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ABSTRACT: Radiological characterization of nuclear waste packages is an industrial issue in order to select the best mode of storage. The alpha‐activity, mainly due to the presence of actinides (235U, 238U, 239Pu, …) inside the package, is one of the most important parameter to assess during the characterization. Photon Activation Analysis (PAA) is a non‐destructive active method (NDA method) based on the photofission process and on the detection of delayed particles (neutrons and gammas). This technique is well‐adapted to the characterization of large concrete waste packages. However, PAA methods often require a simulation step which is necessary to analyze experimental results and to quantify the global mass of actinides. The weak point of this approach is that characteristics of the package are often not well‐known, these latter having a huge impact on the final simulation result. High‐energy radiography, based on the use of a linear electron accelerator (LINAC), allows to visualize the content of the package and is also a performing way to tune simulation models and to optimize the characterization process by PAA. In this article, we present high‐energy radiography results obtained for two different large concrete waste packages in the SAPHIR facility (Active Photon and Irradiation System). This facility is dedicated to PAA study and development and setup for a decade in CEA Saclay. We also discuss possibilities offered by the coupling between high‐energy radiography and PAA techniques.
AIP Conference Proceedings. 12/2009; 1194(1):3-12.
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ABSTRACT: Characterization of nuclear waste packages is crucial to select the best mode of storage. Passive and active non-destructive methods are well-adapted to this problem and their coupling can be extremely useful in order to optimize data analysis. Photon Activation Analysis (PAA), based on the photofission process and on the detection of delayed particles emitted after this reaction, is a powerful tool for the analysis of bulky concrete waste packages. Methods developed around PAA allow to locate, identify and quantify the mass of actinides (<sup>235</sup>U, <sup>238</sup>U, <sup>239</sup>Pu) present in a given package in order to estimate its α-activity. In this article, we present experimental and simulated results obtained in PAA during the characterization of a real nuclear waste package in the SAPHIR facility (Active Photon and Irradiation System). For the first time, several non-destructive methods (passive gamma-ray spectrometry, high-energy radiography) are combined with traditional PAA techniques (altitude scan, global photofission, photofission tomography) in order to optimize the characterization process.
Advancements in Nuclear Instrumentation Measurement Methods and their Applications (ANIMMA), 2009 First International Conference on; 07/2009
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ABSTRACT: Being able to characterize and classify nuclear waste packages is crucial for an appropriate mode of storage. The alpha-activity due to the presence of actinides inside the packages can be determined using non-destructive active (NDA) methods. CEA-LIST is developing one of those, based on fission induced by photons that allows us to quantify the global mass of actinides in large concrete packages and localize it by the means of a tomography using delayed particles emitted after the fission process.
Nuclear Science Symposium Conference Record, 2007. NSS '07. IEEE; 12/2007
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ABSTRACT: In the 1990's, CEA has developed one of the most compact operational gamma cameras in the world, CARTOGAM, capable of mapping the surrounding radioactivity and representing it superimposed onto a visible-light image. Since, the camera has been successfully industrialized and commercialized. In the same time, the Kurchatov Institute has developed a coded-aperture gamma camera. The two teams have joined their efforts to develop a compact coded-aperture gamma camera. This paper presents the first results obtained with a coded mask adapted to the existing CARTOGAM camera. According to preliminary simulations compact coded-aperture gamma camera could enable Cs-137 or Co-60 source imaging. Innovative masks have been achieved that lead to the following results: a significant increase in the sensitivity (up to 10 times), an acceptable angular resolution (2° to 3°) and a large field of view (about 30°). The tungsten-alloy masks were produced and the adaptation of the camera was carried out. The laboratory results of Cs-137 and Co-60 imaging, including shadowgrams and reconstructed images for point sources, are presented.
Nuclear Science Symposium Conference Record, 2003 IEEE; 11/2003
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ABSTRACT: This paper describes a method based on photofission developed in our laboratory to characterize in depth large waste packages. The method consists in using photons of high-energy (Bremsstrahlung radiation) in order to induce reactions of photofission on the heavy nuclei present in the wastes. The measurement of the delayed neutrons allows quantifying the actinides in the wastes. We present the first results of measurement performed with a concrete mock-up of 870l and two real waste packages.
Applied Radiation and Isotopes 63(5-6):613-9. · 1.17 Impact Factor
