Production and Quality Assurance of Main Busbar Interconnection Splices During the LHC 2008–2009 Shutdown

Bertinelli, F.; Bottura, L.; Dalin, J.-M.; Fessia, P.; Flora, R.; Heck, S.; Pfeffer, H.; Prin, H.; Scheuerlein, C.; Thonet, Pierre; Tock, Jean-Philippe; Williams, L. R.

doi:10.1109/tasc.2010.2085072

Cited by 12 publications

(9 citation statements)

References 5 publications

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“…The two main reasons for this was a large interconnection resistance > 5 μΩ [11] and geometrical imperfections of the interconnections. This would have prevented the shunt application due to required copper surface preparation by unacceptable reduction of the busbar copper thickness [12].…”

Section: A Increased Amount Of Main Splices To Be Repairedmentioning

confidence: 99%

Consolidation of the 13-<roman>kA</roman> Superconducting Magnet Circuits of the LHC at CERN

Lackner

Duret

Grand-Clement

et al. 2015

IEEE Trans. Appl. Supercond.

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The first long shutdown (LS1) of the LHC machine at CERN started in February 2013. The main trigger for LS1 was the consolidation of the bus bar joints in the 13-kA superconducting magnet circuits. Before LS1, the copper continuity of these joints was not sufficiently good to ensure a safe passage of the current in case of a quench in the superconducting cable at currents larger than 7-8 kA. The consolidation mainly consists in adding shunts made of high conductivity copper across each joint connecting the bus bars of the neighboring magnets in order to ensure the copper continuity. After LS1, the LHC can then be operated up to the original nominal conditions, i.e., a collision energy of 14 TeV. There are 1695 interconnects, each containing six 13-kA joints, of which two belong to the main dipole circuit and four to the main quadrupole circuits. This paper describes the different steps of the consolidation work performed on the 10 170 magnet-to-magnet joints. The work on the splices proper has been organized in the form of a train made of six production teams, all together consisting of about 90 persons, including operators, supervision, and quality assurance. The work flow is managed with the help of a web-based tool called WISH. This paper describes as well the quality control and quality assurance methods put in place to ensure the quality of the work throughout the project, and it summarizes the benefits of the consolidation work in terms of copper continuity, operation margin, and robustness of the new insulation system. Index Terms-LHC long shutdown one, quality assurance, SMACC, superconducting splices.

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Section: A Increased Amount Of Main Splices To Be Repairedmentioning

confidence: 99%

Consolidation of the 13-<roman>kA</roman> Superconducting Magnet Circuits of the LHC at CERN

Lackner

Duret

Grand-Clement

et al. 2015

IEEE Trans. Appl. Supercond.

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“…In addition the specified 20,000 current cycles from 2 kA to 14 kA and one thermal cycle were performed. The quality control [4]- [5] after the test campaign has shown that this extensive test has not shown any measurable increase of the resistance of the shunted interconnections resistance. In addition no degradation or sign of fatigue was observed on the insulation hardware.…”

Section: The Final Validation Of the Designmentioning

confidence: 99%

An Improved Insulation System for the LHC Main 13 kA Interconnection Splices

Lackner

Savary

Prin

et al. 2013

IEEE Trans. Appl. Supercond.

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In 2013, a long shutdown of the Large Hadron Collider (LHC) at CERN will allow comprehensive maintenance plus consolidation of the machine components, in particular of the 13 kA circuits that feed the main superconducting magnets around the 27-km ring. This shutdown will prepare the accelerator for operation at nominal energy, 14 TeV, with adequate margin on the critical performance parameters. An essential part of the consolidation program consists of adding to the 13 kA splices of the magnet interconnects a copper shunt of high RRR (> 300) that will carry the current in the event of a busbar quench. An important R&D program was conducted in 2010 to design a sound solution for the shunt and for an improved insulation system. The development of the insulation system has required iterations aiming at adequate solution. The functional requirements for the insulation are a breakdown voltage of at least 3.1 kV in superfluid helium and sufficient mechanical strength to withstand stresses of the order of 50 MPa. The insulation system shall provide mechanical restraint for the shunted splices so that their transversal deflection is limited to 0.25 mm. This paper describes the final design of the insulation and the optimization process. The results from dielectric tests and numerical optimization of the insulation cover will be also presented. Finally the performance of the new insulation will be compared to the previous version.

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“…Initially, splice quality is insured by peeling apart solder joint and inspecting for voids. Room temperature resistance measurement can also be used as was performed during the LHC 2008-2009 shutdown [7]. …”

Section: Bus Splice Designmentioning

confidence: 99%

Superconducting link bus design for the accelerator project for upgrade of LHC

Nobrega¹,

Brandt²,

Cheban³

et al. 2012

AIP Conference Proceedings

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The Accelerator Project for Upgrade of LHC (APUL) is a U.S. project participating in and contributing to CERN's Large Hadron Collider (LHC) upgrade program. Fermi National Accelerator Laboratory in collaboration with Brookhaven National Laboratory was developing sub-systems for the upgrade of the LHC final focus magnet systems. Part of the upgrade called for various lengths of superconducting power transmission lines known as Superconducting (SC) Links which were up to 100 m long. The SC Link electrically connects the current leads in the Distribution Feed Boxes to the interaction region magnets. The SC Link is an extension of the magnet bus housed within a cryostat. The present concept for the bus consists of 22 power cables, 4 x 13 kA, 2 x 7 kA, 8 x 2.5 kA and 8 x 0.6 kA bundled into one bus. Different cable and strand possibilities were considered for the bus design including Rutherford cable. The Rutherford cable bus design potentially would have required splices at each sharp elbow in the SC Link. The advantage of the round bus design is that splices are only required at each end of the bus during installation at CERN. The round bus is very flexible and is suitable for pulling through the cryostat. Development of the round bus prototype and of 2 splice designs is described in this paper. Magnetic analysis and mechanical test results of the 13 kA cable and splices are presented.

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Production and Quality Assurance of Main Busbar Interconnection Splices During the LHC 2008–2009 Shutdown

Cited by 12 publications

References 5 publications

Consolidation of the 13-<roman>kA</roman> Superconducting Magnet Circuits of the LHC at CERN

Consolidation of the 13-<roman>kA</roman> Superconducting Magnet Circuits of the LHC at CERN

An Improved Insulation System for the LHC Main 13 kA Interconnection Splices

Superconducting link bus design for the accelerator project for upgrade of LHC

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