Global Nuclear Fuel (GNF) accident-tolerant fuel assemblies have been loaded into a US reactor for the first time. Lead test assemblies using the company's ARMOR-coated zirconium cladding and IronClad accident-tolerant fuel solutions have been installed at Exelon's Clinton boiling water reactor power plant in Illinois.

The assemblies contain three varieties of GNF's IronClad solution, and are the first fuelled ferritic steel-based cladding assemblies to be installed in a commercial reactor, the company said. Unfuelled IronClad lead test rods and fuelled ARMOR-coated zirconium cladding lead test rods were installed at Georgia Power's Hatch in 2018.

Accident-tolerant fuel - or ATF - is a term used to describe new technologies that enhance the safety and performance of nuclear fuel. ATF may incorporate the use of new materials and designs for cladding and fuel pellets. The GNF assemblies were developed as part of the US Department of Energy's (DOE) accident-tolerant fuel programme and manufactured at GNF's facility in Wilmington, North Carolina.

GE Hitachi Nuclear Energy President and CEO Jay Wileman said the company was, with the support of the industry and DOE, advancing the fuel technology at an "aggressive pace".

IronClad solutions are designed to provide substantial oxidation resistance and superior material behaviour over a range of conditions compared to previous offerings. The low oxidation rates of the material at higher temperatures further improves safety limit margins, GNF said. GE Research supported the development of one of the IronClad solution varieties installed at Clinton by providing engineering support and fabricating components that went into making the fuel rods.

ARMOR-coated zirconium cladding provides enhanced protection of fuel rods against debris fretting, the company said, as well as providing oxidation resistance and superior material behaviour over a range of conditions. This makes it an attractive technology to improve safety limit margins and abrasion resistance.

Framatome and Westinghouse are also developing ATF concepts with the help of DOE funding. ATF development programmes are also under way in China and Russia.

GNF is a GE-led joint venture with Hitachi Ltd and operates primarily through Global Nuclear Fuel-Americas, LLC in Wilmington, North Carolina and Global Nuclear Fuel-Japan Co Ltd in Kurihama, Japan.