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
2026 Nuclear Energy Conference & Expo (NECX)
August 24–27, 2026
Dallas, TX|Hilton Anatole
Latest Magazine Issues
Jul 2026
Jan 2026
2026
Latest Journal Issues
Nuclear Science and Engineering
August 2026
Nuclear Technology
July 2026
Fusion Science and Technology
Latest News
The deadline arrives: Checking in on the Reactor Pilot Program
On May 23, 2025, President Trump signed Executive Order 14301, “Reforming Nuclear Reactor Testing at the DOE,” which instructed the Department of Energy to create a Reactor Pilot Program (RPP)—a new system in which companies could pursue DOE authorization to build and test their first-of-a-kind nuclear technologies. EO 14301 set an ambitious goal for that program: three reactors achieving criticality by July 4, 2026.
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.