Economic, Safety and Environmental Characteristics of Commercial Fusion Power

Transcription

1 Economic, Safety and Environmental Characteristics of Commercial Fusion Power I. Cook Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon, OX14 3DB, UK ABSTRACT. This paper gives a review of the key economics, safety and environmental attributes of fusion power, based on results from the extensive studies that have been performed. A variety of conceptual designs for commercial power plants have been developed, especially within the European Power Plant Conceptual Study (PPCS) and the American ARIES series. Analyses have been made, using well-authenticated models, of the safety and environmental impacts of the plants, of the cost of generating electricity and of the impacts of fusion power on future scenarios. Fusion has very well-attested and attractive inherent safety and environmental advantages, in particular: no emissions of greenhouse gases; limited consequences of the worst possible accidents; no need for repository disposal of activated material produced by the operation and dismantling of the plant. The cost of fusion electricity is likely to be comparable with that from other environmentally responsible sources of electricity generation. The analyses also show which plasma, materials and engineering developments are the keys to improving further the economics of fusion. 1. Introduction Environmental and safety advantages, together with widespread and abundant supplies of fuel, are the main motives for the development of fusion power. Fusion power must also have acceptable or attractive economic attributes. This paper gives a review of the key economics, safety and environmental attributes of fusion power and issues arising from the extensive studies that have been performed. More technically detailed reviews of fusion economics, and fusion safety and environmental considerations, have been published by Ward et al. [1] and Taylor [2] respectively. From 1990 to 2004 studies within the European and US fusion programmes examined the safety and environmental impacts and economic potential of fusion power, based on conceptual design studies of commercial fusion power plants [3-16]. Important studies were also performed in Japan [17,18]. The results show that fusion power could be a key contributor to reconciling global economic development with safety and protection of the environment. In the EU and US conceptual design studies the parameters of the designs were chosen to minimize the calculated cost of generating electricity, given the specifically assigned constraints on plasma and technology performance. The conceptual designs were then developed in detail. Analyses were made of their safety, environmental impacts and economic attributes. The analyses in the EU, US and Japanese studies are in essential technical agreement: the illustrative results in this paper are taken from the EU studies, with reference made to US and Japanese results. 2. Basic Features of the Conceptual Designs In the European Power Plant Conceptual Study (PPCS), four conceptual designs (termed Model A, B, C and D) for commercial fusion power plants were developed [8-12]. The power plant conceptions in these studies, and in the US [13-16] and Japanese [17,18] studies, span a range from relatively near term, based on limited plasma physics and technology

2 extrapolations, to advanced conceptions. These specific conceptual designs are illustrative of a wider spectrum of possibilities. In the EU and US studies, the parameters of the conceptual designs were chosen by systems analysis to minimize the internal (see section 5) cost of electricity, given the specifically assigned constraints on plasma and technology performance. Those analyses also show which plasma, materials and engineering parameters are keys to further improving the economics. All the conceptual designs considered in this paper are based on the main line of tokamak fusion development, proceeding through ITER. Attractive visions have also been developed for commercial fusion power plants based on the stellerator and spherical tokamak concepts: these are not discussed in this paper, but their safety, environmental and economic attributes are broadly similar to the concepts covered here. The environmental and safety attributes of fusion power plants are primarily determined by the generic and inherent advantages of fusion, in conjunction with the specific choices of the materials employed for the plant components. The economic attributes are determined by a much broader range of factors relating to plasma physics regime, materials performance and engineering. Full accounts of these matters are given in the Reports on the studies. Here we very briefly summarise only the basic points needed for the understanding of the economic, environmental and safety analyses Plasma Physics, Materials and Technology Basis For a chosen value of the net electrical output of the plant the required fusion power is determined primarily by the thermodynamic efficiency and power amplification of the blankets and by the amount of gross electrical power recirculated for purposes including current drive and coolant pumping. These are in turn determined by the materials technology and plasma physics bases. Given the fusion power, the plasma size and power density are primarily determined by the assigned constraints on plasma core physics, and by the tolerable heat load to the divertor. The broad features of the plasma physics and materials technology of the four PPCS Models [8-12], chosen for illustration in this paper, are outlined in Table 1 below. TABLE 1. SUMMARISED PLASMA PHYSICS AND MATERIALS BASES OF THE PPCS MODELS PPCS Model Plasma physics Main structural material Other blanket materials Other divertor materials A Near-term Eurofer LiPb/water W/Cu/water B Near-term Eurofer Li4SiO4/Be/helium W/helium C Intermediate Eurofer/ODS LiPb/SiC/helium W/helium D Advanced SiC/SiC LiPb W/SiC/LiPb For the two near-term models, A and B, the plasma physics scenario represents broadly parameters about thirty percent better than the conservative design basis of ITER. Models C and D are based on progressive improvements in the level of assumed development in plasma physics, especially in relation to plasma shaping and stability, limiting density and in minimisation of divertor loads without penalising the core plasma conditions. Eurofer is a reduced activation ferritic-martensitic steel.

