Fusion for Energy is delivering 5 out of 6 ITER superconducting poloidal field coils (PF coils), which are composed of stacks of 6 to 8 double-layered circular coils - double pancakes (DPs). The double pancakes range from 17 m to 24 m in diameter and the wound conductor has a NbTi core inside a stainless steel squared jacked. Due to the size of the PF 2-4 coils, they have been manufactured on the ITER site, very close to the assembly hall. This article highlights the manufacturing processes, the learning curve, the main challenges and learned lessons during the winding activities of the 30 double pancakes that comprise 4 PF coils.

Fusion for Energy (F4E), the European Domestic Agency for the International Thermonuclear Experimental Reactor (ITER) is responsible for the manufacturing, test and delivery of 5 out of 6 Poloidal Field Coils of ITER. F4E has currently delivered 4 coils: PF2, PF4, PF5 and PF6, the last two are installed in the Tokamak pit in temporary positions while PF2 and PF4 are stored awaiting the Tokamak torus completion. At the PF coils manufacturing production site in Cadarache, France, few meters away from the ITER Tokamak assembly building, F4E is currently finalizing the manufacturing and testing of the largest coil: PF3, with 24 m diameter and a weight of 384 t , approaching to the end of an endeavor that started back in 2013. This article describes all electrical tests the PF coils underwent to meet the ITER technical requirements during their lengthy manufacturing process, and which lasted several years. Tests performed at key points of the manufacturing process avoided discovering non-conformities at later stages that could otherwise become critical for the project accomplition. The main electrical tests consisted of high voltage DC/AC, partial discharge tests, and local and global Paschen tests. The experimental setups and procedures are presented and discussed in more detail. We also summarize the acceptance test results for the finalized coils i.e., 80 K forced flow pressure drop testing, leak tightness in vacuum before, during and after the thermal cycle to 80 K .

Fusion for Energy (F4E), the European Domestic Agency for the International Thermonuclear Experimental Reactor (ITER), is responsible for the supply of 5 out of the 6 Poloidal Field (PF) Coils: PF2-PF6. One coil, PF1, is being manufactured by the Russian Federation Domestic Agency (RFDA). While the 10 m diameter PF6 was manufactured by the Institute of Plasma Physics Chinese Academy of Sciences (ASIPP) and tested in the cold test facility at Cadarache under a collaboration agreement with F4E; coils PF2-PF5 are currently being manufactured on site, close to the Tokamak building, their size ranging from 17 to 24 m diameter and weights from 200 to 400 T. This article describes the final acceptance tests performed on the coils PF5 and PF6, the testing setup, paying special attention to the tests performed before, after and during the cool-down at 80 K. The tests cover a wide range of aspects of the operation at cryogenic temperatures: ranging from the high voltage electrical insulation performance during the potential fault conditions during plasma operation, leak tightness under vacuum and pressure drop behavior of its hydraulic system during operation with forced flow helium. In addition, we will briefly introduce the results for the current center line (CCL) calculation obtained for PF5 and PF6.

The plasma confinement of the International Tokamak Experimental Rector (ITER) is provided by the magnetic field generated by 18 toroidal field (TF) coils while 6 poloidal field (PF) coils and 6 central solenoid modules have the function to drive, shape and pre-heat the plasma. Fusion for Energy (F4E), the European Domestic Agency for ITER, is responsible for the supply of 10 TF coils and 5 PF coils to the ITER project. The PF coils utilize NbTi Cable-in-Conduit-Conductor (CICC) and have different diameters between 8 and 24 meters and a weight up to 400 tons. So far two EU PF coils, PF5 and PF6, have been completed. PF6 has been manufactured by the Institute of Plasma Physics Chinese Academy of Sciences (ASIPP) under a collaboration agreement with F4E. The other 4 PF coils are being produced by EU at the ITER site by a cluster of suppliers managed and supervised by F4E. All PF coils will be completed by 2023. The TF coils utilize a Nb3Sn conductor. So far six TF coil have been completed, of which five delivered to ITER and one will be delivered within 2021. The remaining TF coils will be delivered by end of 2022. We will report on the main aspects of the coils completed so far, on the main results obtained together with some statistical analysis as well as on the status of the remaining coils.

