Nuclear Analyses for the ITER ECRH Launcher

Computational results of the nuclear analyses for the ECRH launcher integrated into the ITER upper port are presented. The purpose of the analyses was to provide the proof for the launcher design that the nuclear requirements specified in the ITER project can be met. The aim was achieved on the basis of 3D neutronics radiation transport calculations using the Monte Carlo code MCNP. In the course of the analyses an adequate shielding configuration against neutron and gamma radiation was developed keeping the necessary empty space for mm-waves propagation in accordance with the ECRH physics guidelines. Different variants of the shielding configuration for the extended performance front steering launcher (EPL) were compared in terms of nuclear response functions in the critical positions. Neutron damage (dpa), nuclear heating, helium production rate, neutron and gamma fluxes have been calculated under the conditions of ITER operation. It has been shown that the radiation shielding criteria are satisfied and the supposed shutdown dose rates are below the ITER nuclear design limits.JRC.F.4-Safety of future nuclear reactor

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.JRC.F.4-Nuclear Reactor Integrity Assessment and Knowledge Managemen

Radiation Shielding Analyses for the ITER Upper Port ECRH Launcher

The International Thermonuclear Experimental Reactor (ITER) will use an electron cyclotron resonance heating (ECRH) system in the upper port of the device for plasma stabilization, heating, and current drive by injecting millimeter wave beams into the plasma chamber. The millimeter waves are transmitted to the plasma through long and narrow waveguide channels. The required plasma wall openings could result in enhanced neutron radiation loadings to the ECRH launcher and neighboring reactor components. The analyses aimed at proving that the shielding requirements and all related nuclear design limits specified by ITER can be met for the proposed ECRH launcher design concepts. The nuclear criteria included human safety issues, nuclear waste regulation aspects, and radiation shielding requirements. The proof was conducted by calculating the radiation loads to sensitive components such as the diamond window of the ECRH launcher, the vacuum vessel, and the superconducting magnets and assessing the potential radiation doses to work personnel during shutdown periods. Dedicated computational approaches were developed to handle the related neutron streaming and shielding problems on the basis of threedimensional Monte Carlo calculations by the MCNP code. Suitable MCNP models of the launcher were generated by the automatic conversion of the underlying computer assisted design models using a newly developed interface program. The results of the analyses show that all radiation design limits can be safely met for the considered launcher and shield designs.JRC.F.4-Nuclear Reactor Integrity Assessment and Knowledge Managemen

Neutronic Modeling Challenges for the ITER ECRH Launcher Shielding Design

Comprehensive neutronic analyses are being performed for different variants of the International Thermonuclear Experimental Reactor (ITER) electron cyclotron resonance heating upper launcher under development in the European Union making use of modern computation tools such as the McCad code for geometry conversion and the rigorous two-step (R2S) interface for rigorous shutdown dose rate calculation. There were many reasons for the challenges encountered during the shielding analyses: deep-penetrated radiation transport in the complex geometry of the launcher, frequent need to introduce changes in the three-dimensional MCNP model, and necessity to meet a broad range of nuclear sufficiency requirements specified for ITER. The challenges were successfully addressed and resulted in radiation shielding and nuclear safety support for the current version of the launcher design, which should be workable in ITER. During the process of the launcher design development, a comprehensive knowledge of neutronic characteristics has been gained, and computation methods were matured accordingly.JRC.DG.F.4-Safety of future nuclear reactor