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[show abstract]
[hide abstract]
ABSTRACT: During vertical displacement events (VDEs) plasma halo currents can flow partly through the passive structure. Additionally induced currents occur in the passive structure. Due to these electrical currents, major electromagnetic forces act on the passive structures and hence on the vacuum vessel (VV). As these forces change in time the vessel response is dynamic. This response determines important design drivers such as the reaction forces at the vessel supports, the vessel displacements and stress levels in the vessel structure, and it affects all components attached to the vessel. It is expected that the most severe dynamic response of the vessel occurs during asymmetric VDEs with slow current quench. Experiments on existing tokamak machines have shown that asymmetric loads can rotate around the vertical machine axis. This possible rotation is considered here. Using the finite element (FE) method the dynamic response of the vessel was analyzed in full transient dynamic analyses for the worst case VDEs according to the ITER VV load specification. A 360° FE model of the VV is used since the loads are partly asymmetric. One major difficulty in this assessment was to predict how the sideways load is shared between three simultaneously acting support types. Attention was therefore given to the modeling of the VV supports including the coupling effect with the toroidal magnetic field.
Fusion Engineering, 2009. SOFE 2009. 23rd IEEE/NPSS Symposium on; 07/2009
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[show abstract]
[hide abstract]
ABSTRACT: The substantial mechanical loads which can develop in multiple components are a major technical challenge associated with the design of the ITER tokamak. The various loads acting on ITER can be grouped into several types: inertial loads, associated with gravity and seismic events; pressure loads, particularly significant for the ITER pressure equipment; electromagnetic loads, which affect all conducting structures as a consequence of transient events inducing rapid magnetic field changes and which possibly involve currents flowing between the plasma and in-vessel components; thermal loads, which are extremely severe in the plasma facing components; assembly loads, typically due to preloads imposed during assembly.
Fusion Engineering, 2009. SOFE 2009. 23rd IEEE/NPSS Symposium on; 07/2009
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K. Koizumi,
M. Nakahira,
Y. Itou,
H. Takahashi,
E. Tada,
K. Ioki,
G. Johnson,
M. Onozuka,
Y. Utin, G. Sannazzaro,
F. Elio,
K. Takahashi
[show abstract]
[hide abstract]
ABSTRACT: Fabrication of full-scale sector model of ITER vacuum vessel,
which was initiated in 1995 as a one of the Large Seven ITER R&D
Projects, has been completed in September 1997. The full-scale sector
model corresponds to an 18° toroidal sector made of SS 316L+N, is
composed of two 9° sectors, Sector-A and B, which are spliced at the
port center according to the current ITER design. In order to satisfy
tight manufacturing tolerances of ±20 mm and to assure the
structural integrity of double-walled structure, a combination of TIG
(Tungsten Inert Gas Arc)/EB (Electron Beam) welding and TIG/MIG (Metal
Inert Gas Arc) welding were adopted for Sector-A and B, respectively.
Although the different poloidal segmentation and welding process were
employed for the fabrication, the dimensional accuracy of within
±6 mm to the nominal values has been successfully demonstrated in
the fabrication of both sectors. After the pressure and vacuum leak
test, both sectors were shipped to the test site in Japan Atomic Energy
Research Institute (JAERI) for the first demonstration test of automatic
welding of the field joints between sectors. This paper describes the
design, fabrication procedures, results obtained by the fabrication and
the latest status of the full scale sector model
Fusion Engineering, 1997. 17th IEEE/NPSS Symposium; 11/1997
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M. Onozuka,
G. Johnson,
K. Ioki, G. Sannazzaro,
Y. Utin,
K. Takahashi,
T. Iizuka,
R. Parker,
K. Koizumi,
E. Kuzmin,
H. Neilson,
B. Nelson,
C. Vallone
[show abstract]
[hide abstract]
ABSTRACT: Recent design progress of the vacuum vessel for the International
Thermonuclear Experimental Reactor is presented. A structural design
strategy has been developed for the VV in which the VV will be designed,
fabricated, and tested per the requirements of the ASME Code Section
VIII, Div. 2. The inboard structure that was originally designed
polygonal cylinder has been modified to a cylindrical shape in order to
resist the induced forces due to the fast current discharge of the TF
coil. The shielding material under the TF coils in the upper outboard
region has been changed to a ferromagnetic material (SS 430) instead of
SS 30467 to reduce toroidal field ripple. The thermal and hydraulic
analyses indicate sufficient heat removal capability from the VV.
