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The construction of magnet system for the tokamak device of JT-60 super advanced (JT-60SA) was completed in March 2020. The manufacturing of CS had been finished in March 2019. The circularity of 4.0 mm is requirement for CS manufacturing from the point of view of plasma control. The high accurate manufacturing method and jigs had been developed and the circularity of CS achieves 1.44 mm, which meets the requirement of 4.0 mm. The clearance between the CS and the TF coils is very small, only 14 mm in design. The CS touches the TF coils and is subjected to load, the CS can be broken. Thus the surface dimension of the CS and the TF coils was measured before the installation of CS to confirm the clearance sufficient large to avoid the CS crashing in-to the TF coils. The CS was successfully installed to the tokamak center without any damages in December 2019 as the final step of magnet assembly of JT-60SA. In this paper, the manufacturing results and the installation of the CS are described

本小特集は、JT-60SA計画(第1章)、超伝導コイル(第2章)、極低温冷凍機システム(第3章)、電源設備(第4章)、真空容器及び容器内機器(第5章)、本体機器組立(第6章)、プロジェクト管理(第7章)、まとめ(第8章)という構成となっており、JT-60SAの機器の設計・製作・組立などに関する要点を記述するとともに、次期装置に向けての提言や展望も記述している。

超電導コイルのコミッショニングでは、冷却前試験としてクエンチ検出用の高圧計測線の導通確認や、冷媒の温度計、圧力計、差圧計の動作確認およびコイル・給電機器の耐電圧試験を実施し異常のないことを確認した。冷却開始後は、コイルに20Aの電流を通電し、コイルの抵抗値変化および超伝導遷移温度の測定を実施する。4Kへの冷却が完了した後は、通電試験を実施し、問題なくプラズマ運転が行えることを確認する。発表では、コミッショングの状況・結果について報告した。, 第100回 低温工学・超電導学会研究発表会

The construction of a magnet system for the tokamak device of JT-60 super-advanced (JT-60SA) was completed in March 2020. The manufacturing of central solenoid (CS) had beenfinished in March 2019. The circularity of 4.0 mm is a requirement for CS manufacturing from the point of view of plasma control. The high accurate manufacturing method and jigs had been developed, and the circularity of CS achieves 1.44 mm, which meets the requirement of 4.0 mm. The clearance between the CS and the TF coils is very small, only 14 mm in design. In case the CS touches the TF coils and is subjected to load during operation, the CS can be damaged. Thus the surface dimensions of the CS and the TF coils have been measured before the installation of CS to confirm if the clearance is sufficient large to avoid the CS crashing into the TF coils. The CS was successfully installed to the tokamak center without any damages in December 2019 as the final step of the magnet assembly of JT-60SA. In this paper, the manufacturing results and the installation of the CS are described., Applied Superconductivity Conference 2020 (ASC2020)

The mechanical loading technology has been developed for the pre-compression of central solenoid for the tokamak device of JT-60 super advanced (JT-60SA) being constructed in Japan. Four central solenoid modules were manufactured one by one, then 4 modules were stacked. The pre-compression were conducted to bind stacked 4 modules by support structure called tie-plate as a final process of the central solenoid manufacturing. The pre-compression jigs were designed by using the finite element analysis taking into account of plastic deformation of the jigs and the tie-plate. The pre-compression was performed using developed jigs.The hydraulic jacks and pumps were separately installed to the each tie-plate to control the pre-compress load individually. Since the pre-compress load changed by insulation creeping after initial loading, additional shims were inserted for the tie-plate with small load. Finally, pre-compress load of all tie-plate became within the target range. These results indicate that the pre-compression has been successfully completed using the developed jigs. In this paper, the design and analysis of the pre-compression jigs and the result of the pre-compression are reported.

