Converts Into Lithium to Maintain Concrete Integrity by Inhibiting Aggregate Decomposition
This concrete formulation and or cementitious coating contains boron to protect against radiation-induced volumetric expansion. Many facilities use concrete to shield against radiation, such as nuclear power plants or radiological medical facilities. The global nuclear power plant and equipment market is projected to reach $4.9 billion by 2025. Concrete is prone to degradation in certain environments, a result of chemical reactions between alkalis and other materials in the concrete mixture. Some concrete formulations use boron aggregates to make concrete structures resistant to radiation, but the inherently uneven aggregate dispersion leaves surfaces exposed and the structure susceptible to radiation-induced volumetric expansion (RIVE), which may lead to further degradation due to alkali silica reactivity (ASR) of aggregates that are otherwise non-reactive.
Researchers at the University of Florida have developed a formulation for concrete or concrete coatings to help prevent degradation due to radiation. The formulation utilizes boron compounds that decay into lithium, which can suppress the expansive chemical reactions that cause degradation.
Application
Boron-containing compounds in concrete and cementitious coatings to protect against radiation damage and increase concrete’s durability and service-life
Advantages
- Boron turns into lithium in situ due to neutron radiation, inhibiting the volumetric expansion of concrete from alkali silica reactivity (ASR) after irradiation
- Replaces lithium salts, reducing cost of suppressing alkali-silica reaction
- Mitigates spot degradation, increasing service-life and durability of concrete-shielding structures
- Coating installs with or without formwork in a matter of days, applying to new and existing structures and allowing easy periodic replacement
Technology
Concrete formulations often use lithium salts to reduce the potential for alkali silica reactivity degradation and boron aggregates to provide neutron shielding. This formulation includes boron-containing compounds, such as fine powders, liquid solutions, or liquid suspensions, in the mixture of cementitious materials. When exposed to neutron radiation, the boron transforms in situ through radioactive decay into lithium. The formulation also contains hydrogenous compounds to aid in providing shielding from thermal neutrons as well as the thermalization of fast neutrons for additional shielding benefits. This protects the radiation-damaged aggregates and prevents alkali-silica reactions due to radiation-induced volumetric expansion. A shielding coating for concrete using this formulation can be applied directly to a surface prepared for bonding or mechanically as pre-formed panels that secure onto an existing structure. The protective coating can be applied in just days, reducing facility downtime and installation costs while allowing for regular inspection and replacement.
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