Robert W. Lyczkowski

Characteristics and Stability Analyses of Transient One-Dimensional Two-Phase Flow Equations and Their Finite Difference Approximations

AbstractEquation systems describing one-dimensional, transient, two-phase flow with separate continuity, momentum, and energy equations for each phase are classified by use of the method of characteristics. The main purpose of this paper is to study the mathematical nature of these equations, not their physics, although it is realized that these two problems are not entirely independent. Many of the equation systems possess complex-valued characteristics and hence, according to well-known mathematical theorems, are not well-posed as initial-value problems (IVPs). Real-valued characteristics are necessary but not sufficient to ensure well-posedness. In the absence of lower order source or sink terms, that can affect the well-posedness of IVPs, the complex characteristics associated with these two-phase flow equations imply unbounded exponential growth for disturbances of all wavelengths.Analytical and numerical examples show that the ill posedness of IVPs for the two-phase flow partial differential equatio...

Safety consideration and economic advantage of a new underground nuclear power plant design

A conceptual design of an underground nuclear power plant is proposed to make undergrounding of nuclear reactors not only environmentally desirable but also economically feasible. Expedient to the underground environment, this design capitalizes on the pressure-containing and radiation filtering characteristics of the new underground boundary conditions. Design emphasis is on the containment of a catastrophic accident — that of a reactor vessel rupture caused by external means. The High Capacity Rapid Energy Dissipation Underground Containment (HiC—REDUCE) system which efficiently contains loss-of-coolant accidents (LOCAs) and small break conditions is described. The end product is a radiation-release-proof plant which, in effect, divorces the safety of the public from the safety of the reactor.