IAEA Nuclear Scientists Employ More Precise "Fingerprinting"
German-funded Spectrometer Advances IAEA Safeguards Analysis Capabilities
Mass Spectrometry Specialist Sergei Bulyha acquaints Ambassador Rolf Nikel of the German Foreign Office with the environmental swipe sampling materials and techniques of IAEA safeguards inspectors. To ensure accurate und unbiased measurements, samples taken on cotton swipe pads in nuclear facilities are prepared for analysis in an ISO-Class 5 (U.S. Class 100) cleanroom, which minimizes airborne impurities to a high standard.
The IAEA is implementing a multi-year project to modernize the safeguards analytical capabilities that will help it meet the verification challenges of the next thirty years and beyond. On 2 May 2012 the Agency celebrated a milestone in this project when new spectrometry equipment of unparalleled precision was put in service.
The IAEA Office of Safeguards Analytical Services is now operating the latest-generation "multi-collector inductively coupled plasma mass spectrometer", or MC-ICP-MS. The new spectrometer gives the Agency a significantly improved ability to identify previously imperceptible differences in nuclear "signatures". For instance, Agency analysts should be able for the first time to detect each sample's "fall out" signature, composed of trace quantities of plutonium or uranium that may possibly have been carried and deposited from nuclear activities. IAEA scientists will use this data to be able to demonstrate with great confidence when a sample contains only the historical residue of "background" plutonium and no new plutonium is detectable.
According to Gabriele Voigt, Director of the IAEA Office of Safeguards Analytical Services:
"More precise techniques in mass spectrometry enable IAEA scientists to detect and measure minute particles found in the swipe samples collected by IAEA inspectors, to isolate particles of enriched uranium or plutonium and measure their isotopic compositions. This capability provides indications about enrichment processes and constitutes a powerful tool for detecting the presence of any undeclared materials and activities in States under safeguards."
The new measurement instrument stands in a dedicated clean room in the IAEA's Environmental Sample Laboratory in Seibersdorf, Austria. On the spectrometer's ceremonial first day in service, Ambassador Rolf Nikel, Commissioner of the German Federal Government for Arms Control and Disarmament, and Ambassador Rüdiger Lüdeking, Germany's Resident Representative to the IAEA, visited the Environmental Sample Laboratory and were briefed on the scientific capabilities that IAEA experts are exploring with the new equipment. Germany's generous financial support made the spectrometer's acquisition possible.
One of the techniques to be employed will involve bulk analysis, during which the environmental swipes are dissolved and chemically separated, then measured with the spectrometer at ultra-low levels: weights of one femtogram or below (a femtogram of material is about a million atoms, weighing less than the DNA in a single human cell). The new spectrometer will enable IAEA scientists to detect plutonium at levels about ten times lower than had previously been possible using other instruments. In the majority of cases, subjecting samples to such sensitive measurement increases the Agency's level of confidence in verifying the absence of undeclared activities; conversely, it also reinforces the ability to detect indications of possible undeclared experiments or plutonium production that may have occurred.
The spectrometer will also be used in combination with 'laser ablation', the process of removing material from a surface by irradiating it with a laser beam. This technique provides measurements of micrometer-sized particles of either uranium or plutonium in a rapid and accurate way which complements the capabilities of another advanced instrument in the IAEA's clean laboratory, a Large Geometry Secondary Ion Mass Spectrometer. That device measures about up to 50 particles - one at a time - using the ion microprobe method; however, when there are many hundreds of uranium particles present the remaining particles can be measured by laser ablation on the MC-ICP-MS to give more safeguards-relevant data and ensure that important nuclear and chemical signatures are identified.
Advancing its environmental sample analysis is part of the IAEA's strategy to maintain independent, quality-assured scientific capabilities in order to fulfill its mission to implement nuclear safeguards in every state that has a safeguards agreement in force. As IAEA Assistant Director General Rafael Grossi stated on 30 April 2012 in his address to the Preparatory Committee for the 2015 Nuclear Non-Proliferation Treaty Review Conference: "Technology is a major enabler of our safeguards work," and the IAEA is acting on the recommendation of the States parties to the NPT that it "further develop a robust, flexible, adaptive and cost-effective international technology base for advanced safeguards."
-- By Mark Scheland, IAEA Department of Safeguards
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