Three out of six Poloidal Field Coils (PFC) are already delivered to the ITER Organization. The PF Coils are built winding, impregnating, and vertically stacking double pancakes (DPs) of NbTi Cable-in-Conduit conductors into a Winding Pack (WP). Later, the Winding Pack (WP) is impregnated for ground insulation and clamping devices are installed for structural support and interface with the rest of the ITER machine. One of the main parameters characterizing the PFCs is the Current Centre Line (CCL), defined as the barycentre of its WP conductors. Ideally, the CCL would be in the WP's symmetry plane but due to solutions in the construction design and manufacturing deviations, it may vary. Double Pancakes (DPs) may be wound with different dimensions, or a deviation during their stacking would cause a misalignment of all the conductors contained in that ill-positioned DP, affecting the CCL. The manufacturing process starts with the conductor winding and insulation, forming a DP. The DP is then impregnated with resin and a scan of its surface is used to reconstruct the DPs virtually. The DPs are then stacked, forming a WP, and measurements of points on the surface are used to recreate the process virtually. Finally, the WP is insulated and impregnated with resin. At this stage, both surface scans and point measurements are used to align the WP in the coordinate system of the ITER machine. This paper explains the process to calculate the CCL of the three first PF Coils using manufacturing data, defining the uncertainty associated with the calculation and comparing against the target tolerances defined for the proper ITER machine operation.

The plasma confinement of the International Tokamak Experimental Rector (ITER) is provided by the magnetic field generated by 18 toroidal field (TF) coils while 6 poloidal field (PF) and 6 central solenoid coils have the function to drive, shape and pre-heat the plasma. Fusion for Energy (F4E), the European Domestic Agency for ITER, is responsible for the supply of 10 TF coils and 5 PF coils to the ITER project. The ITER Organization (IO) team is instead responsible for the design of such coils as well for the coordination of the activities of the different Domestic Agencies (DAs) producing the different components, and their assembly into the Tokamak. The PF coils utilize NbTi Cable-in-Conduit-Conductor and have different diameters between 8 and 24 meters and weights of up to 400 tons. Regarding the PF coils produced by F4E, so far one has been completed by the Institute of Plasma Physics Chinese Academy of Sciences (ASIPP) under a collaboration agreement with F4E. The other 4 PF coils are being produced at the ITER site in Saint Paul lez Durance, France, under F4E supervision. The first of these (PF5) will be completed by July 2020 while the last coil (PF3) will be ready be the end of 2023. The TF coils utilize Nb3Sn conductor and are manufactured with the “Wind, React & Transfer” method. The first TF coil is close to completion and will be delivered to the ITER site in early 2020. Subsequent TF coils will follow at a rate of about one every 3-4 months. In this article we will report on the production status of both PF and TF coils and, in particular, the different manufacturing strategies employed. The main challenges faced so far and the results obtained are also described.

Background and Aim: To evaluate early surgical results of grown-up congenital heart disease(GUCH) in a single center experience. Methods: A retrospective analysis of GUCH patients operated on from 2002 to 2016. Variables included: primary diagnosis, surgical procedures, intraoperative data, early postoperative results. Analysis of variables and mortality was performed with Square-Chi test and t-test when indicated. Results: 409 operations were performed among 397 patients. Mean age at surgery was 38,2 ± 14,8 years. Main disease at operation was: septal defects in 30%, right ventricular outflow tract disease 29%, single ventricle 4%, valvular disease 28%, coronary arteries disease 5%, others4%. Seven patients were on heart transplant waiting list. Surgical procedures are described in table 1. In-hospital mortality was 1.7%. Age at operation and preoperative creatinine clearance, emergency procedure, prolonged by-pass time resulted as risk factors for intraoperative mortality(p = 0.007,0.009,0.003,0.002 respectively). Conclusions: A large number of GUCH patients lead a healthy life without any treatment, but some of them require cardiac surgery for primary repair, correction of residual or acquired pathologies, reoperation for sequelae following previous surgery or acquired heart disease. The complexity of this kind of population, due to the risk factors associated with it, therefore requires the need for adequate preoperative management, appropriate surgical planning and consequently a rigorous follow-up.

