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Austenitic stainless steels for cryogenic service

Description: Presently available information on austenitic Fe-Cr-Ni stainless steel plate, welds, and castings for service below 77 K are reviewed with the intent (1) of developing systematic relationships between mechanical properties, composition, microstructure, and processing, and (2) of assessing the adequacy of these data bases in the design, fabrication, and operation of engineering systems at 4 K.
Date: September 19, 1985
Creator: Dalder, E.N.C. & Juhas, M.C.
Partner: UNT Libraries Government Documents Department

Investigation of the cryogenic mechanical properties of low thermal-expansion superalloys

Description: Four Fe-based superalloys, JBK-75, Incoloy 903, Incoloy 905, and Incoloy 909 were evaluated as tube materials for ICCS Nb/sub 3/Sn superconductors. Evaluation consisted of 4-K tensile and elastic-plastic fracture-toughness testing, and a microstructural characterization of unwelded and autogenously gas-tungsten-arc welded sheet given a simulated postweld processing treatment of 15% cold reduction by rolling followed by a Nb/sub 3/Sn-reaction heat treatment of 96 hours at 700/sup 0/C plus 48 hours at 730/sup 0/C. Results indicate that JBK-75 and Incoloy 903 showed satisfactory combinations of strength and toughness for ICCS tube use requiring long Nb/sub 3/Sn-reaction heat treatments. Incoloy 905 welds and 909 showed unacceptable fracture toughness. Results are discussed in terms of microstructural changes caused by the extended Nb/sub 3/Sn-reaction heat treatment.
Date: July 30, 1985
Creator: Summers, L.T. & Dalder, E.N.C.
Partner: UNT Libraries Government Documents Department

Development of nitronic 50 fusion welding techniques for 4 K service

Description: The Mirror Fusion Test Facility (MFTF-B) is a large magnetic fusion energy experiment in the tandem mirror configuration. The requirement that each pair of Yin-Yang magnets, one pair at each end of the experiment, not undergo excessive lateral motion during seismic events was found to require excessively thick (> 12.7 mm) walled tubing in the support-struts, which accelerated the flow of heat inward to the 4 K magnet case from the nearby 300 K wall of the rector vessel, when any of the Cr-Ni austenite stainless steels, such as Type 304 with a 300 K yield-strength (sigma y) of 307 mpa (min.) was considered. Since the cold end of the lateral restraining strut was to be at or near 4 K, the additional constraints of good austenite stability and resistance to brittle fracture at 4 K existed. After consideration of these constraints against available information on Cr-Ni and Cr-Mn-Ni-N/sub 2/ austenitic stainless steels, grade XM-19 (Fe-22 Cr-12 Ni-5 Mn-.04 C-.02 N/sub 2/ was chosen. The mechanical properties of these welds were studied. (MOW)
Date: September 23, 1981
Creator: Dalder, E.N.C. & Juhas, M.C.
Partner: UNT Libraries Government Documents Department

Structural materials for fusion magnets

Description: Of major technical and cost impact to Magnetic Fusion Energy development are the materials for the magnet structure. Those materials and fabrication techniques that are attractive to fusion magnets are discussed and relative comparisons made. Considerations such as strength, toughness, and joining techniques are balanced against recommended design criteria to reach an optimum design. Several examples of material selection are cited for large fusion magnets such as Base II, the Mirror Fusion Test Facility, the Toroidal Fusion Test Facility, and the Large Coil Project.
Date: March 20, 1979
Creator: Henning, C.D. & Dalder, E.N.C.
Partner: UNT Libraries Government Documents Department

Results of fracture mechanics analyses of the Adorer cranes in the device assembly facility using actual, rather than conservative, stress-components

Description: Fracture mechanics analyses were done on 3 critical locations on the lower flange of the load beam of the Ederer 5 ton and 4 ton cranes in the D.A.F. Facility. This was done to determine appropriate flaw sizes for NDE detection during periodic inspection, and appropriate inspection intervals.
Date: December 26, 1996
Creator: Dalder, E. N. C.
Partner: UNT Libraries Government Documents Department

