Benchmark experiments of fusion neutron induced gamma-ray radioactivity invarious structural materials

The fusion reactor inventory code FISPACT, together with the European Activ ation File EAF, is the European reference software for calculating the neut ron-induced activation of fusion reactor relevant materials. Experimental v erifications (benchmarks) of the code predictions have been performed at EN EA Frascati by means of an irradiation facility consisting of a D-T neutron generator and a moderator/reflector structure which is employed to mimic t he neutron spectrum at the a fusion device first wall. Various materials (v anadium alloy, SIG, AISI 316, martensitic steel F82H. copper, tungsten. iro n. niobium), candidates to be used in a fusion reactor, have been exposed t o neutrons produced in the facility (about 10(9) n.cm(-2).s(-1)) and the sh ort and medium-lived induced radioactivity has been measured by gamma-ray s pectroscopy. The experimental results have been used to validate the invent ory code FISPACT, the physical database EAF, including its uncertainty pred ictions, and the composition of the material irradiated in particular for i ts minor elements and impurities. The comparison between calculated (C) and experimental results (E) is reported as C/E values and shows a satisfactor y agreement for almost all radionuclides. Radionuclides for which there is not agreement between calculations and experiments are also discussed and a n analysis of the causes of the lack of agreement is carried out.