Experimental investigation of radioactivities induced in fusion reactor structural materials by 14-MeV neutrons

The aim of the present study is the experimental validation of European act ivation system (EASY-97) for structural materials irradiated with 14-MeV ne utrons. Samples of the stainless steel 316 (AISI 316 LN (IG)), which is the structural material of international thermonuclear experimental reactor (I TER), of the low-activation steels MANET and F82H and of the vanadium alloy s V-3Ti-1Si, V-4Ti-4Cr and V-5Ti-2Cr were used for benchmarks. Pieces havin g the mass of approximate to1 g were irradiated at the high-intensity neutr on generator SNEG-13 at Sergiev Posad with neutrons of 14.93 and 14.37 MeV mean energy. Fluences applied were of the order of 10(14) cm(-2). gamma -Sp ectra of the samples were measured several times during the decay up to abo ut I-year. The activities of 27 different radionuclides, identified by gamm a -energies and half-life, were determined. Their half-lives range from a f ew min up to 5.3 years. For each of the measured values the activity was ca lculated with EASY-97, and calculated-to-experimental values (CIE) were det ermined. If the uncertainty of the CIE is estimated with both the experimen tal errors and the calculational one, including cross-section as well as ha lf-life uncertainties, validation of EASY-97 can be stated for most of the activities. The pathways of production are analysed for all activities, and the corresponding cross-sections are discussed if larger deviations were o bserved. (C) 2000 Elsevier Science B.V. All rights reserved.