Results of fracture mechanics analyses of the Ederer cranes in the Device Assembly Facility: The effect of using a general expression for fatigue crack growth of the crane material

Description: The subject analyses were conducted on 3 critical locations on the lower flange of the load-beam of the Ederer 5 ton and 4 ton cranes in the D.A.F. facility. An expression for the fatigue-crack growth behavior of ferritic-pearlitic constructional steels (``Barsom Equation``) was used in place of the previously used equation to describe fatigue-crack growth behavior in this steel (base-line equation) to evaluate the effects of varying the fatigue-crack growth rate. Results appear that: (1) Propagation of a 1/4-in. long flaw, previously undetected by NDE, to a length sufficient to cause failure of either flange, should not occur in at least 70.8 times the postulated operating scenario, down from 104 times as calculated using the base line equation. (2) Should each crane undergo annual inspection, any surface flaw with a length greater than 1.10 in. should be removed and repaired by qualified and approved repair procedures. This flaw length has increased from a surface flaw length of 0.9 in. (base line equation). (3) The indicated change in empirically measured fatigue-crack growth equation did not adversely affect the previous work on modeling fatigue performance of these cranes.
Date: February 3, 1997
Creator: Dalder, E. N. C.
Partner: UNT Libraries Government Documents Department

Testing of the MFTF magnets

Description: This paper describes the cooldown and testing of the first yin-yang magnet for the Mirror Fusion Test Facility. The introduction describes the superconducting magnet; the rest of the paper explains the tests prior to and including magnet cooldown and final acceptance testing. The MFTF (originally MX) was proposed in 1976 and the project was funded for construction start in October 1977. Construction of the first large superconducting magnet set was completed in May 1981 and testing started shortly thereafter. The acceptance test procedures were reviewed in May 1981 and the cooldown and final acceptance test were done by the end of February 1982. During this acceptance testing the magnet achieved its full design current and field.
Date: May 5, 1982
Creator: Kozman, T.A.; Chang, Y. & Dalder, E.N.C.
Partner: UNT Libraries Government Documents Department

Results of fracture mechanics analyses of the ederer cranes in the device assembly facility using reduced static fracture-toughness values

Description: The effects of a decreased static fracture-toughness value from that used in the previous fracture-mechanics analyses of the Ederer cranes in the Device Assembly Facility were examined to see what effects, if any, would be exerted on the fatigue crack growth and fracture behavior of the cranes. In particular, the behavior of the same 3 critical locations on the lower flanges of the load beams of the Ederer 5 ton and 4 ton cranes, were examined, with the reduced static fracture-toughness value.
Date: November 1, 1996
Creator: Dalder, E. N. C.
Partner: UNT Libraries Government Documents Department

Failure analysis of Ti - 15% Ta getter wire used for sublimation in the vacuum chambers of the Tandem Mirror Experiment

Description: The Tandem Mirror Experiment uses Ti-15% Ta getter wire for sublimation in the vacuum chambers in which the magnets are located. These wires have failed prematurely in service, resulting in increased costs and downtime. We have used optical metallography to show that the reason for these failures was the cycling of the material through the alpha-beta transition temperature, causing alpha-titanium precipitation at the grain boundaries, depression of the melting temperatures of those boundaries, and the subsequent melting of those boundaries in areas where the wires had achieved localized higher temperatures.
Date: August 19, 1983
Creator: Kershaw, R.P.; Gross, R.J. & Dalder, E.N.C.
Partner: UNT Libraries Government Documents Department

Cryogenic structural materials for superconducting magnets

Description: This paper reviews research in the United States and Japan on structural materials for high-field superconducting magnets. Superconducting magnets are used for magnetic fusion energy devices and for accelerators that are used in particle-physics research. The cryogenic structural materials that we review are used for magnet cases and support structures. We expect increased materials requirements in the future.
Date: February 22, 1985
Creator: Dalder, E.N.C. & Morris, J.W. Jr.
Partner: UNT Libraries Government Documents Department

