Graphite Components for Molten Salt Reactors

A new ASTM International standard will help in the design and monitoring of graphite components for molten salt design nuclear reactors. Building on ASTM standard D8091, which presents guidelines on how to impregnate graphite with molten salt, a new standard has been developed by ASTM’s committee on petroleum products, liquid fuels, and lubricants (D02) which provides a guide on how to measure the strength of impregnated graphite at elevated temperatures.

ASTM International member Martin Metcalfe notes that there is growing interest in next-generation nuclear reactors of the molten salt design.

“Such designs include graphite components which, when submerged in the molten salt, will experience penetration of their porosity by the molten salt,” says Metcalfe, an independent consultant. “To test the performance of graphite components impregnated with molten salt, it is necessary to provide methods both for producing representative material and for subsequent testing of that material.”

According to Metcalfe, the new standard, soon to be published as D8377, will be useful to graphite manufacturers, reactor designers, reactor operators, and regulatory bodies.

“Measurements such as those described in the new standard may be required to qualify graphite for selection, but also to monitor material performance and assess component integrity on material extracted or discharged from an operating plant,” says Metcalfe.

The subcommittee on manufactured carbon and graphite products plans to develop further new standards in this area of application, including a proposed guide for the testing of other graphite properties at elevated temperatures, representative of a reactor environment in which the salt is in a molten state. All interested parties are invited to join in the subcommittee’s activities.