US-based Lightbridge Corporation and Enfission, a joint venture between Lightbridge and Framatome, have demonstrated the manufacturing process and fabrication of Lightbridge Fuel surrogate rods in a length that could be usable in NuScale Power’s small modular reactors (SMRs).

The demo included the production of several coextruded rods using an internally developed and patented coextrusion process. The fuel rod design is expected to increase core performance, extend core life, lessen the number of refuelling outages, and offer reduced levelised cost of electricity.

The NuScale length Lightbridge Fuel rods (6ft) were coextruded from billets contained in a zirconium canister and resulted in a bonded cladding surrounding the surrogate fuel material core. The surrogate materials were designed to simulate the flow stresses, including temperatures and extrusion pressures, expected in the manufacture of the Lightbridge Fuel rods utilising a uranium-zirconium alloy.

Lightbridge President and CEO Seth Grae said this represents “first reduction to practice for our proprietary manufacturing process and confirms rod fabrication feasibility to 6 feet in length as a first step” and “a leap forward towards commercial production of Lightbridge Fuel”. He added: “We are now moving rapidly towards a similar demonstration of full-length (12ft) coextruded rods for the existing US fleet of large commercial nuclear power plants and we look forward to providing further updates.”

Demonstration of the coextrusion manufacturing process follows a May memorandum of understanding between NuScale and Enfission on collaboration to develop research and testing programmes to explore the application of the Lightbridge Fuel technology in NuScale’s natural circulation SMR design.