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collaboration under the auspices of the International Energy Agency (IEA) in Paris has been launched to
design the International Fusion Material Irradiation Facility (IFMIF)
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All these activities, i
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ITER, advanced concepts and technological development will form the basis for
DEMO, the detailed design of which can be started after ITER has operated for about five years
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0

Characterisation of fusion as power source

5
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On the basis of these studies it is possible to analyse
economic and environmental impact
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The argument is based on the abundance of the
fusion fuels - lithium and deuterium - and the very small quantities required [18]
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Deuterium is a hydrogen isotope
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Given the above annual consumption rates it can be shown that fusion could continue to
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supply energy for many millions of years
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4 * 10 kg and therefore
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contain 4
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One of the main applications is the production of heavy water for heavy water-moderated
fission reactors
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This would be enough to supply deuterium for 500 fusion plants each with 1 GWe
capacity
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What about
tritium? As we have mentioned above, tritium, also a hydrogen isotope, will be bred from lithium using the
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high flux of fusion neutrons
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4 %) and Li (92
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The two nuclear reactions
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Li + n -> T + He + 4
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5 MeV

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are relevant Since the second reaction is endothermic only neutrons with an energy higher than the
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threshold can initiate this process
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Lithium can be found in:
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salt brines, in concentrations ranging from 0
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2 %
minerals: spodumene, petalite, eucrypotite, amblygonite, lepidolite
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6 % and 2
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+
sea water; the concentration in sea water is 0
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The land-based reserves are given in table I according to two different sources
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Material
Lithium

Current Production Reserve [19]
15,000 t
3,400,000 t

Reserve base [19]
9,400,000 t

Reserve [20]
1,106,000 t

While the annual consumption of lithium in a fusion plant is low, the lithium inventories in the blankets are
much larger [21, 23]
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It is
expected that most of the lithium can be recovered and re-used, although radioactive impurities such as
tritium will complicate the handling
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The lithium supply is, however, a minor problem in the context of the construction of the whole plant:
lithium can be purchased today for around 17 Euro/kg and the blanket containing 146 t of lithium needs to
be replaced five times in the life of a fusion plant, which would amount to only 12 MEuro
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24 * 10 t lithium in sea water
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The associated energy consumption has also been
investigated [26]
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Ratio of specific material
requirements to current reserves

1000
100
10

Model 1

1

Model 1 A

0
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01
0
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0001
Be

V

Cr Mn Ni Cu Nb Mo Sn Ta

W Pb

Figure VIII: The picture shows the ratio of specific materials necessary to construct 1000 fusion plants (for
various plant models) normalised to current reserves of this material
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A first idea of the availability of these materials is sketched in figure VIII
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Beryllium and tantalum seem to pose problems, but this is because these materials are hardly used today
and the proven reserves are probably much smaller than the actual resources
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15 TWh [27,28]
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Conceptually the plant can be divided up between the fusion core - the heat source - and the rest
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consisting of turbines, generators, switchboards
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If progress in fusion technology is
faster, it might of course lead to considerably lower costs
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The basis for the cost estimates of
these components is (i) existing experience with operating fusion experiments, (ii) the experience with
designing ITER [30] and (iii) numerous system studies
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As mentioned earlier, part of the
ITER activities to date have been the design, construction and testing of central components of the
experiment
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Magnets make up 30 % of the investment costs of the fusion core for a prototype and another big item are
the buildings
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Blanket and divertor make up 14 % and 3 %,
respectively, although these items will have to be replaced regularly
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Two possible technological developments should be mentioned
which might lead in the long run to cost reductions
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For specific physical reasons, however, the magnetic pressure needs to much
higher than the plasma pressure in current installations
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Also a
lower replacement frequency of blanket and divertor due to the development of advanced materials might
lead to a further reduction
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An annual load factor of 75 %, an operating lifetime of 30 years
and an real interest rate (corrected for inflation) of 5 % are also assumed
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Collective construction and operation experience are expected to lead to considerable cost reduction due
to accumulated learning processes [33]
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The slope of the curve - the so-called progress ratio gives the cost reduction for a doubling of the capacity
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8 is assumed for the novel
components in the fusion core
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Figure IX shows the expected cost development with time
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Further cost reductions can be achieved by scaling up the plant size or by siting two or more plants at the
same site
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Table II: Cost of electricity for different fusion plant models
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The underlying assumptions do not violate any physical principles but assume tremendous progress in
technology
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Environmental and safety characteristics (external costs)

