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Qualification of primary loop manifold of a liquid metal thermoelectric converter

Description: The mechanical cycling test was required to verify the integrity of the welded joints and the thin wall tube bends in the primary loop manifold assembly of a four pack thermo electric module and to help establish structural and mechanical requirements of any possible redesign. The test section was subjected to more severe loading conditions than will be experienced during actual operating conditions. The test was a mechanical simulation of the differential thermal expansion which occurs due to the approximately 600{degrees} F temperature differential in the subassembly. The actual load exerted on the test section represented this deflection. The effects on the joints and tube material were observed. The test was conducted on a test segment of manifold designed to duplicate two of the flexible elbows; the transition joints between the elbows and the tubular module inner clad; and the welded joints of the elbows to the primary loop header. The assembled test segment and hold-down bracket are shown. The bracket was mounted to the base of the Universal Test Machine. Dial indicators measured the relative displacement between the line of applied load (through the vertical axis of the primary loop header) and the attachment point at the holddown bracket. In the first test, the load was applied in fifty pound increments until the relative displacement of nine mils was measured between the loop header and the welded joint on the feedline elbow. The remaining tests were cycling the header assembly at increasing relative displace ment. The summary of these tests are tabulated. The testing had no noticeable affect on the structural integrity of the weldment.
Date: June 10, 1969
Creator: Bryant, E P; Cottam, A E; Ettenson, N J; Harves, T O; Kenney, J; Letchford, T A et al.
Partner: UNT Libraries Government Documents Department

Effects of low Z impurities during the startup phase of a large tokamak

Description: The requirements placed on a tokamak ohmic heating system (i.e. loop voltage) to initiate the plasma become more severe as the size increases because of the current density decrease. During the startup phase even small concentrations of low Z impurities can affect the plasma energy balance very substantially and have very important effects on the evolution of the discharge. The startup phase has been studied using a simple zero dimensional computer code. Because the dominant energy loss mechanisms during startup, radiation, and ionization are a volume effect, the zero dimensional code was adequate to treat this phase. The results of this study which have been applied to TFTR indicate that the plasma evolution is a sensitive function of the applied loop voltage, impurity concentration, initial filling pressure and the manner in which gas is fed into the discharge. (auth)
Date: January 1, 1976
Creator: Hawryluk, R. J. & Schmidt, J. A.
Partner: UNT Libraries Government Documents Department

Self-diffusion of Co$sup 60$ in crystals of Co$nu$sub 1-x/O

Description: Tracer self-diffusion coefficients were measured as functions of temperature and deviations from stoichiometry. The arc-transfer technique of crystal growth was found to produce crystal of Co/sub 1-x/O of essentially the same purity as the starting Co rod, and the quality was comparable to commercially available crystals grown by Verneuil process. Measurements at x = 0.005 in Co/sub 1-x/O showed the Co tracer self-diffusion coefficient to be D = 3.88 x 10$sup -4$ exp (--31600 +- 2400/RT) cm$sup 2$/s between 1037 and 1350$sup 0$C. This activation energy is in agreement with measurements made in air, if proper compensation is made for the effect of variation in stoichiometry. Measurements on crystals having deviations between 0.002 and 0.008 at 1150$sup 0$C showed the diffusion coefficient to depend on p/sub O$sub 2$/ as D = 9.74 x 10$sup -9$ p/sub O$sub 2$//sup 1/(3.59)/ cm$sup 2$/s, where p/sub O$sub 2$/ varied between 10$sup -2$.$sup 5$ and 10$sup -0$.$sup 25$ atm. Comparison with thermogravimetric and electrical conductivity measurements confirms that the defects responsible for Co diffusion in the range of temperature and p/sub O$sub 2$/ of this investigation are singly ionized cobalt vacancies. The Co tracer self-diffusion coefficients in single crystals are nearly identical to those in polycrystalline Co/sub 1-x/O. 53 references, 29 fig, 6 tables (DLC)
Date: January 1, 1976
Creator: Rahman, S. F.
Partner: UNT Libraries Government Documents Department

