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ORNL isotopic power fuels quarterly report for period ending December 31, 1973

Description: Heat soak periods were completed on the remaining 49 couples of the compatibility matrix which was put on test in May 1973. Examination of the 18 couples which were taken off test in August 1973 was completed. The planned short-term ceramic compatibiliiy matrix exposures were completed, and optical microscope examinations were done. Experiments were started to develop fabrication techniques for preparation of an 11-couple compatibility matrix scheduled for FY 1974. The design of this matrix was finalized, and component procurement was started. Free energy calculations were made for the reactions of Cm/sub 2/O/sub 3/ fuel with Haynes 188, Ta-10% W, and TZM alloys and with beryllium. Measurements of the helium release characteristics of hot-pressed / sup 244 Cm/sub 2/O/sub 3/ were started at 500, 650, and 800 deg C. A vapor pressu re determination was run on curium metal in the temperature range from 900 to 1800 deg C. Vapor pressure measurements of/sup 244/Cm/sub 2/O/sub 3/ in the range from 1200 to 1600 deg C were begun these will continue next quarter. Examinations by x-ray diffraction were made on materials resulting from exposures of/sup 244/Cm/sub 2/O/sub 3/ to flowing seawater, boiling scawater, and dry air as well as on/sup 244/Cm/sub 2/O/sub 3/ sam ples taken at various stages in the fuel forming process. The equipment which will be used for emissivity measurements was improved and checked with nonradioactive samples. Observations of two 25-W//sup 244/Cm/sub 2/O/sub 3/ pellets stored in argon ond one 25-W/sup 244/Cm/sub 2/O/sub 3/ pellet stored in dry air continued. A /sup 244/Cm/sub 2/O/ sub 3/ pellet was leac hed with boiling distilled water and the rate of/sup 244/ Cm loss measured. Calculational studies of /sup 244/Cm yields and isotopic abundances from various types of reactor operations were continued. A study of the potentinl fur criticality problems in/sup ...
Date: February 1, 1974
Creator: Lamb, E.
Partner: UNT Libraries Government Documents Department

Savannah River Laboratory monthly report: {sup 238}Pu fuel form processes

Description: In direct-strike {sup 238}PuO{sub 2}, agglomeration occurs in the oxalate precipitate and is unaffected by washing agent or calcining temperature. The evaluation of an automatic pulverizer-classifier for the PuFF Facility was begun. Difference between the mini-hot press at SRL and the LASL full-scale hot press require higher pressures to be used at SRL to obtain the density specified for PPO. Hot-pressed density was found to vary with applied pressure and, to a lesser extent, with size of feed. The new contained metallograph has been installed. A wire saw has been placed in containment for precise cutting of PPO pellets. The scanning microscope was mounted within the glove boxes.
Date: April 1, 1974
Partner: UNT Libraries Government Documents Department

Savannah River Laboratory monthly report: {sup 238}Pu fuel form processes

Description: Progress during August 1975 in the development of {sup 238}PuO{sub 2} heat sources is reported. In studies to characterize {sup 238}PuO{sub 2}, the following were concluded: particle size was determined to be the most important characteristic affecting the variation in fabricability of {sup 238}PuO{sub 2}; problem feed consists of smaller particles (2 to 4 {mu}m) than older, acceptable feed (4 to 6 {mu}m). The particle size of new feed has varied from 3 to 10 {mu}m primarily as a result of varying precipitation temperature; equations have been developed from statistically designed precipitation experiments that relate precipitation temperature, nitric acid concentration, and plutonium concentration. to particle size; characteristics of acceptable feed have been defined: a particle size mode of 4.5 to 6.0 $mu$m, with an agglomeration index of 20 to 50 wt percent, and 0 to 15 wt percent of fines (less than 2 $mu$m particles); precipitation temperature is the most important variable affecting particle size; and desired particle characteristics can be achieved by precipitating at 35 +- 5$sup 0$C, 1.2 +- 0.1M nitric acid, and 4 to 7 g/l plutonium in the feed solution. No deleterious effects from ultrasonic decontamination were observed on either fuel form simulants or the iridium containment shells. Helium release studies show that shards can be stored for over a year without producing microstructural damage in hot-pressed products. Temperature gradients of only 50$sup 0$C during shard seasoning can affect product quality. Presintering of cold-pressed pellets before breakup produces shards for the Milliwatt Radioisotopic Thermoelectric Generator Program (Milliwatt) with a minimum of fines. Fines content of these shards compares favorably with the fines associated with the Mound Laboratory hydroxide shards. (auth)
Date: August 1, 1975
Partner: UNT Libraries Government Documents Department

