Tihiro Ohkawa

Archimedes Plasma Mass Filter

Some 60,000 and 46,000 MT of sodium rich nuclear waste are now in storage in the US at Hanford a nd SR S facilities, respectively. We have de veloped a technology that uses the high sodium content to advantage: aqueous slurry wastes are first calcined into sodium hydroxide ( NaOH) melt slurries, then vaporized an d injected into a pl asma. The Archimedes Filter separates plasma ions into light and hea vy mass groups. For the first time, it is feasible to economically separate large amounts of material in a single-pass plasma device. Such a s eparation would s ubstantially decontaminate H igh Level Waste since most radionuclides partition to the h eavy fraction. The p lasma process is based o n setting up fast ExB rotation of a cylindrical plasma. At a certain critical rotational velocity E > B/2 ions are not confined by axial magnetic field and are lost radially. Because the critical rotational velocity depends on magnetic field the plasma and machine parameters can be set u p to separate heavy radionuclides from majority of the light elements in the plasma and, thus, accomplish waste cl ean up. The paper discusses the F ilter process, describes a de monstration device t hat has been constructed i n San Diego, USA, and presents the first experimental results.

Compact open NMR systems for in situ measurement of moisture, salinity, and hydrocarbons

A nuclear magnetic resonance device has a hollow cylindrical magnet that forms a void. The magnet has a plurality of south poles and an equal plurality of north poles, the poles being dimensioned and disposed on the magnet to establish a toroidal zone external to the magnet wherein the field of the magnet is of substantially constant strength. A solenoidal antenna is positioned within the void of the magnet. Electrical insulating material is positioned to cover the bases of the combined cylindrical structure and may also be disposed between the antenna and the magnet. Associated electronic power, signal processing, and indicating equipment may then be mounted adjacent the electrical insulator and the entire assembly contained in a suitable housing.

Fabrication of long length Bi-2223 superconductor tape using continuous electrophoretic deposition on round and flat substrates

We have developed a continuous fabrication process for producing long lengths of Bi-2223 superconductor tapes. The process involves sequentially electrophoretically depositing and sintering superconductor and then silver layers on a substrate, followed by rolling and thermal processing. Both round and flat silver substrates have been used. Bi-2223 tapes made using flat silver substrates require only a few processing steps. Transport critical current densities at 77K in zero applied magnetic field exceeding 20000 A/cm2 have been obtained.

Report of panel 3: Concept improvement

The charge to Panel 3 was to look at the idea of concept improvements in the context of US DOE management of the magnetic fusion program. The panel suggested that if DOE were commited to the idea of concept improvement, it needed to overcome the existing impression it was not receptive to new ideas. In part the long time scale for development of fusion energy, coupled with the rate of change of scientific programs and research based on emerging knowledge, means that in general the program will be much different ten to twenty years in the future. To be able to meet this changing direction, the US program must maintain an openness to look at promising alternative ideas, spend money on developing the ideas, and consider funding some to intermediate development levels. Stellerator research was offered as one alternative to consider in light of present international work. The panel urged supporting the development of new concepts and ideas, as well as continued support for plasma physics basic research.

Fabrication of long length Bi-2223 superconductor tape using a continuous electrophoretic coating process

We have developed a unique fabrication process for producing long lengths of Bi-2223 superconductor tapes. The process uses a continuous electrophoretic coating technique for sequentially depositing superconductor and silver layers on a substrate, by heat treating and rolling steps. The process offers a number of advantages over competing techniques.<<ETX>>

Development of High Temperature Superconductor Coated Metal Fiber and Multifilamentary Wire

Long superconductor fibers have been continuously produced by electrophoretically depositing REBa2Cu3O7−x powder onto a metal substrate fiber and sintering, then eletrophoreticaly depositing silver and sintering. After collecting the coated fiber on a take-up spool, the entire spool is batch-oxygenated to form the 90 K superconducting phase. Multiple fibers are then continuously unspooled and soldered into a copper channel to form the final multifilamentary high temperature superconductor wire. Superconducting fibers over 1000 meters long and multifilamentary wire 450 meters long have been produced.