Senior Safety Analysis Engineer

Senior Safety Analysis Engineer

Location:
Houston, TX, Bellevue, WA or Remote Employment Type: Full Time Reports To: Director, Safety and Thermal Hydraulics

About Us
We are a next-generation nuclear technology startup pioneering the commercialization of High-Temperature Gas-cooled Reactors (HTGRs)
- a proven, safe, and transformative technology for delivering ultra-high-temperature heat and enabling a carbon-neutral future. Our mission is to deploy the world’s first global fleet of Advanced Modular Reactors, redefining how clean energy powers industries, communities, and economies. As a fast-growing company in its early stage, every team member — whether in engineering, program management, partnerships, operations, or business development — plays a direct role in shaping our technology, culture, and impact. You’ll join a collaborative, mission-driven team of internationally recognized experts and innovators working together to bring advanced nuclear energy to the world. The Role The Senior Safety Analysis Engineer will be a core member of the Safety & Thermal Hydraulics team, responsible for performing and developing deterministic safety analyses that support the design, licensing, and deployment of ZettaJoule’s HTGR technology. You will perform Licensing Basis Event (LBE) analyses, develop and qualify thermal hydraulic analysis methods tailored to helium-cooled reactor systems, and contribute directly to the nuclear safety case. This is a high-impact role at a startup where your work will directly shape how ZettaJoule’s reactor is licensed and built.

Key Responsibilities
• Perform deterministic Licensing Basis Event (LBE) analyses and support the reactor design process.
• Support development of the Preliminary Safety Analysis Report (PSAR) and other licensing basis documents submitted to the NRC.
• Assess reactor safety behavior under transient scenarios including depressurization, loss-of-forced-circulation, air ingress, and reactivity insertion events.
• Develop and qualify system-level TH analysis methods for helium-cooled reactor systems, including modeling strategies, closure models, and numerical approaches.
• Perform steady-state and transient TH analyses to characterize model behavior and define method fidelity requirements.
• Document methodologies, assumptions, and method applicability in accordance with NQA-1 quality assurance requirements for licensing use.
• Develop automated workflows for model setup, execution, post-processing, and repeatable method application.
• Collaborate across core design, licensing, and plant design disciplines to ensure TH methods integrate with plant design and coupled simulation workflows. What You'll Bring:
• B.
S. or M.
S. in Nuclear, Mechanical or closely related field.
• 5+ years of experience in nuclear safety analysis or thermal hydraulic methods development.
• Experience performing system-level TH analyses using GOTHIC (preferred), RELAP5, FLOWNEX, or equivalent.
• Solid understanding of thermal-fluid phenomena in advanced reactors: natural circulation, high-temperature heat transfer, helium coolant behavior, and graphite thermal properties.
• Familiarity with NRC deterministic safety analysis methodology, LBE categorization, and the safety classification framework for advanced non-light-water reactors.
• Experience with V&V processes, including benchmark against SETs/IETs and scaling analysis.
• Working knowledge of NQA-1 quality assurance requirements for analysis tools and documentation.
• Scientific programming proficiency (Python, MATLAB, or equivalent) for workflow automation and post-processing.
• High integrity, collaborative mindset, and ability to manage multiple priorities in a fast-moving startup environment. Citizenship: U.
S. citizenship or U.
S. permanent resident status is required. Access to EAR-controlled and 10 CFR 810-governed nuclear technology requires authorization consistent with U.
S. export control law. Even Better
• Direct experience with HTGR-specific analyses: TRISO fuel behavior, pebble-bed or prismatic core modeling, graphite dust transport, or air ingress scenarios.
• Experience with coupled neutronics–TH codes.
• Familiarity with NRC licensing pathways.
• M.
S. or Ph.
D. in Nuclear Engineering with a focus on reactor safety or thermal hydraulics. Why Work for Us
• Competitive salary.
• Flexible hours & remote options.
• Health/Life/Disability benefits.
• Vacation/Sick leave.
• Work alongside internationally recognized experts shaping the future of nuclear energy. EEO Statement ZettaJoule is an Equal Employment Opportunity employer committed to diversity and inclusion.