Transmutation of 241Am in a high thermal neutron flux

Amongst the minor actinides issued from the spent nuclear fuel, 241Am is present in high concentration and contributes significantly to the long-term radiotoxicity of nuclear waste. A major uncertainty was present in the transmutation chain of 241Am when irradiated by a high intensity thermal neutron flux. This uncertainty was brought about by the poor knowledge of the 242gsAm neutron capture cross section. A dedicated experiment has been performed at the Institut Laue-Langevin in Grenoble, which gives a definitive experimental answer to this problem.