DHS changes tack on radiation detection

The US Domestic Nuclear Detection Office (DNDO) has terminated a seven-year effort to develop next-generation radiation monitors for screening cargo at US ports of entry. The Advanced Spectroscopic Portal (ASP) system, a sodium iodide–based monitoring system that was first proposed in 2004, failed to attain its design specifications after multiple rounds of testing and software tweaking. Conceived to be capable of discriminating nuclear materials from harmless radioactive sources that are often shipped in cargo containers, the ASP system was claimed by vendors to reduce by 80% the number of false alarms that occur with today’s polyvinyl toluene (PVT) portal monitors. Unlike the scintillator-based PVT, ASP technology allows the specific isotopic source of radiation to be identified by its characteristic emission spectrum (see PHYSICS TODAY, June 2010, page 22 ).

Warren Stern, DNDO director, announced ASP’s termination in testimony to the House Committee on Homeland Security on 26 July. Stern said the agency has no current plans to develop another portal monitoring system. Instead, the DNDO is adopting a “commercial first” approach that will make use of commercially available detection equipment, he said. The agency also is focusing on developing radiation detection standards and testing devices against those metrics.

The DNDO did not respond to requests for details of the commercial systems mentioned by Stern. But SAIC, TSA Systems, Canberra Industries, Berkeley Nucleonics Corp, Princeton Gamma-Tech, and Textron Systems all advertise spectroscopic radiation portal monitoring systems. Such monitors are already in use at major non-US ports as part of a nonproliferation program operated by the Department of Energy’s National Nuclear Security Administration. In July, Barcelona, Spain, became the 38th port to install portal monitors with funding and technology supplied by NNSA’s Megaports program. More than 100 ports, handling 50% of the world’s global shipping traffic, eventually will be covered.

To replace with ASPs the more than 1400 PVTs now in operation at US ports of entry would have cost up to $2 billion, according to a 2009 Government Accountability Office report. Even a scaled-back acquisition the Department of Homeland Security proposed last year would have cost $350 million, said Representative Brad Miller (D-NC), the former chairman of a House subcommittee that held two hearings on the ASP program. Miller said ASP was “one of the most technically troubled, poorly managed programs I have ever seen.” He welcomed its termination.

False alarms were the major motive for ASP’s development; according to the 2009 report, PVT monitors log up to 600 false alarms each day at the nation’s busiest ports, Los Angeles and Long Beach, where nearly half of all sea containers enter the US. The detectors are triggered by naturally occurring radioactive materials in such benign products as cat litter, ceramics, fertilizers, televisions, and abrasives. Because PVTs cannot identify the radiation source, labor-intensive inspection of those containers must be performed by Customs and Border Protection agents with handheld detectors.

Impeding the flow of commerce

Virtually all cargo containers imported to the US by road and sea, and all vehicles entering through border crossings, are now scanned for radiation. But Congress has not required radiation monitoring for rail and air freight. Stern said it will be “years, not months” before those imports are routinely monitored. Railroad companies have resisted such screening, and they typically own the land where portal monitors would have to be installed. Stern said that variation among US airports makes a generic monitoring system for air freight infeasible. But he also said that the DNDO has five mobile radiation detection units that can be deployed quickly to railroad crossings or airports should intelligence indicate a heightened threat of nuclear materials smuggling.

A National Research Council report issued in January said that ASP vendors had not provided the modularity that was specified by the DNDO in order to match the best available hardware with the optimum data-analysis algorithms and to allow upgrades as experience was gained with the system. The report also noted that upgraded software for existing handheld detectors had improved performance to such an extent that handhelds should be evaluated as an alternative to ASPs.

Stern said the DNDO is now acquiring a next-generation handheld device called RadSeeker, which employs a “novel detection material” that he did not identify. The same technology could “in theory” be used in next-generation portal monitors, he said. The Obama administration’s request for fiscal year 2012 includes $20 million to acquire handheld units. Stern said a standard for handheld radiation detectors is now being finalized in cooperation with NIST.