This book presents an overview of the thermo-hydraulics of the nuclear reactors designed to produce power using nuclear fission. The book began many years ago as a series of notes prepared for a graduate student course at the California Institute of Technology. When, following the Three Mile Island accident in 1979, nuclear power became politically unpopular, demand and desire for such a course waned, and I set the book aside in favor of other projects. However, as the various oil crises began to accentuate the need to explore alternative energy sources, the course and the preparation of this book were briefly revived. Then came the terrible Chernobyl accident in 1986, and the course and the book got shelved once more. However, the pendulum swung back again as the problems of carbon emissions and global warming rose in our consciousness and I began again to add to the manuscript. Even when the prospects for nuclear energy took another downturn in the aftermath of the Fukushima accident (in 2011), I decided that I should finish the book whatever the future might be for the nuclear power industry. I happen to believe, despite the accidents – or perhaps because of them – that nuclear power will be an essential component of electricity generation in the years ahead.

The book is an introduction to a graduate-level (or advanced undergraduate-level) course in the thermo-hydraulics of nuclear power generation. Because neutronics and thermo-hydraulics are closely linked, a complete understanding of thermo-hydraulics and the associated safety issues also requires knowledge of the neutronics of nuclear power generation and, in particular, of the interplay between the neutronics and the thermo-hydraulics that determine the design of the reactor core. This material necessarily leads into the critical issues associated with nuclear reactor safety, and this, in turn, would be incomplete without brief descriptions of the three major accidents (Three Mile Island, Chernobyl, and Fukushima) that have influenced the development of nuclear power.

Some sections in Chapter 6 of this book were adapted from two of my other books, Cavitation and Bubble Dynamics and Fundamentals of Multiphase Flow, and I am grateful to the publisher of those books, Cambridge University Press, for permission to reproduce those sections and their figures in the present text.