Solid state physics program. Final report

Description: During the 17 year period of this research, experimental and theoretical investigations were completed in many aspects of cohesive properties of metals and alloys and dielectric properties of various crystals and glasses together with the temperature and pressure derivatives of both properties. Studies of the magnetization and magnetic anisotropy indicate superparamagnetism is common in oligatomic condensed films and any decreased magnetic moment must be associated with surface atoms. Large intrinsic stresses are associated with growth morphology and impurities at grain boundaries. Transport properties in normal metals have been investigated theoretically. A number of basic theorems for disordered systems were derived. (204 references) (auth)
Date: June 1, 1975
Partner: UNT Libraries Government Documents Department

Some effects of parallel energy propagation on the structure of dissipative trapped electron modes

Description: The limitation of ballooning by parallel energy propagation is investigated for the dissipative trapped electron mode, wherein the local energy influx is proportional to the poloidally dependent trapped particle fraction. For small energetic asymmetries [mg less than 2.5 ($Omega$/sub i/a/c/sub s/) (a/R/ sup $sup 3$/$sub 4$/] the structure along the field line is predominantly a phase shift, dictated by the condition that the asymmetric energy input be compensated by parallel energy flow. For large asymmetry, mode number, and parallel arc length, the phase and amplitude variations necessitate an integral equation treatment. (auth)
Date: January 1, 1976
Creator: Sauthoff, N. R.
Partner: UNT Libraries Government Documents Department

Status of 2XIIB plasma confinement experiments

Description: This report describes the status of 2XIIB neutral beam injection experiments with stabilizing plasma. The stream suppresses ion-cyclotron fluctuations and permits density to 5 x 10$sup 13$ cm$sup -3$. The ion energy is 13 keV, and electron temperature reaches 140 eV. Plasma confinement increases with ion energy and n tau reaches 7 x 10$sup 10$ cm$sup -3$.s at 13 keV. The n tau energy scaling is consistent with electron drag and ion-ion scattering losses. Buildup on a streaming plasma in a steady-state magnetic field is described. (auth)
Date: February 11, 1976
Creator: Coensgen, F. J.; Clauser, J. F. & Correll, D. L.
Partner: UNT Libraries Government Documents Department

Optical properties of Nb--Mo and other alloys of Nb with its nearest neighbors in the periodic table

Description: Optical properties of Nb alloys were investigated. Calorimetric measurements of absorptivity between 0.2 and 5.5 eV were taken for Nb samples with 20, 50, and 80 percent Mo and for Nb samples containing 10 percent Zr, 20 percent V, and 20 percent Ta. Reflectivity data for two of these samples in the ultraviolet region and known reflectivities for the pure metals to 35 eV provided the basis for extrapolation to high energies. The data were Kramers--Kronig analyzed to determine the dielectric function. The structure is discussed in terms of interband transitions as predicted by a rigid band model for the NbMo alloys. (auth)
Date: October 1, 1975
Creator: Black, E. S.
Partner: UNT Libraries Government Documents Department

Present status of mirror stability theory

Description: A status report of microinstability as it applies to 2XIIB and MX theory for mirror machines is presented. It is shown that quasilinear computations reproduce many of the parameters observed in the 2XIIB experiment. In regard to large mirror machines, there are presented detailed calculations of the linear theory of the drift cyclotron loss-cone mode, with inhomogeneous geometry and nonlinear diffusive effects. Further, the stability of a mirror machine to the Alfven ion-cyclotron instability is assessed, and the Baldwin- Callen diffusion is estimated for a spatially varying plasma. (auth)
Date: February 11, 1976
Creator: Baldwin, D. E.; Berk, H. L. & Byers, J. A.
Partner: UNT Libraries Government Documents Department

Progress report No. 51, July 1, 1974--June 30, 1975. Technical summary

Description: Research work in the following areas is briefly reviewed: applied mathematics and mechanics (computational fluid dynamics, controlled thermonuclear research, numerical analysis); computational physics, chemistry, and biology; computer science research (computer netting; programing languages and compilers; operating systems, micro-processor networks, and modular systems); and systems programing, user services, and hardware support. A list of publications is also given. (RWR)
Date: November 1, 1975
Partner: UNT Libraries Government Documents Department

Application of soft x-ray appearance potential spectroscopy to light lanthanides, 4d transition metals, and insulators