Background and Aim: To evaluate early surgical results of grown-up congenital heart disease(GUCH) in a single center experience. Methods: A retrospective analysis of GUCH patients operated on from 2002 to 2016. Variables included: primary diagnosis, surgical procedures, intraoperative data, early postoperative results. Analysis of variables and mortality was performed with Square-Chi test and t-test when indicated. Results: 409 operations were performed among 397 patients. Mean age at surgery was 38,2 ± 14,8 years. Main disease at operation was: septal defects in 30%, right ventricular outflow tract disease 29%, single ventricle 4%, valvular disease 28%, coronary arteries disease 5%, others4%. Seven patients were on heart transplant waiting list. Surgical procedures are described in table 1. In-hospital mortality was 1.7%. Age at operation and preoperative creatinine clearance, emergency procedure, prolonged by-pass time resulted as risk factors for intraoperative mortality(p = 0.007,0.009,0.003,0.002 respectively). Conclusions: A large number of GUCH patients lead a healthy life without any treatment, but some of them require cardiac surgery for primary repair, correction of residual or acquired pathologies, reoperation for sequelae following previous surgery or acquired heart disease. The complexity of this kind of population, due to the risk factors associated with it, therefore requires the need for adequate preoperative management, appropriate surgical planning and consequently a rigorous follow-up.

Objective: Treatment of infants with functional single-ventricle and heterotaxy syndrome is challenging due to multistage palliation with high operative mortality and morbidity. We report our experience. Methods: Between 1996 and 2017, 20 patients with heterotaxy syndrome underwent their first palliative surgery and form the study population. All relevant preoperative, operative and follow-up data were analyzed retrospectively. Results: Fourteen (70%) patients required neonatal palliation including a modified Blalock-Taussig shunt (n = 11; 55%), Norwood procedure (n = 1; 5%) or pulmonary artery banding (n = 2; 10%); two patients underwent TAPVC repair during first-stage palliative operation. In the remaining 6 patients (30%), primary bidirectional cavopulmonary anastomosis (BCPA) was the initial palliative surgery. 13 patients underwent BCPA operation as second-stage palliation, whereas one died in the interstage period. Nowadays, 12 of these patients have already undergone total cavopulmonary connection (TCPC) as a third-stage operation after BCPA. In case of Kawashima operation, median time interval before TCPC was 7 years (min 4 years; max 8 years). Mean follow-up time was 9,6 ± 7,9 years. One patient died during long-term follow-up after TCPC. Overall survival for the entire cohort following first surgery were 94,4% at 1 and 5 years and 82,6% at 10 years. Conclusions: Despite recent advances, the management of infants with heterotaxy syndrome with single-ventricle physiology is still a challenge for pediatric cardiac surgeons with high described morbidity and mortality. Conversely, in our experience overall mortality is inferior compared to other single-center reports and these patients may expect satisfying mid-to-long term survival. Further studies are needed to assess long-term morbidity.

The Ross procedure for replacement of a diseased aortic valve is effective in children where growth capability is essential. Long-term outcomes are generally excellent. Here, we present our technique of choice: the reimplantation of the pulmonary autograft and the implant of a pulmonary Homograft for RVOT replacement in an infant with congebital LVOT stenosis treated with percutaneous balloon angioplasty.

The ITER toroidal field (TF) strand procurement initiated the largest Nb3Sn superconducting strand production hitherto. The industrial-scale production started in Japan in 2008 and finished in summer 2015. Six ITER partners (so-called Domestic Agencies, or DAs) are in charge of the procurement and involved eight different strand suppliers all over the world, of which four are using the bronze route (BR) process and four the internal-tin (IT) process. In total more than 500 tons have been produced including excess material covering losses during the conductor manufacturing process, in particular the cabling. The procurement is based on a functional specification where the main strand requirements like critical current, hysteresis losses, Cu ratio and residual resistance ratio are specified but not the strand production process or layout. This paper presents the analysis on the data acquired during the quality control (QC) process that was carried out to ensure the same conductor performance requirements are met by the different strand suppliers regardless of strand design. The strand QC is based on 100% billet testing and on applying statistical process control (SPC) limits. Throughout the production, samples adjacent to the strand pieces tested by the suppliers are cross-checked (`verified') by their respective DAs reference labs. The level of verification was lowered from 100% at the beginning of the procurement progressively to approximately 25% during the final phase of production. Based on the complete dataset of the TF strand production, an analysis of the SPC limits of the critical strand parameters is made and the related process capability indices are calculated. In view of the large-scale production and costs, key manufacturing parameters such as billet yield, number of breakages and piece-length distribution are also discussed. The results are compared among all the strand suppliers, focusing on the difference between BR and IT processes. Following the completion of the largest Nb3Sn strand production, our experience gained from monitoring the execution of the QC activities and from auditing the results from the measurements is summarised for future superconducting strand material procurement activities.

