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Engineering Physics

Kumar Sridharan, Mark Anderson, Paul Wilson, Michael Corradini, Bob Agasie and Todd Allen

From left: Senior Scientist Kumar Sridharan, Associate Scientist Mark Anderson, Assistant Professor Paul Wilson, Wisconsin Distinguished Professor Michael Corradini, Reactor Director Bob Agasie and Assistant Professor Todd Allen (seated) have conducted research totaling more than $9 million on the U.S. Department of Energy's Generation IV initiative. The group is pictured in the College of Engineering Nuclear Reactor Lab. (22K JPG)

UW-Madison research fuels Generation IV nuclear power initiative

With approximately $9 million in Department of Energy funding over the last five years, engineering physics faculty and staff are helping create the future of nuclear power. Their work falls under the DOE Office of Nuclear Energy, Science and Technology's Generation IV initiative, which aims to design safer, more efficient and more reliable plants that minimize waste and resist proliferation.

In supercritical water reactor studies, researchers are developing reliable materials for the proposed reactor, which cools via water at very high temperatures and pressures. They have identified ways to modify structural surfaces so that in the presence of the high-temperature, high-pressure water, corrosion rates are substantially reduced.

Additionally, they are determining how radiation fields affect water chemistry and the associated corrosion. They are conducting heat-transfer experiments and have developed a model that verified test results on flow stability. In addition, they developed a unique "mixed-spectrum" supercritical water reactor design that burns waste as it produces power; early results indicate that such a reactor could be devised with no net production of minor actinides.

In projects that focused on the liquid metal reactor design, researchers dynamically imaged two-phase flow where water vaporized in the presence of liquid metal. They measured the local heat-transfer coefficients and compared them with traditional measurements of volumetric heat transfer. And applying their results to current reactors, they developed a technique of heat transfer in which they demonstrated coolability under a worst-case accident scenario. They also are studying corrosion behavior of structural materials in the presence of molten lead.

Collaborators on various projects include Argonne National Laboratory, Sandia National Laboratories, Idaho National Engineering and Environmental Laboratory, University of Notre Dame, the University of Michigan, Westinghouse Corporation, and the Korea Atomic Energy Research Institute. UW-Madison's researchers include Wisconsin Distinguished Professor Michael Corradini, Assistant Professors Todd Allen and Paul Wilson, Senior Scientist Kumar Sridharan, Associate Scientist Mark Anderson, and Reactor Director Bob Agasie.

New method enables researchers to get a "handle" on manipulating nanowires

Maneuvering macro-scale material samples with a tweezers can be difficult enough, but for researchers who study at the nanoscale, moving materials easily into a particular position can be nearly impossible.

But a simple solution developed by Assistant Professor Wendy Crone, chemistry PhD student Anne Bentley, Chemistry Professor Art Ellis and Jeremy Trethewey (MS '04, Materials Science Program) will enable researchers to get a handle — literally — on manipulating nanowires. They attached nickel "handles," or caps, onto the ends of their nanowires and, using magnetic fields, easily can position the wires to test their mechanical properties or for a variety of other applications.

Initially, the group tried manipulating the wires with electric currents, but those efforts were only moderately successful. The magnetic manipulation technique enables researchers to work with large numbers of wires simultaneously. In addition, they could put the nickel handles onto almost any material they can deposit into a porous-membrane template. And researchers could use the technique to create circuitry, devices and structures out of small-scale materials such as nanowires.

Simulating spheromak behavior in 3-D

New simulation code developments by Assistant Professor Carl Sovinec and colleagues will enable plasma researchers to model more completely the behavior of a magnetic-confinement fusion experiment called a spheromak.

A spheromak has no central column and relies on currents flowing within the plasma to generate magnetic fields that also confine the plasma. Although previous spheromak simulations generated lots of information about how the experiment's magnetic fields evolved, researchers were skeptical of the results.

The new developments incorporate several finite-temperature effects, enabling researchers to model thermal energy transport, including the anisotropies and temperature-dependent coefficients of collisional plasmas. Simulations with the added modeling capability show relatively low temperatures initially, consistent with experimental results, but ensuing pulses and transients lead to improved confinement and high temperatures. In addition, simulation results provide new insight into the different nature of the experiment's initial drive and subsequent current pulses.

Sovinec's group includes PhD student Giovanni Cone and collaborators from Science Applications International Corporation, San Diego; Utah State University; the University of Colorado; and Lawrence Livermore National Laboratory. His three-year, $415,000 junior faculty award from the Department of Energy's Office of Fusion Energy Science supported the research.

 





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Date last modified: Thursday, 17-Feb-2005 14:09:29 CST
Date created: 17-Feb-2005