Design Issues of the Pre-Compression Rings of Iter

Knaster, J.; Baker, Will C.; Bettinali, L.; Jong, C.; Mallick, Kaushik; Nardi, C.; Rajainmäki, H.; Rossi, Paolo; Semeraro, L.

doi:10.1063/1.3402295

Cited by 13 publications

(9 citation statements)

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“…Among these are joining fibres from different rolls by adhesive bonding, ring/flange interface to be composite/steel, treated with Molykote® which was found to be better than low friction plastic layers and reinforcement in the radial direction. The Fibre Efficiency Ratio for the model rings as defined by Zhao [4], is the ratio between the actual and theoretical strength of the composites (1) where σ u is the ultimate tensile stress of the composite, σ f is the fibre strength measured by the single fibre strength test [5] and V f is the volume fraction of fibres (0.65) would yield 62%. However, this value might be improved by a custom design sizing on the fibres and by minimizing damage to filaments during the winding / lay-up process.…”

Section: The Lessons Learned From the Ten Years Randd Phase At Eneamentioning

confidence: 99%

“…Its full description was provided in a different paper [1]. In outline, these rings will be 4975 mm internal diameter and 337 x 288 mm cross section.…”

Section: Introductionmentioning

confidence: 99%

“…The 70 MN inward loads that the pre-compression rings (located at the top and bottom of the coil case inner straight leg (FIGURE 1)) will apply on each TF coil in order to mitigate the cyclic stresses in the IIS and in the Outer Intercoil Structures (OIS) will ensure the 20 years of machine design life without fatigue failure [1].…”

Section: Introductionmentioning

confidence: 99%

“…They are designed to withstand various thermal cycles reaching up to 400 MPa hoop tension and up to 40 MPa radial compression without degradation. The rings will be fabricated (pre-dominantly) by hoop wound S-glass tow to result in a high glass content (>65% in volume) structure [ 1 ]. During manufacture emphasis will be placed on obtaining a structure with a low void content (<1.5%) and that is free from inclusions, faults, cracks and de-laminations.…”

Section: Introductionmentioning

confidence: 99%

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Assessment of possible failure modes and non-destructive examination of the ITER pre-compression rings

Knaster¹,

Evans²,

Rajainmäki³

2012

AIP Conference Proceedings

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The pre-compression rings (PCRs) for the International Thermonuclear Experimental Reactor (ITER) represent one of the largest and most highly stressed composite structures ever designed for long term operation at 4K. Three rings, each 5m in diameter and 337 x 288 mm in cross-section, will be installed at the top and bottom of the eighteen "D" shaped Toroidal Field (TF) coils to apply a total centripetal load of 70 MN per TF coil. The interaction of the 68 kA conductor current circulating in the coil (for a total of 9.1MA) with the required magnetic field to confine the plasma during operation will result in Lorentz forces that build in-plane and out-of-plane loads. The PCRs are essential to keep the stresses below the acceptable level for the ITER magnets structural materials. Each PCR will be pre-loaded at room temperature and cooled to 4K. They are designed to withstand various thermal cycles reaching up to 400 MPa hoop tension and up to 40 MPa radial compression without degradation. The rings will be fabricated (pre-dominantly) by hoop wound S-glass tow to result in a high glass content (>65% in volume) structure [ 1 ]. During manufacture emphasis will be placed on obtaining a structure with a low void content (<1.5%) and that is free from inclusions, faults, cracks and de-laminations. The biaxial loading conditions that exist in the PCRs can lead to complex behaviour patterns while the few existing studies on ring like structures have been limited to testing tubular specimens with axial loading and either internal pressure or a torsion load applied. This paper will study the possible failure modes of the PCRs and consider available nondestructive evaluation techniques that may be applied to the full scale rings after manufacture.

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Section: The Lessons Learned From the Ten Years Randd Phase At Eneamentioning

confidence: 99%

“…Its full description was provided in a different paper [1]. In outline, these rings will be 4975 mm internal diameter and 337 x 288 mm cross section.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Assessment of possible failure modes and non-destructive examination of the ITER pre-compression rings

Knaster¹,

Evans²,

Rajainmäki³

2012

AIP Conference Proceedings

Self Cite

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“…With a cross section of 337 mm x 288 mm, each item will weigh more than 3,000 kg. In operation -at 4 K and under high vacuum -they will control the deflection of the 18 TF coils that will induce, on each of the 6 rings, hoop tensile stress of around 450 MPa and radial compressive stress of 50 MPa [3].…”

Section: Introductionmentioning

confidence: 99%

The ITER pre-compression rings – A first in cryogenic composite technology

Rajainmäki

Foussat

Rodríguez

et al. 2014

AIP Conference Proceedings

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Abstract. The ITER Pre-Compression Rings represent one of the heaviest composite structures ever manufactured as a single piece and the largest -the outer diameter will be above 5.5 meters -intended for use in a cryogenic environment. With a cross section of 337 mm x 288 mm, each item will weigh more than 3,000 kg. A development program, based on filament wound and dry wound S2 glass unidirectional fibers, the latter processed by VARTM, was completed on one fifth scale rings, and these materials and techniques were shown to be satisfactory. The paper describes how a technology applied to build up primary structures of European launchers is being accommodated to produce the ITER PreCompression Rings, fulfilling its extremely challenging requirements. In addition, we will describe how the structural analysis is correlated with the test results of scaled down rings, as well as how the pre-compression rings' manufacturing process will be qualified.

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