Full-Time

Mechanical Systems Design Engineer

X-energy

X-energy

1,001-5,000 employees

Develops SMR reactors and TRISO fuel

Compensation Overview

$115k - $200k/yr

+ 401(k) employer match

Gaithersburg, MD, USA

Hybrid

Four days in the office per week; standard hours are 8:00am–5:00pm Eastern Time. Travel up to 10% as needed.

Bachelor's

Category
Mechanical Engineering (1)
Required Skills
HVAC
Metrology
Quality Assurance (QA)
FEM/FEA

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Requirements
  • A bachelor's degree in mechanical engineering or a related engineering discipline from an accredited institution is required.
  • Proficiency with engineering hand calculations is required.
  • Experience using Computer-Aided Design and product lifecycle management software is required.
  • Experience owning hardware, including manufacturing and testing oversight, is required.
  • At least one year of demonstrated hands-on experience developing and delivering hardware or manufacturing processes in a production environment is required; qualifying experience may include industry internships, hobbies, or collegiate engineering projects.
  • Experience designing and developing mechanical or fluid systems, assemblies, or components is required.
  • Typically, five years of engineering experience are required for Level III, ten years for Level IV, or fifteen years for Level V.
  • 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.
Responsibilities
  • Develop mechanical and physical concepts and support processes to create or identify structures, systems, and components for nuclear products or facilities, with a focus on nuclear safety.
  • Identify, collect, and document applicable requirements, interfaces, design bases, and criteria by coordinating with stakeholders and systems engineers.
  • Support identification of applicable industry codes and standards under the direction of project leads and systems engineers.
  • Plan and perform analyses to assess whether structures, systems, and components can perform their intended functions and meet technical specifications and design requirements.
  • Perform hand calculations and analytical-tool computations for structural, thermal, hydraulic, and other scoping calculations.
  • Develop mechanical solutions for reactors, including pressure vessels and piping, reactor internals, nuclear fuel, and high-temperature materials such as graphite.
  • Integrate design activities across engineering team members, partners, and suppliers, and perform scoping and sizing calculations to select design features that meet requirements.
  • Create and maintain computer-aided design engineering models of reactor structures, systems, and components.
  • Support assessments of manufacturability, assembly, and integration considerations.
  • Write and develop 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.
  • Provide independent and acceptance reviews of engineering deliverables and data.
  • Lead core tasks and responsibilities with limited supervision and independent judgment, depending on level.
  • Coordinate multiple individual contributors within a technical scope and lead small groups of engineers to solve complex technical problems, depending on level.
  • Provide feedback, guidance, teaching, and mentoring to junior team members.
  • Stay current with industry and academic trends, breakthroughs, and best practices.
  • Perform other duties assigned by the manager.
Desired Qualifications
  • Experience with commercial nuclear power plant operations.
  • Experience using hand tools and handling equipment to assemble mechanical systems or components.
  • Familiarity with metrology techniques for component inspection, fit checks, and mechanical troubleshooting.
  • Familiarity with selecting and using instrumentation to test and characterize mechanical systems and components.
  • Experience in hazardous industrial or manufacturing environments, including training in pressurized or stored energy, high/low-voltage safety, lockout/tagout, hoist and rigging operations, machining, or hazard awareness.
  • Professional experience in commercial nuclear power and in design, qualification, licensing, and construction to ASME Boiler and Pressure Vessel Code Section III or Section VIII.
  • Experience with Nuclear Regulatory Commission regulations and licensing requirements for safety-related systems.
  • Experience designing with ASME Boiler and Pressure Vessel Code, ASME B31.1, ASME B31.3, and other industry standards.
  • Experience designing heat exchangers, boilers, or steam generators.
  • Experience selecting, sizing, and specifying mechanical process equipment, including piping, ducting, HVAC, fire suppression, pumps, pressure vessels, valves, and structural supports.
  • Experience designing control, gate, globe, ball, or check valves for high-pressure and high-temperature fluid or gas applications.
  • Experience with procurement and manufacturing oversight of pressure vessels or large metallic components.
  • Hands-on experience with graphite or other non-metallic components, fabrication or assembly sequencing, or tooling development.
  • Experience designing and executing vibration, shock, and modal test programs to qualify mechanical components for high-reliability applications.

