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Mar 19, 2023

“We have to get this right": GE Hitachi's Sean Sexstone on new nuclear

Watch below for our one-on-one with Sean Sexstone, GE Hitachi’s Executive

Watch below for our one-on-one with Sean Sexstone, GE Hitachi's Executive Vice-President of Advanced Nuclear.

As consensus grows that advanced nuclear could play an important role in decarbonizing the electric grid and other sectors, companies are racing to deploy grid-connected small modular reactors (SMR) by the end of the decade.

GE Hitachi (GEH) has hopes for its BWRX-300, the 10th evolution of GE's boiling water reactor design. The 300 MW water-cooled reactor design is based on the company's Economic Simplified Boiling-Water Reactor (ESBWR), which is already licensed by the U.S. Nuclear Regulatory Commission.

GEH Executive Vice President of Advanced Nuclear Sean Sexstone refers to the BWRX-300 as a "simply made reactor" because it uses the same equipment and fuel that are already in GE reactors around the world.

"Ninety-five percent of it has been done," said Sexstone in an exclusive interview with Power Engineering. "Maybe these are a little smaller in scale, but very proven."

This is one reason why GE Hitachi believes the BWRX-300 can become the cheapest, quickest and lowest-risk SMR to market.

Sexstone said the company took the basic ESBWR design and simplified it, including several design safety features which are new to boiling water reactor technology.

The safety relief valves, deemed the most likely cause of a loss of coolant accident (LOCA), were eliminated in the design. The isolation condenser system (ICS) provides overpressure protection in accordance with ASME BPV code, section III, class 1 equipment (Status Report – BWRX-300 – GE Hitachi and Hitachi GE Nuclear Energy). In order to accommodate this change, the design pressure has been raised by 20% from previous boiling water reactors. GE Hitachi has also implemented integral isolation valves, which close to stop the loss of coolant in an accident scenario.

In general, because of their relatively small physical footprints, reduced capital investment and more flexible siting, SMRs are viewed as an antidote to the cost overruns that have plagued large-scale nuclear projects.

Sexstone said GE Hitachi has been able to eliminate roughly 90% of the concrete and steel from the ESBWR, leaving a total power plant footprint smaller than a football field. The company projects the BWRX-300 to have up to a 60% lower capital cost per megawatt compared with the typical water-cooled SMR.

But despite policy support and market growth for new nuclear, the economics are daunting.

First of a kind (FOAK) SMR costs could be as high as $8,000 per kilowatt (kW) and as low as $6,000 per kW, according to industry estimates cited by Wood Mackenzie. Analysts there expect that FOAK costs will be at the high end of this range, and could be even higher, as developers build out early-stage projects.

Sexstone told Power Engineering supply chain partnerships will be crucial to success.

"If we’re going to build two, three hundred or more of these [BWRX-300s], I think it's going to be crucial that we have really good partnerships and we’re able to grow the supply chain in Canada, in the U.S., and globally," he said.

In March 2023 the company announced a technical collaboration agreement with Ontario Power Generation (OPG), Tennessee Valley Authority (TVA) and Synthos Green Energy (SGE) aimed at speeding up the regulatory process and deployment.

Through the agreement, the partners will invest a total of around $400 million in the development of the BWRX-300 standard design and detailed design for key components, including reactor pressure vessel and internals. The collaborators are forming a Design Center Working Group with the purpose of ensuring the standard design is deployable in the U.S., Canada, Poland and beyond.

"The goal is, once that standard is set, it doesn't change," said Sexstone. "Then we can work on driving down the cost curve as we deploy multiple reactors."

He added: "We have to get this first one or two right."

OPG aims to deploy the BWRX-300 at its Darlington New Nuclear Project site in Clarington, Ontario. A commercial contract between GE Hitachi, Ontario Power Generation, SNC-Lavalin and Aecon was inked in January 2023. In 2022 the Canada Infrastructure Bank committed C$970 million ($713 million) toward the project in the bank's largest investment in clean power to date.

This would be the first grid-scale SMR in North America. Site preparation is currently underway, with GE-Hitachi expecting approval to begin construction by late-2024. The reactor could be built by late-2028 or early-2029.

"We’re getting the site ready, finalizing both standard and site-specific design, ordering long lead engineering equipment important to maintaining the construction schedule," Sexstone said.

In August 2022, TVA began planning and preliminary licensing for potential deployment of the BWRX-300 at its Clinch River Site near Oak Ridge, Tennessee. In June 2022 SaskPower announced that it had selected the BWRX-300 for potential deployment in Saskatchewan in the mid-2030s.

GE Hitachi, NuScale and Holtec are among the companies developing water-cooled SMRs. Other advanced reactor technology under development includes the use of nontraditional coolants such as liquid metals, salts and gases.

"We’ve got all these projects starting and funded by the government and private industry to develop new designs," said Doug True, who is chief nuclear officer of the Nuclear Energy Institute (NEI). "It's just a really exciting time to be in the industry."

Another boost came from the federal Inflation Reduction Act (IRA), which offers a generous tax credit for advanced nuclear reactors and microreactors.

This has helped SMRs become even more attractive to utilities. True said NEI surveyed Chief Nuclear Officers at U.S. utilities in 2022, asking how much advanced nuclear they would need to meet decarbonization goals. He said the cumulative response was greater than 90 GW.

NEI updated the survey following the IRA's passage and saw about a 10% increase, with personnel saying they’d need about 100 GW in new nuclear.

For another perspective, recent assessments cited in the Electric Power Reserarch Institute (EPRI) Advanced Reactor Roadmap suggest that over the next 10-20 years, the need to deploy advanced reactors in the United States and Canada will rival, and likely exceed, the scale of the entire existing operating nuclear energy capacity in North America.

"There are going to be challenges," said True. "But the way that other countries have gotten their costs down for nuclear [reactors] is by getting good at building them. These first plants will get there, and we’ll learn, and we’ll get better and better."

Wood Mackenzie's modeling shows that if costs fall to $120/MWh by 2030, SMRs will be competitive with nuclear pressurized water reactors (PWRs), gas and coal – both abated and unabated – in some regions of the world.