The construction of a full-superconducting tokamak referred as JT-60 Super Advanced (JT-60SA) is in progress under the JA-EU broader approach projects. The magnet system of JT-60SA consists of 18 toroidal field (TF) coils, 4 modules of central solenoid (CS) and 6 equilibrium field (EF) coils. CS modules are manufactured one by one, then 4 modules are stacked. Finally, the pre-compression are conducted as a final process of CS manufacturing. There are two methods for pre-compression, one is shrink fitting method, and the other is mechanical compress method. The shrink fitting method is simple method for pre-compression because it is not needed additional jig. However it is difficult to control compress load because the height and the amount of shrinkage by compress load of CS module is not completely uniform. In addition, if compress load become reduced, re-compress will be required after starting operation, but re-compress is impossible with the shrink fitting method. Mechanical compress process was selected for pre-compression of JT-60SA CS to avoid above problems. Nine sets of hydraulic jacks and compress jigs, and stainless steel shims were used for pre-compress process to subject compress load by mechanically. Compress load of each sector can be controlled independently with this method. And re-compress after starting operation can be conducted. It means hydraulic jacks and compress jigs can be inserted from manhole of cryostat. Pre-compression of CS module was successfully performed using mechanical compress process. The compress load of each sectors measured by strain gauges on tie plates was more than requirement of 4.2 MN/sector. In this paper, procedure and result of pre-compression with mechanical compress process will be described., 第26回国際磁石技術会議（MT26 International Conference on Magnet Technology）

The construction of a full-superconducting tokamak referred as JT-60 Super Advanced (JT-60SA) is in progress under the JA-EU broader approach projects. The magnet system of JT-60SA consists of 18 toroidal field (TF) coils, 4 modules of central solenoid (CS) and 6 equilibrium field (EF) coils. TF coils are procured by EU and CS, EF coils and current feeding system are procured by JA. The current feeding system consists in-cryostat superconducting feeders and coil terminal boxes (CTBs). High Temperature Superconductor Current Leads (HTSCLs) are installed to the CTBs between room temperature busbars and superconducting current feeders to reduce the heat load for the cryoplant. There are five separated CTBs (CTB1-CTB5) to be installed to JT-60SA magnet system because of the small available space in torus building. Since the maximum allowable magnetic field of HTSCL is 33 mT, CTB main body is more than 12 m away from tokamak center. Design of in-cryostat feeders are complicated because they are required to have flexibility and rigidity. In-cryostat feeders need to withstand large displacement of coils up to 38 mm in vertical direction, 20 mm in radial direction and 16 mm in toroidal direction due to shrinkage during cooling down and electromagnetic force during operation. Therefore some in-cryostat feeders have loop shape parts to increase the flexibility of in-cryostat feeders. On the other hand, in-cryostat feeders are required to withstand acceleration due to earthquake of 0.4 G (+1.0 G) in vertical direction and 0.6 G in horizontal direction. Therefore we added the supports at suitable position to increase the rigidity and keep the flexibility of in-cryostat feeders. The design of in-cryostat feeders for JT-60SA were fixed using FEM calculation. Manufacturing of CTBs and in-cryostat current feeders started in 2014. First CTB (CTB1) was completed in February 2017 and CTB1 was used for the cold tests to validate the manufacturing design. CTB4 and CTB5 were completed in December 2017 and in-cryostat current feeders were also completed in May 2018. Manufacturing of remaining 2 CTBs (CTB2 and CTB3) will be finished in October 2018. CTBs and in-cryostat current feeders will be installed to the tokamak in 2019. In this paper, the final design of CTBs and in-cryostat current feeders are described. And the results of cold test of CTB1 is reported., Applied Superconductivity Conference 2018 (ASC2018)

The JT-60SA is a superconducting tokamak and the components of the over 10 m size are designed to be assembled in less than several millimeter error. Especially, TF coil is planned to be in the tolerance of ±1 mm, which is just a 0.02% error. In order to achieve successful construction work, the following techniques are developed, 1) 3D CAD is used for the confirmation of the fabrication tolerances, the designed position and interference at the intermediate assembly route, 2) laser tracker is used for the positioning of each component to know three dimensional position and to confirm the data in 3D CAD quickly, 3) special jigs are used for the positioning of the components. The assembly procedure for the coil system including the final sector of Vacuum Vessel and Thermal Shield is established. As a results, TF coils and upper EF coils are installed in less than 1mm error in position.

