Summary of the Test Results of ITER Conductors in SULTAN

Abstract. After completing the qualification tests of the ITER cable-in-conduit conductors (CICC), the tests of samples from the series manufacture are running in the SULTAN test facility in Villigen, Switzerland. The key test for the conductor samples is the current sharing temperature, Tcs, at the nominal operating field and current, i.e. the maximum temperature at which the conductors operate before developing an electric field of 10 μV/m. All the TF samples fulfilled the ITER requirement of Tcs ≥ 5.8 K after 1000 load cycles. The Tcs results have a broad scattering among the suppliers, from 5.8 K up to 6.6 K. The assembly of the Nb3Sn based CICC samples (for TF and CS coils) is carried out at CRPP. The NbTi CICC samples (for PF, CC and bus bars) are assembled at the suppliers, with a U-bend replacing the bottom joint. The poor performance of some Main Busbar (MB) conductor samples, caused by poor sample assembly, triggered the effort to assemble a MB sample at CRPP with solder filled terminations and a bottom joint. The superior test results of the MB-CRPP sample, closely matching the performance assessment carried out using 3-D field distribution and n-index behavior was a successful achievement of the last year of operation. According to the Procurement Arrangement for the ITER coils, the winding companies must qualify the joint and termination manufacture by SULTAN samples. The first joint sample tested in SULTAN was a TF joint from EU, followed by a Correction Coil (CC) joint sample from China. Other joint samples are being assembled in USA (Central Solenoid), in Russia (PF1), in EU (PF2 - PF5) and in China (PF6). All the ITER coils use the “twin box” design for joints, except the Central Solenoid. At the first test in SULTAN of a twin-box TF joint sample in 2013, an unexpected resistance increase was observed after an accidental dump of the SULTAN field, causing a large field transient parallel to the joint contact surface, with large eddy currents and electromagnetic loads at the pressure-contact between strand bundle and copper plate of the twin box. The resistance requirement for the TF joint was still fulfilled after the dump. The initial performance of the joint sample for Correction Coil conductor was not satisfactory and a second qualification sample is being prepared