3 Discussion of the influence of the plasma physics, materials and technology bases on economics is given in section 5, with reference also to US and Japanese studies. An additional key factor is the development of maintenance schemes capable of supporting high availability (greater than 75%). The frequency and the duration of in-vessel maintenance operations are the prime determinants of the availability. The frequency of in-vessel maintenance operations depends upon the lifetime of the components in the fluxes of fusion neutrons and charged particles, which in turn depend upon materials choices and the power density. Several families of maintenance schemes have been studied and evaluated. The PPCS scheme [8] was similar to that of ITER, but with segmentation of the blanket into the smallest possible number of large modules. An alternative scheme, based on a completely different segmentation of the internals, is exemplified in the ARIES studies [16,19]. In this scheme, complete radial sectors of the tokamak are handled as individual units Basic Design Parameters The basic design parameters, which derive from optimizing the cost of electricity subject to the complex interrelationships of plasma performance, materials performance, engineering, economics and other factors, were, in the EU and US studies, selected using systems codes, supplemented by the understanding gained from analytical studies. The systems code studies employed very extensive self-consistent mathematical models, as described and used in the studies [1, 6-11]. They incorporate plasma physics and engineering relationships and limits, and availability, together with costing models validated against the well-assessed ITER costs and by comparison with one another. As one element of the validation of the systems models, a comparison was made between the breakdown of the contributions to the code-calculated PPCS Model C capital costs and those for the ITER98 design [9]. To make a like-for-like comparison, the ITER98 costs were adjusted to reflect the learning effects appropriate to a tenth of a kind ITER. The agreement was very good, apart from items (especially turbines!) that ITER does not have Capital cost (M$) ARIES RS PROCESS 0 direct cost land+structures magnets blanket/fw turbines vacuum heating power supplies Figure1. Comparison between the capital cost contributions obtained in the ARIES-RS study and an independent calculation of these using the systems code, PROCESS, used in the European studies.

4 As a second illustration of validation, Fig 1 shows a comparison between the capital cost contributions obtained in the ARIES-RS study [15] and an independent calculation [20] of these with the systems code, PROCESS, used in the European studies. Though there are interesting differences in detail, the overall agreement is again very good. The high degree to which the code calculations agree with each other and with the very well validated and detailed ITER capital costs gives confidence in the robustness of the economic modelling in these studies. The parameters thus arising from the systems calculations were used as the basis for the conceptual design of the PPCS and ARIES Models. In the course of the design process, feedback of engineering results and of reviewed plasma physics assessments was input to reiterated systems calculations, and led to further iterations of the designs. The main parameters of the four PPCS Models, so arising, are given in the PPCS Report and published papers [8-12]. Figure 2 illustrates the poloidal cross-sections of the plasmas. 8 Z(m) 6 4 ITER D C B A 2 R(m) Fig. 2. Illustration of the sizes and shapes of the plasmas in the PPCS Models. For comparison, ITER is also shown: this is similar in size and shape to Model D. The axis labels denote major radius (R) and height (Z) in metres. 3. Safety and Environmental Impacts To begin with a very generic, and very significant, feature: fusion power plants will not emit any of the greenhouse gases: a major environmental advantage in itself. (There would also be no acidic emissions.) In addition, fusion power plants have a number of further inherently favourable characteristics relevant to safety and environmental impacts: They have extremely low levels of fuel inventory in the burning chamber, their power production stops with no fuelling and power excursions are self-limited by inherent processes; They make no use of any fissile material and their stored energies are several orders of magnitude lower than in fission reactors of similar power; Their power density after shutdown ( decay heat ) is moderate. They have relatively low levels of long-term activation.

