New accident tolerant fuel (ATF) developed by France’s Framatome is being tested at the Idaho National Laboratory (INL), the US Office of Nuclear Energy (ONE) announced on 15 June. The fuel was recently installed for testing at INL’s Advanced Test Reactor (ATR). This is the second experiment currently in progress in the ATR that is being developed through the US Department of Energy’s (DOE’s) accident tolerant fuel programme. Earlier this year, General Electric (GE) installed ATF fuel cladding at the commercial Edwin I. Hatch NPP in Georgia. ATF has advanced cladding and fuel pellet designs that increase its safety and performance. The program was developed in 2012 after the Fukushima accident to bring new advanced fuel concepts to market by 2025.
Framatome is testing two new concepts at the laboratory: a chromium-coated cladding, designed to protect the fuel cladding from damage and oxidation at higher temperatures; and chromia-doped fuel pellets. Twenty-six miniature fuel rods are being tested in a special test loop that mimics the coolant conditions of a commercial light water reactor. The special coating is designed to protect the fuel cladding from damage and oxidation at higher temperatures, while the new fuel pellet mixture of chromium oxide and uranium oxide powders is expected to help the pellet last longer and perform better under accident conditions—leading to more affordable and efficient operations at commercial nuclear plants.
Twenty-six miniature fuel rods are being tested at INL in a special test loop that mimics the coolant conditions of a commercial light water reactor. The ATR can rapidly age fuel samples and duplicate years or even decades of neutron damage in only months. The fuel performance data will be used to help qualify the fuels with the US Nuclear Regulatory Commission. GE’s Global Nuclear Fuel, Framatome and Westinghouse are all working with DOE to commercialise their fuel concepts by 2025. Lead test assemblies of GNF's IronClad and ARMOR ATFs were loaded into Southern Nuclear Operating Company's Hatch unit 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 unit 2 in early 2019.
The timeframe is critical to the current fleet of reactors, ONE said. Many of them have 60 year operating licences and without renewal are set to expire in the 2030s. Getting these ATFs to market before then would increase their performance and improve their prospects for extended operation.
The current experiment will be tested at INL until January 2021 with additional fuel rods from GE and Westinghouse expected to be added in this autumn. The fuels will then be used in future tests at INL’s Transient Reactor Test Facility (TREAT) to determine each fuel concept’s failure point for additional qualifying data.
The ATR can rapidly age fuel samples to duplicate years of neutron damage in months. The fuel performance data will then be used to help qualify the fuels with the US Nuclear Regulatory Commission. The current experiment is due to run until January 2021, with additional fuel rods from other ATFs being developed under the DOE's ATF programme expected to be added later this year. The fuels will then be used in tests at the Transient Reactor Test Facility, also at Idaho National Laboratory, to help determine their safe operating limits. Similar ATF fuels are under development at Russia’s AA Bochvar Research Institute of Inorganic Materials (VNIINM), part of fuel company Tvel.