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 Jobs

Simplify's Take

What believers are saying

  • DOE raised ARDP support to $2.115 billion in August 2026, strengthening execution runway.
  • NRC issued a May 2026 FONSI for Seadrift, accelerating Dow permitting toward 2027.
  • TX-1 reached 80% construction completion in August 2026, de-risking TRISO-X supply.

What critics are saying

  • Dow's first reactor still depends on NRC construction permit issuance in Q1 2027.
  • X-energy burned $97.3 million operating cash in Q2 2026 while losses widened.
  • A failed first-of-a-kind build kills customer confidence and shuts the pipeline.

What makes X-energy unique

  • X-energy's Xe-100 pairs industrial steam with power, targeting chemical plants like Dow's Seadrift site.
  • TRISO-X fuel and NRC Part 70 licensing create a vertically integrated reactor-fuel moat.
  • DOE-backed first commercial deployment with Dow and Amazon, Centrica pipeline validates customer pull.

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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

5%

1 year growth

11%

2 year growth

7%
StocksToTrade
Sep 9th, 2026
XE stock slides as price action diverges from strong cash position.

XE stock slides as price action diverges from strong cash position. TIM BOHEN - UPDATED SEP. 9, 2026, 12:32 PM ET X-Energy Inc. stocks have been trading down by -10.03 percent after reports of major project delays and financing concerns. Key takeaways. * XE has faded from an early high near $18.91 to close around $17.23, signaling profit taking and short-term selling pressure. * X-Energy Inc. posts roughly $94.26M in annual revenue but runs very heavy losses, with profit margins deeply negative. * A massive cash pile over $1.07B, minimal debt, and a current ratio above 17 give XE a long financial runway. * Intraday XE trading shows tight consolidation around $17.20, hinting at a potential base or continuation move. * With a price-to-sales ratio above 50, traders are clearly paying up for X-Energy Inc.'s growth narrative, not current profits. Live Update At 12:31:51 EDT: On Wednesday, September 09, 2026 X-Energy Inc. stock [NASDAQ: XE] is trending down by -10.03%! Discover the key drivers behind this movement as well as its expert analysis in the detailed breakdown below. Quick financial overview. XE is a classic high-expectation story stock. X-Energy Inc. generates about $94.26M in revenue, but the company is nowhere near breakeven. Profit margins sit around -225%, and both return on assets and return on equity are firmly negative. That tells traders XE is still in heavy build-out mode rather than cash-harvesting mode. At the same time, XE's balance sheet is unusually strong for a loss-making name. X-Energy Inc. finished the latest quarter with roughly $1.15B in cash and $1.64B including short-term investments. Long-term debt is only about $24.93M. The current ratio is a huge 17.2, and the quick ratio is 16.1, which means XE can cover its short-term obligations many times over. The flip side is valuation. With a market value implied by an enterprise value near $6.17B and price-to-sales around 54.6, traders are paying a premium for future potential. X-Energy Inc.'s book value per share is about $4.47, while XE trades several times above that, signaling strong faith in the long-term story despite current losses. Why traders are watching XE price action. On the chart, XE is not trading like a sleepy value play. X-Energy Inc. has been swinging between the high teens and low 20s over the last several sessions. The recent high near $22.28 was followed by a grind lower: multiple closes in the $18-$19 zone, and now a sharper pullback to $17.23. That's the kind of retrace that gets active traders locked in on support levels and risk control. Look at the latest daily candle. XE opened at $18.33, pushed to $18.91, then reversed and closed near the low of the day. That intraday rejection from the highs shows sellers hit the tape hard. For short-term traders, X-Energy Inc. is now in "prove it" territory - it needs to hold the mid-$17s or risk a deeper flush back toward prior base zones. Zooming into the 5-minute chart, the morning session in XE showed a quick pop above $18 followed by a series