Qualification in a Representative Environment of an Alpha Spectrometer Prototype Operating at Ambient Air Pressure

In previous works, a first prototype of alpha spectrometer operating at ambient air pressure has been developed to improve the in situ radiological characterization of legacy waste contaminated with alpha emitters. This non-destructive measurement technique aims, through spectrometric selectivity and the use of a grid collimator, to identify the same radionuclide combinations as alpha spectrometry in a vacuum chamber, namely 239Pu + 240Pu, 241Am + 238Pu, and 244Cm. Contrary to a laboratory measurement, the measurement is carried out on swipes sample of nuclear waste obtained beforehand using remote manipulators. This article presents the results of the tests carried out in a representative environment in order to qualify this prototype. Although the measured alpha spectra are degraded compared to those measured in laboratory conditions on electrodeposited sources, the qualitative analysis shows that it is possible to identify the three groups of radionuclides of interest. Furthermore, a spectral deconvolution with the COLEGRAM software allowed to obtain quantitative information required to estimate the activity ratio of each radionuclide group to the total alpha emitters for each sample. These results of non-destructive alpha spectrometry measurements are in agreement with the results of radiochemical analysis performed in laboratory.