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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!
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Powering the future: How the DOE is fueling nuclear fuel cycle research and development
As global interest in nuclear energy surges, the United States must remain at the forefront of research and development to ensure national energy security, advance nuclear technologies, and promote international cooperation on safety and nonproliferation. A crucial step in achieving this is analyzing how funding and resources are allocated to better understand how to direct future research and development. The Department of Energy has spearheaded this effort by funding hundreds of research projects across the country through the Nuclear Energy University Program (NEUP). This initiative has empowered dozens of universities to collaborate toward a nuclear-friendly future.
Mary E. Ward, John C. Lee
Nuclear Science and Engineering | Volume 97 | Number 3 | November 1987 | Pages 190-202
Technical Paper | doi.org/10.13182/NSE87-A23501
Articles are hosted by Taylor and Francis Online.
An investigation of the potential behavior of large amplitude nuclear-coupled density-wave oscillations in a boiling water reactor (BWR) was performed. A simplified, nonlinear BWR core model was developed and used to predict the growth of oscillations as a limit cycle is approached. For high-power/low-flow initial conditions, large density-wave oscillations could cause periodic pulses in core power. The fuel temperature, which rapidly increases at high-power conditions and slowly recovers, is considered as the fast variable in a relaxation oscillation. With an appropriate transformation of the system equations, the approximate limit cycle trajectory can therefore be determined using singular perturbation analysis. In the first approximation, where the relaxation is assumed to occur infinitely fast, the phase-space trajectory combines the slow part with an instantaneous jump between end points to form a closed cycle. The accuracy of this approximation is improved with appropriate perturbation series expansions on both the slow and fast parts, as well as introduction of a separate expansion for the connections between these parts. The approximate solution is considerably simpler to obtain than a conventional numerical solution of the original equations.