Online Laboratory Magazine


A novel device for better plutonium analysis


In collaboration with professionals from the Finish Radiation and Nuclear Safety Authority, JRC scientists built a new conversion electron spectrometer for analysing the isotopic composition of plutonium. This novel tool set up at the JRC can be applied for better nuclear security and environmental measurements.

The measurement of isotopic amount ratios is an important topic in safeguards and nuclear forensics application. Vigilance against the diversion of plutonium is of growing concern in a context of increasing stocks of excess fissile material from weapons dismantlement, as well as plans to utilise this material in power reactors. Safeguards laboratories use various techniques to analyse the isotopic composition of plutonium to identify "weapon-grade" material. Environmental scientists use the same information to distinguish "global fall-out" from local plutonium contaminations, e.g. in the Fukushima area.

A team of scientists from the JRC-Institute for Reference Materials and Measurements (IRMM) and the Finish Radiation and Nuclear Safety Authority (STUK) has built a new conversion electron spectrometer, using a silicon drift detector. They measured highly enriched plutonium sources and demonstrated that the fissile isotope 239Pu can be well distinguished from the non-fissile isotopes 238Pu and 240Pu. Therefore, the method is complementary to the popular alpha spectrometry technique, which however has a problem distinguishing between these isotopes. Further research will be performed on spectrum analysis techniques and will provide reference emission data to validate the method.

The presented method is an affordable and potentially powerful measurement technique that could be used as a complementary tool for plutonium analysis in safeguards and environmental laboratories.

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Source: European Commission, Joint Research Centre