World's largest chloride salt system in place

Wednesday, 19 October 2022

"The test is the world's largest chloride salt system developed by the nuclear sector," Southern and TerraPower said in a joint statement. "The project culminates years of separate effects testing and is expected to demonstrate how the MCFR technology will perform in delivering a commercial-scale, cost-effective, carbon-free molten salt reactor energy source by 2035."

The Integrated Effects Test (IET) is a multi-loop test facility that builds off a series of smaller testing campaigns to inform its design. The non-nuclear system is heated by an external power source. Data from operation of the test will be used to help validate the thermal hydraulics and safety analysis codes needed to demonstrate molten salt reactor systems.

The IET also supports the development and operation of the Molten Chloride Reactor Experiment (MCRE) at Idaho National Laboratory (INL), a proof-of-concept critical fast-spectrum salt reactor. At less than 200 kW, the reactor will provide experimental and operational data.

Both the IET and the MCRE will inform the design, licensing and operation of an approximately 180 MW MCFR demonstration planned for the early 2030s time frame.

The IET project continues work initiated in 2015 by Southern subsidiary Southern Company Services and TerraPower under the US Department of Energy (DOE) Advanced Reactor Concepts (ARC-15) award, a multi-year effort to promote the design, construction and operation of Generation-IV nuclear reactors. The project team also includes Core Power, EPRI, INL, Oak Ridge National Laboratory and Vanderbilt University. The programme represents a USD76 million total project investment with a 60%-40% public-private cost share.

"The completion and installation of the Integrated Effects Test is an important step to advancing TerraPower's Molten Chloride Fast Reactor technology," said Jeff Latkowski, TerraPower's senior vice president of innovation programmes. "The MCFR will play a pivotal role in decarbonising heavy industries, and we are proud to work with Southern Company, Core Power and other partners to develop the systems necessary to bring new reactors to market."

The IET will be used to help train a new crop of molten salt project personnel. Southern's research and development organisation and TerraPower will work with US universities to submit research proposals through the DOE's Nuclear Energy University Program to train students and research the additional instruments, equipment and components that would be compatible with molten salt systems.

TerraPower's MCFR technology uses molten chloride salt as both reactor coolant and fuel, allowing for so-called fast spectrum operation which the company says makes the fission reaction more efficient. It operates at higher temperatures than conventional reactors, generating electricity more efficiently, and also offers potential for process heat applications and thermal storage. An iteration of the MCFR - known as the m-MSR - intended for marine use is being developed.

TerraPower is also developing Natrium technology - featuring a sodium fast reactor combined with a molten salt energy storage system - a demonstration plant for which is to be built at Kemmerer in Wyoming.