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.
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.
Meeting Spotlight
2024 ANS Annual Conference
June 16–19, 2024
Las Vegas, NV|Mandalay Bay Resort and Casino
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!
Latest Magazine Issues
Apr 2024
Jan 2024
Latest Journal Issues
Nuclear Science and Engineering
June 2024
Nuclear Technology
May 2024
Fusion Science and Technology
Latest News
Commercial nuclear innovation "new space" age
In early 2006, a start-up company launched a small rocket from a tiny island in the Pacific. It exploded, showering the island with debris. A year later, a second launch attempt sent a rocket to space but failed to make orbit, burning up in the atmosphere. Another year brought a third attempt—and a third failure. The following month, in September 2008, the company used the last of its funds to launch a fourth rocket. It reached orbit, making history as the first privately funded liquid-fueled rocket to do so.
Defu Zhang, Gary A. Hallock, Alan J. Wootton, Robert H. Flake, John R. Uglum
Fusion Science and Technology | Volume 32 | Number 3 | November 1997 | Pages 431-443
Technical Paper | Plasma Control Issues for Tokamaks | doi.org/10.13182/FST97-A6
Articles are hosted by Taylor and Francis Online.
A linear, second-order transformer model using magnetic sensor coils has been developed to describe the position control of a tokamak. This model is used to analyze the behavior of a proportional-derivative controller, which has been implemented on TEXT-Upgrade (TEXT-U). The magnetic sensor coils may be placed internal or external to the conducting vacuum vessel. If placed externally, however, eddy currents induced in the vessel wall introduce an error in the position measurement. It is found that this error signal introduces a positive zero in the system transfer function. The transfer function becomes a non-minimum-phase function, which restricts the response speed, stable area, and utilization of the power supply capability. Although the position control system is stabilized by use of a proportional-derivative controller, the controller cannot affect the positive zero. This analysis has been experimentally verified on TEXT-U. With external sensors, the stable operating area is small, and the sensors exhibit an initial undershoot to a step position change, as expected. The observed stable area is predicted by the model, although the model overestimates the size of the actual stable area.