Nuclear Analysis for Near Term Fusion Devices

A Next Step Options (NSO) study was initiated to consider the logical steps that might be undertaken to restructure the U.S. Fusion Sciences Program. Most of the effort was concentrated on designing the Fusion Ignition Research Experiment (FIRE), which is in the preconceptual design phase. It utilizes 16 cryogenically cooled wedged copper TF coils with beryllium copper in the inner legs and OFHC copper in the outer legs. We provided significant contributions in the areas of neutronics, shielding and activation analyses. The design went through different changes. Early in the year 2002 the baseline design changed from a major radius of 2 m to a major radius of 2.14 m and an aspect ratio of 3.6. In addition the fusion power during the DT pulses changed from 200 MW to 150 MW. We spent significant part of the effort calculating the nuclear performance parameters for the final baseline design. While pulses producing a total of 5 TJ of DT fusion energy and 0.5 TJ of DD fusion energy were considered in the previous designs, a detailed experimental plan was developed that results in higher total fusion energy. We assessed the impact on the peak magnet insulator dose. Multi-dimensional calculations were performed also to determine the impact of plasma shape and profile on he peak radiation effects in the TF coils. We performed multi-dimensional calculations for one of the most critical diagnostics ports to assess streaming and determine the nuclear environment at the sensitive components. The radwaste level and volume was quantified for the different components of FIRE

Shielding analysis for a heavy ion beam chamber with plasma channels for ion transport

Neutronics analysis has been performed to assess the shielding requirements for the insulators and final focusing magnets in a modified HYLIFE-II target chamber that utilizes pre-formed plasma channels for heavy ion beam transport. Using 65 cm thick Flibe jet assemblies provides adequate shielding for the electrical insulator units. Additional shielding is needed in front of the final focusing superconducting quadrupole magnets. A shield with a thickness varying between 45 and 90 cm needs to be provided in front of the quadrupole unit. The final laser mirrors located along the channel axis are in the direct line-of-sight of source neutrons. Neutronics calculations were performed to determine the constraints on the placement of these mirrors to be lifetime components