LDX March, 2001
Helium Vessel, Cryostat and Charging Station
In preparation for final welding of the floating coil helium pressure vessel, Ability Engineering Technology has (1) found and repaired a leak on the heat exchanger tubing, (2) identified and replaced slightly magnetic stainless-steel coil supports with non-magnetic Inconel 625 springs, and (3) repaired a welding flaw that was discovered by radiographic examination. The pressure vessel code inspector is visiting Ability this week to give approval for final closure welding.
The cryostat vacuum vessel has been electropolished for improved vacuum performance. The space frame supports are now being fitted to the vacuum vessel. Ability is currently making final modification to the lead shield mold so that its manufacture can begin.
The bumper coins that make up the He vessel supports were modified according to results of tests and have been ordered from Connecticut Coining. The first samples of the bumper coins made of cold-worked 316L SS were received. These pieces have been rejected as out-of-spec and Connecticut Coining is now working to remedy the situation. The surface finish and most dimensions have been agreed upon with the vendor.
The first samples of the anti-rotation device for the Helium vessel within the cryostat have been made and tested to determine the room temperature loading ability of the proposed rod-sleeve joint. Inconel 625 has been selected for the anti-rotation rod. The results are promising in that they exceed the design requirements. Additional tests will be performed to obtain the necessary reliability and repeatability of rod-sleeve joints of the anti-rotation device.
Phil Michael visited the Efremov Institute from Feb. 28 through Mar. 2. The primary purpose of this trip was to participate in the test group meeting for the TF Insert coil which will be tested in the CS model coil facility in Naka Japan later this summer. However, since the LDX C-coil is under construction at the same facility, he extended his visit by a day to review recent progress on the C-coil construction.
While at the Efremov Institute, Phil met with Valery Belyakov, who is the Deputy Director of Sintez. Dr. Belyakov acknowledged the importance of the LDX C-coil program to the US fusion energy program and promised that Sintez would do everything possible to complete the C-coil construction by July. Dr. Belyakov mentioned that there were a few delays obtaining discretionary funds from the Ministry of Atomic Energy at the start of the present fiscal year, but that those had been resolved within the past few days. Also in attendance at the TF Insert coil meeting was Victor Sytnikov of the cable institute. During this meeting he and Dr. Belyakov came to agreement on the financing for the balance of the C-coil cable production, enabling cable construction to resume.
The rest of Phil's meetings were with Valery Korsunsky, the project manager for the C-coil, and his design staff. The practice winding for the C-coil had been completed the week before Phil's visit. However, the copper channels needed to complete the joint fabrication had not yet arrived until the day Phil departed from Russia. Due to manufacturing conflicts with the TF insert coil, the technicians needed for the practice winding joint fabrication were available only at the start of the week of March 19. The joint fabrication for the 5 joints of the practice coil and their insulation should be completed the week of March 19, with vacuum-pressure impregnation (VPI) to follow. After the VPI, the coil will be cold tested to determine its elastic moduli and integrated thermal contraction properties, values that are needed to determine the mechanical preload applied to the full scale winding. These measurements will be completed before the first set of coil clamps are made. The practice coil tests will be used to determine the necessary assembly pre-loading of the coil.
There has been considerable progress on the redesign of the cryostat from a bolted to a welded construction. Phil brought several hard copy drawings of the revised design back for review. Most drawings of the tools (about 3000 kg weight) for the real coil winding have been sent to vendors for quotations and should be ordered soon.
Alex Zhukovsky is spending the present week at the Efremov Institute reviewing the design and manufacturing plans for the completion of the program. Additionally, Alex Zhukovsky will review the necessary documentation before release of the final manufacturing drawings, and he has been promised a complete and official project schedule. Dr. Valdimir Ivkin has been recently hired to develop the quench detection circuitry for the C-coil. Dr. Ivkin proposes a microprocessor based system for this quench detection scheme because of the complex interaction between the C-coil and the F-coil, caused by the change from normal to superconducting state in the F-coil during charging. A design description for this system is in preparation.
MIT has completed a detailed conceptual design of the high-temperature-superconductor L-coil winding and cryostat in LDX-MIT-BASmith-031501-01. MIT has also completed a Specification and Statement of Work for the final design and fabrication of the winding and cryostat in LDX-MIT-BASmith-031601-01. These documents, together with a cover letter, were sent to 16 prospective vendors on March 16, requesting bids. Vendors were told they could bid on either the winding, or the cryostat, or both. Vendors are to respond with their intent to bid by March 23, and are to submit their quotations, including work schedules, for their proposed scope of work by April 4. A vendor or pair of vendors will be chosen from those submitting proposals by about mid-April.
The launcher bellows (which permit motion through vacuum) have arrived at MIT on March 23. Fabrication of the major mechanical components is underway at Hollis Line Machine Company. Design of the lifting structure for supported operation is underway.
The 6.4 GHz klystron system has been repaired and now works up to nominal power levels. The remote operation capability is also functional. We have begun to make the 10 GHz klystron functional and a search is underway for a source and high voltage power supply.