5
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1 Effluents in normal operation
A fusion power plant is a nuclear device with large inventories of radioactive materials
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Besides tritium the other source of the radioactivity in the plant is the intense flux of fusion neutrons
penetrating into the material surrounding the plasma and causing “activation”
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Small fractions of
the radioactive materials are released during normal operation
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The releases
during normal operation for two different plant models are summarised in table III
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Table III: Doses to the public due to normal operation effluents for two different fusion plant models
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Model 2
0
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95

0
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2 Possible accidents
Detailed accident analyses have been performed within the framework of system studies [35] and in even
more detail for ITER [37]
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Different methods (bottom-up and top-down) are applied to guarantee a
complete list of the accident sequences
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Therefore, the most severe accidents are all related to failures of the cooling system
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As an example
of one of the most severe accident sequences, a total loss of coolant accident, should be described
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This happens because the walls
surrounding the plasma are no longer cooled and their temperature increases
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The larger impurity content in the plasma disturbs its energy balance and
more energy is radiated, thus cooling down the plasma
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With no more
fusion reactions, only the decay heat of the activation products in the structural materials and the blanket
produce heat
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Temperatures in the structural materials will stay well below the melting
temperature and keep the confinement barriers intact
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Doses for the population would stay in the range of 1 mSv [35,38]
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The initiator of such an accident could only be very energetic
outside events such as an aeroplane crash on the plant
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3 Waste
All the radioactive material produced in a fusion plant is neutron-induced
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Time evolution of the
radiotoxicity of the waste is shown in figure X
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The picture shows a rapid decrease in radiotoxicity once the plant is shut down
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The radiotoxicity of the waste of fission plants hardly
changes on the time scale of a few hundred years and stays at a high level
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It is a fair conclusion to say that the radiotoxicity of fusion waste does not
place a major burden on future generations
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It is
assumed that all the plants produce the same quantity of electricity
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The impact on the population is rather low
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The value
represents a rather conservative estimate
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4
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Comparison on the basis of environmental performance or safety issues is often more interesting
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One promising approach in this
direction is the concept of "external costs" or “externalities” [39]
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Examples of externalities are the damages to public health, to agriculture or to the ecosystem
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The method used is a bottom up, site specific and marginal
approach, i
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it considers extra effects due to a new activity at the site studied
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The whole fuel and life cycle of the
plant is considered
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Two
different fusion plant models are considered
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The first model utilises a vanadium alloy for the structural
materials and helium as coolant (Model 1)
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The parts of the plant not included in the above-mentioned study are
taken from the ITER design and from data for a fission plant
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1

Site restoration

Waste disposal

Decommissioning

Operation

Construction

0

Material
manufacturing

0
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The results (Figure XI) indicate that the external costs of fusion do not exceed those of renewable energy
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sources
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Nevertheless, the individual doses related to theses
emissions are orders of magnitude below the natural background radiation
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5
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5
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For a good review article on this question, see [42]
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In case of fusion, invention would be the point in
time when the first commercial power plant goes into operation
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It
usually follows very general patterns, which can be described by an S-shaped curve, starting with a
smooth increase in market share, followed by a robust growth and finally a smooth approach to a
saturation level
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In the nineteenth century wood was replaced by coal
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Extrapolation of the current
trend would mean that gas would become the most important primary energy carrier in the first half of the
21st century [43]
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Therefore fusion can not play a
role as greenhouse gas mitigation technology before that time
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In comparison with coal this combined advantage would produce roughly a factor of three
lower CO2 emissions per kiloWatthour delivered
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Third, the time
when the share of natural gas will pass its maximum roughly coincides with the “invention” (the
technological and economic proof of principle) of fusion
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Scenarios made by the International Institute of Applied System Analysis (IIASA) and
the World Energy Council (WEC) describe various possible paths into the future [44]
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Even in the C scenario electricity consumption will increase considerably even after 2050,
leaving enough space for fusion, even without replacing older technologies
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While predicting winners or losers is obviously a very long shot, continued R&D
is an absolute necessity for all of them
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5
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The scenario horizon is based the complete 21 century
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Details of the analysis can be found in [29]
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The first scenario is called Market Drive (MD):
interest rates on power generation investments are 8%, interest rates on end-use investments are higher
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The second scenario is called Rational Perspective (RP): discount rates are 5 % across
the whole energy sector, but only 10,5 % of the world fossil fuel resources are available to WesternEurope
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Energy demand is higher in scenario Market Drive
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Fission is expected
to phase out at 2100
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The demand for energy increases in the two scenarios
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Steady increases in
efficiency keep the overall primary energy demand roughly constant over the whole scenario horizon
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The development of energy supply and conversion technologies, especially further progress in economic
performance and efficiencies, is based upon detailed assessments of the literature and on the studies by
Fusion Associations, and have been, where appropriate, guided by learning curves
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A detailed description of the supply technologies
can be found in [46]
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An increase in the oil
price to $25/bbl (RP) or 29,5/bbl (MD) in 2100 is expected
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The price for hard coal is considerably flat over the whole period investigated
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Fossil fuels remain the
most important primary energy sources
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The use of
st
gas increases considerably until the middle of the 21 century when the easily accessible natural gas
reserves are exhausted and its price has substantially increased
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The picture
change drastically, however, if future CO2 emissions are to be restricted in order to reduce the risk of
climate changes
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Different values for the
stabilisation concentration are assumed
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The time-dependent allowed emissions are constraints in the optimisation
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The share of the electricity
supply technologies in 2100 is shown in figure XII
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The conclusion can be summarised as follows: fusion can win shares in
the electricity market if (i) the further use of fission is limited and (ii) if greenhouse gas emissions are
constrained
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6
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More than 16 MW fusion
power have been produced in the joint European experiment JET at a Q value (fusion power amplification
factor) of 0
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Technologies for the next step in the international fusion programme (ITER) have already been improved
by intense engineering R&D and the construction and test of prototypes
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Sites in France, Canada and Japan are, however, being discussed
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Detailed investigations on the safety, environmental and socio-economic aspects of fusion have been
performed
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Literature
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]
[18]
[19]
[20]
[21]
[22]
[23]
[24]
[25]
[26]
[27]
[28]
[29]
[30]
[31]
[32]
[33]
[34]

