CERN Accelerating science

002894504 001__ 2894504
002894504 003__ SzGeCERN
002894504 005__ 20240404204956.0
002894504 0247_ $$2DOI$$9IEEE$$a10.1109/TASC.2024.3362746
002894504 0248_ $$aoai:cds.cern.ch:2894504$$pcerncds:CERN
002894504 035__ $$9https://inspirehep.net/api/oai2d$$aoai:inspirehep.net:2769357$$d2024-04-03T08:53:13Z$$h2024-04-04T10:13:11Z$$mmarcxml
002894504 035__ $$9Inspire$$a2769357
002894504 041__ $$aeng
002894504 100__ $$aSgobba, Stefano$$jORCID:0000-0002-4473-6058$$uCERN
002894504 245__ $$9IEEE$$aAnalysis of the Leakage Events in the Thermal Shield Cooling Pipes of the ITER Magnet System
002894504 260__ $$c2024
002894504 300__ $$a5 p
002894504 520__ $$9IEEE$$aThe ITER Thermal Shields (TS) consist of actively cooled stainless steel panels. Their role is to minimise the radiation heat load from warm components, such as the Vacuum Vessel (VV) and the cryostat, hence contributing to insulating the magnet system operating at 4.5 K. The panels, cooled by 304L stainless steel pipes stitch welded to 10 mm to 20 mm thick 304LN plates, were coated by a low emissivity silver layer following welding of the pipes and bending operations. Pressurised He gas flows in the pipes at a temperature of 80 K and a pressure of 1.8 MPa at the inlet. These components have been manufactured and delivered to IO and their assembly had been started. Three leaks were detected in Helium leak tests during site acceptance test of the TS. A failure analysis was carried out based on advanced non-destructive and destructive examination techniques, including X-ray microtomography and Focused Ion Beam - Scanning Electron Microscopy (FIB-SEM), confirming crack initiations of different severities, in particular presence of multi-branched “lightning bolt” transgranular cracks through the thickness of the pipes and of corrosion residues featuring high chlorine content. The root cause of the leakages has been univocally associated to Stress Corrosion Cracking (SCC), initiated by halide residues from the silver coating process in combination with the stress induced by the attachment, by welding, of the pipes to the plates. The paper summarises the results of these investigations and the lessons learned, the remedial actions implemented and the planned repair/replacement solutions.
002894504 542__ $$dIEEE$$g2024
002894504 65017 $$2SzGeCERN$$aAccelerators and Storage Rings
002894504 6531_ $$9author$$aWelding
002894504 6531_ $$9author$$aCorrosion
002894504 6531_ $$9author$$aComputed tomography
002894504 6531_ $$9author$$aInspection
002894504 6531_ $$9author$$aScanning electron microscopy
002894504 6531_ $$9author$$aNickel
002894504 6531_ $$9author$$aSuperconducting magnets
002894504 6531_ $$9author$$aHeat Shield
002894504 6531_ $$9author$$aScanning Electron Microscopy
002894504 6531_ $$9author$$aCryopreservation
002894504 6531_ $$9author$$aThermal Stress
002894504 6531_ $$9author$$aFocused Ion Beam
002894504 6531_ $$9author$$aEmissivity
002894504 6531_ $$9author$$aCrack Initiation
002894504 6531_ $$9author$$aFailure Analysis
002894504 6531_ $$9author$$aPresence Of Cracks
002894504 6531_ $$9author$$aLeak Test
002894504 6531_ $$9author$$aStress Corrosion
002894504 6531_ $$9author$$aVacuum Vessel
002894504 6531_ $$9author$$aEnergy-dispersive X-ray Spectroscopy
002894504 6531_ $$9author$$aTensile Stress
002894504 6531_ $$9author$$aCrack Propagation
002894504 6531_ $$9author$$aResidual Stress
002894504 6531_ $$9author$$aMetallographic
002894504 6531_ $$9author$$aPercentage Range
002894504 6531_ $$9author$$aPitting
002894504 6531_ $$9author$$aTungsten Inert Gas
002894504 6531_ $$9author$$aSilver-plated
002894504 6531_ $$9author$$aChronology Of Events
002894504 6531_ $$9author$$aTensile Residual Stress
002894504 6531_ $$9author$$aHigh Residual Stress
002894504 6531_ $$9author$$aHigh Tensile Stress
002894504 6531_ $$9author$$aPresence Of Cl
002894504 6531_ $$9author$$aITER thermal shields
002894504 6531_ $$9author$$astainless steel
002894504 6531_ $$9author$$astress corrosion cracking
002894504 6531_ $$9author$$asuperconducting fusion magnets
002894504 6531_ $$9author$$aweldments
002894504 690C_ $$aARTICLE
002894504 690C_ $$aCERN
002894504 693__ $$aITER
002894504 700__ $$aSantillana, Ignacio Aviles$$jORCID:0000-0002-3768-8377$$uCERN
002894504 700__ $$aCeluch, Michal$$uCERN
002894504 700__ $$aCrouvizier, Mickaël$$jORCID:0000-0002-0113-6757$$uCERN
002894504 700__ $$aPerez Fontenla, Ana Teresa$$jORCID:0000-0002-3440-1609$$uCERN
002894504 700__ $$aCastro, Enrique Rodriguez$$jORCID:0000-0003-3951-5397$$uCERN
002894504 700__ $$aMitchell, Neil$$jORCID:0000-0002-7980-5340$$uEuratom, St. Paul Lez Durance
002894504 700__ $$aKoizumi, Norikiyo$$jORCID:0000-0002-9467-7439$$uEuratom, St. Paul Lez Durance
002894504 700__ $$aPearce, Robert$$uEuratom, St. Paul Lez Durance
002894504 700__ $$aWorth, Liam$$uEuratom, St. Paul Lez Durance
002894504 700__ $$aKang, Dongkwon$$uEuratom, St. Paul Lez Durance
002894504 700__ $$aNoh, ChangHyun$$jORCID:0000-0002-2591-5595$$uEuratom, St. Paul Lez Durance
002894504 773__ $$c4203405$$n5$$pIEEE Trans. Appl. Supercond.$$v34$$y2024
002894504 960__ $$a13
002894504 980__ $$aARTICLE