Fusion Power Systems Research Articles

The tokamak hybrid reactor

At a time when the potential benefits of various energy options are being seriously evaluated in many countries throughout the world, it is both timely and important to evaluate the practical application of fusion reactors for their economical production of nuclear fissile fuels from fertile fuels. The fusion hybrid reactor represents a concept that could assure the availability of adequate fuel supplies for a proven nuclear technology and have the potential of being an electrical energy source as opposed to an energy consumer as are the present fuel enrichment processes. Westinghouse Fusion Power Systems Department, under Contract No. EG-77-C-02-4544 with the Department of Energy, Office of Fusion Energy, has developed a preliminary conceptual design for an early twenty-first century fusion hybrid reactor called the Commercial Tokamak Hybrid Reactor (CTHR) [1]. This design was developed as a first generation commercial plant producing fissile fuel to support a significant number of ‘client’ Light Water Reactor (LWR) Plants. To the depth this study has been performed, no insurmountable technical problems have been identified. The study has provided a basis for reasonable cost estimates of the hybrid plants as well as the hybrid/LWR system busbar electricity costs. This energy system can be optimized to have a net cost of busbar electricity that is equivalent to the conventional LWR plant, yet is not dependent on uranium ore prices or standard enrichment costs, since the fusion hybrid can be fueled by numerous fertile fuel resources. A nearer-term concept is also defined using a beam driven fusion driver in lieu of the longer term ignited operating mode.

Nuclear fusion: Focus on Tokamak: U.S. engineers and physicists will team to attempt commercial demonstration by the year 2000

The general aspects of fusion power systems as well as some approaches to their development, are addressed from the viewpoints of engineering and technology. Focusing on a conceptual fusion power plant design, topics such as structure, materials and maintenance as well as environmental, safety, and economic factors are dealt with. Still in common with all such large-scale undertakings that try to project into the future, fusion power has built-in uncertainties. In this case, they are primarily in the area of plasma physics performance. Within the next five to six years, however, these uncertainties should be resolved and a national commitment could be made to a plan for demonstrating commercial feasibility in this century with a reasonable expenditure of money.

Atomic and cluster injection into D-T mirror fusion power systems

The problem of the penetration of a neutral atomic beam and a cluster ion beam into a fusion plasma is reviewed. The short penetration length of an atomic beam, coupled with certain geometric dependences of the magnet coil costs, implies an optimum injection energy for a D-T mirror fusion power system in the range 200 to 300 keV. The penetration length for a cluster beam is inferred from available data. For certain charge and mass distributions of the cluster fragments, a substantial improvement of beam penetration is possible, allowing for injection as low as 100 keV per deuteron. Additional fragment charge and mass distribution data will be necessary, however, to clarify the role of cluster injection.

Some factors in the choice of D-D, D-T or D-3He mirror fusion power systems

A discussion is given of the relative merits of the D-D, D-T,or D-3He mirror fusion power systems. As a basis for discussion we have used a simple approach for estimating the ratio of Q(D, He) to Q(D, T). When needed, the value of Q(D, T) is considered to be of the order of that calculated by Marx and by Kuo-Petravic, Petravic and Watson. The systems are compared at different assumed plasma temperatures in the range 200 to 1000 keV on the basis of several criteria: the investment costs in dollars per kilowatt, the ratio of waste power to power output, and the tritium and neutron production. We have concluded, based on the estimates of the ratio of Q-values, that subject to these criteria the D-T system appears the more favoured system. On the other hand, should a means be found to enhance the Q-values the D-3He system would be preferred on all but the first criteria. We consider the three-component D-T-3He system and its optimization. Finally, the possibility of further enhancing the D-T system by utilization of tritium breeding in the plasma is discussed.