The US Tennessee Valley Authority (TVA) will load four new 3D-printed fuel assembly brackets at its Browns Ferry NPP in spring 2021, the Department of Energy’s (DOE’s) Office of Nuclear Energy (ONE) announced.
The brackets will be the first of their kind loaded into a commercial reactor and demonstrate the latest innovations in additive manufacturing and artificial intelligence, ONE said.
The components were recently manufactured at Oak Ridge National Laboratory (ORNL) in a joint project with TVA and the utility’s fuel supplier, France’s Framatome, as part of the lab’s Transformational Challenge Reactor (TCR) programme. The new demonstration programme is designed to introduce new manufacturing techniques and approaches to industry partners in order to speed up the deployment of nuclear systems.
ORNL additively manufactured channel fasteners for Framatome’s boiling water reactor fuel assembly using a micro-welding process. The team created a 3D-printed part compliant with reactor safety regulations for deployment in a commercial reactor. The lab is also providing all of the 3D digital data captured during the manufacturing process that details each layer of the print, which can then be used to certify the quality of the bracket.
“This is one of the first steps in ORNL’s coordinated efforts with the Nuclear Regulatory Commission’s Office of Regulatory Research and the nuclear vendors to prove that a new and greatly accelerated approach for qualified part fabrication is possible,” said TCR Director Kurt Terrani.
The channel fasteners perform an essential function in the fuel assembly and are easy to fabricate using the new manufacturing techniques. This made it an ideal part for the team to print and use for the demonstration. It could also open the door to manufacturing more complex parts moving forward, ONE noted.
The new brackets will be loaded into Browns Ferry 2 in March during a scheduled refuelling outage. They will remain in the reactor for six years, with inspections planned during outages and after use.
“TVA is a leader in clean energy and innovation,” said Dan Stout, TVA’s Director of Nuclear Technology Innovation. “Being the first to use these additively manufactured components supports an innovative manufacturing approach that could pave the path for use across the existing nuclear fleet and in advanced reactors and small modular reactors.”
“Partnering with ORNL and TVA to pioneer additive manufacturing for the nuclear industry is a step change in the way we think and how we will design our components in the future,” said John Strumpell, Framatome’s Research and Development Manager for the US Fuel Business Unit.
The fuel assembly channel fasteners printed at ORNL were installed on ATRIUM 10XM fuel assemblies at Framatome’s nuclear fuel manufacturing facility in Richland, Washington, Framatome said. The channel fasteners secure the fuel channel to the boiling water reactor fuel assembly. The fuel channel wraps around the assembly and guides coolant flow up through the fuel rods. Channel fasteners have traditionally been fabricated from expensive castings and required precision machining. Additive manufacturing is a more efficient way to achieve the tight specifications of these components, Framatome explained.
“Our use of additive-manufacturing techniques is a major advancement for Framatome and the nuclear energy industry,” said Ala Alzaben, senior vice president of the Commercial and Customer Centre of the Fuel Business Unit at Framatome. “Working with industry leaders at ORNL and TVA, our team developed a new, innovative way to manufacture components that will help to reduce costs while maintaining plant safety and reliability.”
Framatome’s initiative to introduce additive manufacturing to nuclear fuel began in 2015 and is focused on stainless steel and nickel-based alloy fuel assembly components. Framatome fuel experts in France, Germany and the USA developed this technology in close collaboration with customers worldwide. This initiative is also funded by the European Union and DOE and relies on several industry partners around the world to progress and advance the use of these technologies.
Photo: Additively manufactured channel fasteners for Framatome’s boiling water reactor fuel assembly (Photo: ORNL)