Activation of Eurofer in an IFMIF-like neutron field

Abstract

An activation experiment on the Eurofer-97 low activation steel was performed to provide the database for validating activation cross-section data in the energy range relevant for the International Fusion Material Irradiation Facility (IFMIF). An IFMIF-like white neutron field extending up to energy of 32 MeV was produced at the isochronous cyclotron U-120M of the Nuclear Physics Institute (NPI) Řež, by bombarding a flowing heavy water target with a 37 MeV proton beam. The induced gamma radioactivity for 22 product radio-nuclides was determined by gamma ray spectrometry at different cooling time intervals using calibrated HPGe detectors. Activation calculations were performed with the ALARA inventory code using the activations cross-sections from the Intermediate Energy Activation File IEAF-2001. The neutron spectrum at sample sport was combined from one measured at large distance and calculated by MCNPX for energies below the detector threshold. The comparison of calculated and measured induced activities reveals reasonable agreement for half of the detected radio-nuclides and large discrepancies for the other ones. The analysis of the dominant reactions indicates the need for updating the relevant cross-sections in the IEAF-2001 data library.