Full-Time
CFD/Thermal Hydraulics Engineer 3
Updated on 9/3/2026
X-energy
1,001-5,000 employees
Develops SMR reactors and TRISO fuel
Compensation Overview
$115k - $140k/yr
Rockville, MD, USA
In Person
Four to five days in the office per week; up to 10% travel as needed.
Bachelor's
 Mechanical Engineering (1) |
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- A bachelor's degree in mechanical engineering or a related engineering discipline from an accredited institution is required.
- Typically, five years of experience in an engineering role is required.
- 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.
- Proficiency with engineering hand calculations is required.
- Experience or knowledge in at least one of the following areas is required: UG/NX, SolidWorks, Pro-Engineer, Teamcenter, Windchill, or a similar tool.
- Experience using Computational Fluid Dynamics analysis codes, such as STAR-CCM+ or Fluent, or similar tools, is required.
- Develop mechanical and physical concepts and support development of processes to create or identify structures, systems, and components for use in nuclear products or facilities, with a focus on nuclear safety.
- Identify, collect, and document applicable requirements, interfaces, design basis, and criteria by coordinating with key stakeholders and systems engineers, and support identification of applicable industry codes and standards under the direction of project leads and systems engineers.
- Plan and perform analyses required to assess structures, systems, and components to ensure they can perform their intended functions and meet technical specifications and design requirements.
- Perform computations using hand calculations and analytical tools for structural, thermal, hydraulic, and other scoping calculations as required by project leads and systems engineers.
- Provide heat transfer, fluid mechanics, and particulate mechanics analyses to support the design of developed reactors and supporting subsystems.
- Develop, test, and verify Computational Fluid Dynamics models to support design and analysis forming part of the reactor licensing basis, including steady-state and transient conditions, design-basis events, and anomalies.
- Support assessment of structures, systems, and components for manufacturability, assembly, and integration considerations under the direction of project leads.
- Write and develop design documentation, including design basis documents, technical reports, calculations, and drawings, in accordance with applicable procedures.
- Develop Verification and Validation plans for analytical tools and support qualification of the toolset.
- Perform work in accordance with quality procedures for design and configuration management to ensure project quality requirements are met.
- Provide independent reviews and acceptance reviews of engineering deliverables and data.
- Perform other duties as assigned by the manager.
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 ARDP support to $2.115 billion on August 13, 2026.
- NRC issued Dow's Texas environmental FONSI on May 18, 2026, advancing construction.
- Q2 2026 revenue and grant income rose 154% to $54.6 million; cash hit $1.9 billion.
What critics are saying
- Dow's permit still awaits late-2026 NRC review, pushing first power into early 2030s.
- X-energy lost $59.1 million in Q2 2026 and burned $97.3 million operationally.
- One Seadrift, TX-1, or Centrus delay freezes commercialization and guts the 11.5-gigawatt pipeline.
What makes X-energy unique
- Xe-100 and TRISO-X integrate reactor and fuel, creating tight supply control.
- NRC approved TX-1's Part 70 license in February 2026, first in 50 years.
- SGL's January 2026 graphite deal and Centrus's August 2026 contract de-risk inputs.
