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
Aug 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
September 2025
Nuclear Technology
August 2025
Fusion Science and Technology
Latest News
No impact from Savannah River radioactive wasps
The news is abuzz with recent news stories about four radioactive wasp nests found at the Department of Energy’s Savannah River Site in South Carolina. The site has been undergoing cleanup operations since the 1990s related to the production of plutonium and tritium for defense purposes during the Cold War. Cleanup activities are expected to continue into the 2060s.
T. Trombetti, D. L. Hetrick
Nuclear Science and Engineering | Volume 86 | Number 2 | February 1984 | Pages 129-135
Technical Paper | doi.org/10.13182/NSE84-A18195
Articles are hosted by Taylor and Francis Online.
A multinode treatment of the problem of nonlinear reactor stability is given. The nodal kinetics equations account for nodal powers, precursor concentrations, and temperatures. Nonlinear power-plus-temperature feedbacks are admitted in each node. Quadratic and logarithmic Lyapunov functions are considered. By formulating and solving a suitable nonlinear programming problem, the optimal estimate of the domain of attraction of the reactor-operating equilibrium state that can be afforded by the aforesaid V functions is explicitly constructed. An example of a reactor with two nodal power feedbacks (one destabilizing) and two destabilizing nodal temperature feedbacks is given. These feedbacks are seen to give rise to an unstable equilibrium reactor state, in the region of all-positive perturbations, which is extremely well approached by the boundary of the estimate of the domain of attraction.