5 These favourable generic features lead to substantial safety and environmental advantages. The full expression of these advantages depends upon the details of design and, particularly, materials selection. This report is about commercial fusion power plants, not about nearer-term fusion devices such as the large burning plasma experiment ITER. Very extensive safety and environmental studies have been performed for ITER [21], and it is valuable to bring out the similarities and differences between these and the power plant studies. These differences stem both from differences between ITER and future commercial power plants, and from differences in the aims of the investigations. Commercial fusion power plants differ from ITER in two particularly relevant respects: they have higher power densities, component temperatures, and neutron fluences; they use low-activation structural materials. For these reasons, it is not possible to infer the safety and environmental impacts of a fusion power plant from the results of the ITER studies. Nevertheless, the general understanding developed in the ITER studies has been deployed for the power plant studies, and the methods of investigation are the same. In showing the safety of a near-term device like ITER, for licensing purposes, it is obviously necessary to perform many very detailed investigations. This is possible, since ITER has a very detailed design. But in studying the safety of conceptual designs for fusion power plants the aim is to perform more generic studies establishing the key features. The very limited consequences of hypothesised worst case accidents, and the low long-term burden of activated materials, are among the most attractive features of fusion power plants and provide the main motivations for pursuing fusion development. Accordingly, this paper focuses on the analyses in these areas, while more briefly referring to other issues Bounding accidents In essence, it follows from the generic factors summarized above that there are only limited stocks of energy to drive accidents, and the radiological impacts of any released material would also be limited. To establish the bounding consequences of an accident driven by in-plant energies, bounding accident analyses were performed, in which a hypothetical event sequence is postulated. For PPCS Models A and B, this was assumed to be a total loss of cooling from all loops in the plant, with no active cooling, no active safety system operating, and no intervention whatever for a prolonged period. For Models C and D, the lithium-lead was retained in the model, but not circulated, so as to retain the decay heat generation by the lithium-lead itself. The only assumed rejection of decay heat is by passive conduction and radiation through the layers and across the gaps of the model, towards the outer regions where eventually a heat sink is provided by convective circulation of the building atmosphere. The temperature rise is assumed to mobilise tritium and activation products, both erosion dust loose in the vessel and solid activation products, in structures, mobilised by volatilisation at the surfaces. This inventory, together with the entire contents of one cooling loop, is the source term assumed to be available for leakage from the plant through successive confinement barriers, using conservative assumptions. The fraction of this source that escapes into the environment is then transported, under worst weather assumptions, to an individual at the site boundary. Details of the calculations, which use conservative modeling, are in the PPCS Report [8]. Only the main results are given here.

