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Rugged High-Temperature Superconductor Wire Bundles for Shipboard Installation


OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Advanced Materials The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws. OBJECTIVE: The US Navy is seeking a rugged high-temperature superconducting (HTS) wire bundle for installation on a Navy vessel either during the shipbuilding process, or after the ship is delivered to the Navy, preventing the need for fixed length cables. DESCRIPTION: HTS technology has been developed over the past several decades for multiple applications. There have been several demonstrations of HTS in coils for ship propulsion motors and wind generators; as power cables in the grid between transfer stations; and most recently, nuclear fusion reactors. These applications use the HTS conductor in either a coil form factor (motors, generators, fusion reactors), or in the grid as a 3-phase, high-voltage cable. The Navy is looking at alternative uses of HTS technology that do not require 3-phases or high-voltage, which will change the cables topology, and in some cases make it simpler. However, the simple HTS cable will need to be rugged enough for shipboard installation and use, with immediate application in degaussing systems. US Navy ships must meet magnetic signature specifications to safely transit throughout the world’s oceans and waterways. To accomplish this, a degaussing system is installed on the ship so it can maintain a low-magnetic signature while underway. The principle of degaussing is to mitigate the magnetic signature of the ship by installing a series of coils in three different axis internal to the hull of the ship, which counteract the signature created by the ship within the earth’s magnetic field. When the cables are energized, a uniform magnetic field is produced throughout the ship. Traditionally, advanced degaussing systems use bundles of insulated copper cables to generate the magnetic fields necessary to maintain a ship’s magnetic signature. Recently, the Navy has adopted HTS cables and associated support hardware for use within the advanced degaussing system aboard the LPD 28 (USS Ft Lauderdale). When installing a copper degaussing loop, the cable is pulled through many spaces, which may include conduit through bulkheads and tanks, or the cables may be hung in open passageways and compartments. After the cable is pulled along its intended path, it is cut and terminated at the junctions near the power supply. HTS cable installation differs from copper cable installation. Current HTS cables are manufactured at the factory to a pre-determined length with pre-assembled connectors enabling fast installation into HTS-specific junction boxes. The cables cannot be cut to length at the time of installation and connection. If cable paths need to be re-routed, extra lengths of cable will be required. If the required length of cable is not readily available, they will have to be custom manufactured at the factory. Changing cable configurations will also affect management of magnetic signature. Remanufacture of cable lengths will also add significant cost and result in untenable lead times. The limited bend radius of HTS cables is a function of the cable’s fabrication as a bundle of HTS wires on the inside of a double-walled, corrugated, vacuum cryostat. The Navy is interested in concepts for a second generation (2G) HTS wire bundle that can be pulled throughout the ship inside a pre-installed cryostat and cut to length at the time of installation. The bundle will need to withstand tensions associated with pulling it through either rigid-pipe or flexible, corrugated cryostats with a small bend radius. The bundle should fit within a pipe or corrugated tube with an inner diameter of 0.80 inches. The bundle should withstand 1,000 lbf of tension. The bend radius may be as tight as 12 inches, with a straight run of cryostat 1 ft to 100 ft before making additional bends. The bundle may be 650 ft to 820 ft in length. The bundle must not only rely on the strength of the laminations since there are various lamination configurations that may be used with different tension ratings. A test length of cable should be a minimum of 150 ft with 40 conductors, each with a minimum Ic of 100 A. To demonstrate its flexibility, the bundle must fit in a pipe or tube with a diameter less than 1 inch, make at least six 90 degree turns with a minimum radius of 12 in, spaced 3 ft, and 50 ft apart; have the ability to solder the HTS conductors after installation of the bundle in the cryostat; demonstrate voltage isolation of 600 V both before and after pulling; and demonstrate retention of the Ic after being pulled through a cryostat. Finally, the test bundle must prove that it can withstand up to 1,000 lbf of tension. The installed HTS bundle must carry up to 4000 Amp Turns once terminated and connected. The power supplied to the bundle will be 100 A at 4 Volts. The bundle must be insulated from the cryostat to ensure there are no electrical shorts between the bundle and the cryostat. The bundle will be cooled to cryogenic temperatures using gaseous helium at a range of 50 to 80 K. PHASE I: Provide a concept for the HTS bundle that will meet the requirements within the Description. The concept must prove feasibility through modeling of the bundle for mechanical strength while under tension, flexibility of the bundle, and predicted electrical isolation characteristics. Preliminary testing of a short length of the concept is desirable to demonstrate the bundles capability to retain the HTS critical current (Ic) after being subjected to tension. The Phase I Option, if exercised, will include the initial design specifications and capabilities description to build a prototype solution in Phase II. PHASE II: Develop and deliver a full-scale prototype of the HTS bundle installed in a cryostat that demonstrates it can meet the requirements in the Description. The demonstration should be accomplished by fabricating the bundle and testing its maximum operating current (Ic) prior to installation in a cryostat; installing it in a cryostat containing minimum radius bends; and then retesting the bundle’s maximum operating current (Ic) while in the cryostat. PHASE III DUAL USE APPLICATIONS: Support the Navy in transitioning the technology as a component of the HTS degaussing system. The initial platform that the technology is expected to transition to is LPD 17 Class ships, or other future Navy ship designs. Additional industries that may benefit from the product developed from this SBIR topic may be in electric grid power distribution, wind generators, or in future superconducting areas of generators or fusion reactors. REFERENCES: 1. Kephart, J. T., Fitzpatrick, B. K., Ferrara, P. J., Pyryt, M., Pienkos, J., and Golda, E. M., “High temperature superconducting degaussing from feasibility study to fleet adoption.” IEEE Transactions on Applied Superconductivity, 21(3): 2229–2232, 2011. 2. Wikkerink, D. P., Hanse, I., Mor, A. R., Polinder, H., & Ross, R. “Demonstration of degaussing by copper and HTS windings.” 15th International Naval Engineering Conference and Exhibition, Delft, Netherlands, 2020. 3. Hanse. I., Wikkerink D. P., Vermeer C., Holland H. J., Dhall´e, M. M. J., & ter Brake, H. J. M. “Cryogenics for an HTS degaussing system demonstrator.” 15th International Naval Engineering Conference and Exhibition, Delft, Netherlands, 2020. 4. “AMSC to deliver degaussing system for Fort Lauderdale (LPD 28)”., January 31, 2019. KEYWORDS: High-Temperature Superconductors; HTS; cryostat; rugged HTS bundles; advanced degaussing; HTS degaussing; shipboard HTS systems
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