New material for safer, economical nuclear reactors

Scientists, including one of Indian origin, have created a nanoceramic material which may be used in next-generation nuclear reactors that will operate at higher temperatures and radiation fields, producing energy more efficiently and economically.
The material can not only withstand the harsh effects of radiation, but also becomes tougher under radiation, researchers said.
Traditionally, water has been used as the primary coolant in reactors, absorbing the heat released from fission reactions.
Though water poses fewer risks of corrosion damage to materials, there are also limits to the temperatures up to which water-cooled reactors can operate - and in advanced reactors, increasing their temperature is the best way to increase energy production.

New coolants, such as liquid metals like sodium and lead, are effective at much higher temperatures, but also are much more corrosive to the materials from which a nuclear reactor is made.
"There is a preferred use of metallic materials for structural components, but many of these materials cannot withstand high-temperature corrosion in advanced reactors," said Kumar Sridharan, professor at the University of Wisconsin-Madison in the US.

"Corrosion is a surface phenomenon, so if you put coating on the surface, you need that coating to withstand high radiation doses without becoming embrittled," said Sridharan.
Sridharan and collaborators at the Istituto Italiano di Tecnologia (IIT) in Italy, characterised an aluminium oxide nanoceramic coating - a new material that can withstand the harmful effects of these high-temperature liquid metals in advanced reactors.

This material could be a huge boon to these systems, researchers said.
Many materials tend to harden and crack when exposed to radiation. However, aluminium oxide nanoceramic coatings toughen, ultimately benefiting from irradiation, said Fabio Di Fonzo, a team leader at the IIT Center for Nano Science and Technology.
"The pinpoint of our work is the demonstration that an amorphous or nanoceramic material can improve during irradiation, and this opens the path toward a different view of nuclear materials, specifically where coatings are concerned," he said.
The research was published in the journal Scientific Reports.