Assessment and optimization of the interspace dose rate of the diagnostics equatorial port plug #3 in ITER with Attila

According to ITER integration procurement arrangements, the installment of diagnostics in a port should not increase the shutdown dose rate (SDDR) in the port interspace area by no more than ~50 microSv/hr above the baseline, assuming another 50 microSv/hr is attributed to contribution from the port structure and other ITER in-vessel components, such that the upper SDDR limit of 100 microSv/hr is not exceeded 10⁶ s after shutdown. It was found that placing the initial design of the Motional Stark Effect, MSE, and the Charge Exchange Recombination Spectroscopy, CXRS, in the equatorial port #3 (EPP3) resulted in an increase in the SDDR that far exceeded the limit. When we follow the optimization process discussed in this paper, substantial reduction in the port interspace SDDR was achieved. The results of the present work show that even when we combine the optimized CXRS and MSE diagnostics with a third GDC diagnostic, the excess of the SDDR over the baseline value did not exceed the allowed upper limit. The present work is based on utilizing the 3-D CAD-based Attila code for assessing the SDDR.