Neutronic Analyses for ITER Diagnostic Port Plugs A. Serikov1, L. Bertalot2, U. Fischer1, B. Levesy2, S. Pak2, C.S. Pitcher2, A. Suarez2, V.S. Udintsev2  1Karlsruhe Institute of Technology (KIT), Institute for Neutron Physics and Reactor Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany 2ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul-lez-Durance, France  E-mail contact of main author: arkady.serikov@kit.edu 1) The plasma is a source of 14-MeV D-T neutrons impinging the First Wall (FW) of blanket modules and Port Plugs. 2) Neutron streaming through the diagnostics channels and openings in FW. Critical issues: ITER machine reliability in harsh (neutron and gamma) radiation Nuclear safety issues during and after ITER operation Computation neutronic analysis of ITER systems including its Diagnostics is mandatory. The large size of ITER (~30 m in height and diameter) and complexity of its toroidal geometry with many penetrations for plasma heating and diagnostics due to its experimental nature cause a challenge for creation of computation models. Port plugs play the dual and conflicting roles of providing diagnostic access while ensuring that the vacuum vessel ports are adequately “plugged” against the leakage of nuclear radiation and are vacuum leak tight. Radiation shielding optimization of the Port Plugs is the task of high priority The most suitable method of radiation transport in complex ITER geometry is the Monte Carlo method implemented in the MCNP5 code. MCNP5 parallelism (hundreds of processors) is important to speed-up the time-consuming radiation transport calculations. Use of supercomputers such as Helios in Japan (http://www.iferc.org) is inevitable to solve the MCNP5 tasks of radiation shielding optimization along the design development of the Diagnostic systems integrated inside the Port Plugs. Figure 1. High-resolution map of shutdown dose rate (Sv/h) around the Diagnostic Equatorial Port Plug.