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Division Spotlight
Human Factors, Instrumentation & Controls
Improving task performance, system reliability, system and personnel safety, efficiency, and effectiveness are the division's main objectives. Its major areas of interest include task design, procedures, training, instrument and control layout and placement, stress control, anthropometrics, psychological input, and motivation.
Meeting Spotlight
Utility Working Conference and Vendor Technology Expo (UWC 2024)
August 4–7, 2024
Marco Island, FL|JW Marriott Marco Island
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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Nuclear Science and Engineering
September 2024
Nuclear Technology
August 2024
Fusion Science and Technology
Latest News
Taking shape: Fusion energy ecosystems built with public-private partnerships
It’s possible to describe fusion in simple terms: heat and squeeze small atoms to get abundant clean energy. But there’s nothing simple about getting fusion ready for the grid.
Private developers, national lab and university researchers, suppliers, and end users working toward that goal are developing a range of complex technologies to reach fusion temperatures and pressures, confounded by science and technology gaps linked to plasma behavior; materials, diagnostics, and electronics for extreme environments; fuel cycle sustainability; and economics.
P. Yarsky, Y. Xu, A. Ward, N. Hudson, T. Downar
Nuclear Technology | Volume 197 | Number 3 | March 2017 | Pages 265-283
Technical Paper | doi.org/10.1080/00295450.2016.1273707
Articles are hosted by Taylor and Francis Online.
On November 3, 2008, an unexpected drift of the last three of 177 control rods occurred at the Dresden Unit 3 boiling water reactor. The root cause of the control rod drift was the manner in which the hydraulic control units (HCUs) were isolated during the outage. The U.S. Nuclear Regulatory Commission (NRC) Office of Nuclear Regulatory Research (RES) performed a demonstration study of inadvertent control blade drift using RES-sponsored nuclear analysis tools. The smallest margin to recriticality was determined by calculating the control rod worths at each core state using the core simulator PARCS/PATHS and an innovative algorithm to identify the highest worth combination of rods. This study did not try to evaluate any correlation between drifting rods that may occur in a real plant due to the actual physical configuration of the system. The purpose of the analysis was to demonstrate the tools that could be used to analyze the situation if that information is known.
For the current purpose of this demonstration, Edwin Hatch Unit 1 Cycle 3 (H1C3) was selected as the reference core and cycle. Based on the results of these calculations, it was possible to determine the fraction of rod groups that would produce criticality consequences in each of these scenarios. The results confirmed several aspects of conventional thinking, such as the most reactive point being the beginning of the cycle at the coldest conditions. Further, with a single blade drifting out of the core, the analysis results confirm that shutdown margin is maintained. It was found that a small population (about 1%) of drift scenarios with two rods produced criticality consequences according to our best-estimate-plus-uncertainty method, while this fraction increases to about 3.5% for three rods and about 14% for four rods. The results of the study have confirmed the adequacy of the NRC control rod drift analysis methodology; however, the results are not generically applicable and apply only to H1C3.