U.S. completes border system to monitor cars for nukes

OTTAWA – Every car, truck and passenger entering the United States by land from Canada is now searched for nuclear weapons.

The last of about 600 northern border radiation detectors has been installed at Trout River, N.Y., on the Quebec border, completing a continentwide shield aimed at repelling the smuggling of nuclear bombs, dirty bombs and other malicious nuclear materials from Canada.

Most experts believe there is a low probability that terrorists could muster the technical sophistication and complex planning needed to pull off a strike on U.S. soil, yet Osama bin Laden has made it clear that al-Qaida wants to nuke the U.S.

Even a small chance of that happening is one of the great worries of U.S. leaders and many security officials, magnified by the political strife in nuclear-armed Pakistan, where al-Qaida’s core command has taken sanctuary.

Preventing terrorists from detonating a nuclear weapon in a major U.S. city is therefore a key national security priority, with more than $3 billion US spent since 2002 on nuclear monitors alone at Canadian and Mexican land border crossings and U.S. seaports.

U.S. Homeland Security Secretary Janet Napolitano hails the completion of the Canadian component, two months ahead of schedule, as a “major security milestone.

“This technology enhances our capability to guard against terrorism and criminal threats while expediting border crossings for lawful trade and travel,” she said in a statement.

Meanwhile, the effectiveness of the U.S. radiation monitors is debatable.

The “non-intrusive” monitors are erected alongside the car lane approaches to customs’ booth inspections, with larger monitors for transport trucks stationed in cargo inspection areas. Each detects certain types of energy within a limited area but not the exact radioactive source.

For that, a suspect vehicle is sent for a secondary inspection that includes a scan with a hand-held detection device to identify the source and whether it constitutes a threat. Benign emissions from lingering medical isotopes in people’s bodies, scrap metal, natural sources of radiation and even Kitty Litter trigger frequent false alarms.

Reducing them and the accompanying border-crossing delays with the current polyvinyl toluene (PVT) monitors would mean re-calibrating their detection threshold, or sensitivity. But uranium-235, which in a concentrated, highly enriched form becomes weapons-grade uranium, is already weak radioactively, and reducing the monitors’ threshold would make detection more difficult.

What’s more, PVT monitors can only detect unshielded or lightly shielded sources, which seems unrealistic, considering the sophisticated smuggling tactics determined nuclear terrorists would likely employ.

The U.S. is instead debating the cost-effectiveness of replacing PVT technology with “advanced spectroscopic portals” or ASP, a new type of portal monitor designed to both detect radiation and identify the source.

The U.S. Government Accounting Office reports that ASP monitors use more sophisticated software, and have a more extensive library of radiation signatures that may provide more consistent and rapid screening and may increase the likelihood of correct identification. But they’re also almost three times more expensive than PVT monitors.

In the meantime, the U.S. says the PVT monitors are now scanning 100 per cent of all vehicle traffic entering from Canada and Mexico, plus all mail and courier packages from Mexico and a further 98 per cent of all arriving seaborne container cargo.

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