X-energy to develop second Project Pele microreactor design

Project Pele was launched in 2019 with the objective to design, build, and demonstrate a prototype mobile nuclear reactor within five years. The initiative is led by the DOD's Strategic Capabilities Office (SCO), which is working in collaboration with the US Department of Energy, the Nuclear Regulatory Commission (NRC) and the US Army Corps of Engineers, as well as with industry partners.

BWXT and X-Energy were selected in 2019 to develop a final design for the prototype reactor, with BWXT contracted in June 2022 to build a prototype microreactor. Executing the contract option with X-energy builds upon X-energy's work already completed under Project Pele and continues funding for the company to develop a reactor design which is ready for licensing by the Nuclear Regulatory Commission (NRC) for both commercial ventures and military resiliency, SCO said.

The contract option for one year of work by X-energy "will not result in a completed engineering design, but will allow a thorough analysis of design options, leading to a Preliminary Engineering Design and initiation of a regulatory preapplication process".

"The Strategic Capabilities Office specialises in adapting commercial technology for military purposes," said SCO Director Jay Dryer. "By nurturing and developing multiple microreactor designs, SCO will not just provide options for the military Services, but will also help jump-start a truly competitive commercial marketplace for microreactors."

Prototype progress

The BWXT-designed prototype reactor - a high-temperature gas-cooled reactor fuelled by TRISO (TRIstructural-ISOtropic) high-assay low-enriched uranium (HALEU) - will operate at between 1 and 5 MWe and will be transportable in commercially available shipping containers. The prototype is on schedule for completion over the course of 2024 and operation in 2025, SCO Programme Manager Jeff Waksman told an American Nuclear Society webinar last month.

The project is now in the final design phase prior to receiving final regulatory approval from the US Department of Energy, which is anticipated to happen in spring of 2024, he said. "We are now ordering hardware, we are making fuel, we are forging the containment vessel, we're making moderator blocks … we are no longer a paper reactor, an academic reactor, we are now becoming very real."

Assuming regulatory design approval is granted as anticipated, work will start to assemble the reactor over the course of 2024, with components that will already have arrived at BWXT's Lynchburg, Tennessee facility, Waksman said. By early 2025, the reactor is expected to be shipped to Idaho National Laboratory. It will then be fuelled and shipped to a desert location for initial testing before undergoing a final operational readiness review. "If all goes according to the schedule we have right now we will be able to turn the reactor on before the end of calendar year 2025," Waksman said.

The reactor will then be taken down so that its transportability can be demonstrated, he added.

Testing and operation of the prototype reactor, which is not a commercial project, will be regulated by the US Department of Energy rather than the NRC.

The DOD uses around 30 TWh of electricity per year and more than 10 million gallons of fuel per day, and the US military is the nation's largest single energy consumer. The US Congress, in the 2019 National Defense Authorization Act, directed the DOD to site and operate at least one nuclear reactor at a DOD facility within a decade, to meet energy resilience and assurance needs. Another project to meet the US military's energy needs using nuclear reactors recently saw the US Department of the Air Force, in partnership with the Defense Logistics Agency Energy, select Oklo Inc to site, design, construct, own and operate a microreactor facility to deliver electricity and steam at the Eielson Air Force Base in Alaska.