Shielding analysis for TCP and IVVS bio-shield plugs of ITER

•The ITER MCNP tokamak complex neutronics model has been modified for new TCP and IVVS bio shield plug using SuperMC.•Total neutron flux tally behind TCP and IVVS bio-shield plug were respectively 2.86 × 105 n/cm2/s and 1.71 × 106 n/cm2/s.•Spatial neutron distributions in port cells showed significant shielding improvement compared with the original designs.•Alternative 70 %–90 % improved designs scheme have been proposed via iterative shielding design optimization.