While MSRs have numerous design advantages in safety, waste management, cost, and efficiency over LWRs, the concept requires further development and validation.
Molten salts have a corrosive effect
on the structural materials used in the reactor vessel and heat exchangers. A major area of development is fine tuning the coolant to control its corrosive effects on reactor components (pipes, pumps, et al.) Another focus is on developing metal alloys and structural ceramics that are resilient to radiation or chemical reactions.
Another challenge for MSR is tritium control. It is the only isotope that could escape during normal operating conditions. Tritium stripping technology from irradiated salt still needs to be adequately demonstrated. Researchers are also experimenting with double-walled heat exchanger designs.
The robustness of the MSR control system and related instrumentation also needs to be tested to ensure passive and active safety requirements are met. Instrumentation like flow meters must be made to be tolerant to high temperatures and corrosive materials. To date, researchers are still tackling individual technical challenges expected in a MSR reactor. No startup has yet designed a complete MSR plant for regulator approval.
Lastly, with each MSR reactor type, the fuel cycle must be developed. Specifically, this means how the reactor is refueled and what happens to the waste.
All aspects of the plant equipment and operation then must be qualified to the regulator. The regulators also must come up with a safety and licensing approach that accommodates historical requirements that are appropriate to regulate the unique features of MSR technology.