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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!
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Shifting the paradigm of supply chain
Chad Wolf
When I began my nuclear career, I was coached up in the nuclear energy culture of the day to “run silent, run deep,” a mindset rooted in the U.S. Navy’s submarine philosophy. That was the norm—until Fukushima.
The nuclear renaissance that many had envisioned hit a wall. The focus shifted from expansion to survival. Many utility communications efforts pivoted from silence to broadcast, showcasing nuclear energy’s elegance and reliability. Nevertheless, despite being clean baseload 24/7 power that delivered a 90 percent capacity factor or higher, nuclear energy was painted as risky and expensive (alongside energy policies and incentives that favored renewables).
Economics became a driving force threatening to shutter nuclear power. The Delivering the Nuclear Promise initiative launched in 2015 challenged the industry to sustain high performance yet cut costs by up to 30 percent.
Taeseung Lee, Richard B. Vilim (ANL)
Proceedings | Nuclear Plant Instrumentation, Control, and Human-Machine Interface Technolgies (NPIC&HMIT 2019) | Orlando, FL, February 9-14, 2019 | Pages 209-221
The Supervisory Control System (SCS) provides overall coordination of the plant actuators that includes automatically regulating process variables so that performance goals are safely met for all operating modes. The system during normal electric power production operates through a hierarchical structure with steam demand supplied as an input at the top level, and based on this value, coordinated set points are issued to lower level sub-system controllers. Through the use of the Supervisory Control System, hot-side temperatures can be maintained near-constant during transients so that thermal fatigue is significantly reduced from otherwise. The design strategy for the control system regards the plant response to a change in electric generator load as consisting of two components: steady-state and transient. There is the equilibrium state the plant will reach in asymptotic time (steady-state) in response to the changed condition. The steady-state control algorithm, or Load Schedule as it is known, manages steady-state temperatures. There is the dynamic component of the response (transient) which can be regarded as superimposed on the asymptotic state. The Single-Input Single-Output (SISO) Controllers manage the dynamic response component. In this work, the Supervisory Control System is designed for electric power operation of a pool-type metallic-fueled Sodium-cooled Fast Reactor (SFR). 10% step and 5%/min ramp load change cases were simulated with a one-dimensional system analysis code to assess the performance of the SISO controllers.
