Six years of joint work under the international thermonuclear experimental
reactor (ITER) EDA agreement yielded a mature design for ITER which met the
objectives set for it (ITER final design report (FDR)), together with a co
rpus of scientific and technological data, large/full scale models or proto
types of key components/systems and progress in understanding which both va
lidated the specific design and are generally applicable to a next step, re
actor-oriented tokamak on the road to the development of fusion as an energ
y source. In response to requests from the parties to explore the scope for
addressing ITER's programmatic objective at reduced cost, the study of opt
ions for cost reduction has been the main feature of ITER work since summer
1998, using the advances in physics and technology databases, understandin
gs, and tools arising out of the ITER collaboration to date. A joint concep
t improvement task force drawn from the joint central team and home teams h
as overseen and co-ordinated studies of the key issues in physics and techn
ology which control the possibility of reducing the overall investment and
simultaneously achieving the required objectives. The aim of this task forc
e is to achieve common understandings of these issues and their consequence
s so as to inform and to influence the best cost-benefit choice, which will
attract consensus between the ITER partners. A report to be submitted to t
he parties by the end of 1999 will present key elements of a specific desig
n of minimum capital investment, with a target cost saving of about 50% the
cost of the ITER FDR design, and a restricted number of design variants. O
utline conclusions from the work of the task force are presented in terms o
f physics, operations, and design of the main tokamak systems. Possible imp
lications for the way forward are discussed. (C) 2000 Elsevier Science B.V.
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