J.V. Minervini

Continuous magnetic separation of blood components from whole blood

Direct magnetic separations of red blood cells from whole blood have been carried out using a continuous magnetic separation method based on high gradient magnetic separation (HGMS) and a gas-permeable membrane with nitrogen gas. The experimental results have shown good agreements with the theoretical model taking into account the gravitational force. Based on the analysis, the feasibility of a direct magnetic separation device for white blood cells and plasma from whole blood is discussed.

Test of the ITER central solenoid model coil and CS insert

The Central Solenoid Model Coil (CSMC) was designed and built from 1993 to 1999 by an ITER collaboration between the U.S. and Japan, with contributions from the European Union and the Russian Federation. The main goal of the project was to establish the superconducting magnet technology necessary for a large-scale fusion experimental reactor. Three heavily instrumented insert coils were built to cover a wide operational space for testing. The CS Insert, built by Japan, was tested in April-August of 2000. The TF Insert, built by Russian Federation, will be tested in the fall of 2001. The NbAl Insert, built by Japan, will be tested in 2002. The testing takes place in the CSMC Test Facility at the Japan Atomic Energy Research Institute, Naka, Japan. The CSMC was charged successfully without training to its design current of 46 kA to produce 13 T in the magnet bore. The stored energy at 46 kA was 640 MJ. This paper presents the main results of the CSMC and the CS Insert testing-magnet critical parameters, ac losses, joint performance, quench characteristics and some results of the post-test analysis.

ITER CS model coil and CS insert test results

The inner and outer modules of the central solenoid model coil (CSMC) were built by US and Japanese home teams in collaboration with European and Russian teams to demonstrate the feasibility of a superconducting central solenoid for ITER and other large tokamak reactors. The CSMC mass is about 120 t; OD is about 3.6 m and the stored energy is 640 MJ at 36 kA and peak field of 13 T. Testing of the CSMC and the CS insert took place at Japan Atomic Energy Research Institute (JAERI) from mid March until mid August 2000. This paper presents the main results of the tests performed,.

Test of the ITER TF insert and Central Solenoid Model Coil

The Central Solenoid Model Coil (CSMC) was designed and built by ITER collaboration between the European Union, Japan, Russian Federation and the United States in 1993-2001. Three heavily instrumented insert coils have been also built for testing in the background field of the CSMC to cover a wide operational space. The TF Insert was designed and built by the Russian Federation to simulate the conductor performance under the ITER TF coil conditions. The TF Insert Coil was tested in the CSMC Test Facility at the Japan Atomic Energy Research Institute, Naka, Japan in September-October 2001. Some measurements were performed also on the CSMC to study effects of electromagnetic and cooldown cycles. The TF Insert coil was charged successfully, without training, in the background field of the CSMC to the design current of 46 kA at 13 T peak field. The TF Insert met or exceeded all design objectives, however some interesting results require thorough analyses. This paper presents the overview of main results of the testing - magnet critical parameters, joint performance, effect of cycles on performance, quench and some results of the post-test analysis.

New method of current distribution studies for ramp rate stability of multistrand superconducting cables

The ramp rate limitation phenomena were studied using local field sensors to observe the intrinsic processes within the cable. Sensitive miniature Hall sensors and small pick-up coils placed around cable-in-conduit superconductor were used to measure local magnetic fields and field derivatives associated with currents in the cable. Using this method, both fast jumps and slow changes in local magnetic fields at different conditions mere observed. First jumps occured during ramping background magnetic field and may indicate a fast current redistribution processes. Slow changing of local fields may be associated with current loops closed through the current lead joints. Such current loops may also indicate the nonuniformity of current distribution in the cable strands. The new method is a promising tool for future investigations of stability of multistrand cables.<<ETX>>

