SPECT imaging as a tool to prevent proliferation of nuclear weapons
2006 (English)In: International conference on imaging techniques in subatomic physics, astrophysics, medicine, biology and industry: IMAGING 2006, 2006Conference paper (Other (popular scientific, debate etc.))
International efforts are taken to avoid the proliferation of material and technologies that may lead to the development of nuclear weapons. These activities are called safeguards and involve inspections of spent nuclear fuel at nuclear power plants and storage facilities. At these inspections, various measuring techniques are employed for verifying the presence and identity of spent nuclear fuel assemblies. However, a fuel assembly contains about 100-300 fuel rods and techniques are also requested for verifying that no individual fuel rods have been removed from the assembly. For this purpose, a non-destructive tomographic measurement technique for spent fuel assemblies is being developed at Uppsala University, based on Single Photon Emission Computed Tomography, SPECT.
The technique utilizes the gamma-ray emission from spent fuel. The first step of the methodology is the recording of the gamma-ray flux distribution in a large number of positions around the fuel assembly, using gamma-ray detectors attached to a collimator system. In a following step, a cross-sectional image of the source distribution in the fuel assembly is reconstructed. Because the fuel rods are highly activated during reactor operation and because they are stored in water with practically no radioactive content, they appear very clearly in this type of images.
The technique has earlier been used for determining the power distribution in fuel assemblies . The images obtained in those measurements show that the technique has great potential also for the safeguards application. In the on-going development of the technique specifically for safeguards, image analysis plays an important role. Some crucial points in the analysis are the identification and positioning of the assembly in the image and also the definition of the background activity level. Finally, proper criteria have to be set for confidently stating if a fuel rod would be considered to be missing.
Place, publisher, year, edition, pages
Safeguards, Nuclear fuel, Tomography, SPECT
IdentifiersURN: urn:nbn:se:uu:diva-20572OAI: oai:DiVA.org:uu-20572DiVA: diva2:48345