6 The histories of temperatures throughout the Models were obtained for times up to 100 days. Figure 3 shows the calculated temperature histories for the bounding accident sequences in the outboard first walls of all the Models temperature (C) C B A D time (days) Fig. 3. Conservatively calculated temperature histories, for hypothetical bounding accidents in the outboard first wall of the four PPCS Models. At no time does any component reach a temperature close to melting. Because of its very low level of decay heat power, the temperatures in Model D actually fall in the bounding accident. Conservatively calculated estimates of the consequences to the public of the above worst case hypothetical accidents to Models A and B are shown in Table 2. Table 2. CONSERVATIVELY CALCULATED WORST CASE DOSES FROM HYPOTHETICAL BOUNDING ACCIDENTS 100 Model PPCS-A PPCS-B Dose 1.2 msv 18.1 msv These conservatively calculated doses are not much greater than or are similar to typical annual doses from natural background. For PPCS Models C and D, only a qualitative assessment of the worst case doses was performed. Mainly because of the smaller inventories of mobilisable material in these Models, and the much smaller enthalpies of the primary coolants (essentially zero for Model D), it was assessed that bounding doses from Model C will be similar to or less than the (already small) bounding doses from Model B and the bounding doses from Model D will be much smaller still. Broadly similar safety studies, with similar outcomes were performed for ARIES Models [13-16]. The details differ according to the differing details of materials selection, design and confinement arrangements, but the results demonstrate the same essential points: the

7 maximum public consequences of fusion power plant accidents are very limited, because of the inherently favourable factors listed at the beginning of this section. The fundamentals of fusion safety, namely that low consequences of worst case accidents are guaranteed by inherent characteristics and passive features of design, entail that a fusion power station would be very resistant to adverse human factors. The conservative analysis of worst case accidents presented above was independent of the details of accident initiation and progression, such as might be caused by human factors. The role of external events in accidents is very dependent on the fine details of design. Accordingly, in earlier studies [3-5], external hazard accidents were assessed through consideration of hypothetical bounding cases. For example, in the event of confinement damage by a very rare or hypothetical ultra-energetic ex-plant event, such as an earthquake of hitherto never experienced magnitude, an upper bound to the release of tritium is set by the vulnerable inventory, which is about one kilogram. Even if calculated on very conservative assumptions, the release of one kilogram would result in a maximum dose to a member of the public that would give rise to health effects smaller than the typical consequences of the external hazard itself. On realistic assumptions the maximum dose would be lower. More generally, Taylor [2] has shown that even in these very extreme energetic external events the maximum public doses would be below the commonly used no-evacuation limit (50 msv) provided no more than about one tenth of the potentially mobilisable inventories were actually mobilized and released, and that realistic, non-conservative, modeling is expected to show that this is so. These very hypothetical scenarios could, moreover, be removed by design provision: essentially, external hazards are an economic issue Other Safety Issues In addition to having low consequences from hypothesised bounding accidents, fusion power plants must be designed to lower the consequences and frequencies of lesser accidents. These lesser accident issues have been modelled in the PPCS studies [8] and especially, with great thoroughness, in the ITER safety studies [21], with favourable outcomes. None of the materials needed in a fusion power plant are subject to the provisions of non-proliferation treaties and it would be easy to detect the presence of even small quantities of illicit material [3,5]. Ensuring low doses for workers at the plant is certain to be a regulatory requirement. Almost all such potential doses can be attributed to maintenance operations, but quantification of the expected doses depends strongly on the detail of such operations and with designs for commercial fusion power plants at only a conceptual stage it is not possible to define this level of detail. Detailed assessments of effluent releases, and of resulting doses via both atmospheric and aqueous pathways, have been performed [2,4,5,8]. Doses were found to be very small even on a conservative basis of calculation Categorisation of Activated Material The activation of the materials in the PPCS and ARIES Models decays relatively rapidly [4,5,22]. This is illustrated in Figure 4, which shows, for the four PPCS Models (plus an additional Model, AB, not otherwise covered in this paper), the total radiotoxity (namely the biological hazard potential associated with activation) of all the activated material produced, together with the equivalent numbers for three types of nuclear fission power plants and a coal power plant, all normalized to the same total electricity production [22]. The numbers have been normalized to the initial value for the nuclear fission systems. The radiotoxicity of the

