to any type of situation that comes up," Peterson said.
It remains to be seen whether U.S. airports would receive the next-generation radiation detection systems intended to replace the existing devices, Simmons said.
Advanced Spectroscopic Portal monitors are supposed to correct a major failing of their predecessors by employing identification capabilities for radioactive isotopes. However, government auditors have expressed concerns about the effectiveness and cost of the machines, leading Congress to demand that they be certified prior to deployment (see GSN, Oct. 30, 2008).
Field testing was set to begin last week at four sites and to last four to six weeks. Homeland Security's Science and Technology Directorate plans additional testing, after which the technology could be ready for certification in the spring, Simmons said.
"We're testing them and we don't know yet exactly how we're going to be using them," he said.
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