Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
CONCLUSIONS DOE is currently the principal agent in the U.S. for the development of fusion power. This arrangement is likely to continue for some time into the future, until progress and incentives of sufficient magnitude to attract private investments become apparent. It is nevertheless essen- tial that there be close interaction between DOE and the ultimate custom- er, the utilities, in the course of such a civilian development program. Both parties, the developer and the user, must learn to appreciate their respective requirements. Of course, there is a large worldwide effort on fusion, in addition to the U.S. program. The cooperation and complementarity of this global effort is perhaps unique in the history of technology; the U.S. program is surely a beneficiary of this state of affairs. Nevertheless, DOE and its counterparts in other countries, principally the U.S.S.R., EEC, and Japan, face difficult choices in planning for the orderly development of fusion power. The near-term objectives are in a state of transition. Although scientific feasibility has yet to be demonstrated by any of the approaches now under consideration, there is a growing conviction that this will be achieved relatively soon. No fundamental conceptual difficulties seem to be evident that would indef- initely delay the demonstration of scientific feasibility. The question that remains open is whether one or more of the approaches promising to achieve scientific feasibility in the near future will lend themselves to the development of a practical, commercial fusion-reactor technology. The principal concern revolves around capital cost, minimum plant output, plant availability, plant complexity, and environmental characteristics. A reasonable approach to developing fusion power involves at least the following elements of a program plan: l. Continue to concentrate on the main line approaches showing the greatest physics promise at this time. For magnetic confinement this is the Tokamak, backed up by the mirror, while for inertial confinement it is the laser-driven micro-pellet implosion, backed up by other potential energetic driver sources. It is by this route that we hope to gain further information rapidly on plasma behavior and scaling laws under conditions simulating the reactor regime. 33
34 2. Explore all promising routes to improving the potential reactor performance of the main line approaches. Certain undesirable features that may show up in early generations of conceptual reactor designs (based on extrapolations of our current state of understanding), will serve as valuable guideposts for further improvements. 3. Explore other physics and engineering options in sufficient depth over the next 5 to l0 years to determine how they might lead to fusion systems more desirable to a user in terms of cost, size, opera- tional, and envionmental characteristics. This will require a number of intermediate-sized physics and engineering experiments and tests. Program planners will have the difficult task of selecting the areas that promise the necessary flexibility for a successful development program. Full but premature commitment to a single approach on the one hand, and unfruitful procrastination and dissipation of resources on the other, will detract from an orderly development schedule and should be avoided. 4. Study, over the next 5 to l0 years, all the important generic technological problems inherent in the development of fusion power. Engineering experience under realistic conditions representative of a fusion reactor environment must be pursued as soon as feasible. Pilot- plant-scale experiments, which should be kept at a minimum size but could still be quite large, will be required eventually to provide the necessary test beds for further development. To demonstrate the prac- tical value of fusion and encourage industrial participation, fusion systems with useful outputs should be developed in the smallest possible size at the earliest possible date. The move to pilot-plant-scale experiments, for purposes of scaling eventually to commercial size reactors, should not be attempted, however, until a greater level of understanding is reached in the areas of confinement plasma physics and materials properties. Emphasis, for the time being, must continue to be on developing improved confinement schemes. 5. Because of the importance of meeting needs in the energy field, pursue applications of fusion energy for fission and chemical fuel pro- duction and fission waste disposal in sufficient depth to make possible a meaningful comparison with other options. Fusion physics concepts that hold unique potentials must be investigated adequately to assure a fair evaluation of fusion in these areas. 6. Finally, recognize the cost of the various program elements, the need for continuing expensive physics and engineering experiments, fol- lowed by even more expensive pilot-plant-scale experiments, all leading up to the eventual design and construction of one or more demonstration plants. Some preliminary DOE estimates indicate that cumulative costs over the next 20 to 25 years, arriving at a single demonstration unit, will be on the order of $l5 billion in terms of constant dollars, and it's just possible this figure is on the low side. One might be able to accelerate the pace of development somewhat with even larger expendi- tures of money. This would permit a wider and more rapid exploration of physics and engineering options, and could open up paths to fusion systems that better meet the user's requirements and hence accelerate the time scale to commercialization. Such an action would help avoid
