The US Department of Energy’s (DOE) Office of Nuclear Energy (NE) has awarded $111.2 million to three industry partners to develop Accident Tolerant Fuels (ATF). General Electric (GE), Westinghouse (WEC), and Framatome received the financial assistance awards in late 2018 with FY18 and FY19 funding. (Earlier post.)

The period of performance for these awards goes through 31 January 2021 with DOE and NE planning additional funding of $55.6 million in FY20 and $30 million in FY21, contingent upon Congressional approval.

An accident tolerant fuel is an industry term used to describe new cladding and fuel pellet designs that increase the safety and performance of nuclear fuel. Accident Tolerant Fuels are intended to enhance nuclear fuel reliability and safety, as well as the economics of nuclear reactor operations. The improved heat-tolerance of ATFs contributes to significantly improved reactor safety and security. ATFs also improve economics due to improved heat tolerances and increased agility to power reactors up and down while staying within safety margins.

In an open-access 2017 paper describing GE Global Research’s work, with Oak Ridge National Laboratory (ORNL) and partners, on iron-chrome-aluminum alloy cladding, GE researcher Raul Rebak explained that:

Because of the Fukushima accident of March 2011, the US Department of Energy (DOE) has a mandate from US Congress to develop accident tolerant fuels under cost sharing programs with the nuclear fuel vendors. Today many prefer to call the Accident tolerant fuel (ATF) as Advanced technology fuel (ATF). A fuel may be defined as having enhanced accident tolerance if, in comparison with the current UO₂-zirconium alloy system, it can tolerate loss of active light water cooling in the reactor core for a considerably longer time (called coping time) while maintaining or improving fuel performance during normal operations and operational transients, as well as in design basis and beyond design-basis events.

The enhanced fuel material should have improved reaction kinetics with steam; slower hydrogen production rate; improved cladding and fuel properties; enhanced retention of fission products.

—Rebak (2017)

The primary objectives for the new awards are as follows:

• GE will continue the development of Iron Chromium Aluminum (FeCrAl) alloys cladding trademarked IronClad. GE will also continue to develop its coating program for zirconium alloys trademarked ARMOR and the study of uranium dioxide-based ceramic metal fuels.

• Framatome will continue the development and deployment of chromium-coated zirconium alloy cladding with chromia-doped uranium oxide (UO₂) pellets (Cr-Cr₂O₃). Additionally, Framatome will continue and expand development efforts on its silicon carbide cladding concepts.

• Westinghouse will continue the development of Uranium Silicide (U₃Si₂) and Doped UO₂ trademarked ADOPT in chromium-coated zirconium alloy cladding. Westinghouse will also continue its silicon carbide cladding concepts development.

For the first 14-month budget period, all three fuel vendors are required to:

• Ensure an initial Lead Test Assembly has been installed in a US commercial power plant;

• Ensure prototypic pin segments have been installed in the Idaho National Laboratory (INL) Advanced Test Reactor’s water loop;

• Continue development of licensing approaches for the ATF concept that include the involvement of at least one nuclear power plant owner / operator per ATF concept, and;

• Ensure continued interaction with the US Nuclear Regulatory Commission (NRC) for licensing purposes for each concept.

Should Congress authorize additional funding for the ATF program, the vendors will expand operation of ATF-related concepts in DOE facilities—INL ATR, INL Transient Reactor Test (TREAT) facility, and out-of-pile tests—and commercial reactors with prototypic segments and rods. The companies would be expected to have agreed-upon licensing plans developed for future NRC approval for initial partial core loadings into commercial nuclear power plants during the mid-2020s.

Resources

• Raul B. Rebak (2017) “Iron-chrome-aluminum alloy cladding for increasing safety in nuclear power plants” EPJ Nuclear Sci. Technol., 3 (2017) 34 doi: 10.1051/epjn/2017029