Manufacturing the MFTF magnet

Description: The Mirror Fusion Test Facility (MFTF) is a large mirror program experiment for magnetic fusion energy. It will combine and extend the near-classical plasma confinement achieved in 2XIIB with advanced neutral-beam and magnet technologies. The product of ion density and confinement time will be improved more than an order of magnitude, while the superconducting magnet weight will be extrapolated from 15 tons in Baseball II to 375 tons in MFTF. Recent reactor studies show that the MFTF will traverse much of the distance in magnet technology towards the reactor regime.
Date: October 13, 1980
Creator: Dalder, E. N. C.; Hinkle, R. E. & Hodges, A. J.
Partner: UNT Libraries Government Documents Department

Creep of 304 LN and 316 L stainless steels at cryogenic temperatures

Description: Creep behavior of Type 304 LN plate and 316 L shielded-metal-arc (SMA)-deposited stainless weld metal was investigated at 4/sup 0/K. Testing was performed at constant load in a creep machine with a cryostat designed for long-term stability. Both transient and steady-state creep were observed during tests lasting over 2000 hours. Steady-state creep rates were much greater than expected from extrapolations of 300-K creep data. Creep rates on the order of 10/sup -10/ s/sup -1/ were observed at stresses around the yield stress for both materials. The stress exponent under these conditions if approx.2.3. Possible creep mechanisms at this temperature and the impact of these results on the design of engineering structures for long-term structural stability at cryogenic temperatures are discussed.
Date: August 7, 1985
Creator: Roth, L.D.; Manhardt, A.E.; Dalder, E.N.C. & Kershaw, R.P. Jr.
Partner: UNT Libraries Government Documents Department

Development of forging and heat treating practices for AMS 5737 for use at liquid helium temperatures

Description: To achieve a combination of high yield-strength (sigma y), plane-strain fracture-toughness (K/sub IC/) and resistance to galling when turned against austenitic stainless steels in highly-loaded threaded turnbuckles in the M.F.T.F.-B (Mirror Fusion Test Facility), AMS 5737 (Fe-15Cr-25Ni-1Mo-V-Ti-Al-B), a heat-treatable Fe-base superalloy that is slightly-ferromagnetic under high magnetic fields at 4K, was chosen for large (approx. 340 kg) forged turn buckles. This report describes the forging and heat-treatment optimization program that resulted in good sigma y and K/sub IC/ over the 4 to 300K range of service-temperatures and the verification tests run on a pre-production forging and actual production parts.
Date: August 10, 1981
Creator: Dalder, E.N.C. (Lawrence Livermore National Lab., CA) & Greenlee, M.
Partner: UNT Libraries Government Documents Department

Superconducting (radiation hardened) magnets for mirror fusion devices

Description: Superconducting magnets for mirror fusion have evolved considerably since the Baseball II magnet in 1970. Recently, the Mirror Fusion Test Facility (MFTF-B) yin-yang has been tested to a full field of 7.7 T with radial dimensions representative of a full scale reactor. Now the emphasis has turned to the manufacture of very high field solenoids (choke coils) that are placed between the tandem mirror central cell and the yin-yang anchor-plug set. For MFTF-B the choke coil field reaches 12 T, while in future devices like the MFTF-Upgrade, Fusion Power Demonstration and Mirror Advanced Reactor Study (MARS) reactor the fields are doubled. Besides developing high fields, the magnets must be radiation hardened. Otherwise, thick neutron shields increase the magnet size to an unacceptable weight and cost. Neutron fluences in superconducting magnets must be increased by an order of magnitude or more. Insulators must withstand 10/sup 10/ to 10/sup 11/ rads, while magnet stability must be retained after the copper has been exposed to fluence above 10/sup 19/ neutrons/cm/sup 2/.
Date: December 7, 1983
Creator: Henning, C.D.; Dalder, E.N.C.; Miller, J.R. & Perkins, J.R.
Partner: UNT Libraries Government Documents Department

