X

X-energy

Develops SMR reactors and TRISO fuel

Engineer 4 - Nuclear Safety Analysis

Full-Time
$112k - $221k+ 401(k) match
Expert
Bachelor's
Rockville, MD, USA
In PersonFour to five days in the office each week; travel is 10%.
Mechanical Engineering

About the job

Requirements
  • A bachelor's degree in engineering, such as nuclear, chemical, or mechanical engineering, from an ABET-accredited university is required.
  • Typically, ten years of experience in an engineering role is required for Level IV; fifteen years for Level V; and twenty years for Level VI.
  • A master's degree in engineering or a related field may substitute for two years of experience.
  • A Ph.D. in engineering or a related field may substitute for three years of experience.
  • Previous experience at X-energy meeting performance standards may substitute for years of experience.
  • The standard schedule is 8:00 a.m. to 5:00 p.m. Eastern Time, Monday through Friday.
  • The role expects 10% travel and four to five days in the office.
Responsibilities
  • Perform safety analyses and/or probabilistic risk assessments in accordance with applicable industry standards and guidance; author and review related documents and provide results and insights to support the design of X-energy technologies.
  • Use software to create and maintain models representing the design of X-energy projects and technologies.
  • Produce and review calculation documents that support and control probabilistic risk assessment or safety analysis model files; apply the models to support the design and future operation of projects and technologies.
  • Lead system-level thermal-fluid analyses and process design using one-dimensional system simulation codes.
  • Guide and initiate source-term analyses and radiological consequence analysis.
  • Lead development of models supporting licensing-basis event analysis and evaluations.
  • Perform elementary mathematical model programming for engineering calculations.
  • Develop verification and validation plans, including code verification and validation efforts.
  • Lead the core tasks and responsibilities independently, without close supervision.
  • Provide feedback and guidance to more junior team members in carrying out core tasks and responsibilities.
  • In collaboration with engineering leadership, set enterprise-level technical direction by developing and owning technology- or discipline-specific roadmaps, best practices, and/or design criteria.
  • Interpret, apply, and assess standards with increasing proficiency.
  • Collaborate with engineering and project leadership and the safety analysis team to update stakeholders on project progress, maintain priorities, adapt to changes, and raise concerns about project or timeline issues.
  • Provide engineering and technical expertise and guidance to identify, analyze, and resolve problems of increasing scope and complexity.
  • Contribute to team decisions and business objectives through planning, organizing, estimating, scheduling, and monitoring work; handle changing priorities and make decisions that may affect team work.
  • Prepare technical reports, correspondence, documentation, calculations, and sketches for well-defined problems and analyses of increasing scope and complexity.
  • Conduct engineering and related studies and complete routine engineering projects with minimal oversight, increasingly managing project schedules and interfaces independently.
  • Develop and maintain safety-basis documents and program procedures.
  • Identify and describe how safety-basis requirements relate to existing and new designs and operations.
  • Develop, maintain, and produce technical documentation informing system and subsystem requirements and specifications.
  • Interface with customers and regulators in nuclear safety reviews and technical working-group meetings to meet requirements and project objectives.
  • Perform other duties as assigned by the manager.

About the company

X-energy designs and develops advanced nuclear reactors and fuel, aiming to commercialize small modular reactors based on a Generation IV high-temperature gas-cooled pebble-bed design and its TRISO-X fuel. The reactor uses ceramic-coated TRISO fuel in pebbles within a modular, sealed unit that operates at high temperatures to generate electricity or process heat, with safety features baked into the fuel and design. It differentiates itself by pursuing a specific Generation IV high-temperature gas-cooled, pebble-bed, TRISO-X fuel approach in a modular platform backed by significant financing to move toward commercialization. The company’s goal is to bring cleaner, safer nuclear energy to the market by completing design, obtaining regulatory clearance, and deploying its SMR technology and fuel at commercial scale.

