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Division Spotlight
Thermal Hydraulics
The division provides a forum for focused technical dialogue on thermal hydraulic technology in the nuclear industry. Specifically, this will include heat transfer and fluid mechanics involved in the utilization of nuclear energy. It is intended to attract the highest quality of theoretical and experimental work to ANS, including research on basic phenomena and application to nuclear system design.
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ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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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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Latest News
Norway’s Halden reactor takes first step toward decommissioning
The government of Norway has granted the transfer of the Halden research reactor from the Institute for Energy Technology (IFE) to the state agency Norwegian Nuclear Decommissioning (NND). The 25-MWt Halden boiling water reactor operated from 1958 to 2018 and was used in the research of nuclear fuel, reactor internals, plant procedures and monitoring, and human factors.
Nam Zin Cho, Lawrence M. Grossman
Nuclear Science and Engineering | Volume 83 | Number 1 | January 1983 | Pages 136-148
Technical Paper | doi.org/10.13182/NSE83-A17995
Articles are hosted by Taylor and Francis Online.
A simple core control model is developed for the control of xenon spatial oscillations in load following operations of a current-design nuclear pressurized water reactor. The model is formulated as a linear-quadratic tracking problem in the context of modern optimal control theory, and the resulting two-point boundary problem is solved directly by the techniques of initial value methods. The system of state equations is composed of the one-group diffusion equation with temperature and xenon feedbacks, the iodine-xenon dynamics equations, and an energy balance relation for the core. Control is via full-length and part-length control rod banks, boron, and coolant inlet temperature. The system equations are linearized around an equilibrium state, which is an eigen-solution of the nonlinear static equations with feedback. The nonlinear eigenvalue problem is shown to have a unique positive solution under certain conditions by using the bifurcation theory, the solution being obtained by an iteration based on the use of monotone operators. A modal expansion reduces the linearized equations to a lumped parameter system. Minimization of an objective functional that expresses tracking the load with small control effort leads to a stiff two-point boundary value problem with boundary layers at both initial and final times, which is solved numerically. In a number of cases, results show that the optimal solution closely follows the desired load demand and maintains the desired power distribution with a small control effort.