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This study focuses on the mechanical properties of two kinds of solders for high temperature interconnections (melting temperature above 280 °C after reflow). They are both lead-rich solders in wire form: 93.5Pb/5Sn/1.5Ag and 92.5Pb/5Sn/2.5Ag. The mechanical constitutive tests conducted in this study include: (i) monotonic elastic-plastic stress-strain response at constant strain rates and constant temperatures; and (ii) isothermal, viscoplastic creep strain response at several constant stress levels and different temperatures. The sensitivities of the material viscoplastic constitutive response to temperature, loading rate and stress level were systematically studied, so that the mechanical performance of these two solders could be compared with those of other solders, at similar test conditions. Both the Pb-rich solders studied had statistically similar behavior at the tested stress levels and temperatures in creep tests. The Ramberg-Osgood model and the Garofalo model were used to represent the elastic-plastic and creep behavior, respectively, of each solder and the corresponding model constants are presented in the paper.Copyright © 2015 by ASME

A pressurized water reactor with a supercritical water primary loop is analyzed (PWR-SC) within this paper. It will be shown that the PWR-SC offers considerable advantages in the fields of safety, economy and efficiency compared with a conventional PWR design. A cycle analysis shows that the net plant efficiency increases by 2% compared to currently operated or built systems. In addition, the mass flow rate of the primary side is strongly decreased, which enables a reduction of the primary pump power by a factor of 4. In the secondary loop, the mass flow rate can be decreased by about 15%, which allows downscaling of all secondary side components such as turbines, condensers and feed-water preheat systems as a consequence of the high core exit temperature. A coupled core analysis and a hot channel factor analysis are performed to demonstrate the promising safety features of the PWR-SC and to show the technical feasibility of such a system.Copyright © 2006 by ASME