ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Explore membership for yourself or for your organization.
Conference Spotlight
2026 ANS Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
Latest Magazine Issues
Mar 2026
Jan 2026
Latest Journal Issues
Nuclear Science and Engineering
April 2026
Nuclear Technology
February 2026
Fusion Science and Technology
Latest News
Going Nuclear: Notes from the officially unofficial book tour
I work in the analytical labs at one of Europe’s oldest and largest nuclear sites: Sellafield, in northwestern England. I spend my days at the fume hood front, pipette in one hand and radiation probe in the other (and dosimeter pinned to my chest, of course). Outside the lab, I have a second job: I moonlight as a writer and public speaker. My new popular science book—Going Nuclear: How the Atom Will Save the World—came out last summer, and it feels like my life has been running at full power ever since.
V. Deniz
Nuclear Science and Engineering | Volume 28 | Number 3 | June 1967 | Pages 397-403
Technical Paper | doi.org/10.13182/NSE67-A28954
Articles are hosted by Taylor and Francis Online.
A general transport-theory formulation of lattice kinetics is obtained by studying an infinite lattice with a macroscopic spatial-flux variation of the form exp(i B · r). A study is first made of the variation of the asymptotic inverse period and of the flux distribution as a function of the buckling vector, these being, respectively, the eigenvalue and the eigenfunction of the balance equation for the nonstationary system. This allows one to define the parameters which characterize the anisotropic migration of neutrons in the lattice. One also sees in the process that the introduction of a macroscopic curvature not only introduces net leakage,. but also modifies the mean disappearance probability from the net effect of production and absorption. The finite-medium kinetic parameters which follow are defined in terms of the corresponding zero-buckling parameters and of the buckling-dependent part of the inverse period. All the parameters are expressed in terms of integrals of periodic functions only over a unit cell instead of over the whole pile. In particular, for homogeneous systems, the volume integral drops out. In the context of the formulation of this paper, the following known facts are restressed. First, there exists a choice in defining multiplication factors, which depends on whether the production operator employed is characteristic of instantaneous production rates or of production rates in stationary systems. Second, and added to this, there is a further arbitrariness in the definition of parameters such as mean lifetimes and multiplication factors, which stems from the freedom one has in the choice of weight functions. This arbitrariness is characteristic of all parameters that are not eigenvalues. However, with a proper choice of weight functions, the multiplication factors can be made identical to the eigenvalues of static-theory balance equations. These eigenvalues have the unambiguous meaning of being the reciprocals of the factors by which v is uniformly changed in order to stabilize nonstationary systems. Apart from its application to nonstationary systems around the critical point, the study is also applicable to pulsed systems which may be multiplying or non-multiplying. An extension to exponential experiments on nondiverging infinite lattices can be very easily obtained.