Характеристика пациентов с первичной цилиарной дискинезией

Primary ciliary dyskinesia (PCD) (Online Mendelian Inheritance in Man - OMIM - #242650) is a rare hereditary disease, which is based on a defect in the ultrastructure of the cilia epithelium of the respiratory tract which leads to the motor function disorder. Data about health characteristics of patients with PCD in the Russian Federation are incomplete.The aim of the study was to investigate the clinical, laboratory, and instrumental characteristics of patients with PCD.Methods. The data of 90 patients (22 adults (24.4%) and 68 children (75.6%)) from several medical centers were studied. The following methods were used: medical history, spirometry, microbiological examination of the respiratory tract, video microscopic analysis of the functional activity of the nasal mucosa ciliated epithelium, transmission electron microscopy of the ciliated epithelium, and DNA testing.Results. The median age at diagnosis was 17.0 years for adults and 5.0 years for children. Kartagener syndrome was detected in 23 (27%) people, including 6 (26.0%) adults. Hearing loss was noted in 5 (26.3%) adult patients and 15 (26.8%) children. Light microscopy of the ciliated epithelium was performed in 14 (82.3%) children and 3 (17.7%) adults. In 12 patients, cilia motor activity was not registered at each of the magnifications (x 100, x 400, x 1,000). Transmission electron microscopy showed that absence ofinternal and external dynein handles (51%) and absence of internal dynein handles (17.9%) were the most common disorders. DNA testing was performed in 55 (61.2%) patients: 16 (29.1%) adults and 38 (70.9%) children. The most common genetic variants were found in the DNAH5 and HYDIN genes. Lung function was reduced in both adults and children, but a significant decrease was noted in adult patients. P. aeruginosa predominated in the culture and accounted for 21.3% (intermittent detection in 13.2%, persistent detection in 9%). It has increased resistance to antibiotics.Conclusion. The results correlate with the European data. Infection caused by P. aeruginosa with the increased resistance to antibiotics was prevalent in patienths with PCD.Первичная цилиарная дискинезия (ПЦД) (код по медицинской базе данных известных заболеваний с генетическим компонентом и генов, ответственных за их развитие, «Менделевское наследование у человека» (Online Mendelian Inheritance in Man — OMIM — #242650) — редкое наследственное заболевание, основу которого составляет дефект ультраструктуры ресничек эпителия респираторного тракта и аналогичных им структур, что приводит к нарушению их двигательной функции. В Российской Федерации информации о характеристиках здоровья пациентов с ПЦД недостаточно.Целью исследования являлось изучение клинико-лабораторной и инструментальной характеристики пациентов с ПЦД.Материалы и методы. Изучены данные пациентов (n = 90: 22 (24,4 %) взрослых и 68 (75,6 %) детей) из нескольких медицинских центров. При обследовании использовались анамнестический метод, спирометрия, микробиологическое исследование дыхательного тракта, видеомикроскопический анализ функциональной активности реснитчатого эпителия слизистой оболочки носа, трансмиссионная электронная микроскопия реснитчатого эпителия, ДНК-диагностика.Результаты. Медиана возраста установления диагноза у взрослых составила 17,0 лет, среди детей — 5,0 лет. Синдром Картагенера выявлен у 23 (27 %) больных, из них 6 (26,0 %) взрослых. В анамнезе пациентов преобладали рецидивирующие бронхиты, пневмонии, отиты. Снижение слуха отмечено у 5 (26,3 %) взрослых пациентов и 15 (26,8 %) детей. Световая микроскопия реснитчатого эпителия выполнена у 14 (82,3 %) детей и 3 (17,7 %) взрослых. У 12 (3 взрослых и 9 детей) пациентов двигательной активности ресничек на каждом из увеличений микроскопа (к 100, к 400, х 1 000) не зарегистрировано. При трансмиссионной электронной микроскопии чаще встречалось полное отсутствие наружных и внутренних динеиновых ручек (51 %) и внутренних динеиновых ручек (17,9 %). Молекулярногенетическое исследование выполнено у 55 (61,2 %) пациентов (16 (29,1 %) взрослых и 38 (70,9 %) детей). Наиболее часто встречались генетические варианты в генах DNAH5 и HYDIN. Функция легких была снижена как у взрослых, так и у детей, но в значительной степени снижение отмечено у взрослых пациентов. В микробиологических посевах превалирует Pseudomonas aeruginosa — 21,3 % (интер-миттирующий высев — у 13,2 %, хронический высев — у 9 %), обладающая повышенной резистентностью к антибактериальным препаратам (АБП).Заключение. Полученные результаты коррелируют с европейскими данными. У пациентов с ПЦД обнаружено преобладание инфекции, вызванной P. aeruginosa, характеризуемой повышенной резистентностью к АБП

The use of Nb3Sn in fusion: Lessons learned from the ITER production including options for management of performance degradation

The overall 30 year Nb3Sn conductor program for ITER provides an unusual opportunity to look at the issues created by the application of novel Nb3Sn technology on a large scale. ITER design criteria have evolved to make use of the features of the industrialized material, exploiting advantages as well as managing the disadvantages. There are lessons from the successes and failures to be learned for the future application of very high current Nb3Sn strands in fusion and high energy physics. The behaviour of Nb3Sn strands in the large compound ITER conductors is still producing surprises after 25 years of development, industrial production and testing, with the Nb3Sn strain sensitivity and brittleness producing many more subtle design impacts than originally foreseen. The results now obtained at the end of the ITER production suggest that, as a novelty for Nb3Sn, there are options for conditioning the strands in the ITER conductors that can be applied during commissioning and which could reduce the impact of brittleness by as much as one third

Advanced mechanical modeling of cyclically loaded cable-in-conduit conductors for fusion magnets

International audienc

Impact of mechanical and thermal cycles at different operating conditions on the ITER toroidal field coil conductor performance

