Articles tagged with "graphite"
Nuclear reactor fears eased as US lab clears graphite of safety risk
Researchers at Oak Ridge National Laboratory (ORNL) have resolved a decades-old debate regarding the impact of microscopic pores in graphite used in nuclear reactors. Their study, published in the journal Carbon, confirms that the natural porosity within graphite blocks does not affect the material’s atomic vibrations or its fundamental neutron moderation properties. This finding is significant because graphite has been a key component in nuclear reactors since the first reactor in 1942, valued for its ability to withstand extreme temperatures and slow down neutrons to sustain controlled nuclear chain reactions. The research provides greater confidence in the safety and design of current and next-generation reactors, including very high-temperature reactors (VHTRs) and molten salt reactors. The study addressed a critical flaw in previous models that treated graphite porosity by randomly removing atoms, which artificially distorted the material’s vibrational properties and led to overestimations in reactor criticality calculations. Using advanced neutron scattering experiments combined with machine-learned atomic potentials, the ORNL team demonstrated that the increased neutron
energynuclear-reactorsgraphitematerials-scienceneutron-scatteringreactor-safetyhigh-temperature-reactorsMIT study could help predict graphite lifespan in nuclear reactors
A recent MIT study has advanced understanding of how graphite, a critical material in nuclear reactors, behaves under radiation. Graphite is widely used as a neutron moderator and reflector in reactors, playing a key role in sustaining controlled nuclear chain reactions. However, radiation exposure causes graphite to deform through swelling, shrinking, and cracking, complicating predictions of its lifespan. The MIT team applied a statistical method called the Weibull Distribution alongside X-ray scattering techniques to analyze irradiated graphite samples from Oak Ridge National Laboratory. Their research revealed unexpected pore behavior: initially, pores fill as graphite degrades, but over prolonged irradiation, a recovery or annealing process occurs where new pores form and existing pores smooth and enlarge, influencing the material’s volume changes. This discovery sheds light on graphite’s complex composite structure—comprising crystalline filler particles, a less crystalline binder matrix, and pores ranging from nanometers to microns—that affects its radiation response. The study’s findings could lead to more accurate, non-destructive predictions of graphite’s
materialsgraphitenuclear-reactorsradiation-damagematerial-lifespancomposite-materialsenergy-materialsChina Dominates Global Trade of Battery Minerals - CleanTechnica
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