Although detailed design modifications continue to be made to reinforce
areas of high stress and to accommodate interfaces with other systems,
problems completing the design from a structural standpoint are not
anticipated
Fusion Engineering, 1997. 17th IEEE/NPSS Symposium; 11/1997
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[show abstract]
[hide abstract]
ABSTRACT: The interleaved structure of the TF coils allows to obtain a
programmable TF ripple field by feeding the two sub-sets of the TF coils
with different currents. This would allow to vary the ripple field
within one JET pulse and allow a direct assessment of the increased
ripple on confinement time, fast particle losses, plasma rotation and
H-mode. The TF ripple experiment (RIPPLE 2) was carried out in the
pumped divertor configuration in conditions relevant to ITER. In this
configuration, the normal field ripple at the plasma edge is about 0.1%.
In the experiment, the ripple field was varied up to 2% at the plasma
edge, the plasma current was typically 2-3 MA and the TF field 2-2.5 T
Fusion Engineering, 1995. SOFE '95. 'Seeking a New Energy Era'., 16th IEEE/NPSS Symposium; 11/1995
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[show abstract]
[hide abstract]
ABSTRACT: Four coils have been built and installed in the JET vacuum vessel
to produce divertor plasmas. The coils are copper with glass epoxy
insulation and are enclosed in vacuum tight Inconel cases. At the coil
contractor's factory, the coil parts were manufactured and process
techniques qualified. In the JET vacuum vessel the conductors bars were
brazed to form the coils, which were inserted in the casings and
impregnated and cured with epoxy resin
IEEE Transactions on Magnetics 08/1994; · 1.36 Impact Factor
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A. Tesini,
E. Bertolini,
N. Dolgetta,
J.R. Last,
P. Presle, G. Sannazzaro,
J. Tait,
G. Dal Mut,
C. D'Urzo,
A. Laurenti,
A. Maragliano
[show abstract]
[hide abstract]
ABSTRACT: The JET tokamak magnetic system has been enhanced by adding four
resistive magnets inside the vacuum vessel to produce divertor plasmas.
In factory the coil parts were manufactured and process techniques
qualified. Assembly took place at JET, inside the vacuum vessel,
including welding into Inconel casings and impregnation with epoxy resin
Fusion Engineering - Supplement, 1993., 15th IEEE/NPSS Symposium on; 11/1993
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[show abstract]
[hide abstract]
ABSTRACT: The paper describes a new Coil Protection System (CPS) which is
planned to be installed at JET before the next experimental campaign
with a pumped divertor. The protection system will make circuit equation
integration, computations of forces on and stress in the coils and check
current and voltage levels and coil heating effects in real time. If
acceptable values for any of these parameters are exceeded, the pulse
will be terminated. A fully digital implementation of the algorithms is
being designed using a high performance Digital Signal Processor (DSP).
A programme has been written for convenient off-line calculation and
checks of model parameters with JET data
Fusion Engineering - Supplement, 1993., 15th IEEE/NPSS Symposium on; 11/1993
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[show abstract]
[hide abstract]
ABSTRACT: The authors discuss the problems associated with the decay of the
plasma current in JET (Joint European Torus) disruptions. It is noted
that the slow mode of plasma current decay may offer the best chances of
minimizing the forces in high current disruptions. However, the plasma
position needs to be controlled during the decay of the plasma current.
The radial field position can be controlled by a sufficiently fast
vertical field amplifier. For the control of the vertical position the
two problems to be solved are the magnetohydrodynamic perturbations of
the magnetic signals and the increased vertical destabilization, which
coincides in time with the measured energy quench. It has been
demonstrated that a substantial reduction of the vessel forces can be
achieved by reducing plasma elongation prior to the disruption
Fusion Engineering, 1991. Proceedings., 14th IEEE/NPSS Symposium on; 11/1991
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M. Huguet,
H. Altmann,
P. Barabaschi,
E. Bertolini,
K. Dietz,
E. Deksnis,
H. Falter,
C. Froger,
M. Garribba,
A. Kaye, [......],
W. Obert,
S. Papastergiou,
A. Peacock,
M. Pick,
P.H. Rebut,
L. Rossi,
C. Sborchia, G. Sannazzaro,
A. Tesini,
R. Tivey
[show abstract]
[hide abstract]
ABSTRACT: The JET (Joint European Torus) pumped divertor aims at
demonstrating an effective method of impurity control with
quasi-stationary plasmas of thermonuclear grade in a next step relevant,
axisymmetric configuration. The magnetic configuration is produced by a
set of four coils internal to the JET vacuum vessel. These coils can
produce a range of configurations and also sweep the magnetic field
lines along the target plates. The target plates will initially use
radiation-cooled beryllium tiles, but actively cooled target plates able
to operate in steady state at up to 40 MW are planned in a second phase.
