Fusion Technology 1996

991 Pages·1997·89.736 MB·English

by  C. Varandas and F. Serra (Eds.)

FUSION TECHNOLOGY 1996
Proceedings of the 19th Symposium on Fusion Technology,
Lisbon, Portugal, 16-20 September 1996
VOLUME!
19th
SOFT
edited by:
C. VARANDAS
and
F. SERRA
Centro de Fusao Nuclear
Instituto Superior Tecnico
Lisboa, Portugal
1997
ELSEVIER
AMSTERDAM • LAUSANNE • NEW YORK • OXFORD • SHANNON • TOKYO
ELSEVIER SCIENCE B.V.
Sara Burgerhartstraat 25
P.O. Box 211, 1000 AE Amsterdam, The Netherlands
Pages 1-176 are reprinted from
Fusion Engineering and Design, Volume 36/1 (1997)
ISBN: 0 444 82762 5
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V
PREFACE
The Symposium on Fusion Technology (SOFT) is held every two years with the objective to set the
stage for the exchange of information on the design, construction and operation of fusion experi-
ments and on the technology which is being developed for the next step devices and fusion
reactors.
The 19th Symposium was held at Culturgest, in Lisbon, on September 16—20, 1996. It was
hosted and organized by "Centro de Fusäo Nuclear" of "Institute Superior Técnico" on behalf of the
Association EURATOM/IST.
By decision of the International Organizing Committee SOFT-96 has included invited talks, oral
contributions and posters in the following topics:
A. First Wall, Divertors and Vacuum Systems
Plasma facing components; wall conditioning; first wall materials.
B. Plasma Heating and Control
Neutral beams, RF systems; current drive; related power supplies.
C. Plasma Engineering and Control
Interaction between plasma and machine components.
D. Experimental Systems
Design and operation of complete systems; diagnostics; data acquisition and control systems;
future machines.
E. Magnet and Related Power Supplies
F. Fuel Cycle and Tritium Processing Systems
Fueling and pellet injection, exhaust gas pumping and purification; tritium separation, storage
and extraction.
G. Blanket Technology/Materials
Irradiation sources; neutronics; hydraulics; breeder, multiplier and structural materials;
shielding.
H. Assembly, Remote Handling and Waste Management and Storage
I. Safety and Environment, Reactor Studies
A total of about 580 papers were submitted for poster presentation. Due to poster space
limitations and taking into account their scientific contents, some papers had to be rejected and
others had to be rewritten or combined. In the end, 470 papers were accepted, of which 430 were
presented at the conference (420 as posters and 10 as oral contributions). Of those, 413 were
submitted as author-prepared, camera-ready manuscripts, which are now published in these
Proceedings. Table 1 contains the distribution of these papers by the Symposium topics. The
editors wish to point out that, even though some editorial improvements were suggested and layout
vi
and technical improvements were carried out on some papers, the authors are themselves
responsible for the final quality and content of the contributions. The invited papers, reprinted from
a special issue of the Journal of Fusion Engineering and Design published after a standard review
process, are also included in these Proceedings.
Topic No. Topic No.
A 72 F 43
B 48 G 81
C 22 H 22
D 51 I 41
E 33
Table 1 — Number of published paper per symposium topic.
Simultaneously with SOFT-96, an exhibition of industrial companies active in fields associated
with nuclear fusion (see list of Industrial Exhibitors) was organized.
The International and Local Organizing Committees would like to thank the financial support
received from the following Institutions and Companies:
• The Commission of the European Community
• Caixa Geral de Depösitos
• Junta Nacional de Investigaçao Cientifica e Tecnolögica
• Europa Metalli Spa
• Consortium EFET
• Consortium AGAN
• Air Liquide
Finally, the editors wish success to the organizers of the next Symposium, which will be held
in France in the Autumn of 1998.
