Alejandro Alcolea
WriterWriter at Xataka. I studied education and music, but since 2014 I've been writing about my passion: video games and technology. I specialize in product analysis, photography, and video. My body is 70% coffee.
It’s hard to imagine a world without concrete. This material has played a crucial role in human history and remains a foundational element in modern construction. Although researchers are exploring more sustainable alternatives like wood, there are still many structures, such as nuclear power plants, where concrete is essential due to its strength and insulation properties.
A recent study has examined the effects of nuclear radiation on concrete, revealing a surprising finding: Radiation has a “healing” effect on this material.
The study. Researchers at the University of Tokyo didn’t start studying concrete with the goal of developing a self-repairing material. Instead, they focused on understanding how nuclear radiation impacts concrete. This composite material serves as the primary structural and shielding material in nuclear power plants and reactors. As such, concerns exist about how radiation might accelerate the aging of these shielding structures.
Specifically, the study aimed to investigate the impact of radiation on quartz, a common mineral used in concrete mixes worldwide. By measuring the effects on quartz, researchers wanted to gain insights into how radiation influences the integrity of concrete structures. Interestingly, these concrete structures could theoretically be more stable over the long term than previously believed. The radiation appears to induce relaxation processes in the quartz, which allows some recovery of its internal structure.
Irradiating quartz. Researchers investigated the effects of neutron irradiation on various types of quartz, including synthetic quartz, meta chert, sandstone, and granodiorite. They irradiated samples at temperatures ranging from 113 to 144 degrees Fahrenheit, with displacement damage varying from 0.01 to 0.23 dpa.
Study author Ippei Maruyama pointed out that neutron radiation “distorts the crystal structure, causing and expansion.” This distortion is concerning because it indicates instability in the material. However, surprisingly, due to the roles of silicon and oxygen within the quartz grains, a healing process is activated that alleviates the radiation-induced expansion of the material’s volume.
Self-repair. “There is also a phenomenon where the distorted crystals recover, and the expansion diminishes,” Maruyama added. This self-repair process depends on the size of the mineral crystals within the concrete. Specifically, larger grains exhibited less expansion. As such, the degradation of concrete–a significant concern in the construction and maintenance of nuclear power plants–might be less severe than previously thought.
Maruyama also said that “a lower rate affords more time to heal,” allowing nuclear power plants to “operate more safely over longer periods” than experts anticipated.
Next steps. Researchers acknowledge that they still have work to do. The University of Tokyo team has been studying the impact of radiation on concrete since 2008. However, this is a costly field of study, making extensive research challenging.
However, with the recent findings, Maruyama is confident that the team will continue to investigate the effects of nuclear radiation beyond quartz. Researchers aim to determine whether the expansion phenomenon occurs in other minerals present in concrete. The goal isn’t only to predict how cracks form due to the expansion of minerals exposed to radiation but also to identify the best materials for creating stronger concrete for future nuclear power plants.
Beyond power plants. It’s evident that achieving self-healing concrete has become a major focus for the Japanese team. Due to the CO2 emissions associated with concrete production, its high maintenance costs, and the depletion of the world’s sand reserves, the development of a self-repairing material is a key area of research for teams around the globe.
Progress has been made, with innovations such as mixtures containing sugar or coffee enabling some concrete to self-repair. Yet, it remains uncertain how long it’ll take for this new concrete to be implemented in everyday use.
Image | Jakob Madsen
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