Fusion Reactor Economic, Safety, and Environmental Prospects

Abstract

Controlled fusion energy is one of only a few energy sources available to mankind in the future. Progress in fusion reactor technology and design is described for both magnetic and inertial confinement fusion energy. The projected economic prospects show fusion will be capital intensive and the historical trend is towards greater mass utilization efficiency and more competitive costs. Recent studies emphasizing safety and environmental advantages show that fusion’s competitive potential can be further enhanced by specific material and design choices. Fusion’s safety and environmental prospects appear to substantially exceed those of advanced fission and coal but will not be achieved automatically. A significant and directed technology effort is necessary. Typical parameters have been established for fusion reactors, and a tokamak at moderately high magnetic field (about 7 T on axis) in the first regime of MHD stability (s ≤ 3.5 I/aB) is closest to present experimental achievement. Directions to further improve economic and technological performance include the development of higher magnetic fields to lower the required plasma current and reactor size, improvement in the beta value in the second stable MHD regime to lower requirements of field and plasma current, and improvement in techniques for plasma current drive to efficiently achieve steady-state plasma operation. For inertial confinement, reactor studies are at an earlier stage but two essential requirements are a high-efficiency (> 10%) repetitively pulsed pellet driver capable of delivering up to 10 MJ of energy on target, and targets capable of yielding an energy gain (ratio of energy produced to energy on target) of 100.