Nuclear Reactor Physics , Weston M. Stacey Wiley, New York, 2001. $125.00 (707 pp.). ISBN 0-471-39127-1
Being a nuclear reactor physicist is very difficult. It is not merely the social opprobrium connected with the practice of the craft. (I write in California, where mere rumor that a microcurie of reactor-produced technetium is passing through town, a wisp remaining from the diagnosis of some poor soul’s ailing heart, is sufficient to bring the environment mujahedeen into the streets for antinuclear jihad.) It is the essence of the subject, as well; a self-respecting reactor physicist should understand everything going on in the reactor core—and be aware of what is happening in its environs, too.
The discipline demands competence in nuclear physics, with emphasis on fission physics and neutron-induced reactions, and an understanding of the interaction of every variety of radiation with matter, from radiation damage to core material to “Is it safe to eat an irradiated strawberry?” Also required is an appreciation of the interaction of thermal neutrons with liquid and solid moderating materials—on so small a scale that the neutron “field” or distribution is described by the mathematics of neutron (and photon) transport theory, a branch of nonequilibrium statistical mechanics. At another level, the reactor is a macroscopic object and its macroscopic behavior is described— overall—by challenging nonlinear equations that describe subtle feedback mechanisms—often complicated by stochastic sources. Finally, since one tries to answer questions as well as possible, the reactor physicist attempts to master the latest and best numerical schemes for solving the complex equations one encounters.
Much of this material is treated in Nuclear Reactor Physics , by Weston Stacey. The book is 700 pages long, packed densely with text and equations and rich charts and tables and graphs. It is encyclopedic; the prose is clear, its style is relentless. One finds, along with the expected displays of cross-sections and coordinate systems, figures titled “Predicted frequency of fatality due to accidents from a number of technologies” and “Risk factor for LWR spent fuel without recycle.” The book treats—in addition to the conventional material—topics like the R-matrix representation of neutron cross-sections, fuel processing and recycling, transverse integrated nodal integral transport theory models (TINITMo), and what happened at Chernobyl and at Three Mile Island.
The author’s command of this diverse material is awesome. But the book has a point of view, an “attitude,” which I think of as the MIT tilt: One’s efforts should be directed towards the solution of “real” (rather than “academic”) problems; one’s goal is to build a machine, not to waltz in the complex plane. Hence the strong emphasis on computational methods that one finds throughout the book.
Nuclear Reactor Physics is presented as two textbooks. It is designed so that the first half, some three hundred pages, may be used for an undergraduate or beginning graduate course; the second half, a collection of chapters dealing with special topics, furnishes the material for an advanced course. At $125.00, the price crosses the threedigit barrier—not unusual these days. The book’s publisher is John Wiley & Sons Inc, a firm that has been optimistic about the future of nuclear energy for several decades. One might think of Nuclear Reactor Physics as the successor to James J. Duderstadt and Louis J. Hamilton’s Nuclear Reactor Analysis, a Wiley success that celebrated its 25th birthday in 2001.
Indeed, references to Duderstadt and Hamilton are sprinkled throughout Stacey. A comparison shows Nuclear Reactor Analysis to be relaxed, chatty, and careful, as one needs to be with beginners. The tradeoff is reduced coverage. (Perhaps its easy style stems from its origin: an early version, a set of illustrated course notes, which was described by some as “the only X-rated book on reactor theory in the Western world.”)
Nuclear Reactor Physics treats much, perhaps too much, in its Part I, and its treatment of several academic issues suffers. As examples, the definition of cross-section is surely hurried and a bit puzzling, and the definition of the importance function as a probability cannot be correct. And I cannot imagine an undergraduate breezing through the section on the Rossi technique. Understanding those clever experiments requires an understanding of stochastic processes that is not immediate.
The second half of the book, part II, titled “Advanced Reactor Physics,” begins by devoting almost 100 pages to a chapter on neutron transport theory, treated in a nontraditional manner. If this is to be the student’s first (and only?) encounter with transport theory, it will be an unusual one. The essay tilts away from mathematical elegance and physical insight toward facility in numerical calculation in “real” situations. Nowhere is there reference to the classic Milne Problem or to the beautiful work of Kenneth Case and Paul Zweifel and their students. It is as though in writing a text one dropped Mozart in favor of an extended treatment of electronic music. The second and third chapters of Part II, dealing with slowing-down theory and resonance absorption, maintain the tone. (Newcomers using the book will not discover Robert Marshak’s classic, precomputer, essay on slowing-down theory.) Other chapters in Part II deal with powerful and impressive computational techniques, TINITMo, its diffusion-based cousin, TINDTM, homogenization, nodal and synthesis methods, finite element coarse-mesh methods, and more, all dedicated to determining criticality, power distributions, and other features of both the static and the dynamic reactor. The text concludes with a 12-page section on stochastic kinetics—for the strong.
The fourth chapter of Part II is somewhat special in that it treats neutron thermalization, a subject rich in physics. The discussion is rather similar to that in Duderstadt and Hamilton. True to tone, much of the academic “fun”—the developments of the 1960s— is omitted, and there are a few misstatements about the physics. But it gave me particular pleasure to see graphs displaying “Calculated and Measured Cross-Sections…” Measurement and Calculation! Good, old-fashioned physics! For, rarely does one see the results of the elaborate computational schemes described in the other chapters set against good experimental data. Where are the data? Which calculation fits the better, TINITMo, or TINDTM? Why? Indeed, the lack of such comparison suggests that the book be titled “Nuclear Reactor Design” or “Nuclear Reactor Analysis,” rather than Nuclear Reactor Physics.
I hope that publication of this impressive text, whose strength lies in its breadth and its modernity, will accompany a renewed interest in nuclear power expressed through fission reactors. And may that interest produce a new band of enthusiastic students, comfortable with both physics and applied mathematics, who will enjoy studying, designing, and perfecting these elegant machines!