8 fusion material falls below that of the coal waste after about two hundred years, and at that time is about a hundred thousand times lower than the equivalent value for nuclear fission. 1.0E E+00 Radiotoxicity Index (Ingestion) 1.0E E E-03 Coal PWR EFR A 1.0E-04 EFR B Model A 1.0E-05 Model B Model C 1.0E-06 Model D Model AB 1.0E Time after final shutdown (y) Figure 4. Comparison of the total radiotoxicity of the materials produced by the PPCS Models and by three types of nuclear fission plant and a coal-fired plant, all normalized to the same total electricity production. Not surprisingly, for much of this material, after an adequate decay time, the activity falls to levels so low that it would no longer be regarded as radioactive, but could be cleared from regulatory control and processed as normal scrap. Other material - simple and complex recycle material - can be recycled for further use, employing straightforward processes in the case of simple recycle material. Only a small amount, if any, would require long-term disposal in a waste repository. Using the same criteria as in the earlier studies [4,5] (which have been assessed to be conservative for recycling) the categorisation of the materials accumulated from the operation and decommissioning of the PPCS Models has been performed. Detailed results are available [8,22]. The most important point is that, after a hundred years, there is no material in the permanent disposal waste category. In the US ARIES studies [13-16] essentially equivalent calculations have been performed, and a different approach to categorisation has been used to make the same essential point. The US studies show that the activated materials arising qualify for shallow land burial under US regulations. Whether or not the fusion activated materials would actually be recycled or given shallow land burial is a matter for future generations to determine, using their own criteria including economic criteria: however, the fact that long-term repository disposal is not needed is a telling indication of the relative benign-ness of the fusion material. 5. Economics There are two classes of contributions to the cost of electricity from any power source: internal costs and external costs [1,6,7]. Internal costs refers to the contributions to the cost

9 of electricity from constructing, fuelling, operating, maintaining and disposing of, power plants. Internal costs do not include costs such as those associated with environmental damage or adverse impacts upon health. In the case of some present sources of electricity, these external costs are substantial. The internal costs of electricity from the PPCS and ARIES Models were calculated using the systems codes briefly described in section 2 above. The total capital cost, including interest during construction, is combined with replacement costs, other operating costs, payments into a decommissioning fund, and the availability, to obtain the internal cost of electricity. This is done in a standard manner, the levelised cost methodology, which is used for example in OECD and IAEA studies. The Models differ in physical size, fusion power, the re-circulating power used to drive the current in the plasma, the energy multiplication that occurs in the blanket, the efficiency of converting thermal to electrical power, and in other respects. Accordingly, the internal cost of electricity varies between the Models. All these differences originate in differences in the assigned constraints on plasma, materials and engineering performance. It has been found [9], and confirmed and elucidated by analytical studies, that the dependence of internal cost of electricity on the key parameters is well represented by the following expression. coe 1 A 0.6 η th P 0.4 e β 1 (1) 0.4 N N 0.3 Here coe is cost of electricity, A is the availability, η th is the thermodynamic efficiency, P e is the net electric power, β N is the normalised plasma pressure, and N=n/n G is the Greenwald normalised plasma density. Figure 5 shows the (central estimate) internal cost of electricity for each of the PPCS Models, and also for three of the ARIES designs (ARIES-I, ARIES-RS and ARIES-AT) as calculated in detail in those studies, plotted against the above scaling expression [20]. The good agreement shown, between the detailed validated calculations and the simplified transparent expression (1), together with the successful validation exercises summarized in section 2, points to two important general points: The level of understanding within, and technical agreement between, the economic studies is high. The Models are good representatives of a wide class of possible economically optimized conceptual designs of commercial fusion power plants. These conclusions also apply for the Japanese studies [17,18]. As with all systems, the absolute value of the internal cost of electricity depends on the level of maturity of the technology. For an early implementation of these power plant models, characteristic of a tenth of a kind plant, the cost range of the PPCS plant models is calculated to be 5 to 9 cents/kwh [1,8,9]. In a mature technology in which technological learning has progressed, the costs are expected to fall in the range 3 to 5 cents/kwh [1,8,9]. In more detail, the ranges of calculated internal cost of electricity from the four Models [1,8,9] are shown in the second column of Table 3.

