Identification of Actinides Inside Nuclear Waste Packages by Measurement of Fission Delayed Gammas
ABSTRACT A characterization of the alpha-activity due to the presence of actinides inside nuclear waste packages is necessary to select the best mode of storage. Non-destructive active methods, based on fission process, allow to quantify the global mass of actinides. However, these measurements give no information on the nature of isotopes in most cases. We are currently developing a method to identify actinides (235U, 238U, 239Pu), based on the detection of delayed gammas emitted by fission products. The delayed gamma spectrum can be regarded as a "fingerprint" of the irradiated sample. Qualitative and quantitative analysis of peaks allow an identification of actinides. The main purpose of this paper is twofold. First, basis of this method of differentiation are described. Then, experimental results obtained in fission and photofission are presented, in particular in the case of mixtures containing several actinides.
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ABSTRACT: Characterization of nuclear waste packages is crucial to optimize waste management (temporary storage, transport, final repository). 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 alpha 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.IEEE Transactions on Nuclear Science 01/2011; · 1.22 Impact Factor