Mechanical Engineer Temperature Stress Analysis

Mechanical Engineer – High-Temperature Stress Analysis

Location:
Houston, TX or Remote

Employment Type:
Full Time

Reports To:
Director, Core Design

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 Mechanical Engineer, High-Temperature Stress Analysis will be a key contributor to Zetta Joule’s reactor design activities, responsible for the structural analysis and code qualification of metallic components operating at elevated temperature in our High-Temperature Gas-cooled Reactor (HTGR). Working at the intersection of design, materials, and licensing, this role performs and oversees design-by-analysis evaluations that demonstrate compliance with ASME Boiler & Pressure Vessel Code Section III, Division 5 (High Temperature Reactors), develops the analysis methods and calculation packages that support ASME Code certification, and works closely with Materials Engineering to ensure that material properties and design curves are applied correctly in creep and creep-fatigue evaluations.

The role also supports the design of non-nuclear pressure equipment under ASME Section VIII.

• Perform elevated-temperature stress analysis of HTGR Class A metallic components — reactor vessel, core support structures, heat exchangers, and hot gas ducting — to demonstrate compliance with ASME Section III, Division 5 (Subsection HB, Subpart
  
  B).
• Evaluate primary and secondary stress limits, strain accumulation (ratcheting), creep-fatigue damage, and creep buckling using Division 5 elastic, simplified inelastic, viscoplastic, and full inelastic design-by-analysis methods.
• Develop nonlinear finite element models (thermal-structural, plasticity, and creep) and the supporting methodologies, and document results in calculation packages and ASME Design Reports.
• Work with Thermal Hydraulics and Systems Engineering to define design loadings, service levels, and thermal transients, and support development of the ASME Design Specifications for high-temperature components.
• Apply material allowables, isochronous stress-strain curves, and creep-fatigue interaction data in collaboration with Materials Engineering, and identify data gaps that require additional testing or code cases.
• Evaluate weldments, bolted and flanged joints, and structural discontinuities under time-dependent loading, including weld strength reduction factors and local strain concentrations.
• Track and contribute to ASME Section III Division 5 code cases and technical positions, and support Zetta Joule’s engagement with code committees and regulators.
• Manage analysis vendors and perform independent review and verification of calculations, including qualification of FEA software and models under a nuclear quality assurance program (10 CFR 50 Appendix B / NQA-1).
• Perform design and analysis of non-nuclear pressure vessels and heat exchangers, such as balance-of-plant, process heat, and helium/gas handling equipment, in accordance with ASME Section VIII, Division 1 (design by…