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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
6 month growth
↑ 5%1 year growth
↑ 11%2 year growth
↑ 7%Sargent & Lundy environmental review earns NRC approval. Firm supports first-of-a-kind project to deploy advanced reactor to power industrial facility August 27, 2026 Based on Sargent & Lundy's detailed environmental review, a proposed 320-megawatt small modular reactor to power an industrial facility along Texas' Gulf Coast surpassed another major milestone in gaining Nuclear Regulatory Commission approval. The NRC recently completed an environmental assessment for Long Mott Energy, a wholly owned subsidiary of The Dow Chemical Company, and X-energy's application to build a first-of-a-kind advanced reactor to power an industrial manufacturing facility in Seadrift, Texas. Following its review, the agency issued a finding of no significant impact, propelling the project forward in the construction permit approval process. The NRC finding comes less than a year after LME, with support from Sargent & Lundy and its project partner WSP, filed the environmental report. The more than 1,000-page report covers the proposed plant's design and operations, as well as its land use, air, water, ecology, socioeconomic conditions, and other potential impacts. The NRC issued few requests for additional information based on the level of detail and due diligence included and was able to determine that an environmental assessment "better addresses the project's limited environmental footprint at an existing industrial location" and allowed for "more efficient review while maintaining rigorous environmental standards." Sargent & Lundy has worked with X-energy and Dow since 2022 to support pre-application activities, including site selection, site feasibility, site characterization, and developing the recently approved environmental report. The firm has also supported the preliminary safety analysis report, which is now under NRC review and is expected to be completed by year-end. The proposed Long Mott Generating Station, being developed by LME under the Department of Energy's Advanced Reactor Demonstration Program, would replace the company's existing energy and steam generation plants that are nearing the end of their operating life spans. The plant would be the first grid-scale advanced nuclear reactor deployed to serve an industrial site in North America and would provide both electricity and high-temperature industrial steam. Dow produces more than 4 billion pounds of plastics and other materials at the Seadrift plant for multiple industries and is seeking a safe, reliable way to reduce the facility's emissions.
X-Energy is positioning its Xe-100 small modular reactor to meet growing power demands from AI infrastructure. The company is working with Dow, Amazon, and Centrica to provide long-term, reliable energy for data centres and industrial operations. The Xe-100 is designed as an 80 MW electric reactor deployed in four-unit blocks to reach 320 MW. X-Energy has an indicative pipeline of approximately 11.5 GW across 144 reactors in the US and UK. The company, with a market capitalisation of about $7.8 billion, reported a Q2 2026 net loss of $59.09 million. However, it generated revenue of $54.6 million for the quarter and $98.02 million for the half year. The key test for X-Energy's AI-focused strategy will be whether anchor customers commit to full financial close and construction start on multi-reactor sites.
TRISO-X, a subsidiary of X-Energy, has started the next construction phase at its advanced nuclear fuel fabrication facility in Oak Ridge, Tennessee. The work includes building auxiliary structures and installing equipment at the 214,000 square-foot plant. Once operational, the facility will produce 700,000 TRISO-X pebbles annually, equivalent to 5 metric tons of uranium, sufficient to fuel up to 11 Xe-100 reactors. It will be the first commercial facility in the US dedicated to fabricating tristructural-isotropic fuel for advanced reactors. The US Nuclear Regulatory Commission has granted TRISO-X a 40-year licence, marking the first Category 2 nuclear fuel facility authorised to process High Assay Low Enriched Uranium. The plant supports X-energy's reactor deployment at Dow's Texas site through the Advanced Reactor Demonstration Program.
X-energy has invested $8 million in SGL Carbon for the development of high-tech graphite for use in advanced nuclear reactors. The investment positions SGL Carbon in a growth market with long-term potential. Industry experts and larger investor groups recognise the potential in the partnership with X-energy. Institutional investors have begun adjusting their positions accordingly. The German carbon and graphite specialist is focusing on applications in next-generation nuclear technology, a sector attracting increasing attention from institutional capital.
The US Department of Energy has committed up to $1 billion in additional funding for X-energy's advanced nuclear project with Dow in Seadrift, Texas. This brings total federal funding available since 2021 to $21.5 billion through the Advanced Reactor Demonstration Program. The project will deploy Xe-100 reactors at Dow's petrochemical facility to provide both electricity and industrial process steam, replacing existing energy systems. The facility aims to become North America's first grid-scale advanced nuclear installation serving a large industrial site directly. The Xe-100 is a high-temperature gas-cooled small modular reactor, with four units planned to deliver 320 MWe capacity. Long Mott Energy submitted a construction permit application to the Nuclear Regulatory Commission in March 2025, with operations targeted for the early 2030s. Funding follows a 50/50 cost-sharing model requiring matching private investment to share commercialisation risks.