10 Table 3. CALCULATED COST OF ELECTRICITY FROM THE PPCS MODELS Model Internal cost of electricity ( cents/kwh) External cost of electricity ( cents/kwh) PPCS-A PPCS-B PPCS-C PPCS-D For all the Models, the internal cost of electricity is within the range of estimates, in the literature, for future costs from other sources [1,7]. In particular, both the near term PPCS Models have acceptable competitive internal costs coe ($96) coe (scaling) Fig. 5 Relative internal cost of electricity, calculated by systems codes, for the four PPCS Models and three ARIES Models, plotted against the scaling shown in equation (1). Equation 1 points to the plasma physics, materials and engineering factors that are the keys to further improving the economics of fusion. In descending order of relative importance to economics: A is the plant availability, which primarily depends upon the lifetime of the blankets and divertors, before they need to be replaced, the maintenance scheme, and the reliability of all the systems, especially the in-vessel components; η th is the thermodynamic efficiency, which primarily depends upon the operating temperature and energy multiplication of the blanket; P e is the net electrical output of the plant. This dependence arises essentially because the plasma physics is such that as the physical size of a burning tokamak increases, the fusion power rises more rapidly than the current drive power requirement. However, integration of a large capacity plant into the grid imposes high requirements on reliability. β N is the normalised plasma pressure. An increase in this parameter allows both a rise in power density and a fall in current drive power requirement;

11 N is the ratio of the plasma density to the Greenwald density. An additional potentially important factor, not included above, is magnet costs. The cost of superconducting magnets is about one third of the capital cost of the plants, and a fall in these costs and/or the introduction of higher temperature magnets, could result in significant falls in the cost of fusion electricity. Most of these issues will be effectively addressed by IFMIF, the ITER Test Blanket Modules, the ITER plasma scenario programme and parallel ancillary programmes. Developments in magnet technology may occur on the same timescale. However, the build-up of in-vessel reliability cannot be effectively addressed until DEMO. Turning now to the external costs of electricity generation, a methodology for evaluating these was developed for the European Union: it is known as ExternE. In earlier studies [6,23], this system was used to evaluate the external costs of fusion electricity and compare these with the external costs of other sources. The results are illustrated in Figure 6. meuro/kwh IGCC PFBC NGCC IGCC with CO2 seq. PFBC with CO2 seq. NGCC with CO2 seq. Fuel cells PAFC Fuel cells MCFC Biomass gasification Geothermal PV with batteries PV without batteries Wind with flywheels Fusion model 1 Fusion model 2 Fusion model 3 Fusion model Figure 6. Fusion belongs to the group of technologies with low external costs, as a result of high levels of safety and low environmental impacts. The PPCS external costs were estimated by scaling from the well-established earlier results. The main external-cost-relevant differences between the PPCS Models and the most closely corresponding models forming the basis of the earlier studies are the masses of material and their activation: these form the basis of reliable scaling. The estimated external costs [8-11] are shown in the third column of Table 3. They are extremely low. The economic impacts associated with climate change are manifold and uncertain, and not easy to capture by an external costs methodology. An alternative way of taking such issues into account is to investigate the implications of imposing constraints on the amounts of electricity production allowed to take place from specific resources. This method can also readily account for constraints arising from social acceptance problems. In a study using this approach, fusion power was incorporated in self-consistent economic modeling of European energy scenarios, to the end of the century [24]. Similar results have been obtained by Indian

