11 Matching Results

Search Results

Advanced search parameters have been applied.

Inconel-600/T-111 alloy compatibility studies

Description: Oxidation resistant Hastelloy-C is the material presently used to clad a small radioisotopic heat source. Inconel-600 has properties and composition similar to Hastelloy-C and is under consideration as an alternate clad material. To serve this purpose, the material must be compatible with the underlying T-111 alloy strength member. Upon completion of compatibility studies, metallographic examination of the specimens revealed reaction zones that appeared to be influenced by time and temperature. The widths of the zones were determined by linear measurements from photomicrographs. These data were used to determine rate curves for the reaction at 1000, 1100, 1225/sup 0/C. The activation energy for the reaction was determined from these rate curves. The data for Inconel-600, when compared to previously accumulated data for Hastelloy-C, indicated that Inconel-600 can be substituted for Hastelloy-C and will pose no compatibility problem in the heat source.
Date: January 1, 1978
Creator: Teaney, P.E.
Partner: UNT Libraries Government Documents Department

/sup 238/PuO/sub 2/ fines generation in radioisotopic heat sources

Description: Fuel aging studies were performed on the fuel form (plutonium-238 dioxide and yttrium) used in the Milliwatt Generator Radioisotopic Heat Source to determine the possibility of fuel degradation and of the resultant generation of respirable fines. In addition to long-term thermal aging of the fuel, evaluations included the effects of thermal ramping of the aged fuel to 1000/sup 0/C and of impacting thermally hot (450/sup 0/C) heat sources at 150 m/sec after thermal aging.
Date: June 23, 1983
Creator: Teaney, P.E.
Partner: UNT Libraries Government Documents Department

/sup 238/PuO/sub 2//Mo-50 wt% Re compatibility at 800 and 1000/sup 0/C

Description: The compatibility of Mo-50 wt % Re with /sup 238/PuO/sub 2/ was investigated after heat treatments of up to 720 days at 800/sup 0/C and 180 days at 1000/sup 0/C. At 800/sup 0/C, a 1-..mu..m thick, continuous layer of molybdenum oxide resulted. At 1000/sup 0/C, the oxide reaction product contained some plutonium and did not appear continuous. At 1000/sup 0/C, a layer of intermetallic formed at the Mo-Re edge, beneath the oxide layer, creating a barrier between the Mo-50 wt % Re and the /sup 238/PuO/sub 2/. The intermetallic layer was promoted by the iron impurity in the /sup 238/PuO/sub 2/.
Date: July 18, 1980
Creator: Schaeffer, D.R. & Teaney, P.E.
Partner: UNT Libraries Government Documents Department

Studies of yttrium gettering efficiency in radioisotopic heat sources

Description: Compatibility specimens were fabricated using different fuel stoichiometries and yttrium shapes, sizes, and material lots to determine which would be the most efficient oxygen getter for use in heat sources. Evaluations were accomplished by comparison of metallography, microhardness, and oxygen and nitrogen analyses.
Date: January 1, 1976
Creator: Teaney, P. E. & Wise, R. L.
Partner: UNT Libraries Government Documents Department

Testing and evaluation of doubly impacted simulant-fueled Milliwatt Generator heat sources

Description: As part of the Milliwatt Generator (MWG) Program, 12 simulant-fueled heat sources were fabricated double impact tested, and evaluated at Mound. Ten assemblies were tested at approx. 80 m/sec, and two were tested at approx. 105 m/sec. None of the strength members were breached; therefore, no fuel would have been released as a result of double impacts at the velocities and orientations tested at 450/sup 0/C. There was little difference in results for duplicate tests conducted approx. 80 and approx. 105 m/sec. Ten units contained liners that were embrittled prior to testing. This resulted in cracks in some of the liner that would not have occurred in normally fueled heat sources.
Date: April 9, 1982
Creator: Teaney, P.E.; Cartmill, W.B. & Wise, R.L.
Partner: UNT Libraries Government Documents Department

An Evaluation of the Use of a Quantitative Image Analyzer to Determine Microhardness Values

Description: The use of quantitative image analyzer to determine microhardness values was investigated. Microhardness traverses were made across chemically polished, partially oxidized T-111 alloy specimens using both Vickers and Knoop indenters. Microhardness values were obtained from both area and diagonal readings using a Classimat image analyzer (Classimat is a registered trademark of E. Leitz, Inc., Rockliegh, N. J.). These values were then compared with those obtained by conventional optical measurements. The data obtained by the various methods are compared and the advantages and disadvantages such as accuracy, time requirements, versatility, and limitations of particular methods are discussed.
Date: October 1, 1971
Creator: Teaney, P. E. & Selle, J. E.
Partner: UNT Libraries Government Documents Department

Development testing of the two-watt RTG heat source and Hastelloy-S/T-111 alloy compatibility studies

Description: The two-watt radioisotope thermoelectric generator heat source capsules were tested to determine their survivability under extreme environmental conditions: high external pressure, high impact, and high internal pressure. Test results showed that the capsules could withstand external pressures of 1,000 bars and impacts at velocities near 150 meters per second. However, the results of the internal pressure tests (stress-rupture) were not so favorable, possibly because of copper contamination, leading to a recommendation for additional testing. A material compatibility study examined the use of Hastelloy-S as a material to clad the tantalum strength member of the two-watt radioisotopic heat source. Test capsules were subjected to high temperatures for various lengths of time, then cross sectioned and examined with a scanning electron microscope. Results of the study indicate that Hastelloy-S would be compatible with the underlying alloy, not only at the normal operating temperatures of the heat source, but also when exposed to the much higher temperatures of a credible accident scenario.
Date: September 29, 1993
Creator: Howell, E. I. & Teaney, P. E.
Partner: UNT Libraries Government Documents Department

Plutonium-238 dioxide/T-111 compatibility studies

Description: The tantalum-base alloy, T-111, is an ideal radioisotope encapsulant from the aspect of mechanical properties, but unfortunately undergoes severe oxygen embrittlement during long-term, high-temperature exposure to PuO$sub 2$. A study was undertaken in an effort to improve T-111/PuO$sub 2$ compatibility by testing the hypothesis that reduction of fuel stoichiometry to the range PuO$sub 1$.$sub 75$ to PuO$sub 1$.$sub 8$ would suspend the embrittlement process by producing a state of thermodynamic equilibrium within the capsule. Test temperatures ranged from 773 to 1373$sup 0$K, with aging times of 60 days, 240 days, and 2 y. The desired reaction did not proceed rapidly enough at the aging temperatures to stop T-111 embrittlement. Capsules heated above 1573$sup 0$K for 1 hr showed no signs of embrittlement during aging, even after 2 y at temperatures as high as 1173$sup 0$K. Results with test specimens employing pelletized fuel indicated the solid-state diffusion of oxygen from the fuel to the T-111 was the dominating transport process. In nonpretreated capsules oxygen diffusion in T-111 was the rate-controlling process. Pretreatment does result in the desired thermodynamic equilibrium at temperatures up to at least 1173$sup 0$K. (auth)
Date: September 19, 1975
Creator: Jones, G.J.; Selle, J.E. & Teaney, P.E.
Partner: UNT Libraries Government Documents Department