Analysis of the Helium Behavior Due to AC Losses in the KSTAR Superconducting Coils

Park, Y M; Lee, H J; Lee, Y J; Park, S H; Kwag, S.W.; Song, N.H.; Chang, Y.B.; Park, H T; Woo, I.S.; Bang, Eunnam; Kim, Y S; Yang, H.L.; Bak, J.S.; Kwon, M.

doi:10.1109/tasc.2009.2038490

Cited by 13 publications

(8 citation statements)

References 5 publications

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“…The flow rate rapidly decreased two times. The flow reduction is proportional to the generated AC losses in the magnet [5], [6]. The first peak is originated from the initial charge of the magnet.…”

Section: A Normal Operationmentioning

confidence: 99%

Stability Analysis of the KSTAR PF Busline

Park

Lee

Chu

et al. 2012

IEEE Trans. Appl. Supercond.

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The Cable-In-Conduit Conductor (CICC) for the KSTAR buslines is made of NbTi superconducting (SC) strands. A busline consists of several electrical joints, which are the major heat load contributors to the busline cryo-system. In the poloidal field (PF) busline helium circuit, the supercritical helium is fed to the electrical joint of current lead end and comes out to the magnet terminal joint. This helium flow configuration has been verified to maintain the cryogenic stability of the buslines through the KSTAR operation. During the normal operation of the KSTAR PF coil, the heated helium coming out to both the coil and the busline meets at the magnet terminal and exchange heat, but the busline outlet temperature still remained less than magnet outlet temperature. As the buslines for the electrical connection in series of the upper and lower coils for PF1 and PF2 have the helium path through the two terminal joints of magnet, they experience higher temperature than the other buslines mainly due to the larger heat exchange. In this case, the connection buslines are considered to have very low safety margin and have the strong possibility of quenches.

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Section: A Normal Operationmentioning

confidence: 99%

Stability Analysis of the KSTAR PF Busline

Park

Lee

Chu

et al. 2012

IEEE Trans. Appl. Supercond.

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“…4 shows the configuration of the primary QD for PF 1 coil. Voltages are measured using both co-wound voltage strips and conventional three voltage taps [7]. Output voltages ( , ,…”

Section: Kstar Cs Magnet System and Its Instrumentationmentioning

confidence: 99%

Performance of the Quench Detection System for the KSTAR CS Magnet System

Chu

Lee²,

Kim³

et al. 2012

IEEE Trans. Appl. Supercond.

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The Korea Superconducting Tokamak Advanced Research (KSTAR) Central Solenoid (CS) magnet system coils are made of Cable-In-Conduit Conductors (CICC) that contains 240 strands and 120 copper strands inside an Incoloy 908 jacket. It consists of 4 symmetric pairs of coils to the equatorial plane. Each coil is wound with no internal joints by the continuous pancake winding method. It operates with pulsing current, which naturally induces inductive voltages across coils. Minimizing the inductive voltages is critical for the quench detection. To suppress the inductive voltages, each coil voltage was measured by using conductive tapes that are wound at the outer surface of the jacket with the same pitch length of the final sub-cable. During the KSTAR campaigns, the voltages were collected and analyzed. In addition, more rejection schemes were applied to enhance the stability and reliability of the quench detection. The paper deals with the up-to-date quench detection method of the KSTAR CS magnet system and its experimental results.

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“…This scenario was tested in run # 2524. Such a waveform leads to AC losses, which are the driver of the ensuing thermal-hydraulic transient in the two coils; this is characterized by a significant temperature increase measured at the outlet of the different channels, but also at their inlet, presumably due to SHe backflow [8]. As the response of PFI Land PFI U is similar, we shall concentrate below mainly on PFI L alone, assuming symmetry.…”

Section: Current Scenario and Available Diagnosticsmentioning

confidence: 99%

“…As flow reversal was observed at the coil inlet during this test [8], we cannot use the measured inlet values as boundary conditions, but we need to model the external cryogenic circuit feeding the coils. The model of the entire cryogenic circuit of KST AR is beyond the scope of the present paper.…”

Section: B Cryogenic Circuit Modelmentioning

confidence: 99%

Simulation of thermal-hydraulic transients in the KSTAR PF1 coil using the 4C code

Zanino

Kholia

Savoldi

et al. 2011

2011 IEEE/NPSS 24th Symposium on Fusion Engineering

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KSTAR is a fully superconducting tokamak, in operation since 2008 at the National Fusion Research Institute in Korea. All coils are wound using cable-in-conduit conductors and cooled with forced-flow supercritical helium (SHe) at 4.5 K and 5.5 bar. We consider here the central pair, PFI U/L, of the central solenoid coils; during operation these coils are subjected to sharp current transients, which induce AC losses in the coil. The thermal hydraulic transient following a trapezoidal current pulse, with ramp up to 10 kA at a rate of 1 kA/s and ramp down to 0 kA at a rate of 10 kA/s, is simulated here using the 4C code, and the results are compared with the measurements.

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Analysis of the Helium Behavior Due to AC Losses in the KSTAR Superconducting Coils

Cited by 13 publications

References 5 publications

Stability Analysis of the KSTAR PF Busline

Stability Analysis of the KSTAR PF Busline

Performance of the Quench Detection System for the KSTAR CS Magnet System

Simulation of thermal-hydraulic transients in the KSTAR PF1 coil using the 4C code

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