JT-60SA is a tokamak device using superconducting coils to be built in Japan, as a joint international research and development project involving Japan and Europe. One design object of JT-60SA is maximization of the plasma volume and the instrumentation port availability in the condition that several buildings, heating instruments, and diagnostics of JT-60U are reused. The cryogenic pipe system of JT-60SA, which transfers cold helium from the helium refrigerator to cold components such as superconducting coils, thermal shield and divertor cryopumps, has two unique features due to the limited space mentioned above. One of them is a complicated path. Relatively small 11 valve boxes and 5 coil terminal boxes are separately installed around the tokamak cryostat asymmetrically, instead of a simple large distribution box and a current feeder box. The other is that several inlets to superconducting coils are placed on upper side of coils, which makes difficult requests for structural analyses because of the higher part of coils, the larger displacement due to the gravity load, the seismic load, vacuuming the cryostat, cooling down the cold components, and the electro-magnetic force by the plasma operation. For example, the cryogenic pipe interface of JT-60SA Toroidal Field Coil is displaced about 8 mm, 11mm and 38 mm toward radius, toroidal, and vertical direction. In order to determine the design, structural analyses are conducted using ANSYS® software, which is a finite element analysis tool. The analysis result must satisfy that the stress for all pipes and their support structures are lower than the allowable stress of the material and there is no physical interference with any other components as a result of displacement. In this work, the strategy of analysis and the design for JT-60SA cryogenic pipe system are reported., 30th Symposium on Fusion Technology (SOFT 2018)

The JT-60SA experimental device will be the world’s largest superconducting tokamak when it is assembled in 2019 in Naka, Japan (R=3m, a=1.2m). It is being constructed jointly by institutions in the EU and Japan under the Broader Approach agreement. Manufacturing of the six NbTi equilibrium field coils, which have a diameter of up to 12 m, has been completed. So far 13 of the 18 NbTi toroidal field coils, each 7 m high and 4.5 m wide, have also been manufactured and tested at 4 K in a dedicated test facility in France. The first three of four Nb3Sn central solenoid modules have been completed, as have all of the copper in-vessel error field correction coils. Installation of the toroidal field magnet, around the previously welded 340° tokamak vacuum vessel and its thermal shield, started at the end of 2016 and is currently underway. The TF magnet will in turn support the EF and CS coils., 25th International Conference on Magnet Technology (MT-25)

The construction of a full-superconducting tokamak referred as JT-60 Super Advanced (JT-60SA) is in progress under the JA-EU broader approach projects. The magnet system of JT-60SA consists of 18 toroidal field (TF) coils, 4 modules of central solenoid (CS) and 6 equilibrium field (EF) coils. The diameter, the height, the number of layers and the number of turns of CS module are 2.0 m, 1.6 m, 52 layers and 549 turns, respectively. The CS module is composed of 6 octa-pancakes (8 layer pancake) and a quad-pancake (4 layer pancake). Each pancake is connected by the butt type joint. The Nb3Sn conductors are used for CS because of high magnetic field of 8.9 T. The procedure of CS manufacturing is as follows: (1) winding of pancake, (2) heat treatment of pancake, (3) transfer process, which includes turn insulation wrapping, pancake connection and setting of disk-shaped pickup coils, (4) vacuum impregnation of turn insulation, (5) ground insulation wrapping, (6) vacuum impregnation of ground insulation. The procedure of (1)-(3) have been reported in previous paper [1]. The winding accuracy and the temperature control precision during heat treatment met the requirements. The results of preproduction samples showed that the current sharing temperature was the same as the estimation based on strand characteristics, and the butt joint resistance met the requirement of, 1st Asian ICMC and CSSJ 50th Anniversary Conference

The JT-60SA experimental device will be the world’s largest superconducting tokamak when it is assembled in 2019 in Naka, Japan (R = 3 m, a = 1.2 m). It is being constructed jointly by institutions in the EU and Japan under the Broader Approach agreement. Manufacturing of the six NbTi equilibrium field (EF) coils, which have a diameter of up to 12 m, has been completed. So far, 13 of the 18 NbTi toroidal field (TF) coils, each 7-m high and 4.5-m wide, have also been manufactured and tested at 4 K in a dedicated test facility in France. The first three of four Nb3Sn central solenoid (CS) modules have been completed, as have all of the copper in-vessel error field correction coils. Installation of the TF magnet, around the previously welded 340° tokamak vacuum vessel and its thermal shield, started at the end of 2016 and is currently underway. The TF magnet will in turn support the EF and CS coils.

