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
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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
Oct 2025
Jul 2025
Latest Journal Issues
Nuclear Science and Engineering
November 2025
Nuclear Technology
October 2025
Fusion Science and Technology
Latest News
The journey of the U.S. fuel cycle
Craig Piercycpiercy@ans.org
While most big journeys begin with a clear objective, they rarely start with an exact knowledge of the route. When commissioning the Lewis and Clark expedition in 1803, President Thomas Jefferson didn’t provide specific “turn right at the big mountain” directions to the Corps of Discovery. He gave goal-oriented instructions: explore the Missouri River, find its source, search for a transcontinental water route to the Pacific, and build scientific and cultural knowledge along the way.
Jefferson left it up to Lewis and Clark to turn his broad, geopolitically motivated guidance into gritty reality.
Similarly, U.S. nuclear policy has begun a journey toward closing the U.S. nuclear fuel cycle. There is a clear signal of support for recycling from the Trump administration, along with growing bipartisan excitement in Congress. Yet the precise path remains unclear.
Daniel Westlén, Janne Wallenius
Nuclear Technology | Volume 154 | Number 1 | April 2006 | Pages 41-51
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT06-A3716
Articles are hosted by Taylor and Francis Online.
We have designed a gas-cooled accelerator-driven system dedicated to transmutation of minor actinides. Thanks to the excellent neutron economy of the uranium-free fuel employed, the pin pitch to diameter ratio (P/D) could be increased to 1.8. The increased coolant fraction allows for decay heat removal at ambient pressure. The large coolant fraction further results in a low pressure loss - 26 kPa over the core, 35 kPa in total. Thanks to the large P/D, the elevation of the heat exchanger necessary to remove decay heat by natural circulation is just more than 1 m. The absence of uranium in conjunction with the presence of 35% (heavy atom) americium in the fuel results in a low effective delayed neutron fraction and a vanishing Doppler feedback, making subcritical operation mandatory.
