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.
Division Spotlight
Fusion Energy
This division promotes the development and timely introduction of fusion energy as a sustainable energy source with favorable economic, environmental, and safety attributes. The division cooperates with other organizations on common issues of multidisciplinary fusion science and technology, conducts professional meetings, and disseminates technical information in support of these goals. Members focus on the assessment and resolution of critical developmental issues for practical fusion energy applications.
Meeting Spotlight
2025 ANS Annual Conference
June 15–18, 2025
Chicago, IL|Chicago Marriott Downtown
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
May 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
July 2025
Nuclear Technology
June 2025
Fusion Science and Technology
Latest News
High-temperature plumbing and advanced reactors
The use of nuclear fission power and its role in impacting climate change is hotly debated. Fission advocates argue that short-term solutions would involve the rapid deployment of Gen III+ nuclear reactors, like Vogtle-3 and -4, while long-term climate change impact would rely on the creation and implementation of Gen IV reactors, “inherently safe” reactors that use passive laws of physics and chemistry rather than active controls such as valves and pumps to operate safely. While Gen IV reactors vary in many ways, one thing unites nearly all of them: the use of exotic, high-temperature coolants. These fluids, like molten salts and liquid metals, can enable reactor engineers to design much safer nuclear reactors—ultimately because the boiling point of each fluid is extremely high. Fluids that remain liquid over large temperature ranges can provide good heat transfer through many demanding conditions, all with minimal pressurization. Although the most apparent use for these fluids is advanced fission power, they have the potential to be applied to other power generation sources such as fusion, thermal storage, solar, or high-temperature process heat.1–3
2021 ANS Annual Meeting Plenary SPeaker
Jeff Lyash is president and chief executive officer of the Tennessee Valley Authority. Appointed by the Board of Directors in February 2019, Lyash leads the nation’s largest public utility in its mission of serving the people of the Tennessee Valley to make life better.
Before coming to TVA, Lyash served since 2015 as president and CEO of Ontario Power Generation Inc., one of the largest electric generating companies in Canada with a diverse fleet of nuclear, hydroelectric, gas, biomass and renewable generating stations.
Lyash was formerly the president of CB&I Power where he was responsible for a full range of engineering, procurement and construction of multi-billion-dollar electric generation projects in both domestic and international markets. He also provided operating plant services for nuclear, coal, gas, oil and renewable generation.
Prior to joining CB&I, Lyash served as executive vice president of Energy Supply for Duke Energy where he led engineering, maintenance and operations of the company’s 42,000-megawatt generation fleet, fuel procurement, power trading, major projects and construction, environmental programs, and health and safety programs.
Before the merger of Progress Energy and Duke Energy, Lyash was executive vice president of Energy Supply for Progress Energy. In this role, he oversaw Progress Energy’s diverse 22,000-megawatt fleet of generating resources including nuclear, coal, oil, natural gas and hydroelectric stations. In addition, Lyash was responsible for generating fleet fuel procurement and power trading operations.
Lyash joined Progress Energy in 1993. Before leading the Energy Supply division at Progress, he served as executive vice president of corporate development, president and chief executive officer of Progress Energy Florida, senior vice president of Energy Delivery Florida, and vice president of Transmission.
Lyash also held a wide range of management and executive roles in Progress Energy’s nuclear program, including operations manager, engineering manager, plant manager, and director of site operations.
Lyash began his career in the utility industry in 1981 and worked for the U.S. Nuclear Regulatory Commission in senior technical and management positions throughout the Northeast and in Washington, D.C. He received the NRC Meritorious Service Award in 1987.
Lyash earned a bachelor’s degree in mechanical engineering from Drexel University, and was honored with the Drexel University Distinguished Alumnus Award in 2009. He has held a senior reactor operator license from the Nuclear Regulatory Commission, and is a graduate of the U.S. Office of Personnel Management Executive Training Program and the Duke Fuqua School of Business Advanced Management Program.
Lyash is an avid golfer and fly fisher. He and his wife, Tracy, enjoy cooking, skiing, reading and charitable work – and spending time with their two married children and nine grandchildren. The Lyashes live in Knoxville, Tennessee.
Last modified April 21, 2021, 3:21pm EDT