We studied the effects of various environmental temperatures on growth and blood pressure in rats. Spontaneously hypertensive rats (SHR) and their mother strain, normotensive Wistar-Kyoto rats (WKY) were used as the experimental animal. Rats of the two strains, SHR and WKY of 1 month old were divided into three groups randomly and they were housed in three rooms, of which temperatures were controlled at a constant, 30℃ (H-group), 22-24℃ (N-group) and 10℃ (C-group), respectively. Effects of environmental temperature on body weight gain were studied. Growth retardation was observed in the H-group of both strains. Maximal body weight gains were higher and reduced more quickly in SHR compared to those in WKY. In both SHR and WKY, at approximately 4 months old, the ratio of the tail to body surface areas was in the order of H-group>N-group>C-group in both strains. Systolic blood pressure (BP) was measured by the tail cuff method at approximately 4 months old. In WKY, BP in the C-group was significantly higher than that in H-group. In SHR, the BPs of the three groups were high compared to those in WKY groups, to which rats were exposed since 1 month old. And the BPs of C-group and H-group were significantly high compared to that in N-group. These facts indicate that effects of environmental temperature, to which rats were exposed since 1 month old, on growth were similar in WKY and SHR, and that the effects of the environmental temperature on systemic BP are clear in normotensive WKY, whereas in SHR, genetic expression of the hypertensive phenotype is consistent at various environmental temperatures., 長崎大学総合環境研究. 2006, 9(1), p. 1-7

Adult Wistar male rats were used for this experiment. Spinal cord was transected between the C_7 and Th_1 vertebrae under anesthetic condition. After the surgical operation, rats were reared in a warm room (30℃) as chronic spinal rats, and experiment was also performed in a climatic chamber (30℃, 60% r.h.). During the experiment, conscious spinal rats were placed in a small wire-mesh cage. Propranolol hydrochloride (Prop., 8mg/kg; β-adrenergic antagonist) was injected intraperitoneally. Rectal temperature (Tre), tail skin temperature (Ttail) and ambient temperature (Ta) were detected by thermistor probes and recorded simultaneously. In some cases, in addition to such parameters mentioned above, heart rate (HR) calculated by electrocardiogram (ECG) and arterial blood pressure (BP) through the femoral catheter were also recorded. As the index of the tail blood flow, the difference (dTtail) between Ttail and Ta was calculated (dTtail=Ttail-Ta). A sustained decrease in dTtail for 50 min was observed after the Prop. injection in Group-A (S, 熱帯医学 Tropical medicine 37(4). p175-183, 1996

The inhomogeneous poloidal magnetic field of tokamak device, which is called error field, has to be reduced because the error field degrades the plasma performance. There are 18 sets of EFC coils installed inside the vacuum vessel for JT-60SA to compensate the error field. The conceptual design of EFC coils has been completed. The water-cooled hollow copper conductor was selected to reduce the conductor size since the available space for EFC coils is small. The outer size of the conductor and the diameter of the cooling channel were optimized in considering hydraulic and thermal characteristics. The design of the conductor was validated by the testing of a mock-up coil. The bar springs are used for the structure of EFC coils. The structural analysis was performed to optimize the parameters of bar springs. The results of structural analysis suggest that the structure of EFC coils can be used for both the conditions of plasma operation and baking operation with the use of Inconel625 for bar springs. In this paper, the specification of the JT-60SA EFC coils, the test results of mock-up coils, and the structural analysis results of the EFC coil structure are described. The manufacture of EFC coils has started based on these designs.

