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Division Spotlight
Robotics & Remote Systems
The Mission of the Robotics and Remote Systems Division is to promote the development and application of immersive simulation, robotics, and remote systems for hazardous environments for the purpose of reducing hazardous exposure to individuals, reducing environmental hazards and reducing the cost of performing work.
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2024 ANS Winter Conference and Expo
November 17–21, 2024
Orlando, FL|Renaissance Orlando at SeaWorld
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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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Don’t get boxed in: Entergy CNO Kimberly Cook-Nelson shares her journey
Kimberly Cook-Nelson
For Kimberly Cook-Nelson, the path to the nuclear industry started with a couple of refrigerator boxes and cellophane paper. Her sixth-grade science project was inspired by her father, who worked at Seabrook power station in New Hampshire as a nuclear operator.
“I had two big refrigerator boxes I taped together. I cut the ‘primary operating system’ and the ‘secondary system’ out of them. Then I used different colored cellophane paper to show the pressurized water system versus the steam versus the cold cooling water,” Cook-Nelson said. “My dad got me those little replica pellets that I could pass out to people as they were going by at my science fair.”
Abhishek Chakraborty, Suneet Singh, M. P. S. Fernando
Nuclear Science and Engineering | Volume 196 | Number 6 | June 2022 | Pages 715-734
Technical Paper | doi.org/10.1080/00295639.2021.2011670
Articles are hosted by Taylor and Francis Online.
Large nuclear reactors operating in the thermal spectrum are prone to both global and regional oscillations in power due to variation of 135Xe concentration. These power oscillations are self-stabilizing up to a certain operating power level, beyond which spatial power control becomes necessary for suppressing these oscillations. Especially for large pressurized heavy water reactors (PHWRs), which are natural uranium–fueled reactors using heavy water as coolant and moderator, the modes of xenon instabilities decide the extent and scheme for spatial power control. In this paper, the effect of spatial control on the bifurcation characteristics is demonstrated using a two-region model. The error signal for movement of the reactivity device has a global component for bulk power control and a local component for regional power control. The amount of regional power control determines the power level at which the spatial xenon oscillations stabilize. Using bifurcation analysis, it is found that in case of limited regional control, both supercritical and subcritical Hopf bifurcations exist, whereas in the case of increased regional control only supercritical Hopf bifurcations exist. However, these supercritical Hopf oscillations are due to time lag in control and have short timescales and lower amplitudes as compared to xenon oscillations. Hence, a proper choice of spatial control enables a PHWR to operate at rated full power capacity without any spatial Xenon instability.
