A Small-Scale Test Facility with a Big Role in Advanced Nuclear Reactor Safety

Professor Mark Anderson of the UW Thermal Hydraulics Laboratory (UW-THL) in Mechanical Engineering has been awarded a large collaborative award contract with TerraPower for the Natrium reactor IET Loop Testing project.

The UW-THL will construct and perform testing on a scaled Integral Effects Test (IET) facility to investigate natural circulation behavior during post-scram cooling phases in sodium-cooled fast reactors. The project will deliver critical experimental data to reduce uncertainty in thermal-hydraulic modeling and assessment of Natrium’s sodium-cooled reactor design, directly supporting passive safety validation and regulatory licensing efforts. By scaling down the full reactor system, the IET facility offers a cost-effective means of generating high-quality, regulatory-grade experimental data in sodium. Key design features include insulated structures that reproduce full-scale thermal behavior, an electrically heated core that simulates decay heat, and carefully scaled flow and heat-removal pathway that preserves important thermal-hydraulic phenomena. These capabilities will provide valuable insight into natural circulation behavior and support accurate prediction of post-scram cooling performance.

Outcomes include:

• Improved confidence in passive safety systems for the Natrium reactor technology.
• Unique specific scaled data sets to validate computational system code tools

Ultimately, this work strengthens the technical foundation for deploying the Natrium nuclear reactor technology and strengthens the regulatory case for post-scram heat removal from core decay heat.

Work is underway with the UW project team including Dr. Mark Anderson (PI), Paul Brooks, Dr. Ian Jentz, Seth Jones, Dr. Michael Corradini, Graduate students, Postdocs, UW-PSL, and administrator Zach Smith.