12 and Japanese [25] studies. In the European study, the technology-oriented optimization model MARKAL-EUROPE was used. This uses variational methods to find the cheapest discounted way to generate Europe s electricity subject to imposed constraints. The most important constraints were on cumulative carbon dioxide emissions. By illustration, Figure 7 shows the composition of Europe s electricity supply in 2100, for a range of stabilization levels of carbon dioxide in the atmosphere. In this scenario nuclear fission is allowed a significant role. It can be seen that fusion nevertheless captures twenty percent of the market in the emission-constrained scenarios. 25 Electricity Production (EJe) solar wind biomass fusion fission gas coal hydro 0 base CO2 target (ppm) Figure 7. CO 2 -constrained European energy scenarios, at the end of this century. In spite of the large role allowed to nuclear fission in this set of scenarios, fusion captures twenty percent of the market in the more constrained scenarios. In scenarios in which nuclear fission is severely constrained, reflecting postulated social acceptance problems, fusion was unable to capture a greater share of the market, because it was constrained by an assigned limit to the speed with which it can be deployed. The other sources capture nuclear fission s share. However, with a Fast track programme to develop and deploy fusion [26], fusion would capture a greater market share. 6. Overall Summary and Conclusions Extensive conceptual design studies of commercial fusion power plants have been performed. The economics, safety and environmental impacts of the designs have been analysed using well authenticated models. There is a very wide measure of agreement in the results of the studies. Fusion has very well-attested and attractive inherent safety and environmental advantages, in particular: no emissions of greenhouse gases; limited consequences of the worst possible accidents; no need for repository disposal of activated material produced by the operation and dismantling of the plant.

13 The calculated costs of fusion electricity are in the range of published estimates for the future costs of electricity from other sources. Even the near-term conceptual designs are economically viable. External costs have also been calculated. External costs are those associated with any environmental damage or adverse effects upon health. For fusion, these costs are very low: similar to wind power and much less than fossil fuels. Energy scenario modeling shows that fusion could contribute significantly to large-scale electricity production during the second half of the century. Results for the near-term conceptual designs suggest that a first generation of fusion power plants those that would be accessible by a fast track route of fusion development [25], going through ITER and the successful qualification of materials currently being investigated in the world fusion programmes will be economically acceptable with major safety and environmental advantages. The remaining results illustrate the potential for more advanced power plants. 5. Acknowledgements This work was funded jointly by the United Kingdom Engineering and Physical Sciences Research Council and by the European Communities under the Contract of Association between EURATOM and UKAEA. The views and opinions expressed herein do not necessarily reflect those of the European Commission. 6. References [1] D.J. Ward, I. Cook, Y. Lechon, R.Saez, The Economic Viability of Fusion Power, Proceedings of Symposium on Fusion Technology, Venice, September 2005, accepted for publication in Fusion Engineering and Design. [2] N.P.Taylor, Key issues for the Safety and Licensing of Fusion, Fusion Science and Technology 47, 859, May [3] J. Raeder, I. Cook, F.H. Morgenstern, E. Salpietro, R. Bunde and E. Ebert, Safety and environmental assessment of fusion power (SEAFP), European Commission DGXII, Fusion Programme, report EUR-FUBRU XII-217/95, June [4] I. Cook, G. Marbach, L. Di Pace, C. Girard, P. Rocco and N.P. Taylor, Results, conclusions and implications of the SEAFP-2 programme, Fusion Eng. Des (2000) [5] I. Cook, G. Marbach, L. Di Pace, C. Girard and N.P. Taylor, Safety and environmental impact of fusion, European Fusion Development Agreement report EFDA-S-RE-1, April [6] Socio-economic aspects of fusion power, EUR (01) CCE-FU 10/6.2.2, European Fusion Development Agreement Report, April [7] I. Cook, R.L. Miller and D.J. Ward, Prospects for economic fusion electricity, Fusion Eng. Des (2002) [8] D Maisonnier, I Cook, P Sardain, R Andreani, L Di Pace, R Forrest, L Giancarli, S Hermsmeyer, P Norajitra, N Taylor, D Ward, A Conceptual Study of Commercial Fusion Power Plants: Final Report of the European Power Plant Conceptual Study. European Fusion Development Agreement (EFDA) Report EFDA-RP-RE-5.0, April 2005.