ITER cable-in-conduit conductor (CICC) used in the superconducting magnet system consists of a cable made of Nb3Sn or Nb-Ti strands inserted in a stainless steel tube (called jacket or conduit). Depending on the coil type, the jacket material is either made of a low carbon AISI 316LN (for toroidal field coil) and AISI 316L grade stainless steels (for poloidal field and correction coils) or a high Mn austenitic stainless steel developed for ITER called JK2LB (for the central solenoid coil). Mechanical properties of base material and weld joint need to be tested at room and/or cryogenic temperature under predefined mechanical deformation and heat treatment conditions. The amount of required steel requires a tight mechanical properties control to ensure homogeneity during production within the ITER defined requirements. This paper will compare test results such as the ultimate tensile strength (UTS), the yield strength (YS), and the elongation to failure (EL) measured by all ITER jacket supplier test laboratories both for seamless tubes and weld joints.

The ITER superconducting magnet system will require approximately 650 tons of toroidal field and central solenoid Nb3Sn strands with different designs, and more than 250 tons of Nb-Ti strands. This called for a significant scale up of the worldwide production of Nb3Sn and Nb-Ti strands. Over the worldwide and mass productions, it is essential to accurately analyze and characterize the properties of ITER superconducting strands in terms of critical current (Ic) and ac loss, and thus determine the operational limits of the conductors, ultimately optimizing the operating scenarios of the Tokamak. In this paper, the proper scaling parametrization Ic(B, T) and n-value as a function of Ic (n(Ic)) are investigated for Nb-Ti strands throughout massive production. Despite the differences in ITER Nb-Ti strand's architecture and their composition, optimized Nb-Ti strand scaling parameterizations throughout production for each supplier have been reached with the minimal deviation (<;15%) for all the measured data in a wide B, T window and even <;5% in the operation condition region. This is to be applied for the analysis of the Nb-Ti conductors made from these stands and to assess possible evolution over production.

The ITER machine will require approximately 275 tons of Nb-Ti strands that will be used in poloidal field (PF) coils, correction coils (CC) and feeder busbars. The performance of all these conductors for the ITER machine is qualified by a short full-size sample (4m) current sharing temperature (T-cs) test in the SULTAN facility at CRPP in Villigen, Switzerland, at the design operating current and peak field. Three ITER domestic agencies participated in PF conductor fabrication (China, the European Union, Russia) while the conductors for feeder busbars and correction coils are entirely produced by the Chinese domestic agency. Each conductor type was qualified by the ITER International Organization after reaching T-cs values in excess of ITER specifications. This qualification enabled the launch of procurement and industrial production of the Nb-Ti cable-in-conduit conductors in each domestic agency. In this paper, we summarize the performance of the qualified Nb-Ti samples of the ITER Project, comparing strand performance with conductor performance. The details of the test results will be discussed in terms of dc performance, ac losses and minimum quench energies of each conductor type.

The present article reports a method for the average grain size evaluation of superconducting nano-particles through their magnetic properties. The use of SQUID magnetometry to determine the average MgB2 particle size was investigated and the results compared with those achieved through other techniques. In particular the data obtained from zero field cooled magnetization measurement as function of the temperature were compared with the results obtained by scanning electron microscopy and Brunauer-Emmett-Teller techniques. The particle magnetization was measured by a commercial SQUID magnetometer in magnetic field (1 mT) and temperatures ranging from 5 to 50 K dispersing the powders in a grease medium. The grain size is obtained by fitting the data taking into account the Ginzburg-Landau temperature dependence of the London penetration depth. Variations on typical modeling parameters were explored in order to gain a better picture of the average grain size and the effectiveness of various measurement techniques. We find that it is possible to use the magnetization measurements to determine the average grain size even if the SEM image analysis allows extracting more information about the grain size distribution. Furthermore a Matlab routine has been developed in order to get automatic analysis of SEM images.

