Dr. Anne Campbell is a research associate at Oak Ridge National Laboratory, and is a preeminent expert on radiation effects in nuclear graphite. Her expertise began in her PhD work at the University of Michigan when she investigated proton irradiation effects in graphite, including changes in dimensions, mechanical properties, crystal structure, and anisotropy under unrestrained and stressed conditions. Now at ORNL, Dr. Campbell continues to investigate the effects of interactions of radiation with graphite, which includes changes to the physical (density/volume), mechanical (strength, elastic properties), and electrical/thermal (electrical resistivity, thermal conductivity, coefficient of thermal expansion) properties, irradiation creep, and the corresponding microstructural changes for a range of graphite grades. Her interests outside of graphite include TRISO fuel, SiC and SiC composite systems, irradiation creep of metals, and the development of novel techniques for measuring materials properties from specimens used in irradiation testing experiments.
"Development of mesopores in superfine grain graphite neutron-irradiated at high fluence"
Cristian Contescu, Jose Arregui-Mena, Anne Campbell, Philip Edmondson,
Microstructural changes induced by neutron irradiation of superfine grain graphite G347A (Tokai Carbon, Japan) were examined by nitrogen adsorption at 77 K and by three microscopy techniques (SEM, TEM and FIB-SEM tomography). The specimens were irradiated at doses of up to 30 dpa, covering stages before and after the turnaround fluence at three temperatures (300, 450, 750 °C) of their irradiation envelope. The initial graphite densification at low fluences did not produce any detectable effect in the pore size range (<350 nm) measured by gas adsorption. However, graphite irradiated at high fluences, after turnaround, showed severe structural changes. At all three temperatures and high irradiation fluences, gas adsorption revealed significant increase of the volume of narrow mesopores (<5–20 nm) and up to five times increase of BET surface area, both in linear relationship with the relative volume expansion. Analysis of microscopy images showed multiplication of fine macropores (>50 nm) at high irradiation fluences and more structural changes on multiple scales, from nanometers to microns. This work demonstrates the unique ability of gas adsorption techniques to analyze open pores with sizes between sub-nanometer and sub-micron in bulk nuclear graphite, with supporting microscopy results.
|"Development of planar PyC/SiC diffusion couples to investigate irradiation effects and microstructural variation on fission product diffusion" Tyler Gerczak, John Hunn, Brian Jolly, Austin Schumacher, Anne Campbell, John Dyer, Xunxiang Hu, Proceedings of HTR 2018 Vol. 2018 0047|
|"Development of Planar PyC/SiC Diffusion Couples to Investigate Irradiation Effects and Microstructural Variation on Fission Product Diffusion" Tyler Gerczak, Rachel Seibert, John Hunn, Brian Jolly, Austin Schumacher, Xunxiang Hu, Anne Campbell, GCR Program Review Meeting June 18-19, (2019)|
|"Fabrication of PyC/SiC diffusion couples using fluidized bed CVD techniques for radiation enhanced diffusion testing" Brian Jolly, Tyler Gerczak, John Hunn, Austin Schumacher, Anne Campbell, The Materials Society Annual Conference March 11-15, (2018)|
|"Neutron irradiation effects on the microstructure of nuclear graphite" Jose Arregui-Mena, Benjamin Maerz, Cristian Contescu, Anne Campbell, Philip Edmondson, Yutai Katoh, NuMat 2018 October 14-18, (2018)|
|"Topological and atomic investigation of nuclear graphite using multi-scale x-ray scattering" David Sprouster, Lance Snead, Boris Khaykovich, Yutai Katoh, Anne Campbell, 45th International Conference and Expo on Advanced Ceramics and Composites (ICACC2021) February 8-11, (2021) Link|