14 [9] I. Cook, D. Maisonnier, N.P. Taylor, D.J. Ward, P. Sardain, L. Di Pace, L. Giancarli, S. Hermsmeyer, P. Norajitra and R. Forrest, European Fusion Power Plant Studies, Fusion Science and Technology 47, 384, April [10] D. Maisonnier, I. Cook, P. Sardain, L. Boccaccini, E. Bogusch, K. Broden, L. Di Pacce, R. Forrest, L. Giancarli, S. Hermsmeyer, C. Nardi, P. Norajitra, A. Pizzuto, N. Taylor and D. Ward, The European Power Plant conceptual Study, Proceedings of Symposium on Fusion Technology, Venice, September 2005, accepted for publication in Fusion Engineering and Design. [11] D. Maisonnier, I. Cook, P. Sardain, L. Boccaccini, E. Bogusch, K. Broden, L. Di Pace, R. Forrest, L. Giancarli, S. Hermsmeyer, C. Nardi, P. Norajitra, A. Pizzuto, N. Taylor and D. Ward, The European Power Plant Conceptual Study, Proceedings of Symposium on Fusion Technology, Venice, September 2005, accepted for publication in Fusion Engineering and Design. [12] D. Maisonnier, I. Cook, P. Sardain, L. Boccaccini, L. Di Pace, L. Giancarli, P. Norajitra and A. Pizzuto, DEMO and Fusion Power Plant Conceptual Studies in Europe, Proceedings of International Symposium on Fusion Nuclear Technology, Tokyo, May 2006, accepted for publication in Fusion Engineering and Design. [13] R.W. Conn et al., ARIES-1: a Steady-State, First Stability, Tokamak Reactor with Enhanced Safety and Environmental Features, Nuclear Fusion Supplement 3, 659 (1991). [14] F. Najmabadi et al., Fusion Engineering and Design, 38 (1997) 3. [15] F. Najmabadi et al., 17 th IAEA Fusion Energy Conference (1998) Yokohama, FTP/08. [16] F. Najmabadi et al., ARIES-AT: an Advanced Tokamak, Advanced Technology, Fusion Power Plant, 18 th IAEA Fusion Energy Conference, Sorrento, Oct [17] M. Kikuchi et al., Recent Directions in Plasma Physics and its Impact on Tokamak Magnetic Fusion Design, Fusion Eng. Des. (1991) 253. [18] M. Kikuchi et al., The Advanced SSTR, Fusion Eng. Des. 48 (2002) 265. [19] S. Malang et al., ARIES-RS maintenance approach for high availability, Fusion Engineering and Design, 41, [20] D. J. Ward, International benchmarking calculations on key issues of fusion economics, UKAEA report SERF/UKAEA/DFCA3.1, [21] Technical basis for the ITER final design report, cost review and safety analysis, ITER EDA Documentation No. 16, IAEA, Vienna (1998). [22] R.A. Forrest, N.P. Taylor and R. Pampin, Categorisation of Activated Material from PPCS Model Power Plants, these Proceedings. [23] R. Saez et al., Externalities of fusion: SERF ( ), Coleccion Documentos CIEMAT (2001). [24] P. Lako, J.R. Ybema and A.J. Seebregts, The Long-Term Potential of Fusion Power in Western Europe, ECN-C , [25] K. Tokimatsu et al., Studies of Breakeven Prices and Electricity Supply Potentials of Nuclear Fusion by a Long-Term World Energy and Environmental Model, Nuclear Fusion 42 (2002) [26] European Council of Ministers, Conclusions of the fusion fast track experts meeting held on 27 November 2001 on the initiative of Mr. De Donnea, President of the Research Council (commonly called the King Report).