Integrated Corrosion Facility for long-term testing of candidate materials for high-level radioactive waste containment

Description: A long-term-testing facility, the Integrated Corrosion Facility (I.C.F.), is being developed to investigate the corrosion behavior of candidate construction materials for high-level-radioactive waste packages for the potential repository at Yucca Mountain, Nevada. Corrosion phenomena will be characterized in environments considered possible under various scenarios of water contact with the waste packages. The testing of the materials will be conducted both in the liquid and high humidity vapor phases at 60 and 90{degrees}C. Three classes of materials with different degrees of corrosion resistance will be investigated in order to encompass the various design configurations of waste packages. The facility is expected to be in operation for a minimum of five years, and operation could be extended to longer times if warranted. A sufficient number of specimens will be emplaced in the test environments so that some can be removed and characterized periodically. The corrosion phenomena to be characterized are general, localized, galvanic, and stress corrosion cracking. The long-term data obtained from this study will be used in corrosion mechanism modeling, performance assessment, and waste package design. Three classes of materials are under consideration. The corrosion resistant materials are high-nickel alloys and titanium alloys; the corrosion allowance materials are low-alloy and carbon steels; and the intermediate corrosion resistant materials are copper-nickel alloys.
Date: October 1, 1994
Creator: Estill, J.C.; Dalder, E.N.C.; Gdowski, G.E. & McCright, R.D.
Partner: UNT Libraries Government Documents Department

Use of fusion-welding techniques in fabrication of a superconducting-magnet thermal-shield system

Description: Success of the thermal shield system was demonstrated by the results of acceptance tests performed with the magnet and all its ancillary equipment. During these tests the thermal shield system was: (1) thermally cycled several times from 300/sup 0/K to 77/sup 0/K; (2) pressure cycled several times from 0 to 5 atmospheres; (3) operated for more than 500 hours at 77/sup 0/K and in a vacuum environment of less than 10/sup -5/ torr; (4) operated in a magnetic field up to 6.0 Telsa; (5) exposed to a rapidly collapsing magnetic field of more than 250 gauss per second; (6) drained of all LN/sub 2/ in a few minutes, without any weld failures. The successful (and relatively problem free) operation of the magnet system validates the choice of the welding processes used, as well as their execution in both shop and field environments.
Date: June 10, 1983
Creator: Dalder, E.N.C.; Berkey, J.H.; Chang, Y.; Johnson, G.L.; Lathrop, G.H.; Podesta, D.L. et al.
Partner: UNT Libraries Government Documents Department

Development of manufacturing methods for 50-cm diameter neutron source targets for RTNS-II

Description: RTNS-II is an accelerator driven neutron source. It was attempted to produce a larger version of the current accelerator target but experienced problems in diffusion bonding and thermal stability of the copper alloy used for target fabrication. The causes of these problems were identified, and a new technique (electroforming) was demonstrated for fabricating targets.
Date: June 1, 1981
Creator: Logan, C.M.; Dini, J.W.; Ludemann, W.D.; Schumacher, B.J.; Dalder, E.N.C.; Kelley, W.K. et al.
Partner: UNT Libraries Government Documents Department

Alloy development for irradiation performance: program strategy

Description: The objective of the Alloy Development for Irradiation Performance Program is the development of structural materials for use in the first wall and blanket region of fusion reactors. The goal of the program is a material that will survive an exposure of 40 MWyr/m/sup 2/ at a temperature which will allow use of a liquid-H/sub 2/O heat transport system. Although the ultimate aim of the program is development of materials for commercial reactors by the end of this century, activities are organized to provide materials data for the relatively low performance interim machines that will precede commercial reactors.
Date: January 1, 1978
Creator: Bloom, E. E.; Stiegler, J. O.; Wiffen, F. W.; Dalder, E. N.C.; Reuther, T. C.; Gold, R. E. et al.
Partner: UNT Libraries Government Documents Department