Summary results of 2005 activation calculation in support of ITER. EFDA Task No. TW5-TSS-SEA4.1/D3, Final Report, ENEA FUS-TN-SA-SE-R-135

During 2005 various analyses have been performed by ENEA in the frame of the EFDA task TW5-TSS-SEA4.1 in support of ITER licensing. Two aspects have been assessed (milestones M1 and M2, respectively): M1: the first one is related to the impact of the cobalt content into the materials of the Vacuum Vessel, with respect to their clearance possibility and, M2: the second one is related to the calculation of the activation of ITER coolant pipes that have been irradiated in OSIRIS fission reactor and then inserted into the CORELE-2 loop (in CEA centre of Cadarache) for material release rate tests and PACTITER code validation. The results related to M1 and M2 were presented in details and discussed respectively in two ENEA reports (deliverables D1 and D2, respectively): D1: ENEA FUS-TN-SA-SE-R-131, July 2005, plus Addendum (September 2005). D2: ENEA FUS-TN-SA-SE-R-133, October 2005. The relevant results obtained are summarised into this final report (Deliverable D3), together with updated analyses of the clearance possibility of ITER Vacuum Vessel materials when the new (August 2004) unconditional clearance levels given in IAEA Safety Guide RS-G-1.7 are used instead of those given in the older (January 1996) IAEA TECDOC-855. The relevant outcomes from that updated analysis are: • the 430 ferritic steel and the SS 304B4 steel of the Outboard VV zone VVSHDO(2) result to be clearable after a longer time if compared with the previous analysis results when TECDOC-855 clearance level data were employed. This is particularly significant for the SS 304B4 steel that becomes clearable only after about 6000 years (with respect to the 90 years of the previous analysis). • the remarkable change for the VVSHDO(2) – SS 304B4 steel is due to the highest contribute (at 100 years cooling time) from the Ni-63, which is now (i.e. with the RS-G-1.7) of about 40% with respect to the older (i.e. with the TECDOC-855) value of about 10%. Detailed results of the new activation calculation are given in the appendix.