Neutronic analysis for the Edge Charge Exchange Recombination Spectroscopy in Equatorial Port of ITER

Abstract

• Neutronics for Edge Charge Exchange Recombination Spectroscopy (CXRS-Edge). • CXRS-Edge Diagnostics installed in Equatorial Port #3 (EP3) of ITER. • New MCNP model of CXRS-Edge Diagnostic system in EP3 was created. • Personnel access to the Inter-Space Structure (ISS) the EP3 is evaluated. • Maps of local shutdown dose rate (SDDR) are shown in EP3 ISS with CXRS-Edge. The neutronic analysis results presented in this paper support the design development of the Edge Charge Exchange Recombination Spectroscopy (CXRS-Edge) system to be installed in Equatorial Port #3 (EP3) of ITER. That is an active optical diagnostic system with a dogleg labyrinth design of two optical pathways and a system of mirrors arranged in Diagnostic Shield Modules #1 and #2 (DSM #1 and #2) of EP3. The shielding performance of the CXRS-Edge system and the radiation effects of its mirror materials have been evaluated. To this end, a neutronic 3D model of the CXRS-Edge system has been created in the format of the MCNP code. The MCNP model of CXRS has been converted from the underlying CAD engineering model using the SuperMC code. Then the model has been integrated with the actual standard MCNP model of the ITER tokamak called “C-Model R181031 (Revision 190110)”. With this C-Model, neutron and photon fluxes, nuclear heating distributions and neutron damage in molybdenum, steel, and silicon carbide (SiC) materials have been calculated. Assessing the possibility of personnel access to the Inter-Space Structure (ISS) of EP3 with CXRS-Edge installed, a map of shutdown dose rate (SDDR) has been calculated using the local approach, without any other diagnostics systems shared by EP3. In conclusion, the suitability of CXRS Edge doglegs for necessary attenuations of neutron and photon fluxes, nuclear heating, and SDDR is demonstrated. As design work is progressing, this paper presents an initial contribution to the complete neutronic analysis.