Radiation damage and He production calculations for the fourth SINQ target irradiation program, STIP-IV

The fourth SINQ target irradiation program, STIP-IV, was performed in 2004 and 2005. More than 1100 specimens of several tens kinds of materials of interest for various applications such as development of high power spallation targets, fusion reactors and next generation fission reactors were irradiated for two years with a total of 10.87 A·h proton charge on target. Neutronic calculations using MCNPX 2.5.0 were performed in support of this program. The spallation target, and the surrounding facility was thoroughly modeled, with particular care in the modeling of the different target rods. The experimental beam profile on target, obtained by gamma mapping of the AlMg3 beam window, was used in the calculations. Calculations of neutron and proton integral fluences and spectra, energy deposition, dpa and He production were performed. With respect to the STIP-III irradiation program the peak irradiation increased on the average by 25%, due to a narrower beam profile. The maximum displacement on steel samples is of 25 dpa, the maximum helium production is of about 2200 appm.