Smarter technology for port defense

[Susan Gawarecki <loc@icx.net>]

Smarter technology for port defense

Livermore lab's neutron beam would expose atomic bombs in ship cargo

- Keay Davidson, Chronicle Science Writer

Monday, June 14, 2004



It would be the ultimate Trojan Horse: a nuclear weapon smuggled into 

the United States inside an innocent-looking cargo container, like those 

stacked atop freighters that routinely slip under the Golden Gate Bridge.



To prevent terrorists from smuggling atomic bombs into the ports of 

Oakland, Los Angeles-Long Beach, New York or other U.S. harbors, Bay 

Area scientists are developing a unique kind of bomb detector this 

summer that uses subatomic particles called neutrons to detect highly 

enriched uranium or plutonium. They hope it'll be ready for scanning 

imported cargo containers as early as 2007.



Just as a doctor uses an X-ray machine to scan a patient's insides, the 

bomb-detector under development at Lawrence Livermore National 

Laboratory would scan a cargo container for a hidden nuclear device. The 

Department of Homeland Security is spending $4 million on the project 

this year alone.



Each year, aboard transoceanic freighters, 6 million of these truck-size 

cargo containers arrive at U.S. ports packed with Japanese DVD players, 

French wines, Chinese circuit boards and other foreign goods.



Even before Sept. 11, U.S. security officials feared that terrorists 

might hide a nuclear weapon or "dirty bomb" inside a cargo container. A 

worst- case result might resemble that portrayed in the 2002 film "Sum 

of All Fears" starring Ben Affleck: Terrorists hide a stolen nuke inside 

a soft-drink machine and sneak it into Baltimore. The bomb explodes, 

vaporizing much of the city.



"If you wanted to do the one thing that would damage the whole fabric of 

our society, this is probably the one," said Eric Norman of the Lawrence 

Berkeley National Laboratory's nuclear astrophysics division, a key 

player in the project.



An August 2003 report from Livermore, titled "Detection of Special 

Nuclear Material in Cargo Containers Using Neutron Interrogation," states:



"The rate of container arrivals at U.S. ports is expected to increase 

dramatically over the coming decade. The West Coast ports of Los 

Angeles-Long Beach, Oakland and Seattle are currently processing 11,000 

containers per day, or eight per minute on a 24/7 basis," says the 

report, authored by Livermore nuclear physicist Dennis Slaughter and 12 

colleagues.



"Because successful delivery of just one such weapon can have 

catastrophic consequences it is essential that all cargo containers 

entering the U.S. be screened with an extremely high probability of 

detecting any (bomb) hidden within. The cost of failure is very high," 

adds the unclassified report.



Ordinary X-ray scanners, like those in airports, can't reliably detect 

nuclear or fissionable materials transported in the cargo containers. 

That's because of the cargo containers' sheer mass: they weigh up to 27 

tons, says Stan Prussin, an applied nuclear chemist at UC Berkeley and a 

central participant in the Livermore project. The containers' mass and 

contents -- everything from Korean tennis shoes to Brazilian nuts to 

Russian vodka -- provides a tremendous amount of shielding, which could 

frustrate ordinary scanners.



So this month, a team of about 20 investigators from Lawrence Livermore, 

UC Berkeley and Lawrence Berkeley hope to begin calibration tests on a 

crude prototype of the nuke-detector inside a barn-size, mundane-looking 

manufacturing building at Livermore.



Later in the summer, if all goes well, they'll begin testing the ability 

of the device to detect a small sample of highly enriched uranium 

concealed inside a simulated cargo container. The container will be 

filled with sheets of plywood, aluminum, steel and other material, to 

simulate materials that terrorists might use to shield a bomb from 

detection.



In theory, the Livermore detector would work by firing a neutron beam 

through a cargo container as it rolls along a conveyor belt between two 

large, flat arrays of detectors. (The scientists jokingly call it a 

"nuclear car wash. ") The high-speed neutrons would split atoms within 

concealed uranium or plutonium. Bursting like eggs, the atoms would then 

expose their presence by emitting their own telltale electromagnetic 

radiation (gamma rays) and neutrons, which could be sensed by the 

detector arrays.



Scientists want to be able to detect at least 5 kilograms (11 pounds) of 

uranium or 1 kilogram (2.2 pounds) of plutonium. Those amounts are 

significantly less than is required to make a bomb. Security experts 

fear that some terrorists, rather than smuggling a fully operational 

bomb all at once, might try to evade security scanners by bringing 

fissionable materials into the country in small chunks, then assembling 

the bomb inside the United States.



Although the detector sounds pretty simple, it isn't. Scientists face a 

number of technical headaches, including:



-- Figuring out how to detect enriched uranium or plutonium even if 

terrorists have shielded the materials with lead, which absorbs gamma 

rays, or with materials rich in hydrogen (such as water, wax or wood), 

which absorb neutrons.



-- Figuring out how to discern the signal of a bomb against the 

background noise of natural radioactivity in the environment. A special 

source of concern is cosmic rays: These high-speed, electrically charged 

particles routinely fall to Earth from outer space. (As you read this 

passage, they're zipping harmlessly through your body like bullets 

through fog.)



The trouble is, bomb-detectors could be confused by the steady "noise" 

of cosmic rays as they plunge to Earth. To determine how much cosmic 

rays might confuse a nuclear detector, the scientists have hired a 

physics student to spend part of this summer measuring the cosmic-ray 

intensity in the Bay Area.



In interviews and an internal Livermore report, the scientists caution 

that not all the challenges are technical in nature. Rather, some of the 

questions are political, diplomatic, economic -- even moral. For example:



-- Can the scanner scan an entire cargo container reliably enough and 

fast enough (ideally, within one minute) to avoid delaying shipments? 

The detector must have an extremely low rate of false alarms. Otherwise, 

repeated scares could paralyze commerce, especially if it results in 

unnecessary public panic.



-- Illegal immigrants sometimes sneak into the United States by hiding 

inside cargo containers. Can the scientists develop a bomb-detector that 

emits neutrons, and possibly gamma rays, intense enough to detect 

fissionable materials without being severe enough to harm human stowaways?



-- The scanner's neutrons would temporarily "radioactivate" -- make 

radioactive, by shattering an atom so that it gushes its energy and 

particles into the environment -- materials inside the cargo container, 

including food. Would importers of French wines and other products 

tolerate even brief radioactivation of their shipments? And would 

consumers later shun such products, even after their radioactivity has 

decayed to a safe level?



Based on what Slaughter calls "back-of-the-envelope" calculations, he is 

"very confident" that the radioactivity would be short-lived and 

normally no more dangerous than natural background radioactivity in 

plants and food. However, he acknowledges that some consumers might not 

be reassured by such calculations.



-- Should the U.S. demand the right to install and use the nuclear bomb- 

detectors at foreign ports of embarkation, before the ships set sail for 

the United States? There's a potential diplomatic downside: Other 

countries might resent the continual presence of U.S. inspectors who are 

empowered to delay and scan suspicious-looking cargo containers.



"How likely is (a terrorist nuclear attack) to happen? I have no idea," 

says Berkeley's Norman. "But in terms of what might happen, it's 

extremely scary, and we have to do everything we can to prevent such a 

thing from happening. I look out my window at the Port of Oakland, and 

you see how many cargo containers come in every day."



URL: 

http://sfgate.com/cgi-bin/article.cgi?file=/chronicle/archive/2004/06/14/MNG9H75MJG1.DTL 





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