Scientists are working to create a green energy future powered by fusion reactors, but achieving this goal requires developing materials that can withstand extreme conditions. A new study from the Massachusetts Institute of Technology (MIT) analyzes ways to prevent cracks in these reactors.
The study focuses on mitigating damage along grain boundaries, or defects in a metal’s atomic structure. The researchers discovered that adding iron silicate to the vacuum vessel helps distribute helium atoms created by high-energy neutrons uniformly across the vessel, rather than congregating at grain boundaries where they can form cracks.
Building robust materials for fusion reactors is crucial, as these devices generate electricity while containing super-hot plasma. The MIT Energy Initiative (MITEI) is dedicated to finding ways to make future reactors more reliable and efficient.
The study’s authors investigate new designs that can keep coolant and plasma apart while allowing neutrons to pass through. However, the high-energy neutrons interact with the material’s atomic structure, creating helium atoms that seek areas with low “embedding energy.” Unfortunately, these areas are often grain boundaries, which can lead to cracks in as little as six months.
To prevent this, Li and his team created a material that distributes helium atoms away from potential failure points. They used a metric called “atomic-scale free volume” to examine candidates and narrowed it down to iron silicate, a ceramic that is mechanically robust, metal-compatible, and resistant to radioactivity.
The researchers tested the material by implanting iron silicate into an iron sample and confirmed that helium atoms were being stored in the bulk lattice. Only 1 percent of the material is needed to prevent catastrophic failures.
This breakthrough offers a significant step forward in developing materials for nuclear fusion reactors, which could provide green energy for homes and industry.
Source: https://www.popularmechanics.com/science/energy/a61997966/mit-vaccum-vessel-helium-iron-silicate/