The detection agency

1 February 2003

Early last November, the UN Security Council adopted resolution 1441, demanding that Iraq "cooperate immediately, unconditionally and actively" with appointed inspectors to ascertain that Iraq had not produced weapons of mass destruction since inspections were last carried out in 1998. By the end of November 2002, officials from UNMOVIC (United Nations Monitoring Verification and Inspection Commission) and the International Atomic Energy Agency (IAEA) had arrived in Iraq to begin their task.

In 1991, following the Gulf War, IAEA inspectors were sent to Iraq and uncovered evidence of the country's clandestine nuclear programme. They discovered Iraq had successfully concentrated uranium from its own ore and produced industrial quantities of feed material for electromagnetic isotope separation. Plutonium and highly enriched uranium was "fully accounted for" and removed from Iraq by the IAEA and sites of former nuclear activity were verified as either having been destroyed during the war or being used for other purposes. UN resolution 707 (1991) prohibited Iraq from engaging in nuclear activities, except for the use of radioisotopes for "medical, agricultural and industrial purposes".

IAEA's team of inspectors left Iraq in 1998 amid safety and security fears, and much of its task commencing November 2002 was to catch-up on activity in the country since that time.

The first job of the IAEA team of inspectors, now known as the Iraq Nuclear Verification Office (INVO), was to re-establish its field office - the Baghdad Ongoing Monitoring and Verification Office (BOMVIC). As well as hosting vehicles, radio equipment and medical support, BOMVIC is where the INVO keeps its equipment and computers, stores suspect items and carries out tests in fully installed radiometric measurement laboratories.

Measurement methods

Indeed, INVO took along a host of advanced technologies to help in its "broad area search". An IAEA spokesman told NEI there had been "significant improvements in technology" since 1998, in particular "software advances that make the equipment more powerful and provide faster results." Among the equipment used on site are advanced multi-channel analysers (MCAs) that make use of software to read the pattern of the energy output from a radioactive source, match it to a signature and then display the result.

One such portable analyser is designed for detection of gamma radiation from radioisotopes and the presence of neutrons for enhanced detection of plutonium. Unlike typical radiation detectors, the device can be used to search for and locate an unknown source of radiation, determine the relative dose rate, and isotopically identify the source. Another type, a portable gamma spectrometer, is specifically designed to measure uranium and whether it has been enriched. The ratio of certain isotopes can yield valuable information - for example, the type of enrichment that was used.

An important lead for inspectors also comes from the discovery of the use of "exotic steels and unusual elements" such as zirconium. Here, INVO use another portable device - ALEX - short for the brand name "alloy expert". The device is an x-ray fluorescence spectrometer and matches the response pattern of elements in the alloy to the x-rays against a built-in database.

Also critical to INVO are an array of environmental monitoring instruments. These are used to reveal "fingerprints" of activity in water, air and vegetation. Water monitoring has been conducted across Iraq using a system that draws raw water through a filter. Also air-sampling stations have been set up across the country and vegetation has been tested for tritium.

Thorough testing of environmental samples is carried out by the Clean Laboratory Unit of the IAEA Safeguards Analytical Laboratory - a branch of the multi-purpose Seibersdorf Laboratories close to the IAEA headquarters in Vienna, Austria.

David Donohue, who heads the Clean Laboratory Unit, explained: "Our lab is fully operational, with state-of-the-art methods for detecting elements like uranium and plutonium and newer, more powerful methods are constantly being developed. We can obtain a truly amazing amount of information from a tiny amount of material in samples." Donohue went on to describe how high-resolution gamma spectrometry (HRGS) is used for any initial radiometric screening of samples when they are first received in Seibersdorf. Such screening can be performed without removing the samples from their bags or bottles, thus further reducing the chances of cross contamination.

"Secondary ion mass spectrometry (SIMS) is used to measure the isotopic composition of micrometer-sized particles. The isotopes uranium-235 and uranium-238 are of greatest interest because they reveal the enrichment of uranium, showing whether it is intended for use in reactor fuel or nuclear explosives." Thus far, INVO has discovered nothing that gives rise to "any new information of significance" for the period up until 1998. However, Mohamed ElBaradei's latest report to the UN is notably more cautious when it talks of post-1998.

Despite the IAEA having visited "all sites identified by it or by States as significant," it said: "No evidence of ongoing prohibited nuclear or nuclear-related activities at those locations has been detected to date during these inspections." However the UN report stresses that "not all of the laboratory results of sample analysis are yet available," adding "further verification activities will be necessary before the IAEA will be able to provide credible assurance that Iraq has no nuclear weapons programme." More time needed then, but will they get it?



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