The activity of several radionuclides has to be estimated during the decommissioning of nuclear facilities for assessing accurately its total inventory and accounting for its variation with time. An accurate characterization of materials is a key point for categorising the produced waste. In a nuclear reactor facility, many radionuclides are produced by neutron activation: among these 40Ca is transformed in 41Ca by a (n,γ) reaction. 41Ca has a half-life of (1.03E+05 y). It is characterized by a high mobility in the environment and decays to the ground state of 41K by pure electron capture, emitting X-rays and Auger electrons of very low energy (between 0.3 and 3.6 keV). For its identification and possibly quantification, mass spectrometry techniques such as accelerator spectrometry (AMS) and resonance ionization mass spectrometry (RIMS) have also been used. Also X-ray spectrometry and liquid scintillation counting are possible, but, due to the poor energy resolution of beta spectra and the low energy of X-rays and Auger electrons of 41Ca, all other radionuclides have to be removed, after the decomposition of the samples ,with time-consuming and potentially expensive chemical purification.
The challenge for radiochemical analyses generally required for the decommissioning processes, is to deal with several different type of materials some of which are difficult to decompose, or conventional analytical methods cannot be applied for various reasons. The aim of this work is to propose a simple and reliable procedure to determine 41Ca by ICP-MS equipped with a reaction or collision cell, in samples produced during a nuclear power plant decommissioning processes. Evidences will be provided that the method is general and robust enough to be applied to different contexts too.