[en] In April, 1973, a decade-long study was begun on nuclear-powered pacemakers. The first 15 of these were designed by the Numec Corporation under a contract from the United States Atomic Energy Commission. Altogether 151 units powered by the isotope plutonium 238 were implanted in 131 patients; the pacemakers of 4 different manufacturers were used. The last nuclear pacemaker was implanted in January, 1983. The actuarial survival at 10 years was 92%, meeting the original performance goal of the Commission of 90%. Ninety pulse generators are still in service today; 25 patients have died and 36 pulse generators have been replaced with non-nuclear units. The most common indication for replacement was an inappropriate pacing mode. This high reliability and superior performance suggest that continued use of a radioisotopic power source is justified, particularly if combined with the electronic circuits of today's dual-chambered, multiprogrammable, and multifunctional pacemakers

[en] An experimental study of secondary flows from transverse Lorentz forces is described. The apparatus consisted of a laboratory-scale MHD channel in which a controlled net Hall current was applied. Plasma velocities were measured using laser Doppler anemometry. Results demonstrate that transverse Lorentz forces can produce intense secondary flows at a value of the magnetic interaction parameter based on the Hall current of approximately one. The peak measured transverse velocities were 15% of the bulk axial velocity. Qualitatively, the basic character of the large-scale secondary flow structure was in accord with a simple model based on a first-order distribution of the axial current density. Measurements were also made under a variety of conditions of the profiles of mean axial velocity and of the axial and transverse components of turbulence intensity, of electrode surface temperatures, and of plasma voltage distributions. These results all support the conclusion that convective transport by secondary flow causes significant asymmetries to develop in the cross-plane distribution of scalar quantities. The major conclusion of the work is that an accurate assessment of the secondary flow effect is essential to the design of high-interaction MHD devices

[en] The Component Development and Integration Facility (CDIF) is one of the Department of Energy's (DOE) Magnetohydrodynamics (MHD) experimental test facilities. The scope of this paper is limited to a brief description of the facility activation and results from the initial MHD testing using an oil fired ash injected combustor (AIC) and a supersonic channel. 1 ref

[en] The MHD generator performance of the High Performance Demonstration Experiment (HPDE) has been analyzed using the ANL quasi-three-dimensional computer model. Computations performed for the operating conditions of tests No. 10 and 14 indicate that, for both tests, the trends and magnitudes of the experimental data for various electrical and gasdynamic variables are in good agreement with the analytical predictions. The variation of the channel performance as a function of the channel wall temperature, surface roughness, load factor, and magnetic field strength is examined, and numerical examples are given. Performance maps, showing channel enthalpy extraction versus isentropic efficiency, are generated for range of magnetic field strengths, loading parameters, and electrode surface temperatures. A 'diagnostic data analysis' (DDA) procedure has been developed for further verification of the accuracy of the predictions of the quasi-three-dimensional model. In this procedure, the experimental data are used to compute the gasdynamic flow parameters and the boundary layer voltage drop characteristics in terms of average electrical conductivity and average electrical resistance. The results of this DDA procedure and those of the quasi-three-dimensional model are in good agreement

[en] Results are discussed of experimental studies extending previously published work on electrode gap breakdown in MHD channels in the U-02 power generator. The technique previously developed is extended further and amplified to permit determination of the parameters of fully developed breakdown. The experiments were carried out using different types of electrodes with widely varying surface temperatures and electrode gaps of varying widths. Conditions are determined for onset of two types of breakdown: plasma breakdown (or ''fast'' breakdown). A mechanism for development of ''slow'' breakdown is studied. The role of ''binding'' of current on the electrodes in the onset of both types of breakdown is established, and differences in the development of processes occurring on the anode and cathode walls are ascertained. Data are obtained over a rather wide range of gap widths on the effects of gap width on the onset and characteristics of breakdown. Data are also obtained on the current and power values for an interelectrode discharge after breakdown

[en] Monitoring temperature regimes is an important part of ensuring the operational safety of a nuclear power plant. Therefore, high standards are imposed upon the reliability of the primary information on the heat field of the object obtained from different sensors, and it is urgent to develop methods of evaluating the metrological reliability of these sensors. THe main sources of thermometric information at nuclear power plants are contact temperature sensors, the most widely used of these being thermoelectric converters (TEC) and thermal resistance converters (TRC)

[en] Short communication

[en] A combination gas seal and electrical insulator having a closed frame shape interconnects a fuel cell stack and a reactant gas plenum of a fuel cell generator. The frame can be of rectangular shape including at least one slidable spline connection in each side to permit expansion or contraction consistent with that of the walls of the gas plenum and fuel cell stack. The slidable spline connections in the frame sides minimizes lateral movement between the frame side members and sealing material interposed between the frame and the fuel cell stack or between the frame and the reactant gas plenum

[en] A fuel cell pack is disclosed comprising a plurality of fuel cells and means internal of said pack holding the cells together

No abstract available