The design also features a cryopump which will remove a fraction of the
particles recycled in the vicinity of the target plates. The
configuration of the ICRH (ion cyclotron resonance heating) antennae and
wall protections has been modified to match the new plasma shape. All
components have been designed to resist the large forces generated by
halo currents
Fusion Engineering, 1991. Proceedings., 14th IEEE/NPSS Symposium on; 11/1991
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K Ioki,
V Barabash,
A Cardella,
F Elio,
H Iida,
G Johnson,
G Kalinin,
N Miki,
M Onozuka, G Sannazzaro,
Y Utin,
M Yamada
[show abstract]
[hide abstract]
ABSTRACT: The design has progressed on the vacuum vessel and First Wall (FW)/blanket for the Reduced Technical Objective/Reduced Cost (RTO/RC) ITER. The basic functions and structures are the same as for the 1998 ITER design. The design has been improved to achieve, along with the size reduction, ∼50% target reduction of the fabrication cost. The number of blanket modules has been minimized according to smaller dimensions of the machine and a higher payload capacity of the blanket Remote Handling tool. A concept without the back plate has been designed and assessed. The blanket module concept with flat separable FW panels has been developed to reduce the fabrication cost and future radioactive waste.
Fusion Engineering and Design.
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[show abstract]
[hide abstract]
ABSTRACT: Recent progress of the ITER vacuum vessel (VV) design is presented. As construction approaches, the VV design has been improved, simplified and developed in more detail. The VV support system has been improved, and the design of the VV shells and the blanket supports has been simplified. The VV design simplifications have been driven by manufacturing requirements and recommendations resulting from cooperation with industry. To simplify the manufacture/maintenance of the port structures, a single wall concept is used for some ports. Structural analyses have been performed to validate all design modifications.
Fusion Engineering and Design.
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K Ioki,
V Barabash,
A Cardella,
F Elio,
Y Gohar,
G Janeschitz,
G Johnson,
G Kalinin,
D Lousteau,
M Onozuka,
R Parker, G Sannazzaro,
R Tivey
[show abstract]
[hide abstract]
ABSTRACT: Design and R&D have progressed on the ITER vacuum vessel, shielding and breeding blankets, and the divertor. The principal materials have been selected and the fabrication methods selected for most of the components based on design and R&D results. The resulting design changes are discussed for each system.
Journal of Nuclear Materials.
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K Ioki,
V Barabash,
A Cardella,
F Elio,
G Kalinin,
N Miki,
M Onozuka,
T Osaki,
V Rozov, G Sannazzaro,
Y Utin,
M Yamada,
H Yoshimura
[show abstract]
[hide abstract]
ABSTRACT: Design has progressed on the vacuum vessel and FW/blanket for ITER-FEAT. The basic functions and structures are the same as for the 1998 ITER design. Detailed blanket module designs of the radially cooled shield block with flat separable FW panels have been developed. The ITER blanket R&D program covers different materials and fabrication methods in order make a final selection based on the results. Separate manifolds have been designed and analysed for the blanket cooling. The vessel design with flexible support housings has been improved to minimise the number of continuous poloidal ribs. Most of the R&D performed so far during EDA are still applicable.
Fusion Engineering and Design.
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R. J. Hawryluk,
D J Campbell,
G. Janeschitz,
P. R. Thomas,
R. Albanese,
R. Ambrosino,
C. Bachmann,
L. Baylor,
M. Becoulet,
I. Benfatto, [......],
E. Tsitrone,
J. Urano,
M. Valovic,
M Wade,
J. Wesley,
R White,
D. G. Whyte,
S Wu,
M. Wykes,
L. Zakharov
Nuclear Fusion, v.49 (2009).