Company Size

1,001-5,000

Company Stage

IPO

Headquarters

Rockville, Maryland

Founded

2009

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Simplify's Take

What believers are saying

  • DOE raised Seadrift support to $2.15 billion on August 13, 2026.
  • NRC issued Long Mott's FONSI in August 2026, clearing a major permitting hurdle.
  • X-energy expanded Gaithersburg to 145,000 square feet, signaling hiring for commercialization and manufacturing.

What critics are saying

  • Waterkeeper's NRC financial-qualifications challenge remains live; denial kills Long Mott's first commercial project.
  • Dow's 4,500-job layoffs and $2.15 billion cost-share expose financing fragility through 2026.
  • NRC safety review still runs through November 2026; any delay pushes commercial revenue beyond 2030.

What makes X-energy unique

  • Xe-100 runs helium-cooled, 750°C reactors for industrial steam, not just electricity.
  • TRISO-X fuel and graphite supply agreements lock safety-critical manufacturing around proprietary reactor design.
  • Dow, Amazon, and Centrica pipeline spans 11-plus gigawatts across industrial and AI demand.

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Benefits

  • 401(k) Retirement Plan
  • Health Insurance
  • Dental Insurance
  • Vision Insurance
  • Paid Time Off
  • Tuition Reimbursement/Professional Development

Growth & Insights and Company News

Headcount

6 month growth

6%

1 year growth

17%

2 year growth

16%
Yahoo Finance
Oct 20th, 2026
X-Energy, AEP and Amazon to assess 960MW Indiana nuclear project at ex-coal site

X-Energy, American Electric Power and Amazon have agreed to assess a 960MW advanced nuclear project in Indiana using X-Energy's Xe-100 small modular reactors. The project would reuse a former coal plant site in Sullivan County. Amazon would fund development and commit to a long-term power purchase. The next test is whether the study leads to a final investment decision. Regulatory steps, site approvals or a construction timeline would show if the concept becomes a contracted project. X-Energy has a market cap of $4.3 billion. It reported revenue of $150.28 million and a loss of $448.87 million.

TechCrunch
Oct 19th, 2026
Amazon backs 960MW Indiana nuclear plant with 12 X-energy reactors on former coal site

Amazon will fund a proposed 960-megawatt nuclear plant in Indiana and be the first customer to buy its power, the companies announced Monday. American Electric Power (AEP) would operate the plant, and X-energy, a designer of small modular nuclear reactors, would supply 12 Xe-100 reactors. The plant would sit on the site of a demolished coal plant just south of Terre Haute. It would connect to the public grid, though Amazon says the power would also serve its data centres. The deal is the second between Amazon and X-energy, and three times larger than the first. Amazon led a $700 million Series C-1 round in X-energy in October 2024. The companies plan 5 gigawatts of new US nuclear capacity by 2039. The timeline depends on X-energy delivering its first plant, at Seadrift in Texas, where it has yet to break ground.

Epium Ltd
Oct 7th, 2026
X-energy targets industrial heat with helium-cooled reactors.

X-energy targets industrial heat with helium-cooled reactors. X-energy is developing the Xe-100, a small modular reactor designed to serve industrial manufacturers that need high-temperature heat for concrete, glass, steel, chemicals, plastics and fertilizers. Unlike traditional water-cooled nuclear plants, the Xe-100 would use helium gas as a coolant, allowing higher operating temperatures and lower pressures. The system would produce super-heated steam for direct industrial use, electricity generation of 80 megawatts (MW), or both. The reactor would use TRISO fuel pebbles that are designed to resist corrosion and melting, with fuel continuously moving through the reactor before being recycled or removed as waste. X-energy says the design is intrinsically safe because rising internal temperatures would naturally slow and stop the nuclear reaction. Industrial heating accounts for 18 percent of annual global greenhouse-gas emissions, making high-temperature processes a major target for decarbonization. The Xe-100 could also serve oil production, refining, data centers and electricity markets. X-energy says up to 12 reactors could be clustered to provide 24/7 on-site power. Major hurdles remain: commercial helium-cooled generation has struggled in China, SMR economics are unproven, and the Xe-100 might produce 10 times the spent fuel volume per unit of energy as existing reactors. A TRISO-X fuel factory is due in 2028, while projects with Dow, Amazon and a planned UK fleet target operation in the 2030s. Originally reported by technologyreview.com Read the source

