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The performance of two Nb3Sn conductors for the ITER central solenoids was tested. The current sharing temperatures (T-cs) were measured over 17 050 electromagnetic cycles, including four thermal cycles between 4.2 K and room temperature. T-cs declined almost linearly over the 10 000 rated electromagnetic cycles. T-cs was nearly constant for 70% of the rated electromagnetic cycles, which implies the existence of a fatigue limit in the conductors. For 85% of the rated cycles, a very sharp T-cs degradation of approximately 0.2 K occurred. Some type of large deformation of strands, such as buckling, may have caused this sharp degradation. The effective strain degraded linearly with the electromagnetic force on the cable. The gradient after 10 000 cycles was 1.5 times greater than that before cycling. After 10 000 cycles, the ac losses of both conductors considerably decreased to less than half of those before cycling. These ac losses before cycling were less than a fourth of those of toroidal field conductors. After the test campaign, destructive inspection of the conductor clarified that on average, the distribution of residual strain along the cable was almost uniform at -32 ppm. It was also clarified that some strands were visibly deformed under a high magnetic field, whereas strands under a low magnetic field did not appear to be deformed. The deformations of the central solenoid cable were larger and wavier in subcables than those observed in the toroidal field cable. This plastic deformation of the strands could be one of the major reasons for the T-cs degradation during cyclic operation.

The performance of tour Nb3Sn conductors for the ITER central solenoids was tested. The current sharing temperatures (T-cs) were measured over approximately 9000 electromagnetic cycles, including two or three thermal cycles between 4.2 K and room temperature. T-cs, increased and became almost constant through the cycling. The gradient of the electric field against the temperature gradually decreased against cycling. The degradations caused by the electromagnetic force of the short twist pitch conductors were smaller than that of the original twist pitch conductor. The ac losses of short twist pitch conductors were several times higher than that of original twist pitch conductor. The dents and the removals of the Cr plating on the strands, which were formed during cabling, decreased the electric resistance between strands, which may cause the observed high ac loss. Inspection of the cable showed neither a clear bias of cable in the cross-sectional surface nor distorted strands in the lateral face. The high rigidity of the short twist pitch cable could prevent these plastic deformations, caused by the Lorentz force.

The optimization of the heat treatment of Nb3Sn conductors for toroidal field coils in ITER was attempted to improve the current sharing temperatures (T-CS). Using the strand, we chose the pattern at 570 degrees C for 250 h and 650 degrees C for 100 h as the best, which increased the critical current and maintained the residual resistivity ratio higher than 100. The behavior of the critical current of the strand vs. the magnetic field, temperature, and strain was also improved. This pattern was used on two conductors, and their performances were tested. T-CS was evaluated over 1000 electromagnetic cycles and one thermal cycle. A sharp T-CS occurred at 50 cycles. Then T-CS linearly. Although this tendency was similar to the conductors that were heat treated with the original pattern, the degradation rates were improved. The ac losses (Q) before cycling were approximately 10% lower than those of the original pattern. Q after cycling became almost equivalent between two patterns. The conductor was inspected after the test, which showed that the conductor under the high-magnetic-field zone had contracted by approximately 600 ppm during the test. Some clearly deformed strands were observed under the high-magnetic-field zone, which could degrade T-CS.

Rational chemotherapy of malignant melanoma could be developed by taking advantage of the presence of melanogenic enzymes in melanoma cells. 4-S-Cysteaminylphenol (4-S-CAP) has been evaluated for melanocytotoxicity and antimelanoma effect. Although 4-S-CAP is selectively toxic to pigmented melanoma cells, it is not potent enough when applied as a single agent. To increase the efficacy of 4-S-CAP, we synthesized 4-S-cysteaminylcatechol (4-S-CAC), an activated form of 4-S-CAP, and compared its biochemical properties and antimelanoma effects with those of the isomers 3-S-cysteaminylcatechol (3-S-CAC) and 2-S-cysteaminyl-hydroquinone (2-S-CAH). 4-S-CAC was found to be a better substrate for melanoma tyrosinase than was L-3,4-dihydroxyphenylalanine, the natural catecholic substrate. 3-S-CAC was a poor substrate, whereas 2-S-CAH was not a substrate. 4-S-CAC was the most cytotoxic to three lines of melanoma cells in vitro, followed by 2-S-CAH and 3-S-CAC. When applied i.p. for 9 days at a dose of 100 mg/kg, 4-S-CAC.HCl, increased by 46-52% the life span of C57BL/6 mice inoculated i.p. with B16 melanoma; this effect was comparable to that of a 50 mg/kg dose of 5-(3,3-dimethyltriazenyl)-1H-imidazole-4-carboxamide. 3-S-CAC was marginally effective, whereas 2-S-CAH was toxic to the host. This systemic toxicity of 2-S-CAH reflected its susceptibility to autoxidation. Growth of B16 melanoma cells inoculated s.c. was significantly inhibited by i.p. administration of 4-S-CAC.HCl (200 mg/kg) for 5 days (P0.05). These results suggest that 4-S-CAC is a potent antimelanoma agent, the effect of which is mostly mediated through tyrosinase oxidation.

At the end of the test campaign of the ITER Central Solenoid Insert (CSI) coil in 2015, after 16,000 electromagnetic (EM) cycles, some tests were devoted to the study of the conductor stability, through the measurement of the Minimum Quench Energy (MQE). The tests were performed by means of an inductive heater (IH), located in the high-field region of the CSI and wrapped around the conductor. The calorimetric calibration of the IH is presented here, aimed at assessing the energy deposited in the conductor for different values of the IH electrical operating conditions. The MQE of the conductor of the ITER CS module 3L can be estimated as ∼200 J ± 20%, deposited on the whole conductor on a length of ∼10 cm (the IH length) in ∼40 ms, at current and magnetic field conditions relevant for the ITER CS operation. The repartition of the energy deposited in the conductor under the IH is computed to be ∼10% in the cable and 90% in the jacket by means of a 3D Finite Elements EM model. It is shown how this repartition implies that the bundle (cable + helium) heat capacity is fully available for stability on the time scale of the tested disturbances. This repartition is used in input to the thermal-hydraulic analysis performed with the 4C code, to assess the capability of the model to accurately reproduce the stability threshold of the conductor. The MQE computed by the code for this disturbance is in good agreement with the measured value, with an underestimation within 15% of the experimental value.