US brings accident-tolerant fuel target nearer

The US Nuclear Energy Institute (NEI) reported yesterday that coordination among the various entities involved in the development of accident-tolerant fuels (ATF) has "progressed to the point that all stakeholders now agree on the feasibility of a 2023 timeline". Citing speakers at the Nuclear Regulatory Commission's (NRC's) 12 April briefing on ATF, the NEI said US research, development and licensing frameworks "need to undergo a paradigm shift" to accelerate the way innovative nuclear technologies such as ATF are brought to market.

Accident-tolerant fuels have the potential to endure the loss of cooling in a reactor core for longer than current fuel designs and widen the existing safety margin for nuclear plants, NEI noted. They can also improve the performance of existing nuclear plants with longer-lasting fuel, and pave the way for licensing fuels for advanced reactors. The industry is currently working on different fuel designs from four primary vendors, it said. These are Framatome, Global Nuclear Fuel (GNF), Westinghouse and Lightbridge.

NEI said the Electric Power Research Institute (EPRI) had concluded that these fuels potentially offer benefits both under normal operations and in various accident scenarios.

"Not only do they promise increased resistance to damage under accident conditions but there also is the potential to allow for more flexibility and efficiency during normal operations, which could bring economic benefits to operators," NEI said.

Southern Nuclear's Executive Vice President and Chief Nuclear Officer Danny Bost said quantifying the safety benefits could result in simplified regulatory requirements and compliance cost reductions for the industry.

The first lead test assemblies for two different ATF designs from GNF have been loaded into Southern Nuclear's Hatch nuclear power plant, a 876 MWe boiling water reactor in Georgia.

Bost also said that, as the operating licences of half or more of the USA's current light water reactor fleet will have expired by the mid-2030s, operators seeking second licence renewals for those reactors should be able to take advantage of the operational economic benefits of ATF if they are available by the mid-2020s. The NRC's role in helping bring ATF to market as soon as possible requires "transformational" changes at the agency in how these innovations are qualified and licensed, he added.

NEI said that, historically, data from experimental testing programmes help inform and establish the development of computer-based modelling and simulation codes that then cause additional rounds of experimental testing and confirmation.

"Now, thanks to the US Department of Energy's superior predictive modelling and simulation technologies, the data assessment and model development can proceed in parallel along with confirmatory benchmark testing," it said. NEI suggested this approach in its February comment letter on the NRC's draft project plan for licensing ATF.

Michelle Bales, senior reactor systems engineer in the NRC's Office of Nuclear Regulatory Research, told the 12 April meeting, "There is alignment with the idea to do parallel activities versus activities in series and to have a lot of interaction."

NEI Chief Nuclear Officer Bill Pitesa said the $85 million that was recently appropriated by Congress for the ATF programme in the fiscal 2018 omnibus budget, and signed into law by the president, "reflects a resounding bipartisan show of support for the work being done on the ATF programme".

Mirela Gavrilas, director of safety systems in the NRC's Office of Nuclear Reactor Regulation, added that the industry goal to have ATF fuel batches loaded by 2023 was feasible.

Researched and written
by World Nuclear News