NetDynamic Web Services
Oct 7th, 2026
X-energy's helium-cooled reactors: A new era in energy.

X-energy's helium-cooled reactors: A new era in energy. X-energy is pioneering the development of small modular reactors (SMRs) specifically designed to cater to industries with substantial energy demands, such as concrete, plastics, chemicals, and fibers manufacturing. These sectors require significant amounts of high-temperature heat, which traditional renewable sources like solar panels and wind turbines cannot adequately provide. Often, heavy industrial processes rely on fossil fuels to meet their thermal needs, making a transition to cleaner alternatives essential. Conventional nuclear reactors have limitations due to their reliance on water for cooling, which restricts their operating temperatures. X-energy's innovative Xe-100 reactor addresses this challenge by utilizing helium gas as a coolant. This approach not only allows for higher operational temperatures but also reduces the pressure requirements compared to traditional water-cooled systems. The Xe-100 can produce super-heated steam to directly supply heat or generate approximately 80 megawatts (MW) of electricity, marking a significant step forward in nuclear technology. The Xe-100 reactor employs advanced TRISO (tristructural-isotropic) fuel technology, known for its resilience against corrosion and melting. This fuel is continuously added to the reactor, ensuring a consistent energy output while also promoting safety. In case of power loss, the reactor's design inherently mitigates risks by slowing down the nuclear reaction. Beyond conventional industrial usage, the Xe-100 can also benefit sectors like oil recovery - notably in tar sands extraction - by providing the necessary heat without relying on extensive natural gas supplies. Despite the promising technology, challenges remain for X-energy. The only existing commercial helium-cooled reactors are in China, where operational issues have been reported. X-energy asserts that its vertically integrated fuel supply will lead to reliable performance over a projected reactor lifespan of 60 years. However, economic viability is still unproven; costs associated with SMRs can be significantly higher than solar energy. Additionally, while TRISO technology enhances safety and nonproliferation efforts, it may generate more nuclear waste than traditional reactors. Looking ahead, X-energy is making strides in regulatory compliance, having received a fuel fabrication license for its TRISO-X pebbles, with its first production facility slated for completion in 2028. The company is also pursuing projects to deploy the Xe-100 reactor to power a Dow chemical facility in Texas, which could become operational by the early 2030s. Concurrently, X-energy is collaborating with Amazon to develop a cluster of four Xe-100 reactors in Washington, along with a larger fleet in the UK, both targeting electricity generation in the next decade.

Electricity Info
Sep 28th, 2026
GE Vernova vs x-energy.

GE Vernova vs x-energy. 28th September 2026 Gas turbines have driven much of GE Vernova's recent growth. But the company offers power solutions beyond gas, including a light-water small modular reactor (SMR), the BWRX-300, which its subsidiary manufactures in partnership with Hitachi. Its SMR is a boiling-water nuclear reactor that uses low-enriched uranium (LEU), which is commonly used in traditional reactors. X-Energy is developing its own SMR, the Xe-100, which uses helium gas for cooling instead of water. By using helium gas, the Xe-100 can reach temperatures up to 750 degrees celcius, making it useful for industrial processes such as hydrogen production, chemical manufacturing, and desalination. In addition, the Xe-100 uses tri-structural isotropic (TRISO) pebbles for fuel, which have been called "the most robust nuclear fuel on Earth" by the U.S. Department of Energy. Motley Fool 27th Sept 2026 read more"