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.
Luisa F. Hansen, John D. Anderson, Eugene Goldberg, Ernest F. Plechaty, Marion L. Stelts, Calvin Wong
Nuclear Science and Engineering | Volume 35 | Number 2 | February 1969 | Pages 227-239
Technical Paper | doi.org/10.13182/NSE69-A21138
Articles are hosted by Taylor and Francis Online.
Neutrons emitted from pulsed spheres have been measured as a function of time in order to stringently test input parameters and computational assumptions in neutron transport calculations. Using the sphere transmission technique in conjunction with the time-of-flight facilities at Livermore, measurements have been made for 0.5, 1.3, and 3.0 mfp of carbon, and for 1.0 mfp of nitrogen, using a 15.3-MeV pulsed neutron beam. The measured neutron time spectra have proved to be sensitive, not only to the magnitude of the elastic and inelastic neutron cross sections, but also to the shapes of their angular distributions. The analysis of the data has been done using the Livermore Monte Carlo Neutron Transport Program (SORS). To obtain agreement with the data, a revision of some of the cross sections and respective angular distributions was required, which resulted in a dramatic improvement in the quality of the fits to the measured time spectra.
