Estimation of radiation conditions in the ITER electron cyclotron upper launcher with state-of-the-art simulation techniques

•Nuclear analyses in support of ECUL port plug design: computation of nuclear heating to the BSM during plasma operation, and mitigation of dose rate during maintenance.•Significant mitigation of dose rate achieved by shielding options located within the port plug itself; further reductions only possible by optimization of the surrounding environment.•Pioneering application of the MCNP conformal unstructured mesh capability for both geometry description and result tallying for computation of the nuclear heating in the BSM.•The UM succeeds in accelerating geometry preparation and result post-processing, and in removing unphysical results inherent to MCNP’s conventional approach.