Exploration of Compact Stellarators as Power Plants: Initial Results from ARIES-CS Study

A detailed and integrated study of compact stellarators as power plants, ARIES-CS, was initiated recently to advance our understanding of attractive compact stellarator configurations and to define key R&D areas. We have completed phase 1 of ARIES-CS study - our results are described in this paper. We have identified several promising stellarator configurations. High particle loss of these configurations is a critical issue. It appears that devices with an overall size similar to those envisioned for tokamak power plants are possible. A novel approach was developed in ARIES-CS in which the blanket at the critical areas of minimum stand-off is replaced by a highly efficient WC-based shield. In this manner, we have been able to reduce the minimum stand-off by ~20%-30% compared to a uniform radial build which was assumed in previous studies. Our examination of engineering options indicates that overall assembly and maintenance procedure plays a critical role in identifying acceptable engineering design and has a major impact on the optimization of a plasma/coil configuration.