Measurements of ramp-rate limitation of cable-in-conduit conductors

The ramp-rate limitation found in the US-demonstration poloidal coil (US-DPC) test was studied in a laboratory scale experiment. The ramp-rate sensitivity has been identified on a 27-strand cable-in-conduit conductor at a background ramped field to 9.5 T with various ramp rates of 0.5 T/s to 2 T/s, simulating the US-DPC test conditions. A model assuming the existence of periodic disturbances is proposed in which the disturbance frequency is directly proportional to the ramp rate of the square of field. A semi-empirical formula was developed which fits the ramp-rate limitation data of both the US-DPC large coil and the 27-strand cable. The ramp-rate limitation does not occur for currents below the conventional limiting current.<<ETX>>

The Levitated Dipole Experiment (LDX) magnet system

In the Levitated Dipole Experiment (LDX), a hot plasma is formed about a levitating superconducting dipole magnet in the center of a 5 m diameter vacuum vessel. The levitated magnet is suspended magnetically during an eight hour experimental run, then lowered and recooled overnight. The floating F-coil magnet consists of a layer-wound magnet with 4 sections, designed to wrap flux lines closely about the outside of the levitated cryostat. The conductor is a niobium-tin Rutherford cable, with enough stabilizer to permit passive quench protection. Lead strips are used as thermal capacitors to slow coil heating. An optimized system of bumpers and cold-mass supports reduces heat leak into the helium vessel. Airbags catch the floating coil on quenches and faults, preventing collision with the vacuum vessel.

Test of the NbAl insert and ITER central solenoid model coil

The Central Solenoid Model Coil (CSMC) was designed and built by an ITER collaboration in 1993-2001. Three heavily instrumented Inserts have been also built for testing in the background field of the CSMC. The Nb/sub 3/Al Insert was designed and built by Japan to explore the feasibility of an alternative to Nb/sub 3/Sn superconductor for fusion magnets. The Nb/sub 3/Al Insert coil was tested in the CSMC Test Facility at the Japan Atomic Energy Research Institute, Naka, Japan in March-May 2002. It was the third Insert tested in this facility under this program. The Nb/sub 3/Al Insert coil was charged successfully without training in the background field of the CSMC to the design current of 46 kA at 13 T peak field and later was successfully charged up to 60 kA in 12.5 T field. This paper presents the test results overview.

Strand production and benchmark testing for the ITER model coils

As part of the technology demonstration for the main features of the ITER Tokamak superconducting coils, two model coils, characteristic bore 2/spl divide/3 m, will be manufactured jointly by the four ITER partners. The coils will require a total of 26 tonnes of Nb/sub 3/Sn strand, supplied equally by each of the partners. The procurement of the strand is proceeding in stages, with performance and continuous quality demonstrated first on about 1t from each party underway since Sept. 93 and due for completion by Oct. 94. The strand uses both the bronze and internal tin routes, achieving jc(noncopper) in the range 550-700 A/mm/sup 2/ at 12 T and 4.2 K, with hysteresis losses from 200 to 600 mJ/cc(nonCu) for +/- 3 T cycle. Unit lengths >1.5 km are required with diameters about 0.8 mm. The status and parameters achieved in the production is reported. One of the first steps in confirming the strand quality has been to establish consistent testing procedures through a benchmark activity using strand exchange between all parties. The first block of testing was completed in May 94 and a second round is now underway. The results of the two rounds and the steps taken to standardise the testing are described.<<ETX>>

Ramp-rate limitation test of cable-in-conduit conductors with supercritical helium

It has been found on the United States Demonstration Poloidal Coil (US-DPC) and in 27 strand subsized cables of pool boiling cable-in-conduit conductor (CICC), that there is critical current degradation due to fast ramping of the magnetic field. The characteristics of this ramp-rate limitation phenomenon are investigated by using a 27 strand Nb/sub 3/Sn cable in supercritical helium at 6 atm. A 3 m long cable-in-conduit conductor is prepared noninductively and tested in a background field up to 9.5 tesla with maximum ramp rate of 1.6 tesla/second. The ramp-rate limitation results are compared with results of the ramp rate test of the US-DPC and previous experiments. The experimental data are analyzed to identify and understand possible sources of ramp-rate limitation.<<ETX>>