France’s Framatome has signed a contract with US utility Entergy to deliver and insert lead use fuel rods that utilise chromium-coated rods into unit 1 at Arkansas Nuclear One nuclear plant in the autumn of 2019.

Chromium coating is a feature of the accident tolerant fuel design that Framatome has been developing for several years as part of the Department of Energy’s (DOE) Enhanced Accident Tolerant Fuel (EATF) programme. This work also builds on collaboration with France's Atomic and Alternative Energies Commission (CEA) and in France, as well as Goesgen NPP in Switzerland.

The addition of a chromium coating to nuclear fuel's existing alloy cladding improves resistance to oxidation at high temperatures, reduces hydrogen generation in accident conditions, and increases wear and debris resistance in normal operations. Framatome said that since 2014, its experts have led the programme, "building on the collective knowledge, skills and expertise of nuclear professionals from utilities, US and French  national labs, universities and industry organisations around the world". Support from DOE allowed Framatome to significantly beat its initial target of 2023 to deploy this technology.

Framatome is also developing chromia-doped fuel pellets, which are intended to last longer and perform better under accident conditions. Fuel rods with both these features are currently undergoing tests in the Advanced Test Reactor at DOE’s Idaho National Laboratory (INL) which are due to run until January 2021. The fuel will then be used in tests at the Transient Reactor Test Facility, also at INL, to investigate their safe operating limits. The fuel performance data will be used to help qualify the fuels with the US Nuclear Regulatory Commission. Four test lead assemblies of Framatome fuel featuring chromia-doped fuel pellets and chromium-coated fuel cladding are expected to be loaded into Vogtle 2 in Georgia in spring 2019.

Other accident tolerant fuel developments

Two other companies are working with the DOE to commercialise their ATF concepts by 2025 - Global Nuclear Fuel (GNF) and Westinghouse. DOE's ATF programme, launched after the 2011 Fukushima Daiichi accident, aims to demonstrate performance by inserting ATF technology into a commercial reactor by 2022, to bring advanced fuel concepts to market by 2025.

Lead test assemblies of GNF's IronClad and ARMOR ATFs were loaded into Southern Nuclear Operating Company's Hatch 1 in March.

Lead test rods of Westinghouse's EnCore ATF, which is being developed in two phases, are due to be loaded into Exelon's Byron 2 in early 2019.

In addition, Russian fuel company TVEL is developing ATF for light water reactors and plans to begin testing it in late 2019. It is proposing a heat-resistant coating based on chromium for fuel rod cladding, the use of the 42HNM alloy, which will completely eliminate zirconium from the reactor core, as well as the use of uranium-molybdenum uranium dioxide fuel, which will increase the density of the fuel matrix.

Photo: Arkansas Nuclear One (Credit: Entergy)

Date: Tuesday, 25 September 2018
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