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Yu. Utin,
K. Ioki,
Ch. Bachmann,
V. Barabash,
G. Federici,
L. Jones,
B.C. Kim,
E. Kuzmin,
M. Morimoto,
M. Nakahira, G. Sannazzaro
[show abstract]
[hide abstract]
ABSTRACT: Recent progress of the ITER vacuum vessel (VV) design is presented. As the ITER construction phase approaches, the VV design has been improved and developed in more detail with the focus on better performance, improved manufacture and reduced cost. Based on the achievements of manufacturing studies being performed in cooperation with the ITER participant teams (PTs), design improvement of the typical VV sector (#1, see the legend to figure 1 in this article) has been nearly finalized. Design improvement of other sectors is in progress—in particular, of the VV sectors #2 and #3 which interface with tangential ports for the neutral beam (NB) injection. For all sectors, the concept for the in-wall shielding has progressed and developed in more detail. The design progress of the VV sectors has been accompanied by the progress of the port structures. Structural analyses have been performed to validate all design improvements.
Fusion Engineering and Design.
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K Ioki,
V Barabash,
A Cardella,
F Elio,
C Ibbott,
G Janeschitz,
G Johnson,
G Kalinin,
N Miki,
M Onozuka, G Sannazzaro,
R Tivey,
Y Utin,
M Yamada
[show abstract]
[hide abstract]
ABSTRACT: Design has progressed on the vacuum vessel, FW/blanket and Divertor for the Reduced Technical Objective/Reduced Cost (RTO/RC) ITER. The basic functions and structures are the same as for the 1998 ITER design [K. Ioki et al., J. Nucl. Mater. 258–263 (1998) 74]. Design and fabrication methods of the components have been improved to achieve ∼50% reduction of the construction cost. Detailed blanket module designs with flat separable FW panels have been developed to reduce the fabrication cost and the future radioactive waste. Most of the R&D performed so far during the Engineering Design Activities (EDAs) are still applicable. Further cost reduction methods are also being investigated and additional R&D is being performed.
Journal of Nuclear Materials.
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[show abstract]
[hide abstract]
ABSTRACT: Since 1994 the JET experiment has been operated with a divertor,
with currents up to 6MA. Disruptions are generally accompanied by
vertical plasma displacements giving rise to vertical forces at the
torus. Vertical force swings up to 5MN were recorded at vessel supports.
The forces are toroidally non-uniform, with peaking factors up to 1.8.
Global sideways displacements of the torus, up to about 5 mm, were also
recorded in a number of disruptions. They are interpreted as consequence
of a large amplitude m=1, n=1 kink mode. Disruptions led to damage of
some components inside and also outside the vessel, such as internal
saddle coils, and beryllium evaporator heads
Fusion Engineering, 1995. SOFE '95. 'Seeking a New Energy Era'., 16th IEEE/NPSS Symposium;
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Yu Utin,
K Ioki,
V Komarov,
V Krylov,
E Kuzmin,
I Labusov,
N Miki,
M Onozuka,
V Rozov, G Sannazzaro,
A Tesini,
M Yamada,
Th Barthel
[show abstract]
[hide abstract]
ABSTRACT: The equatorial and the upper port structures are the most loaded among those of the ITER-FEAT vacuum vessel (VV). For all of these ports, the VV closure plate and the in-port components are integrated into the port plug. The plugs/port structures are affected by plasma events and must withstand high mechanical loads. Based on typical port plugs, this paper presents the conceptual design of the port structures (with emphasis on the supporting system), and the results of analyses performed.
Fusion Engineering and Design.
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Yu. Utin,
K. Ioki,
A. Alekseev,
Ch. Bachmann,
S. Cho,
V. Chuyanov,
L. Jones,
E. Kuzmin,
M. Morimoto,
M. Nakahira, G. Sannazzaro
[show abstract]
[hide abstract]
ABSTRACT: Recent progress of the ITER vacuum vessel (VV) design is presented. As the ITER construction phase approaches, the VV design has been improved and developed in more detail with the focus on better performance, improved manufacture and reduced cost. Based on achievements of manufacturing studies, design improvement of the typical VV Sector (#1) has been nearly finalized. Design improvement of other sectors is in progress—in particular, of the VV Sectors #2 and #3 which interface with tangential ports for the neutral beam (NB) injection. For all sectors, the concept for the in-wall shielding has progressed and developed in more detail. The design progress of the VV sectors has been accompanied by the progress of the port structures. In particular, design of the NB ports was advanced with the focus on the beam-facing components to handle the heat input of the neutral beams. Structural analyses have been performed to validate all design improvements.
Fusion Engineering and Design.
