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
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
Latest Magazine Issues
Sep 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
September 2025
Nuclear Technology
Fusion Science and Technology
August 2025
Latest News
From operator to entrepreneur: David Garcia applies outage management lessons
David Garcia
If ComEd’s Zion plant in northern Illinois hadn’t closed in 1998, David Garcia might still be there, where he got his start in nuclear power as an operator at age 24.
But in his ninth year working there, Zion closed, and Garcia moved on to a series of new roles—including at Wisconsin’s Point Beach plant, the corporate offices of Minnesota’s Xcel Energy, and on the supplier side at PaR Nuclear—into an on-the-job education that he augmented with degrees in business and divinity that he sought later in life.
Garcia started his own company—Waymaker Resource Group—in 2014. Recently, Waymaker has been supporting Holtec’s restart project at the Palisades plant with staffing and analysis. Palisades sits almost exactly due east of the fully decommissioned Zion site on the other side of Lake Michigan and is poised to operate again after what amounts to an extended outage of more than three years. Holtec also plans to build more reactors at the same site.
For Garcia, the takeaway is clear: “This industry is not going away. Nuclear power and the adjacent industries that support nuclear power—and clean energy, period—are going to be needed for decades upon decades.”
In July, Garcia talked with Nuclear News staff writer Susan Gallier about his career and what he has learned about running successful outages and other projects.
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.