Heat tolerance and sweat response to heat load of tropical subjects in Chiang Mai and temperate subjects in Nagasaki were compared under identical conditions. Male students in Chiang Mai (n=10) and in Nagasaki (n=10) volunteered for this study. The Thai subjects were a little shorter and slightly leaner than the Japanese. Heat load was applied on the legs by immersion into hot water (43℃) for 30 min in the room at 26.6℃ and 33%rh. Sublingual (oral) temperature was measured with a thermistor probe and local sweat rate was measured by the capacitance hygrometer-sweat capsule method. Change in oral temperature, sweat onset time and local sweat volume were compared between Japanese and Thai. Initial oral temperatures (36.76±0.11℃ in Japanese, 36.71±0.23℃ in Thai) were identical, and no sweat was observed before heat load. Mean sweat onset time (9.3±2.1 min chest in Japanese, 16.6±5.6 min chest in Thai) were significantly longer and local sweat volume (10.19±5.00 mg/cm^2, chest in Japanese, 1.39±0.91 mg/cm^2, chest in Thai) was significantly smaller in Thai subjects than Japanese, however, oral temperature (37.18±0.32℃) of Thai subjects was kept slightly lower than oral temperature (37.42±0.10℃) of Japanese even under a 30 min heat load. Sweat volume on the abdomen was larger than on the chest in 9 of 10 Thai subjects. On the contrary, sweat volume on the chest was larger than that on the abdomen in 7 of 10 Japanese subjects. These results suggest that heat tolerance of tropical subjects in due to a more efficient evaporative ability due to a greater heat loss brought about by their long term exposure to heat. Furthermore, the habituation phenomenon related to the reduction of thermoregulatory effector mechanisms were also considered so as to clarify the mechanisms of thermal acclimatization., 熱帯医学 Tropical medicine 35(1). p23-34, 1993

Male adult rats of the three strains, spontaneously hypertensive rats (SHR), Wistar-Kyoto rats (WKY) and Wistar rats (WIS) were used. Rats of each strain, at 1 month old, were randomly divided into three groups and chronically exposed to 3 different temperatures, 10℃, 30℃ and 22-24℃. Systolic blood pressure (BP) measured by the tailcuff method and stress-induced elevation of core temperature were compared. In cold-acclimated WKY and WIS, BP was significantly higher than that in the heat-acclimated rat. In SHR, genetically hypertensive rats, there was no significant difference in BP between cold- and heat-acclimated young adult rats, and BP in heat-acclimated older adult rats was higher than that in cold-acclimated SHR. In normotensive rats, WKY and WIS, thermal acclimation affected systemic BP. In normotensive strains, WKY and WIS, cold-acclimation increased BP, whereas heat-acclimation decreased BP. Mean body weights in cold-acclimated rats were greater than those of heat-acclimated ones in all strains except for older adult WKY. For restraint stress, the conscious rat was paced in a loosely fitting small cage. Cold acclimated SHR (SHR-C) and WKY (WKY-C) were restrained at 10℃ and heat-acclimated SHR (SHR-H) and WKY (WKY-H) were restrained at 30℃. At the start of restraint, there was no significant difference among the rectal temperatures of these four groups. During the restraint stress, elevated core temperature was sustained and tail skin temperature decreased. Both values of rectal temperature (Tre) at the 30th min and increase of Tre (dTre) in the first 30th min during the restraint stress were in the order SHR-C>SHR-H>WKY-C>WKY-H. Values of Tre and dTre in cold-acclimated SHR were significantly greater than those in cold-acclimated WKY, and those values in heat-acclimated SHR were significantly greater than those in heat-acclimated WKY. Thermal acclimation, which started in one month old rats, scarcely affected development of hypertension in SHR, whereas thermal acclimation produced a significant difference between BPs in cold- and heat-acclimated normotensive strains of rats. As for the influence of thermal acclimation on the responsiveness of stress-induced elavation of core temperature to the restraint stress, the strain difference was greater than the influence of thermal acclimation.