Taking the relay of the large Hadron collider (LHC) at CERN, ITER has become the largest project in applied superconductivity. In addition to its technical complexity, ITER is also a management challenge as it relies on an unprecedented collaboration of seven partners, representing more than half of the world population, who provide 90% of the components as in-kind contributions. The ITER magnet system is one of the most sophisticated superconducting magnet systems ever designed, with an enormous stored energy of 51 GJ. It involves six of the ITER partners. The coils are wound from cable-in-conduit conductors (CICCs) made up of superconducting and copper strands assembled into a multistage cable, inserted into a conduit of butt-welded austenitic steel tubes. The conductors for the toroidal field (TF) and central solenoid (CS) coils require about 600 t of Nb3Sn strands while the poloidal field (PF) and correction coil (CC) and busbar conductors need around 275 t of Nb-Ti strands. The required amount of Nb3Sn strands far exceeds pre-existing industrial capacity and has called for a significant worldwide production scale up. The TF conductors are the first ITER components to be mass produced and are more than 50% complete. During its life time, the CS coil will have to sustain several tens of thousands of electromagnetic (EM) cycles to high current and field conditions, way beyond anything a large Nb3Sn coil has ever experienced. Following a comprehensive R& D program, a technical solution has been found for the CS conductor, which ensures stable performance versus EM and thermal cycling. Productions of PF, CC and busbar conductors are also underway. After an introduction to the ITER project and magnet system, we describe the ITER conductor procurements and the quality assurance/quality control programs that have been implemented to ensure production uniformity across numerous suppliers. Then, we provide examples of technical challenges that have been encountered and we present the status of ITER conductor production worldwide.

In this paper, we report about improved performances of amorphous and nano-structurated boron in MgB2 critical current density of wires and tapes. The boron produced by magnesiothermic reaction, using nano-structurated boron oxide, is used to synthesize nano-structurated MgB2 powders. These powders are used to produce several wires by ex-situ P.I.T. method. Here we applied only the ex-situ technique, in which our group is very well skilled. The same procedure can be applied to obtain in-situ P.I.T. tapes and wires as well. The boron and the MgB2 powders are characterized both from a physical-chemical point of view and from the superconductive point of view. We performed X-ray analysis to compare the home-made boron crystalline degree with respect to the commercial one. SQUID and transport measurements were done to compare the wire's critical current density behavior with respect to our past results using different boron.

In this paper, we report about improved performances of amorphous and nano-structurated boron in MgB2 critical current density of wires and tapes. The boron produced by magnesiothermic reaction, using nano-structurated boron oxide, is used to synthesize nano-structurated MgB2 powders. These powders are used to produce several wires by ex-situ P. I. T. method. Here we applied only the ex-situ technique, in which our group is very well skilled. The same procedure can be applied to obtain in-situ P. I. T. tapes and wires as well. The boron and the MgB2 powders are characterized both from a physical-chemical point of view and from the superconductive point of view. We performed X-ray analysis to compare the home-made boron crystalline degree with respect to the commercial one. SQUID and transport measurements were done to compare the wire's critical current density behavior with respect to our past results using different boron.

The promising results reported in our previous works led us to think that the production process of boron plays a crucial role in MgB2 synthesis. A new method for boron preparation has been developed in our laboratory. This particular process is based on magnesiothermic reaction (Moissan's process) with the addition of an initial step that gives boron powder with nano-metric grain size. In this paper we report our efforts regarding optimization of the powder-in-tube (PIT) method for these nano-metric powders, and the resolution of problems previously highlighted such as the difficulty in powder packaging and the high friction phenomena occurring during cold working. This increases cracking during the tape and wire manufacture, leading to failure. Packaging problems are related to the amorphous nature of boron synthesized in our laboratory, so a crystallization treatment was applied to improve the crystallinity of the boron. To prevent excessive friction phenomena we synthesized non-stoichiometric MgB2 and used magnesium as lubricant. Our goal is the J(c) improvement, but a global physical-chemical characterization was also made to analyse the improvement given by our treatments: this characterization includes x-ray diffraction, rho(T) measurement, and SEM imaging, besides magnetic and transport J(c) measurements.

In the design and feasibility of electric power applications with MgB2 conductors, thermal conductivity plays an important role. In composite wires and tapes it is mainly determined by the amount of stabilizer (usually copper), while for coils the electric insulation and epoxy binder characteristics are added. In this paper we present results on quench development and propagation on isolated superconducting tapes and small single pancake coils cooled by thermal conduction, for three types of MgB2 tape with different stabilizations. The quench parameters at different temperatures, such as minimum quench energy (MQE), minimum propagation zone (MPZ) and quench propagation velocity (vp), are reported. A complete electrical and thermal characterization of the superconducting tapes and of non-superconducting materials used in the coil manufacture has been made. With these data, numerical computational models using finite element simulations have been performed for isolated wires and single pancake coils, and the results of the relevant quench parameters have been compared with the measured values.