of lower highs. By midday, price settled into a tight band between about $17.17 and $17.38. That kind of intraday compression after a drop often sets up the next move. Either X-Energy Inc. will bounce toward $18 on a relief push, or a break under $17.10 can open the door to more downside. For traders who thrive on volatility and clear levels, XE is delivering both. The story - high cash, high valuation, heavy losses - adds fuel to the moves because sentiment can flip fast. When hope is priced in, every breakout and breakdown in X-Energy Inc. matters more. Conclusion. XE sits at the crossroads of hype and hard numbers. On one side, X-Energy Inc. sports over $1.07B in cash, very low debt, and enough liquidity to fund years of operations at current burn rates. On the other side, XE is losing serious money, with negative EBITDA of about $58.45M for the latest quarter and a free cash outflow of roughly $160.62M. The market is clearly paying today for what it expects X-Energy Inc. to become tomorrow. For traders, that gap between present reality and future promise is exactly where opportunity lives - and where risk spikes. XE's price-to-sales multiple above 50 and price well above book value tell you sentiment is still bullish on the long-term story. But the recent drop from the low-$20s to the mid-$17s shows how quickly that sentiment can swing. In a tape this volatile, it's easy to chase strength or panic on weakness, but as Tim Bohen, lead trainer with StocksToTrade says, "Time and experience have taught me that missed opportunities are part of the game. There's always another setup around the corner." That mindset can help traders avoid forcing trades in XE when the risk/reward just isn't there. Active traders in XE should focus on clean technical levels, the intraday trend, and the company's runway. X-Energy Inc.'s fat cash stack means dilution and credit stress are less urgent, giving more room for the chart to drive short-term trading. As Tim Sykes likes to say, "The market doesn't owe you anything - it just rewards those who prepare." For XE, that preparation means knowing the numbers, respecting the volatility, and cutting losses fast when the trade breaks. This is stock news, not investment advice. StocksToTrade News delivers real-time stock market updates tailored to highlight the key catalysts driving short-term price movements. Its coverage is designed for active traders and investors who thrive in fast-moving markets, with a focus on volatile sectors like penny stocks, AI stocks, Robinhood stocks and other momentum plays. From earnings reports and FDA approvals to mergers, new contracts, and unusual trading volume, StocksToTrade, Inc. break down the events that can spark significant price action. Looking to level up your trading game? Explore StocksToTrade, the ultimate platform for traders. With powerful tools designed for swing and day trading, integrated news scanning, and even social media monitoring, StocksToTrade keeps you one step ahead. Once your watchlist is set, take the next step and trade with confidence using StocksToTrade's robust platform. Don't miss out - grab your 14-day trial for just $7 and experience the edge you need to thrive in today's fast-paced markets. One must-buy stock for Monday. Want to start next week off with a big win? Its new algorithm may have just uncovered a new dirt-cheap stock with a great chance of moving +100% or more this Monday. ...One ticker... ...One trade... ...One MONSTER move... All you have to do is make this one trade on Monday. 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Sargent & Lundy
Aug 27th, 2026
Sargent & Lundy environmental review earns NRC approval.

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.

Yahoo Finance
Aug 27th, 2026
X-Energy targets AI power demand with Xe-100 reactor pipeline for Dow, Amazon and Centrica

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.

Yahoo Finance
Aug 24th, 2026
TRISO-X advances construction of first US advanced nuclear fuel facility in Oak Ridge

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.

Hebelschein-Spekulant
Aug 15th, 2026
X-energy invests $8M in SGL Carbon for advanced nuclear reactor graphite development

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.