Overview of the testing activities on ITER sub-scale pre-compression rings

Rossi, Paolo; Capobianchi, M.; Crescenzi, F.; Massimi, Alberto; Mugnaini, Giampiero; Pizzuto, A.; Knaster, J.; Rajainmäki, H.

doi:10.1016/j.fusengdes.2012.01.035

Cited by 5 publications

(2 citation statements)

References 8 publications

(11 reference statements)

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“…In addition, ultimate tensile stress on 5 specimens showed an average of 2201 MPa at room temperature with 2766 MPa at 77 K with 61 GPa of elastic modulus. The work performed has been recently summarized [7].…”

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

confidence: 99%

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%

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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“…A R&D program, based on filament wound and dry wound S2 glass unidirectional fibers, the latter processed by vacuum pressure impregnation, was completed on 1/5 sub-scale rings, and the ring concept, materials, and utilized techniques were shown to be satisfactory [4,5]. These processes allow practically only unidirectional rings, except the outer layers, where radial and axial layers can be applied.…”

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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