C. Varandas
F. Serra
COMMITTEE MEMBERS
International Organizing Committee
E. Bertolini JET, Abingdon, U.K.
H. Conrads KFA, Julich, Germany
U. Finzi CEC, Brussels, Belgium
P. Fenici JRC, Ispra, Italy
M. Gasparotto ENEA, Frascati, Italy
G. Rostagni CNR, Padova, Italy
E. Salpietro NET, Garching, Germany
G. Tonon CEA, Cadarache, France
C. Varandas (Chairman) 1ST, Lisboa, Portugal
G. Vecsey CRPP, Lausanne, Switzerland
J.E. Vetter KfK, Karlsruhe, Germany
R. Wilhelm IPP, Garching, Germany
Local Organizing Committee
J.A.C. Cabrai (Chairman)
F. Serra (Scientific Secretary)
C. Vitorino (Administrative Secretary)
M. Fernanda
A. Moreira
A. Soares
viii
INDUSTRIAL EXHIBITORS
Dutch Scientific
Apeldoorn, The Netherlands
Consortium AGAN (Ansaldo, GEC Alsthom, Preussag Noell, ACCEL)
Wurzburg, Germany
Canadian Fusion Fuels Technology Project
Mississauga, Ontario, Canada
EFET (Ivo, Belgatom, Citif, Framatome S.A., Ibertef A.I.E., NNC LTD., Siemens AG)
Erlangen, Germany
JRC-IAM
Petten, The Netherlands
Europa Matalli Spa
Firenze, Italy
Air Liquide
Sassenage, France
SEP
Vernon, France
IST/OGMA
Lisboa, Portugal
Fusion
Engineering
and Design
Fusion Engineering and Design 36 (1997) 1-8
ELSEVIER
Nuclear fusion, an energy source
R. Toschi
The NET Team, Boltzmannstr. 2, D-85 748 Garching, Germany
Abstract
The final phase of the feasibility demonstration of fusion, namely the construction and operation of ITER, will
require a large and prolonged effort and strong determination by all parties involved. The time is therefore
appropriate to revisit the motivations in support of fusion development. The supply of energy would become an issue
today if due consideration were given not only to the limits 'internal' to the energy systems but also to those
'external', to it. The first ones are not so stringent because reserves in particular of fossil fuels are ample, but the
second ones are very stringent because of the limited capability of self-regeneration of the environment. Energy
consumption is anticipated to triple in the next 50 years and if the share among the sources remains as of now the
risk of a major climate change due to the release of C0 from burning of fossil fuels, with catastrophic consequences
2
on the environment, is high. The development of sources with better compatibility with the environment and
acceptable to society, such as fusion, as well as of more efficient energy technologies, should be pursued with a great
determination. The potential of fusion as an energy source could be demonstrated in all of its main aspects by
carrying out the ITER programme. © 1997 Elsevier Science S.A.
1. Introduction quires on the part of the partners strong deter-
mination, which can only stem from the
The development of thermonuclear fusion as conviction that fusion is an energy source with
an energy source has now reached the crucial such a potential of social acceptability that it
stage of launching the full feasibility demonstra- must be made available to mankind. In the fol-
tion phase with the construction and operation lowing we shall discuss reasons in support to
of an experimental reactor, called ITER (Inter- this conviction, addressing the following ques-
national Thermonuclear Experimental Reactor) tions:
[1]. ITER will have the size, the power and most • Is energy an issue today?
of the technologies of a reactor and it will re- • How can future energy demand be met?
quire a large, prolonged and coordinated effort • How can fusion contribute to future energy
from the partners involved. supply?
To be successful, such an enterprise, which • How and when is fusion going to demonstrate
has no precedent in the history of science, re- its potential as an energy source?
0920-3796/97/$ 17.00 © 1997 Elsevier Science S.A. All rights reserved.
PJJ S0920-3796(97)00007-0
2 R. Toschi / Fusion Engineering and Design 36 (1997) 1-8
2. Is energy an issue today? energy production in particular. Since the selec-
tion of primary energy sources for electricity pro-
2.1. Energy and environment duction is driven by economic considerations it is
now time that energy sources be judged and
At this time when the supply of fossil fuel is ranked for the best combination of 'all' costs
plentiful, cheap and apparently secure many be- including the so called 'externalities' [3], namely
lieve that there is no 'energy issue'. In fact, energy the costs to the environment and to human health
becomes an issue only in conjunction with politi- associated with the use of each energy source,
cal instabilities in the oil producing countries. costs which are now, in general, passed over to
Even a slight turbulence like the one in early society and to future generations.
September '96 in the Middle East has prompted a
few editorials in newspapers reminding us that 2.2. Present energy consumption and sources of
energy supply should receive more attention and, energy [4]
this time, with some emphasis on environmental
compatibility. Once these political and regional The total energy consumption in the world
instabilities are suppressed then the 'energy issue' amounts to about 13 TWY1. The average con-
rapidly disappears. Only the 1973 energy crisis sumption pro capita is about 2.2 kWY but vast
had somewhat longer lasting effects on the energy disparities among different countries exist, e.g.
