Progress in neutronics for the ITER ECRH launcher

The paper reports the latest achievements in the neutronics modelling of the electron cyclotron resonance heating (ECRH) launcher installed in the ITER upper port. The computational neutronics analyses have been performed for the extended performance (EP) front steering launcher design, which is accepted by the ITER project as reference. The aim of the paper is to show that the considered launcher design satisfies to the nuclear criteria specified for ITER machine. Results of calculations for the essential nuclear responses such as the neutron fluxes, neutron damages, helium production, and nuclear heating are discussed. The methodology used is focused on Monte Carlo variance reduction techniques for deep-penetration neutron radiation calculations in a very heterogeneous geometry. The Monte Carlo N-particle (MCNP) code was used for the radiation transport calculations with a 3D geometry model of the launcher in ITER machine. The complexity of the launcher geometry makes inevitable to use an automated interface programme McCad for the direct conversion from CAD to MCNP. The results obtained are in compliance with the ITER nuclear regulations. The analyses reveal the necessity of detailed consideration of the most critical launcher components.