The Senior Committee on Environmental, Safety, and Economic Aspects of Magnetic Fusion Energy (ESECOM) summarizes its recent assessment of magnetic fusion energy's (MFE's) prospects for providing energy with economic, environmental, and safety characteristics that would be attractive compared with other energy sources (mainly fission) available in the time frame of the year 2015 and beyond. Accordingly, ESECOM has given particular attention to the interaction of environmental, safety, and economic characteristics of a variety of magnetic fusion reactors, and compared those fusion cases with a variety of fission cases. Eight fusion cases, two fusion-fission hybrid cases, and four fission cases are examined, using consistent economic and safety models, to permit exploration of the environmental, safety, and economic potential of fusion concepts using a wide range of possible materials choices, power densities, power conversion schemes, and fuel cycles.

Exploring the Competitive Potential of Magnetic Fusion Energy: The Interaction of Economics with Safety and Environmental Characteristics

A simplified physics, engineering, and costing model of a tokamak fusion reactor is used to examine quantitatively the connection between physics performance and power-plant economics. The material contained herein was generated as part of a broader study of the economic, safety, and environmental impact of fusion based on a range of confinement schemes, fusion fuels, blanket/shield configurations, power-conversion schemes, and commercial end products. Only a DT-fuelled tokamak reactor that produces electricity through an intermediate heat exchange and a conventional thermal-electric conversion cycle is considered; a self-cooled lithium-metal blanket with vanadium-alloy structure, steel shield, and superconducting magnets is used for all cases studied. An optimistic extension of Troyon scaling is applied to a high-elongation (κ = 2.5) and low-safety-factor (q

 ψ
 =2.3) plasma with β=0.1 and efficient (I

 φ
 
P

 CD
 =0.2 A/W) current drive. This 1200-MWe (net) power plant provides an economically competitive base case with which to compare other approaches to tokamak fusion power. The base case chosen for comparisons represents an optimistic extrapolation of present tokamak physics and technology. Troyon scaling with a coefficientβ
B

 φ
 a/I

 φ
 equal to 0.04 is applied; the impact of an ad hoc but pessimistic scaling that diminished the Troyon coefficient with plasma elongation was also examined. Additionally, a constant current-drive efficiency, ϒ=nI

 φ
 
R

 T
 /P

 CD
 =0.2 A/W, atT=10 keV plasma temperature is assumed; although representing an aggressive R&D target relative to present experience, the realization of bootstrap currents for the basecase, and especially for the second-stability-region tokamak, can significantly reduce this problem. The impact and reoptimization for a constant normalized current-drive efficiency, ϒ=nI

 φ
 
R
T/P
CD, was also examined. Although the focus of this study has been the optimistic basecase tokamak, comparisons are made with tokamaks based on (a) operation in the second-stability region (β=0.2, increased aspect ratio, reduced elongation), (b) super high-field but low-beta operation, (c) very low aspect ratio and highly elongated spherical torus, and (d) a direct application of the present database using a long-pulsed, low-beta tokamak. The economic impact of a range of base-case parameters and operating variables is examined, including current-drive efficiency, beta, stability limits, advanced magnets, economy of scale, blanket/shield lifetime, blanket thickness, and plant lead time. It is found that a range of tokamak options, relative to the optimistic base case selected for this study, may provide economically competitive power plants. Areas where physics and technology advances are needed to achieve this attractive end product are quantitively elucidated for all tokamak options considered.

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Connections between physics and economics for Tokamak fusion power plants

Progress in Commercial Magnetic Fusion Energy Reactor Designs

A computerized systems model of a heavy-ion fusion (HIF) reactor power plant is presented. The model can be used to analyze the behavior and projected costs of a commercial power plant using an induction linear accelerator (Linac) as a driver. Each major component of the model (targets, reactor cavity, Linac, beam transport, power flow, balance of plant, and costing) is discussed. Various target, reactor cavity, Linac, and beam transport schemes are examined and compared. The preferred operating regime for such a power plant is also examined. The results show that HIF power plants can compete with other advanced energy concepts at the 1000-MW(electric) power level (cost of electricity (COE) --50 mill/kW . h) provided that the cost savings predicted for Linacs using higher charge-state ions (+3) can be realized. The induction Linac driver is still a major component of the total capital cost (43%), but it no longer appears that large 4000-MW(electric), $5 billion (1984) power plants will be required to make the economics of HIF look favorable. More importantly, the results also indicate that there are several different combinations of target and reactor cavity options that lead to COEs within 10% of the overall minimum. The induction Linac's highermore » efficiency (>20%) is able to compensate for changes in target concept (gain) and cavity type with minimal change in COE. The potential cost reductions and apparent flexibility identified by this study together with the established performance data base from present-day accelerators are leading to renewed interest in induction Linacs for near-term target development applications.« less

An Induction Linac Driven Heavy-Ion Fusion Systems Model

A consistent method for the comparison of environmental, safety, and health (ES&H) characteristics of fusion power plant designs is developed. Such comparisons enable identification of trends in fusion ES&H characteristics and can be used to increase the likelihood of fusion achieving its full potential with respect to ES&H characteristics. A large number of radiological hazard indexes are defined in three different categories of hazard: accidents, occupational and routine exposures, and waste disposal. Using a consistent set of computer codes, data libraries, and assumptions, these radiological hazard indexes are calculated and compared for five inertial and two magnetic fusion energy power plant designs. The results of the analysis are threefold: The utility of low-activation materials (LAMs) is confirmed, the tremendous potential for the use of thick-liquid system for first-wall protection is validated, and the strong need for materials that can last for the lifetime of the power plant is shown. The conservative radionuclide release fractions that are used show that all but one of the designs has only a minute chance of producing any early fatalities during an accident. The need for remote maintenance in most designs is confirmed, and the possibility of disposing of most fusion wastes via shallow land burial (if the methodology ofcurrent regulations is applied to fusion wastes) is shown. The need for more research in LAMs and for the experimental measurement of radionuclide release fractions under accident conditions is emphasized.

Inertial fusion energy : A clearer view of the environmental and safety aspects

This report summarizes the results of the second year of a two-year study on the design and evaluation of the Cascade concept as a commercial inertial confinement fusion (ICF) reactor. We developed a reactor design based on the Cascade reaction chamber concept that would be competitive in terms of both capital and operating costs, safe and environmentally acceptable in terms of hazard to the public, occupational exposure and radioactive waste production, and highly efficient. The Cascade reaction chamber is a double-cone-shaped rotating drum. The granulated solid blanket materials inside the rotating chamber are held against the walls by centrifugal force. The fusion energy is captured in a blanket of solid carbon, BeO, and LiAlO/sub 2/ granules. These granules are circulated to the primary side of a ceramic heat exchanger. Primary-side granule temperatures range from 1285 K at the LiAlO/sub 2/ granule heat exchanger outlet to 1600 K at the carbon granule heat exchanger inlet. The secondary side consists of a closed-cycle gas turbine power conversion system with helium working fluid, operating at 1300 K peak outlet temperature and achieving a thermal power conversion efficiency of 55%. The net plant efficiency is 49%. The reference design is a plant producing 1500more » MW of D-T fusion power and delivering 815 MW of electrical power for sale to the utility grid. 88 refs., 44 figs., 47 tabs.« less

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E.T. Cheng

Papers

Inertial confinement fusion reaction chamber and power conversion system study. Final report