supply structure in some countries in favour of US, 11 kWY; EU 5, kWY; China, 0.8 kWY and
nuclear fission and on new energy sources devel- India, 03 kWY. The richest 20% of the world
opment. In spite of several initiatives, such as the population use 55% of the primary energy and
Earth Summit in Rio de Janeiro in 1992, public their pro capita consumption is almost five times
opinion seems insufficiently aware of other 'insta- as much as for the rest of the world population.
bilities', related to the energy 'quality' rather then The global consumption of 13 TWY is shared
'quantity', which may have far more dramatic among different sources as follows: nuclear (6%),
consequences and not only on a regional scale but hydro (7%), biomass (10%), fossil (77% of which
on a planetary scale. 45% from oil, 30% from coal, 25% from natural
Some energy related issues on a planetary scale gas).
were addressed in the early seventies in the MIT Electricity production is responsible for about
study 'The Limits to Growth' [2] where it was 30% (3.7 TWY) of the total energy consumption
argued that due to the depletion of non-renewable and the primary sources for it are: fossil (60%),
resources, population growth and pollution, a ma- nuclear (20%) and hydro (20%).
terial limit to growth would be reached leading to These data confirm the dominant role of fossil
a sudden and uncontrollable economic decline of sources in the supply of energy both globally and
society. Even this alarm did not last very long for electricity. The role of fossil fuels is justified
because, under the pressure of the 1973 energy by the oil price (at a constant dollar today's price
crisis, new oil/gas resources were found, nuclear is only twice as much as it was before 1973 crisis),
energy was allowed to expand and technical inno- by the prospects of abundant reserves which, in
vations were believed to reduce substantially the spite of increased consumption are today esti-
'energy intensity' (i.e. energy required to produce mated to last longer then 25 years ago (50 vs. 25
a unit of gross national product). In the seventies years) and, finally by the dramatic increase in the
the concern was mainly on possible limits 'inter- natural gas reserves estimated to be at least as
nal' to the energy system rather than on limits
'external' to it such as the finite absorptive capac-
ity of the environment as a whole. We should
instead be aware that the environment simply
1 TeraWattYear (TWY) corresponds to the energy produced
cannot absorb for much longer at the present rate
in 1 year, for instance, by 1000 electrical power stations of 1
the 'waste' of human activities in general and of GW each.
R. Toschi /Fusion Engineering and Design 36 (1997) 1-8 3
large as the oil reserves. Furthermore, the present 75% of all electricity. This share of electricity is
trend is to increase further the role of fossil fuels very close to the share of the world Gross Domes-
in electricity generation using natural gas because tic Product.
of its more favourable economic prospects than
other sources (e.g. smaller size, shorter construc-
2.4. Can the present energy sources meet the
tion time, higher efficiency).
future energy demand?
2.3. How the energy demand may evolve till mid
2.4.1. Energy reserves
next century
The proven recoverable reserves of energy can
be summarised as follows (measured in TWY and
The world population, according to most stud-
in years of duration at present consumption
ies [4], will increase from the present 5.3 billion to
rates):
about 10-11 billion in the middle of next century
and possibly stabilise thereafter. This increase is
Coal 800 TWY 300 years
expected to occur mostly in the developing coun-
Oil 200 TWY 50 years
tries and to be accompanied by a large concentra-
Gas 200 TWY 80 years
tion in urban areas (from present 50 up to 75%).
Nuclear (U) 80 TWY 100 years
In the period 1970-1990 the pro capita total
energy consumption has increased by 1% per year
Nuclear reserves refer to the Uranium cycle as
and electricity consumption by 3% per year. For
used in most of today's reactors: thorium cycle or
the future a most prudent scenario assumes a
fast breeder reactors would increase the reserve by
significant decrease of energy intensity (0.5%/year)
two orders of magnitude or more.
allowing pro capita primary energy consumption
The ultimately recoverable reserves, namely
to increase at a lower rate than in the past (0.5%/
those yet to be identified, and likely at higher cost,
year). This assumption implies a development of
are larger by a factor of between three to five than
energy efficient technologies which would require
the proven ones.
important resources not necessarily available at
The 'internal' limits to energy sources, namely
times of abundant fossil fuel supply. According to
the availability of reserves appear not so stringent
this scenario by the year 2050, the pro capita
as to exclude a 'business as usual' approach for
primary energy consumption would increase by
the next 50 years. It is therefore appropriate to
about 30%. This means that, even if such an
verify the implications of this approach and in
increase is concentrated only on developing coun-
particular its compatibility with 'external' limits
tries, they would reach in 2050 a pro capita
such as the finite capacity of the self-regeneration
energy consumption still less than half of the one
of the environment.
in the EU today.
