Jan. 21, 2016—Seth Grae, the head of Reston, Virginia-based Lightbridge Corp., is excited. In the next few years, his company will test an innovative all-metal nuclear fuel that should allow operators of existing nuclear plants to increase the power output of their facilities—and therefore their economic performance—while simultaneously improving their safety.
Lightbridge Corp.’s CEO Seth Grae says his innovative fuel can be used to uprate operating and advanced water-cooled reactors and meet EPA rules on reducing power plant carbon emissions. [Photo: NEI]
Grae’s company had been working, mostly overseas, on a different fuel type based on a thorium rather than a uranium fuel cycle, when it started to pay attention to what was happening in the United States. In the face of all-time low natural gas prices, as well as expensive equipment upgrades after the 2011 Fukushima accident, U.S. nuclear operators expressed the need to improve their plants’ economic performance while continuing to pay the utmost attention to plant safety. With most U.S. nuclear plants already having gone through major equipment upgrades to increase their power output, Lightbridge’s work with advanced nuclear fuels seemed an attractive opportunity for further power uprates.
The fuel’s economics are favorable, Grae notes, enabling up to 17 percent additional power uprates in operating reactors and up to 30 percent uprates in new-build reactors such as the Westinghouse AP1000.
“Lightbridge-designed metallic fuel enables existing reactor fleets to expand their generating capacity at the lowest total levelized cost per megawatt-hour of incremental electricity, which is a lower cost than even a new-build combined cycle gas-fired power plant,” Grae says.
In addition, reactor operators using this fuel can increase the time between refueling from the present 18-month average to 24 months, again improving economics. The fuel could be used in pressurized and boiling water reactors, as well as in small modular reactors.
Grae believes his company’s metal-based fuel offers several other advantages over the uranium oxide ceramic nuclear fuels used in nearly all commercial reactors worldwide. Partially based on fuels used in Russian nuclear-powered icebreaker ships, Lightbridge’s fuel design is easier to fabricate than the traditional ceramic uranium oxide pellet-in-tube design. The Lightbridge fuel is stronger, has better heat conductivity and will contain the products of the fission process much better, Grae says.
The fuel’s composition and unique “helical-twist” geometry—being “self-spacing” in the reactor core, there is no need for separate spacer assemblies—give it better heat transfer characteristics, allowing it to operate at considerably lower temperatures (by 1,000 degrees C) than oxide fuels, thus substantially increasing safety margin both in normal operation and in accident conditions.
Lightbridge fuel rods in a test fuel assembly. The company is preparing to produce fuel samples for testing under commercial operating reactor conditions in Norway. [Photo: Lightbridge]
In April 2015, the Nuclear Utility Fuel Advisory Board (NUFAB), a group of electric utilities that own and operate about 50 percent of the nuclear plants in the United States—including Exelon Generation, Southern Co., Dominion Generation and Duke Energy—asked the U.S Nuclear Regulatory Commission to prepare to review Lightbridge’s advanced fuel design in 2017, with a goal of testing fuel samples in an operating U.S. pressurized water reactor as early as 2020. The group also plays an advisory role to Lightbridge.
“NUFAB believes this fuel product provides opportunities to significantly improve safety and fuel cycle economics,” the group said.
Grae says the interest shown by the four utilities NUFAB represents—and by fuel vendor suppliers—is greater than the company initially expected.
Lightbridge has signed contracts for work to fabricate and test the fuel design outside of the United States. “The company has all the approvals it needs to proceed,” Grae says.
Last September Lightbridge signed a contract with Canadian Nuclear Laboratories to begin fabricating, by the end of 2016, prototype fuel assemblies for irradiation testing. On Jan. 12, the company contracted with BWXT Nuclear Energy Inc., to provide backup fuel samples.
The same day, Lightbridge announced that the Norwegian Radiation Protection Authority had given approval for the country’s Halden research reactor to conduct a five-year irradiation testing program of Lightbridge’s metallic fuel under commercial reactor operating conditions, beginning next year. Post-irradiation testing will be conducted at Sweden’s nearby Studsvik Laboratory and the results shared with the NUFAB group and with the fuel supplier community.
“Our growing list of partners is further validation of the global interest in our patented fuel technology,” Grae says.
He notes that last month’s Paris climate agreement commits virtually all countries to reduce CO2 emissions. For the United States, the U.S. Environmental Protection Agency’s Clean Power Plan provides that power uprates to reactors will count towards each state’s compliance with the plan’s emissions reduction requirements.
“Our fuel is uniquely designed to achieve power uprates while improving power plant economics and increasing the safety margins, helping to decarbonize energy supply.”
For more details on the Lightbridge metallic fuel prototype, see here.