Mechanical Systems Design Engineer

Deep Fission is a nuclear technology company pioneering the development of a revolutionary deep borehole pressurized water reactor. We recently completed a private placement financing and Alternative Public Offering and are now operating as a public company while maintaining our startup agility and innovation focus. With strategic partnerships in place, strong private and public investment, and active engagement with the U.S. Nuclear Regulatory Commission (NRC), we are executing our next phase of growth as we advance our groundbreaking nuclear technology toward commercial deployment. Job Summary Deep Fission is seeking a Mechanical Systems Design Engineer to support the engineering and design of surface mechanical systems for the reactor pilot project. This person will contribute to the design for standard nuclear mechanical systems such as the chemical volume control system, secondary coolant system, and balance of plant systems. The ideal candidate will bring expertise in mechanical-fluidic system design, nuclear systems, construction, interdisciplinary interface and technical subcontract management. This role requires comfort operating in first-of-a-kind environments where precedent is limited, requirements evolve, and creative problem-solving is essential. The Mechanical Systems Design Engineer will support alignment between multiple engineering disciplines, construction, procurement, and licensing. Key Responsibilities: Perform mechanical system engineering tasks for the development of Deep Fission’s surface facilities - from conceptual development through licensing, fabrication, construction, startup, and turnover. Coordinates or prepares diagrams, specifications, procurement documents, and award recommendations. Ensure effective coordination with the other engineering disciplines to maintain alignment on technical scope. Advance designs rapidly in a dynamic environment, applying sound engineering judgment and calculated risk management. Support interface activities between partner organizations and major subcontractors, participating in face-to-face events to create effective work and decision-making environments. Contribute to general design coordination events such as mechanical system design reviews and in-person design workshops. Promote a proactive nuclear safety culture across office and field-based activities. Advocate for the Deep Fission company and its technology. Participate in project planning (schedule and budgeting) and be prepared to commit to delivery against the project plan. Provides assistance to project and construction management for mechanical system requirements, identifying issues as they arise during project execution. Required Skills & Experience: 5+ years of experience in the relevant engineering discipline, including successful delivery of mechanical system designs. Background in regulated environments such as nuclear, aerospace, defense, utility or industrial capital projects. Bachelor’s degree in Engineering or related technical field with a deep understanding of engineering fundamentals and modern design practices. Understanding of nuclear QA programs (e.g., NQA-1), and compliance documentation. Ability to perform in a design role supporting large design efforts with multiple interfaces and stakeholders. Ability to maintain communication and stakeholder engagement in a virtual and hybrid team environment. Ability to travel - candidate will be required to travel on a moderate basis depending on the project phase up to 20% Must be a U.S. person eligible to meet DOE Export Control requirements under 10 CFR 810. Desired Skills & Experience: Licensed Professional Engineer (PE) or pursuing professional registration is a plus Experience with SMRs, Gen IV technologies, or first-of-a-kind nuclear reactor development. Demonstrated experience navigating NRC or DOE regulations. Strong understanding of nuclear QA programs (e.g., NQA-1), and compliance documentation. Background in nuclear construction, site development, or commissioning of safety-related systems. Proficiency with engineering software tools, AI-enabled platforms. Key Competencies: Design Acumen – Ability to make assumptions and establish design concepts based on wisdom gained from experience and education. Organizational – Experience on structured engineering teams functioning with other engineering disciplines, and subcontractors to support project objectives. Adaptability/Resilience - the capacity to adjust actions, strategies, and behaviors in response to unexpected or ambiguous situations, learning and pivoting quickly. Decision-Making – Balances technical rigor with business trade-offs; uses data and judgment effectively. Our Commitment: Deep Fission is an equal opportunity employer committed to building a diverse and inclusive workplace. We welcome applicants from all backgrounds who share our passion for advancing clean nuclear energy and creating a sustainable future. We do not discriminate on the basis of race, color, creed, religion, ancestry, age, sex, marital status, national origin, disability, veteran status, or any other characteristic protected by applicable law.