[35]

Bethe H
...
: "Energy production in stars" Phys
...
55 (1939) 434 an references therein
th
Beiser, A: Perspectives of Modern Physics, McGraw-Hill, 14 printing 1984
Artsimovich L
...
:"Tokamak devices", Nucl
...
, 12, 2 (1972) 215
http://www
...
gov/nif/index
...
W
...
, Phys
...
, 105:1127-1128, 1957
...
Wagner, 1982 Phys
...
Lett
...
et al
...
Rev
...
83 1790
Zohm H
...
, 1999 Nucl
...
et al
...
, 1997 Plasma Phys
...
Fusion 39 1771
Keilhacker M
...
Fusion 39 209
Tsuji H
...
, 1999 Fusion Eng
...
40 115 (remote)
Tivey R
...
Des
...
, Materials Research towards a Fusion Reactor, 21 Symposium on Fusion
Technology, Madrid, 2000, to be published in Fusion Eng
...

Cozzani F
...
Des
...
et al, Kontrollierte Kernfusion, 1981, Stuttgart
st
S
...
H
...
S
...
S
...
Raeder et al
...
, Studies on Recovery of Lithium from Sea
Water by Manganese Oxide Adsorbent, The Shikoku National Industrial Research
Institute 2217-14
Quantitative Analysis of Economy and Environmental Adaptability of
Tokamak Fusion Power Reactors, The University of Tokyo, December 1997
R
...
, Socio-Economic Research on Fusion, SERF: 1997-98
...
Sub Task : Life Cycle assessment of a fusion power
plant
...
1 RIS∅ National Laboratory, 1998
...
, 1999, ECN-C--98-095, Petten
Barabashi, S
...
UR 17521, Office for
Official Publications of the EU, Luxembourg
Hender, T
...
et al, 1996, Fusion Technology 30 1605
Knight P
...
, Donovan, S
...
, 1998, Calculations with SUPERCODE for SERF Task E1,
Progress Report, 5 February
...

Argote L
...
, 1990 Science, 247 920
Najmabadi, F
...
, 1991, The ARIES-1 Tokamak Reactor Study
...
G
...
Fusion
Technology 26, 1105 - 1110
...
et al
...

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[36]
[37]
[38]
[39]
[40]
[41]
[42]
[43]
[44]
[45]
[46]
[47]
[48]

ICRP Publication 60, Recommendations of the International Commission on Radiological
Protection, 1990, Pergamon Press
FDR Safety Assessment, Cahpter IV in Technical Basis for the ITER Final Design Report,
Cost Review and Safety Analysis (FDR), IAEA, Vienna, 1998
Cook et al, The Safety and Environmental Impact of Commercial Fusion Power Stations,
to be published by the European Commission
Pigou, Wealth and Welfare, 1912
ExternE, Externalities of Energy, Vol
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, Externalities of the Fusion Fuel Cycle, CIEMAT, 1999
Grübler, Technology and Global Change, IIASA 1998
Ausubel et al
...
Global Energy Perspectives, IIASA 1998
Lako et al
...
, Characterisation of Power Generation Options for the 21 Century,
ECN-C--98-085
K
...
, private communication

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