35 a premature decision to concentrate on an uneconomic concept due to inadequate funds to explore other options. When all this is said, we realize that the fusion effort is still in relatively early stages of development; ultimate success in terms of a viable commercial entity cannot be predicted with certainty; and it will surely take time, money, and the dedication of skilled workers to make progress in removing the uncertainties. Because of its reliance on virtually unlimited and cheap fuel and its relative safety, a strong program of fusion power development deserves the full support of the federal government. A number of crucial scientific and engineering questions remain to be answered, including: How high a B can be achieved in closed magnetic confinement schemes? What ultimately governs anomalous diffusion rates which in turn govern nt in a device? Can effective end-stoppering be achieved for mirrors? Can efficient and suitably matched drivers for inertial confinement schemes be developed? How high a magnetic field strength can be produced by superconducting coils? What will be the lifetime of first walls? Can low-activation material be found to stand up to the fusion environment? The fusion program should be guided by continued systems studies and evaluations that incorporate new physics, materials, and engineering data and respond to feedback from the utility industry. As a result of the early system designs made over the past few years, and the extensive planning efforts at ERDA that in part have been inspired by these studies, the fusion effort has come under a certain amount of criticism. Some of this has come from electric utility spokesmen and should be taken seriously, in view of the fact that the utilities are the principal potential customers of fusion reactors. The early systems studies enabled the users to point out objection- able features that should be avoided in future fusion designs, such as excessively large size (installed unit capacity) by current standards, low power densities (fundamentally the same fault), questionable relia- bility, cold start requirements (e.g. l500 MWe startup power required for a particular 840 MWe mirror unit), increased cooling requirements resulting from large circulating power, energy storage for cyclic opera- tion, remote maintenance in the presence of high background radiation inherent to fusion reactors, additional complexity as witnessed in several early designs, imprecise knowledge of reactor control and safety handling, and so forth. Workers in the field are quite sensitive to all of these issues. Con- tinual conceptual fusion reactor designs will be required in varying degrees of depth to test the significance of new ideas, data and con- cepts against realistic requirements. However, we feel that l985 is perhaps the earliest date by which enough new scientific and engineering understanding will have been reached to enable anything resembling a realistic preliminary reactor design. These reactor designs should be considerably more detailed and include many features left out of the current generation of reactor studies. Towards the end of this century, it is conceivable that a demonstration reactor might be constructed and operated, although it is likely that such an early model will be far from optimal.
36 It is clearly somewhat meaningless at this stage to speculate on the earliest date by which fusion will begin to have a significant economic impact (say, the production of l quad equivalent of energy per year) . The conclusion we are prompted to reach at this point is that with gradually improved scientific understanding and technological advance, achievable in a vigorously supported program, fusion, with its multiple approaches and techniques will appear continuously more attractive as an ultimate long-range solution to the energy problem. SUMMARY l. It seems highly probable that scientific feasibility for fusion will be demonstrated for magnetic confinement, and perhaps for inertial confinement, within roughly the next 5 years. 2. Early generation conceptual designs based on conservative physics and materials properties have led to reactor systems that do not appear to be commercially attractive. There are obvious paths to follow, leading many to believe that the shortcomings of the above are soluble, and most of us share this optimism. 3. A critical step is to learn what plasma performance will be ob- tained in the reactor physics regime, so we must forge ahead with scaled-up, mainline approaches. In parallel, the technology program has to be pushed hard. 4. There is considerable room for improvement, in terms of evolution of present confinement concepts, development of new ones, and development of superior materials; an R&D atmosphere that stimulates innovation is highly desirable. Many options are permitted by the physics, and those that appear promising should be explored. 5. If the fusion program is continued at a high enough level of funding, we would expect that progress achieved by l985 or thereabouts would permit a realistic appraisal of the prospects for embarking on a commercial demonstration project. 6. It is plausible, though one can give no guarantee, that a success- ful demonstration in a prototype commercial fusion reactor could be achieved within the next 20 to 25 years for an estimated l5 to 20 billion dollars (exclusive of inflation). These numbers are highly speculative and could be either high or low.
