Site:           Furukawa Electric Co., Ltd.
                Nikko Works
                500, Kiyotaki, Nikko-shi, 
                Tochigi-ken 321-14, Japan
                http://www.furukawa.co.jp/english/cover.htm
Date Visited:   3 June 1996
WTEC Attendees: J. Willis (report author), 
                R.D. Blaugher, 
                D. Gubser, 
                D. Larbalestier
Hosts:          Masaru Ikeda, General Manager, 
                   Superconductivity Research Dept., R&D Division
                Shin-Ichiro Meguro, General Manager of Sales 
                   Engineering, Superconducting Products Dept., 
                   New Business Development Div.
                Naoki Uno, Manager, Superconductor Section, 
                   Superconductivity Research Dept., R&D Division
                Dr. Yasuzo Tanaka, Chief Engineer, R&D Division

BACKGROUND

Furukawa Electric Company, Ltd., was founded in 1884 and is a leading producer of electric wire in both Cu and Al forms. The Nikko Works, located in a resort town of great beauty, is nestled (some would say confined) in a valley and combines both traditional Cu smelting and large product manufacture with low volume, high value added products. The work at Nikko is organized into several product divisions: Casting, Wire and Rod, Strip, Special Metals, and Bare Conductor, and the R&D Division. There are about 1,500 employees at Nikko, about 1,000 in Cu products (output of 9,000 tons/month) and about 500 in Al products (output of 4,000 tons/month). The company as a whole employs a total of about 9,000 persons. Furukawa's major customers are Tokyo Electric Power Company (TEPCO) and aluminum can producers. The WTEC team's visit was with staff coming primarily from the R&D Division and with one member of the New Business Development Division, where the superconducting wire manufacture is carried out. Most of Furukawa's superconductivity-related work is performed at the Nikko Works.

SUPERCONDUCTIVITY BUSINESS

Furukawa has long been in the superconductor business, starting in 1963 just after the discovery of high field superconductivity. It is and has been a supplier of a broad range of high quality LTS wire, both Nb-Ti and Nb₃Sn. It was also a manufacturer of MRI magnets in a joint venture with Oxford Instruments, but this has now lapsed, and its MRI business is limited to maintenance of existing MRI systems in Japan through an affiliate called Superconducting Magnet Service Company. From all suppliers there are about 3,000 MRI systems in Japan. Furukawa Electric is a special supporting member of the International Superconductivity Technology Center (ISTEC) and has employees at ISTEC's Superconductivity Research laboratory (SRL). Furukawa also supplies personnel to the Super-GM (Superconducting Generator and Materials) project of the Ministry of International Trade and Industry (MITI), contracted through the New Energy and Industrial Technology Development Organization (NEDO). A booklet of Furukawa's 1995 publications related to superconductivity contains reprints of nearly 30 articles and is 133 pages long.

Furukawa's present work in superconductivity covers several product lines within the New Business Development Division's Superconductivity Products Department. Foremost among these is wire and cable for magnet systems. When the WTEC team visited, a recent large order was for 7.6 tons of bronze-route Nb₃Sn for the International Thermonuclear Experimental Reactor (ITER). This is the largest share of the Japanese Nb₃Sn ITER order, other parts of which went to Hitachi Cable (2.0 tons) and Mitsubushi Electric (4.0 tons). Furukawa has also produced aluminum-stabilized Nb-Ti conductors for a 30 kA bus line of the Large Helical Device. The company has also completed a Bi-2223 cable for TEPCO. The cable is 38 mm in diameter, 50 m long, and has a 77 K I_c of 1,700 A and a steady state ac current capacity of 1,200 A rms. The company has supplied a coaxial Pb cable for an anti-proton ring at Fermilab in the United States, and some laboratory magnets fabricated from Nb-Ti and Nb₃Sn that produce fields up to 15 T.

