Numerical simulation of critical current performance in Nb 3Sn strand subjected to periodic bending deformation

Haruyuki Murakami, Hiroshi Ueda, Atsushi Ishiyama, Norikiyo Koizumi, Kiyoshi Okuno

Research output: Contribution to journalArticle

Abstract

In the ITER Engineering Design Activity (EDA), four Nb 3Sn model coils were developed and successfully tested. However, it was revealed that the critical current of the conductor degraded with the increase of electromagnetic force. One of the explanations of this phenomenon is a strand bending caused by enormous electromagnetic force. The authors therefore developed a simulation code using the distributed circuit model to investigate dependency of the critical current performance on the periodic bending deformation. The simulation results were in good agreement with the experiments. The dependence of the critical current on the periodic transverse load, temperature, periodic load pitch, thickness of Ta barrier which prevents Cu stabilizer to be contaminated by Sn, twist pitch of the strand and RRR of the bronze matrix was investigated using the developed code. The results showed that the critical current degraded less with decreasing the pitch of the transverse load and increasing the Ta barrier thickness. It suggests that the shorter cabling pitch and the larger bending stiffness prevent the critical current degradation.

Original languageEnglish
JournalIEEJ Transactions on Power and Energy
Volume128
Issue number6
Publication statusPublished - 2008
Externally publishedYes

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Keywords

  • Bending strain
  • CIC conductor
  • Critical current
  • Degradation
  • Nb Sn

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Energy Engineering and Power Technology

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