Under these prudent extrapolations the total
energy demand in 2050 would more than double, 2.4.2. Fossil fuels
approaching 30 TWY. The pollution of the atmosphere with C0 pro-
2
Over a third of the total energy would be used duced in fossil fuel combustion raises the highest
to produce electricity having taken into due ac- concern. Every day 60 million t of C0 are re-
2
count both the likely faster increase rate in the leased into the atmosphere, i.e. 730 g kWh-1 for
demand and the improvement in the conversion coal, 560 g kWh"1 for oil and 430 g kWh"1 for
efficiency. Actually, in the last 5 years in the gas. The 'greenhouse' effect, which controls the
richest 20% of the world population, primary earth's climate, is due largely ( ~ 60%) to the C0
2
energy demand grew at the same rate as the content in the atmosphere which has increased
economy, i.e. energy intensity did not improve. exponentially, due to fossil fuel burning, from 280
This extrapolation is also prudent considering to 360 ppm in the last 130 years and the average
that today the richest 20% of the population use temperature on earth has increased by 0.6° [5].
4 R. Toschi /Fusion Engineering and Design 36 (1197) 1-8
If the present rate of fossil fuel consumption essential in the medium term to the developing
continues, by the year 2050, the C0 content in countries (for example the coal share in the en-
2
the atmosphere will reach 560 ppm and the tem- ergy supply of China and India is 75 and 50%,
perature may further increase by 1° or more. respectively) which will account for most of the
The increase in the C0 content corresponds to increase in energy demand in the next 50 years.
2
about half of C0 released annually by fossil A reduction of the overall fossil consumption
2
burning ( ~ 20 billion t) the other half being ab- can only come from economically developed
sorbed largely by oceans. Although the exchange countries by reducing primarily the fossil share
rate among the large reservoirs of C0 (oceans, in their electricity generation.
2
biosphere and atmosphere) is probably one or-
der of magnitude larger than the C0 release
2
2.4.3. Nuclear fission
rate in the atmosphere, still the delicate equi-
Uranium cycle reactors, provided that their
librium between these large fluxes may be al-
social acceptability improves, could contribute to
tered either by saturation phenomena in the
lessen the dependence on fossil fuels but, in any
ocean absorptive capacity or by approaching an
case, only for the medium term. Thorium cycle
unstable regime. Deep ice drilling in Greenland
reactors, recently proposed [7], would have the
and in the polar regions indicate [6] that large
potential for long term energy supply if proven
changes in the climate occurred in a very short
to be feasible and superior to the U-cycle reac-
time, say a few decades, suggesting that the rela-
tors as for safety and environment. Fast breeder
tively fast accumulation of C0 , as occurring
2
reactors would also have the potential for long
now, may lead to an instability in the climate
term energy supply but their social acceptability
[6]. Although large uncertainties exist in the
is seriously in doubt in most countries.
global warming predictions, it is very dangerous
to wait for their experimental validation because
the time constant for climate changes may be
2.4.4. Renewable
much shorter than the time constant (at least
100 years) of C0 exchange between surface wa-
2 • Hydropower: further exploitation of this
ter and deep ocean. It is well known that the
source is limited and not exempt from a nega-
consequences of this climate change would be
tive impact on the environment and on local
catastrophic and some of them almost irre-
community life.
versible, e.g. sea level increase, increasing climate
• Biomass: this source is already covering a large
turbulence and instabilities, desertification, mod-
fraction ( ~ 10%) of the total energy consump-
ification of ocean streams, glaciation, etc.
tion and meets a variety of needs particularly
Studies have been made to sequester the C0
2 in the developing countries. Any further ex-
produced by electrical power stations either in
ploitation for industrial use on large scale
the oceans or in the gas/oil empty well. This would imply an excessive use of land, fertiliser,
approach, in addition to an increase of electric- water (e.g. 15/30% of today's world agricul-
ity cost of 40/80%, would not exclude on the tural land to produce 1 TWY).
long term damage to the environment. • Photovoltaic: this source can be very valuable
In addition to the environmental damage such for specific applications (e.g. limited power,
a high share of fuel consumption would be remote locations, high solar radiation) but due
likely to induce strain on oil and gas availabil- to land requirements (e.g. 100 km2 for 1000
ity, affecting industry and services now based on MWe), service discontinuity and cost (e.g. up
these fuels (e.g. transport, chemical, pharmaceu- to ten times conventional sources) photovoltaic
tical, etc.) and causing political instabilities given sources will not be able to play a quantitatively
the high concentration of these fuels in a few significant role in future electrical energy sup-
areas. On the other hand the use of fossil fuel is ply.