AbstractA 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 whichvis 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.