Results of a New Generation of ITER TF Conductor Samples in SULTAN

Bruzzone, P.,Stepanov, B.,Wesche, R.,Salpietro, E.,Vostner, A.,Okuno, K.,Isono, T.,Takahashi, Y.,Hyoung Chan Kim,Keeman Kim,Shikov, A.K.,Sytnikov, V.E. IEEE 2008 IEEE transactions on applied superconductivity Vol.18 No.2

<P>A new generation of ITER TF conductor samples has been assembled and tested in SULTAN in 2007 following a common procedure agreed among the ITER parties. The test results of six SULTAN samples, made of twelve conductor sections manufactured in Europe, Japan, Korea and Russia, are reported here. The conductor layout reflects the ITER TF conductor design, with minor differences for the Nb<SUB>3</SUB>Sn strand characteristics, void fraction and twist pitch. The object of the test is a straight comparison with the ITER requirement of 5.7 K current sharing temperature at 68 kA current and 11.3 T field. A broad range of behavior is observed.</P>

Nonlinear effects on motions and loads using an iterative time-frequency solver

Bruzzone, Dario,Gironi, C.,Grasso, A. The Society of Naval Architects of Korea 2011 International Journal of Naval Architecture and Oc Vol.3 No.1

A weakly nonlinear seakeeping methodology for predicting motions and loads is presented in this paper. This methodology assumes linear radiation and diffraction forces, calculated in the frequency domain, and fully nonlinear Froude-Krylov and hydrostatic forces, evaluated in the time domain. The particular approach employed here allows to overcome numerical problems connected to the determination of the impulse response functions. The procedure is divided into three consecutive steps: evaluation of dynamic sinkage and trim in calm water that can significantly influence the final results, a linear seakeeping analysis in the frequency domain and a weakly nonlinear simulation. The first two steps are performed employing a three-dimensional Rankine panel method. Nonlinear Froude-Krylov and hydrostatic forces are computed in the time domain by pressure integration on the actual wetted surface at each time step. Although nonlinear forces are evaluated into the time domain, the equations of motion are solved in the frequency domain iteratively passing from the frequency to the time domain until convergence. The containership S175 is employed as a test case for evaluating the capability of this methodology to correctly predict the nonlinear behavior related to wave induced motions and loads in head seas; numerical results are compared with experimental data provided in literature.

Nonlinear effects on motions and loads using an iterative time-frequency solver

D. Bruzzone,C. Gironi,A. Grasso 대한조선학회 2011 International Journal of Naval Architecture and Oc Vol.3 No.1

A weakly nonlinear seakeeping methodology for predicting motions and loads is presented in this paper. This methodology assumes linear radiation and diffraction forces, calculated in the frequency domain, and fully nonlinear Froude-Krylov and hydrostatic forces, evaluated in the time domain. The particular approach employed here allows to overcome numerical problems connected to the determination of the impulse response functions. The procedure is divided into three consecutive steps: evaluation of dynamic sinkage and trim in calm water that can significantly influence the final results, a linear seakeeping analysis in the frequency domain and a weakly nonlinear simulation. The first two steps are performed employing a three-dimensional Rankine panel method. Nonlinear Froude-Krylov and hydrostatic forces are computed in the time domain by pressure integration on the actual wetted surface at each time step. Although nonlinear forces are evaluated into the time domain, the equations of motion are solved in the frequency domain iteratively passing from the frequency to the time domain until convergence. The containership S175 is employed as a test case for evaluating the capability of this methodology to correctly predict the nonlinear behavior related to wave induced motions and loads in head seas; numerical results are compared with experimental data provided in literature.

Performance Test of TFKO2 Qualification Sample of ITER TF Conductor

Dong Keun Oh,Soo-Hyeon Park,Keeman Kim,Bruzzone, Pierluigi IEEE 2010 IEEE transactions on applied superconductivity Vol.20 No.3

<P>According to the pre-qualification program for the production of Korean conductor for ITER TF magnet, a CICC(Cable In Conduit Conductor) sample for SULTAN test was developed based on the ¿Option 2¿ specification which is the improved one among the two established baseline designs. For the assessment of performance, SULTAN test of the conductor sample was carried out in CRPP employing recently updated instrumentations on the sample and the joint of two conductor pieces, which has been discussed and modified for the proper estimation of . As a course of the analysis, the assessment of values was presented using the basic protocol of data reduction, and the discussion was made on the standard process of analysis. In addition, we investigated some exposed problems in the data manipulation such as non-linear voltage slopes being possible to be related to conductor characteristic itself and the initial offset problem in the calorimetric method. On the presentation of the test results, we also report the manufacture of the conductor with the qualification of the components including carefully designed Nb3Sn internal-tin superconducting strands for an improvement of conductor performance.</P>

Development and Sultan Test Result of ITER Conductor Samples of Korea

Hyoung Chan Kim,Dong Keun Oh,Soo-Hyeon Park,Keeman Kim,Bruzzone, P. IEEE 2008 IEEE transactions on applied superconductivity Vol.18 No.2

