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Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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Nuclear Technology
Fusion Science and Technology
August 2025
Latest News
New coolants, new fuels: A new generation of university reactors
Here’s an easy way to make aging U.S. power reactors look relatively youthful: Compare them (average age: 43) with the nation’s university research reactors. The 25 operating today have been licensed for an average of about 58 years.
Erick Martinez-Loran, Daniel Schwen, Benjamin W. Spencer, Jose Boedo, Eric Hollmann
Fusion Science and Technology | Volume 81 | Number 3 | April 2025 | Pages 208-218
Research Article | doi.org/10.1080/15361055.2024.2395133
Articles are hosted by Taylor and Francis Online.
Carbon pebble rods are a promising candidate for use in high heat flux regions of magnetic fusion energy reactor walls. Under high (10 to 50 MW/m2) heat loads, carbon pebble rods release hot pebbles from the exposed surface, carrying away heat as the pebble rod surface recedes. In this work, we show that the surface recession rate during heating can be adjusted by changing the mechanical strength of the extruded rods, modifying the heat removal rate; this is accomplished here by varying the fill fraction of the inter-pebble matrix. A three-dimensional finite element model is presented that captures many experimental observations, including the sphere temperature and the surface recession rate. The model predicts that pebble release is caused by thermally driven crack propagation through the matrix and that the matrix strength against breaking is the single most important material parameter setting the pebble release rate; this prediction is supported by experimental results.