Design, testing, and fabrication of heat sources for underwater application

Description: The sequence of events in the design, testing and fabrication of a radioisotopic heat source using available $sup 238$PuO$sub 2$ fuel that would be amenable to a Navy 0.5-W (electrical) Radioisotopic Thermoelectric Generator for undersea application is discussed. Various designs were considered as a function of heat leak in order to adopt the most desirable capsule for a volume- constrained application. Testing considerations are discussed for capsule compliance with IAEA/ENEA Safety Series 6 and 33 and 10 CFR 71. (auth)
Date: November 1, 1975
Creator: Luthy, D.F. & Anderson, C.G.
Partner: UNT Libraries Government Documents Department

Mound Laboratory isotopic power fuels programs: July--September 1973

Description: Progress in the isotopes fuel program during July to Oct 1973 is reported. Preparation and fuel characterization studies of /sup 238/Pu fuels continued. The effect of lower pressing temperatures on pressed plutonium oxide (PPO) spheres was evaluated. Plutonium-238 dioxide feed material that was sintered to a maximum of only 900 deg C was pressed under otherwise normal conditions into a Multihundred Watt (MHW) type fuel sphere. This pressing resulted in a sphere with near-perfect surface texture. The surface was bright and totally free of any visible cracks. However, upon subjection to the normal 1500 deg C vacuum heat treatment, the sphere cracked severely. Metallographic examination of selected areas of MHLV- PPO spheres showed that the spheres were not uniform in microstructure. They possessed nonuniform grain size and porosity distribution. Spheres exposed to high-temperature heat treatments also were nonuniform in microstructure. Calculations were performed to determine the stresses that appear in MRW PPO spheres due to temperature gradients. Thermal shock analyses were also performed. The data obtained as a result of these analyses were used in establishing a controlled heating and cooling cycle for the 1500 deg C, 1-h outgassirg process for development and production spheres. In order to evaluate the performance of a quadrupole mass spectrometer capable of evolved gas analysis of PuO/sub 2/ up to 1850 deg C, a residual gas analysis system utilizing a quadrupole mass spectrometer was installed in an alpha glovebox. The installation and cold check-out of the system are essentially completed. Several nonradioactive samples and standands were analyzed to establish the sensitivity and to calibrate the instrument. Samples of iridium hemishells were examined using the quadrupole mass spectrometer and both transmission and scanning electron microscopy. These examinations were performed in an attempt to better identify the nature of the iridium being used in the Multihundred ...
Date: November 21, 1973
Partner: UNT Libraries Government Documents Department

Pacific Northwest Laboratory quarterly report to USERDA Advanced Nuclear Energy Systems, Space and Special Purposes Division, for July--September 1975

Description: Progress during July to October 1975 in research on radioisotope heat sources is reported. The design of the long-term $sup 90$SrF$sub 2$ compatibility tests has been finalized. The effect of thermal aging on the impact strength of Hastelloy C-4 is being evaluated using Charpy test specimens. The solubility of SrF$sub 2$ in seawater and demineralized water was determined at 23$sup 0$C. The equilibrium concentration of Sr in demineralized water is greatly influenced by the presence of fluoride impurities in the SrF$sub 2$, whereas in seawater the presence of fluoride impurities has little effect on the Sr concentration. The effect of impurity fluorides and decay product (ZrF$sub 4$) on the melting point of SrF$sub 2$ was determined using differential thermal analysis. The lowest melting point observed in the system containing SrF$sub 2$, ZrF$sub 4$ and impurity fluorides found in WESF $sup 90$SrF$sub 2$ was 851 +- 5$sup 0$C. Two reports on potential applications of isotopes were prepared, and theoretical work continued on the effect of source geometry on the radiation efficiency of $sup 137$CsCl capsules. (LCL)
Date: October 1, 1975
Creator: Fullam, H.T. & Harmon, K.M.
Partner: UNT Libraries Government Documents Department

Data sheets for PPO radioisotopic fuel

Description: PPO is the acronym for Pure Plutoniunn Oxide. The thermal energy of this fuel results from the radioactive decay of /sup 238/ Pu this energy is converted into usable electric power for space probe or other applications. The basic fuel module associated with the current MHW heat source is a PPO sphere 1.465 plus or minus 0.015 in. in dia and containing 100 plus or minus 2 thermal watts. The spheres are individually encapsulated and then assembled into geometric arrays to form the working heat source. The following document lists certain properties of PuO/sub 2/ with emphasis on behavior at the proposed operational conditions being discussed. Since many of the desired properties are still being determined, the information is preliminary in nature and will be revised periodically. This report is the first revision of LA-5160-MS (issued 2/ 73) and incorporates additional and more specific data. (auth)
Date: December 1, 1973
Creator: Keenan, T.K.; Kent, R.A.; Mulford, R.N.R. & Shupe, M.W.
Partner: UNT Libraries Government Documents Department