Personnel, Budget, and General Topics

Furukawa has a total of ~50 people working on superconductivity, of whom 30 are in the products department and 20 are in R&D, which is divided into LTS and HTS. The total budget for all superconductivity-related activities varies between $5 and $10 million with time, depending on the specific R&D projects being worked on. There has been a small decrease in the HTS budget from previous years. Most Furukawa projects are jointly funded, typically 66-75% from internal funds, the remainder from national projects or power companies. For jointly funded projects, external money is used to cover R&D and salary expenses. Furukawa occasionally supports small (<$100 thousand) collaborative projects with universities. Furukawa's most important project for HTS power applications is the power transmission cable. A few products, such as current leads and magnetic shields for magnetoencephalography (MEG), are available now, but management does not see a large market because these items are still really in the R&D stage. Small products may come to market in 5 years, and larger items, such as the power transmission cable, will be available in 10-20 years. Furukawa representatives did not make predictions of market size, except to say that it is rather small now.

HTS Conductor Development

About 50% of Furukawa's HTS R&D budget and manpower are devoted to conductor development, with all work being on Bi-2212 and Bi-2223. Some of this work is in collaboration with the Super-GM national project. External organizations contribute about 50% of the funds for conductor development. The standard production material is 400 m long Bi-2223/Ag powder-in-tube tape with performance values at 77 K and self field of critical current I_c = 30 A, critical current density J_c = 20 kA/cm², and engineering (overall) critical current density J_e = 8 kA/cm². The comparable values for Bi-2212/Ag tape at 4.2 K, self field are I_c = 150 A, J_c = 370 kA/cm², and J_e = 70 kA/cm². Furukawa researchers see a limiting factor for further development as low J_c, which ultimately is determined by careful process control to produce good texture and eliminate second phases. Silver alloys are used to reduce ac losses or to improve strain sensitivity in some applications. Target costs are $10/kAm for 77 K cable applications and 3-10 times this value for coil applications.

Generation and Storage

Furukawa has been a member of the Super-GM project since its inception in 1988. Its major contribution is the design and manufacture of quick-response type (LTS) cable for the 70 MW superconducting generator. It also participates in the ISTEC-led national project to develop a 0.1 MWh, 480 MJ SMES. Furukawa is making the cable-in-conduit (CIC)-type LTS cable for a model coil. As part of a different SMES project, Furukawa is making a mixed matrix-type Rutherford cable for KEPCO's 1 kWh, 1 MW (3.6 MJ) coil. Bronze process Nb₃Sn wire for the ITER project completes this category and represents 50% of Furukawa's LTS projects. These are all products of the New Business Development Division, and although there is no discrete R&D component for a project, some production engineering is always required.

Transmission and Distribution

About 25% of Furukawa's R&D funds are devoted to this application area. The main effort is for the power transmission cable, with smaller efforts on fault-current limiters and transformers, all of which have about 50% external funding from power companies. The power cable project, still in the R&D stage, is targeting a 1 GW, 66 kV cable, double the power of standard underground cable.

Furukawa has already developed a 5-meter-long prototype superconducting cable and a 50-meter-long conductor for the power transmission cable using Ag-sheathed Bi-2223 phase multifilamentary tapes in collaboration with Tokyo Electric Power Company (TEPCO). Furukawa has successfully performed a 66 kV, 2 kA peak load test for the 5-meter-long cable, and 2 kA_rms current test and ac loss measurements for the 50-meter-long conductor. AC losses were measured on the whole length of the conductor by changing transport currents of each isolated layer using insulation with externally connected variable resistors. The results were analyzed using the standard Norris's equation and the Uniform Current Distribution Model (UCD Model) introduced by Furukawa, which makes different assumptions about the current distribution.

Furukawa's major role in these projects is as a supplier of wire and cable, although it also performs a full range of functions from design to cost evaluation. Major technical issues are enhancement of the engineering properties of the conductor, electrical insulation, and refrigeration.

End User Applications

This constitutes the remaining 20-30% of Furukawa's SC-related business. The company's wire is used for the onboard superconducting magnets for levitation, guidance, and propulsion of the magnetically levitated trains being tested now at the Yamanashi Test Track. Furukawa also supplies aluminum for the track. Although Furukawa does not appear to be targeting the magnet market, the WTEC team's hosts commented that cryocooled high field magnets (>20 T) and HTS magnets are due to appear early in the next century.