Vacuum vessel contact dose build-up from start to end of ITER operations

The paper presents the ITER vacuum vessel (VV) contact dose build up evaluation from start to end of the machine life (expected to occur after about 20 years of operations, corresponding to an average neutron fluence of 0.5 MWa/m/sup 2/ on the first wall). The reference design used for ITER Generic Site Safety Report (GSSR) has been considered. Results are given for the inboard and outboard VV regions (and for both the front and rear 316L(N)-IG walls) in the radial equatorial plane. The Sn calculation sequence SCALENEA-1 (with the FISPACT-99 activation code) has been used for the analysis. The results point out that after only 20 seconds of irradiation at the nominal neutron power load, the contact dose of the most activated VV zone (i.e. the outboard region, front wall), reaches the hands-on limit of 10 /spl mu/Sv/h just after few months cooling time, requiring remote handling operations on that component in maintenance cells.