Incineration of Am-241 induced by thermal neutrons

An experimental study of the Am-241 incineration in a high-intensity therma l neutron flux was carried out at the high-flux reactor of the Institut Lau e-Langevin in Grenoble. The combination of nuclear gamma -ray spectroscopy and off-line mass spectrometry methods made possible the measurement of sev eral parameters of the transmutation chain and the first experimental deter mination of the unknown Am-242gs thermal neutron capture cross section, whi ch plays an essential role in the Am-241 incineration process. During a 19 days irradiation in a thermal neutron flux of 5.6 x 10(14) n/ (s cm(2)), (4 6 +/- 5)% of the initial Am-241 was transmuted by neutron capture of which (22 +/- 8)% was incinerated by nuclear fission. A value of the thermal neut ron cross section of Am-242gs(n, gamma) of (330 +/- 50) barns was obtained. We show that this keeps the option open to incinerate Am-241 by high-inten sity moderated neutron fluxes. (C) 2001 Elsevier Science B.V. All rights re served.