Hatch unit restarts with accident-tolerant fuel

07 March 2018

Unit 1 of the Edwin I Hatch nuclear power plant in the US state of Georgia has begun operating with test accident-tolerant fuel assemblies. The fuel, loaded during a recent outage, is the first of its kind to be installed in a commercial nuclear reactor.

Hatch NPP - 460 (Southern Nuclear)
The twin-unit Hatch plant (Image: Southern Nuclear)

Southern Nuclear took the 876 MWe (net) boiling water reactor (BWR) offline for a planned refueling and maintenance outage on 4 February. In addition to refueling the reactor and performing regular maintenance and testing, workers made upgrades to plant systems and components. During the outage, in collaboration with Global Nuclear Fuels (GNF), lead test assemblies of accident-tolerant fuel were installed. The reactor was restarted on 4 March.

Lead test assemblies using an iron-chromium-aluminium fuel cladding material, known as IronClad, and coated zirconium fuel cladding, known as ARMOR, were installed in Hatch 1.

IronClad material is designed to provide oxidation resistance and "excellent material behaviour" over a range of conditions, with low oxidation rates of at higher temperatures further improving safety limit margins, GNF says.

Two variants of IronClad material have been installed at unit 1 of the Hatch plant: one in a fuel rod form but not containing fuel, while the other is in the form of a solid bar segment.

The IronClad lead test assemblies are the first developed through the US Department of Energy's Enhanced Accident-tolerant Fuel programme to be installed in a commercial nuclear reactor.

ARMOR coating is applied to a standard zirconium fuel rod. It provides enhanced protection of fuel rods against debris fretting, and greater resistance to oxidation, than standard zirconium cladding. ARMOR lead test assemblies contain fuelled rods have been installed at Hatch 1.

"Our top priority is the safety and health of the public and our employees, and this game-changing technology will make plants even safer, resulting in more flexibility in our operations," John Williams, nuclear fuel director at Southern Nuclear, said. "This is not a small step, but a leap for our industry."

Hatch 1's next refueling outage is in 24 months' time.

Hatch, a two-unit BWR plant, is owned by Georgia Power, Oglethorpe Power, MEAG Power and Dalton Utilities, and is operated by Southern Nuclear.

Lead test assemblies of GNF's accident-tolerant fuel are also planned to be installed at Exelon Generation's Clinton power plant in 2019.

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

Researched and written
by World Nuclear News

Filed under: Nuclear fuel, USA, Innovation