The impact of electromagnetic (EM) and thermal cyclic loading (referred as warm-up-cool-down-WUCD) on the Nb3Sn cable in conduit conductors for the toroidal field magnets of the ITER tokamak should be carefully assessed for the proper operation of the machine. The experience gained during the production phases of the TF conductors revealed that a degradation occurs when thermal and EM cyclic loading is applied at the nominal operating conditions of 10.78 T and 68 kA. Since at the beginning of the tokamak operation the nominal conditions will not be achieved, it is worth investigating to what extent lower EM loads affect the conductor performance, and the threshold of EM load that triggers the WUCD degradation. The aim of this investigation is to identify critical levels which determine the onset of this degradation, both in terms of thermal and EM cycles, and to study the performance of strands from different suppliers. For this assessment, a set of conductor samples were manufactured including all types of strands to be used in the TF coils of the ITER machine. These samples were subjected to a set of EM and thermal cycles representing in a realistic way the actual operation of the conductors in the ITER machine. The tests were performed in the SULTAN facility of the Swiss Plasma Center at working conditions ranging from 5.4 T-34 kA to 10.78 T-68 kA. This work presents the results obtained in these tests in terms of current sharing temperature (Tcs), effective strain, rate of degradation at different working conditions and their implications for the prospected conductor performance in the machine

Advanced Modeling of Electromagnetic Loading of Cable-in-Conduit Conductors for Fusion Magnets

The electrical performance degradation of Nb3Sn cables in the Cable-in-Conduit Conductors CICC has been well documented in literature. The Nb3Sn composite strands exhibit a critical current density that strongly depends on the strain state of the superconducting filaments. During a fusion magnet operation, the conductors are submitted to several electromagnetic and thermal cycles affecting the Nb3Sn mechanical state and consequently the capacity of the conductors to transport current. Different studies based on both a macroscopic and microscopic approaches have been performed so far to identify the mechanisms determining the conductors' behavior. Nevertheless, no theory permitting to predict the electrical performance of cyclically loaded conductors has been developed yet. Therefore, a solid electromechanical model able to tackle the analysis of CICC for fusion cables when they undergo thousands of cyclic loadings would be very useful. In this paper an advanced mechanical model to study the mechanical behavior of ITER TF CICC based on an improved version of the MULTIFIL finite element code is presented. A correction is introduced to solve the problem of the large impact of the boundary conditions in the simulation of the thermal loading, encountered in a previous work. A novel methodology to identify the value of thermal strain to be applied in cool-down simulations has also been developed. The model was adapted to take into account the Lorentz force cumulative effect of the other petals on the one under analysis. An assessment of the electromagnetic behavior based on the mechanical analysis is also presented

Test Results of RF ITER TF Conductors in the SULTAN Test Facility

The cable-in-conduit-conductors (CICC) for the ITER Toroidal Field (TF) Coils are tested in the Sultan test facility in order to estimate their AC and DC performances under operating conditions. The tests are carried out on different stages of conductor procurement implementation starting from Nb3Sn superconducting strand layout and process development to regular checks of production unit lengths. Four TF samples provided by Russia have been successfully tested in the Sultan facility by now in the framework of the ITER collaboration, including Strand Performances Qualification Sample, Qualification Conductor Sample, Pre-production and Production Conductors sample. The test results of all four samples shows pretty good reproducibility of the conductor performances from sample to sample and at the same time good stability of conductor performance under mechanical loading caused by Lorenz force during electromagnetic (EM) cycling can be observed. In the present work a comparison of the conductors and their performance was carried out to show the development of conductor performances from R&D stage to mass production

Testing of RF 100 m TF Qualification Conductor in the SULTAN Test Facility

A conductor for ITER toroidal field (TF) coils is the cable-in-conduit conductor (CICC) type, which is made of Nb3Sn superconducting strands encased in a stainless steel tubular jacket. A 120-m-long prototype has been designed in accordance with ITER requirements and manufactured prior to production of 26 full-sized CICC lengths that are the contribution of Russia to the ITER TF magnet system. Ten meters of the prototype have been used to produce a sample for testing in the SULTAN facility in order to qualify the strand/cable/jacket combination. A test aimed at qualifying the conductor performance based on T-cs measurements in representative condition regarding the transport current and magnetic field has been carried out. At the same time, the test was used to compare the conductor behavior after different heat treatment cycles. Each of two legs has been reacted in accordance with one of the specified heat treatment cycles for the ITER TF conductor. Test results are presented and discussed. Based on the test results, the eligibility of the conductor for the ITER TF magnet system has been assessed