<P>As a way to improve performance of ITER TF conductors, two types of cable-in-conduit conductors were developed in Korea with variations of conduit thickness resulting in the different void fraction of the conductors. The estimated void fractions of the conductors are 31% and 33%. Here we report the details of the TF conductor development and the performance test result of them carried out in SULTAN. Regarding the conductor development, the internal-Sn-processed strand characteristics, strand cabling, twist pitch and characteristics of the conduits for the conductors are presented. For an extended understanding of the conductor design and performance, the SULTAN test results are presented and the effect of the void fraction variations is discussed based on the results.</P>

Preliminary Performance Test Results of First CICC From Korea Destined for an ITER TF Magnet

Soun Pil Kwon,Soo-Hyeon Park,Stepanov, B.,Bruzzone, P.,Keeman Kim IEEE 2013 IEEE transactions on applied superconductivity Vol.23 No.3

<P>The Republic of Korea is participating in the ITER project to construct and operate the ITER tokamak for the purpose of demonstrating the feasibility of fusion power. ITER Korea, the implementing agency for the Republic of Korea that is procuring items for the ITER project on behalf of the Korean government, has established domestic and international contracts for the procurement of cable-in-conduit conductor (CICC) that will be used in the ITER toroidal field (TF) magnets. The CICC for the ITER TF magnets is made of superconducting and copper strand cable inside a cylindrical stainless steel jacket, and is designed to operate at a nominal peak field of 11.8 T at 4.5 K with 68 kA of nominal operating current. Recently, the first CICC from Korea, which will be installed in an ITER TF magnet, has been manufactured and tested including testing performed on a 4 m sample near ITER operating conditions at the CRPP-EPFL SULTAN facility in Villigen, Switzerland under the coordination of the ITER International Organization. This paper provides a brief description of the CICC along with preliminary results of the tests and the conductor performance characteristics derived from the results.</P>

Conductor Performance Qualification of TFKO3 Sample for ITER TF Magnet

Soo-Hyeon Park,Soun Pil Kwon,Keeman Kim,Stepanov, B.,Bruzzone, P. IEEE 2012 IEEE transactions on applied superconductivity Vol.22 No.3

<P>Two identical conductor samples were fabricated from 110 m length cable prepared for qualification of the manufacturing process for Phase II procurement of ITER TF conductor. Superconducting strand characteristics, cabling specifications, and the stainless steel jacket sections are described. Sample assembly and instrumentation of various voltage taps and temperature sensors have been prepared according to specified procedures for conductor performance qualification. The performance test program which was agreed to by the SULTAN working group was applied to the conductor samples. To assess the current sharing temperature , standard analysis procedures were adopted. The of both samples at 68 kA with a background field of 10.78 T after a 1000 cyclic load are well above the acceptance criteria. Behavior of individual “star” voltage taps which are located at different positions and which are possible origins of rather large discrepancies in the of identical samples is discussed. The effective strain and the transition index of the samples are obtained from the experimental data.</P>

ITER TF 초전도 도체 개발과 특성

김형찬,오동근,박수현,김기만,Kim, Hyoung-Chan,Oh, Dong-Keun,Park, Su-Hyeon,Kim, Kee-Man,Bruzzone, P. 한국초전도학회 2009 Progress in superconductivity Vol.10 No.2

As a participant taking part in the ITER TF conductor R&D program, we developed two toroidal field conductors with variations of conduit thickness resulting in the different void fraction of the conductors. The estimated void fractions of the conductors are 31% and 33%. In this paper we present the details of the TF conductor development and performance test results of them carried out by the measurement of current sharing temperature under cyclic loading. Regarding the conductor development, the internal-Sn-processed $Nb_3Sn$ strand characteristics, strand cabling, twist pitch and characteristics of the conduit materials are presented. For the understanding of the conductor design and performance, the conductor test results are presented and the effect of the conductor design parameters such as void fraction and twist pitch is discussed based on the results.

Overview of Performance Test of Korean CICCs for ITER TF Magnet

Soo-Hyeon Park,Soun Pil Kwon,Won Woo Park,Heekyung Choi,Young Jae Ma,Young Ho Seo,Stepanov, Boris,Bruzzone, Pierluigi Institute of Electrical and Electronics Engineers 2016 IEEE transactions on applied superconductivity Vol.26 No.4

<P>The Korean Domestic Agency (KODA) for the International Thermonuclear Experimental Reactor (ITER) project has taken the responsibility of the procurement of cable-in-conduit conductors for the ITER toroidal field magnet. While procuring 27 conductor unit lengths, which are the Korean sharing, 10 conductors have gone through the superconducting performance test, under low temperature and high magnetic field, as one of the final acceptance tests. The sample assembly and instrumentation of various voltage taps and temperature sensors have been done according to the specified procedure, which had been agreed between domestic agencies and the ITER International Organization. The performance test program, which has also been agreed, was carried out. For the assessment of the current sharing temperature (T-cs), the standard analysis procedure has been adopted. T-cs of all samples, at 68 kA and a background field of 10.78 T, after 1000 cyclic current loads are well above the acceptance criterion. By analyzing the electric field as a function of temperature, the effective strain (epsilon(eff)) and transition index (n-value) were reduced, and the behavior of epsilon(eff) will be discussed in terms of the electromagnetic load, i.e., I x B. The effective strain was compared with the physical strain and results with a numerical simulation.</P>