Description: Evaporated films of La, Ce, Yb, Y, Ag--Mn(5 percent), KCl, MnF$sub 2$, CsCl and LaF$sub 3$ were studied using the soft x-ray appearance potential spectroscopy (SXAPS) technique. Studies were also made of bulk polycrystalline samples of Y, Zr, Nb, and Mo. The results are discussed in terms of existing SXAPS theories. Several similarities between soft x-ray absorption (SXA) data and the SXAPS results are discussed, and it is shown that the SXA data can aid in the interpretation of SXAPS spectra when using the well-known self-convolution model. In this approximation the absorption coefficient, $alpha$(E), is substituted for the density of states, N(E-E/sub c/) $Yields$ $alpha$(E). For more localized excitations, a convolution of $alpha$(E) with bremsstrahlung isochromat data, based on Wendin's two density of states formalism is used to predict SNAPS results. (auth)
Date: October 1, 1975
Creator: Smith, R. J.
Partner: UNT Libraries Government Documents Department

Corrosion-induced acoustic emissions from uranium 4.5--weight percent niobium binary alloy

Description: The ability to monitor corrosion and stress-corrosion cracking of uranium 4.5-weight percent niobium was investigated. The acoustic emissions from stress-corrosion cracking were monitored using smooth four-point bend specimens, which were immersed in oxygen-saturated water containing chloride ions. The acoustic emissions from corrosion were monitored from rectangular corrosion coupons. These latter specimens were exposed to nitrogen-saturated and oxygen- saturated solutions of distilled water and distilled water with chloride ions. Dilute solutions of hydrochloric acid were also used. Findings show that stress- corrosion crack monitoring of the alloy was successful. Corrosion monitoring of the alloy showed a direct correlation between corrosion rate (based on weight loss) and total acoustic emissions. For a specific range, one can calculate the corrosion rate of uranium alloys in a corrosive solution from the total acoustic emissions generated. Studies to determine the source of corrosion-induced acoustic emissions were inconclusive.
Date: December 15, 1975
Creator: Mah, R.; Kochen, R. L. & Macki, J. M.
Partner: UNT Libraries Government Documents Department

Quasilinear theory of ion-cyclotron resonance heating of plasmas and associated longitudinal cooling

Description: It is shown from quasilinear theory that an initially isotropic magnetized plasma will be forced into an anisotropic state in ion-cyclotron resonance heating. Strong heating of perpendicular ion temperature and strong cooling of longitudinal temperature should occur simultaneously. The maximum temperature ratio predicted by quasilinear theory is in exact agreement with that predicted from basic thermodynamic arguments by Busnardo--Neto, Dawson, Kamimura and Lin. Heating by fast hydromagnetic wave is also examined. (auth)
Date: February 1, 1976
Creator: Arunasalam, V.
Partner: UNT Libraries Government Documents Department

Radiation effects in solidified high-level waste. Part I. Stored energy

Description: Buildup and release behavior of radiation-induced stored energy was investigated for several synthetic solidified high-level waste forms: two borosilicate glass formulations, calcine, calcine on Al$sub 2$O$sub 3$, and a hot press compact of 50 percent waste oxide--50 percent quartz. Fused silica and Al$sub 2$O$sub 3$, without waste oxides, were also investigated. Average heat capacities of some of the materials were also measured. The materials were irradiated either by internal alpha radiation $sup 244$Cm or by neutron irradiation in ORR. The irradiations simulated the effects resulting from self- irradiation of the waste for storage periods up to nearly 1000 years for wastes from PWR-UO$sub 2$ fuel [equivalent to periods of approximately 10 years for mixed wastes from UO$sub 2$ fuel ($sup 2$/$sub 3$) and plutonium recycle fuel ($sup 1$/$sub 3$)]. Results showed that the amounts of stored energy over a period of about 10 years at relatively low storage temperatures following reprocessing are such that only moderate temperature increases (less than 200$sup 0$C) in the wastes would occur in the event of sudden release of the stored energy. Extrapolation to longer storage times in a geologic repository indicated that saturation of energy storage would occur at 50 cal/g or less for each of the waste types; the $delta$T corresponding to release of 50 cal/g would be about 250$sup 0$ for most of the waste types. The experimental results also showed no apparent way in which a sudden release could occur except as a result of sudden large increases in waste temperature caused by a heat source other than the stored energy.
Date: January 1, 1976
Creator: Roberts, F P; Jenks, G H & Bopp, C D
Partner: UNT Libraries Government Documents Department