Source: International Atomic Energy Agency – IAEA
IAEA safeguards inspectors collect environmental samples in the field. (Photo: D. Calma/ IAEA)
At a side event held on the margins of the 65th IAEA General Conference today, participants gained an insight into how minute traces of uranium and plutonium can be detected by the IAEA. As a powerful tool in the inspectors’ toolkit, environmental sampling supports nuclear verification activities, which contribute to international peace and security.
IAEA safeguards are technical measures, implemented by the IAEA in accordance with safeguards agreements concluded between the Agency and governments, to verify that nuclear material and technology remain in peaceful use. As part of safeguards agreements, countries are required to submit declarations to the IAEA, which include information on their nuclear material and its use. Environmental sampling is among the effective tools to corroborate such a declaration.
To collect environmental samples at a location, inspectors run cotton cloth swipes on surfaces collecting the dust. This dust contains a huge amount of information, including not only if nuclear material is present, but also what type (e.g. separated plutonium or highly enriched uranium), the age of the nuclear material, and the presence of other materials. As a result, it allows verification of current and past activities and for inspectors to detect activities not declared to the IAEA.
“Environmental sampling and analysis enable the IAEA to assure the international community about the correctness and completeness of countries’ declarations,” said Todd Mock, Safeguards Information Analyst, who presented at the event. “By analyzing the cotton swipes that inspectors collect in the field, the IAEA can detect nuclear material at weights below one trillionth of a gram.”
The swipes are shipped to the IAEA Environmental Sample Laboratory in Seibersdorf, Austria. Once received at the laboratory the samples are screened and coded to guarantee confidentiality and anonymity. The laboratory receives and screens all samples collected and works in cooperation with 24 partner laboratories in 11 countries, which perform some of the analysis of the anonymized samples.
Two types of analysis can be performed, often in parallel, in separate laboratories: particle analysis, which is always performed, and bulk analysis. Particle analysis is able to detect individual particles of uranium and plutonium, to examine isotopic signatures and to look into a particle’s elemental composition. This technique also indicates the enrichment status of the material, whether it has been irradiated, the production process it has been through and also a particle’s age. Bulk analysis, on the other hand, is more sensitive and allows the extraction of information about the entire sample. It provides a comprehensive overview of the content on a swipe, and information concerning the average isotopic results.
“On average, over 400 environmental samples are analyzed every year,” said Mock. “To date, that equates to around 15 000 collected samples from more than 450 locations in 84 countries.”
As one of the most powerful tools available in the IAEA nuclear safeguards inspection, environmental sampling has become an indispensable tool supporting the IAEA’s efforts in verifying the peaceful use of nuclear material.
Find out more about environmental sampling.