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.
Lin Hu, Karl D. Hammond, Brian D. Wirth, Dimitrios Maroudas
Fusion Science and Technology | Volume 71 | Number 1 | January 2017 | Pages 36-51
Technical Paper | doi.org/10.13182/FST16-105
Articles are hosted by Taylor and Francis Online.
We report the results of a systematic atomic-scale analysis of small helium cluster dynamics near a Σ3<111>{121} symmetric tilt grain boundary (GB) in tungsten based on molecular-dynamics simulations according to a reliable interatomic interaction potential. We find that small, mobile helium clusters (Hen, 1 ≤ n ≤ 7) in the near-GB region are attracted to the GB due to an elastic cluster-GB interaction force. Moreover, as the clusters drift toward the GB, cluster trap mutation (TM) reactions in the near-GB region are activated at rates much higher than those in the bulk of the material’s grains. This near-GB cluster dynamics has significant effects on the near-GB defect structures and the amount of helium retained in the material upon plasma exposure. Each TM reaction generates a tungsten vacancy, which traps helium by forming an immobile helium-vacancy complex, and an interstitial tungsten atom in the form of an extended tungsten interstitial complex on the GB. This interstitial configuration is characterized by mobility that depends on the location where the TM reaction occurs: It is immobile when the vacancy produced by the TM reaction is located a few lattice planes away from the GB plane and highly mobile along a specific direction when the produced vacancy is located on the GB. The latter mechanism initiates a potentially fast migration path for W atoms along the GB toward a free surface, which may influence significantly the surface morphology of plasma-exposed tungsten.
