Thermal Hydraulics Engineer

Job Description

About the Company

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We’re partnering with a well-funded, early-stage nuclear energy startup based in San Francisco . The company is focused on developing next-generation, compact reactor systems designed for scalable, cost-predictable deployment across large energy applications such as data centers, industrial heat, and grid-scale power.

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Backed by significant private funding and operating in a true builder/startup environment, the team is mission-driven, fast-moving, and deeply committed to tackling complex, first-of-a-kind (FOAK) engineering challenges. This is an opportunity to join at an early stage and play a key role in shaping both the technology and the organization.

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This is a remote role with travel as needed.

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Role Overview

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We are seeking a Thermal Hydraulics Engineer with nuclear industry experience to support the modeling and simulation of advanced reactor systems, including normal operation and transient/accidental scenarios. This individual will contribute to the design, analysis, and optimization of high-performance nuclear systems in a highly collaborative, hands-on startup environment.

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Key Responsibilities

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• Lead accident scenario modeling and safety analysis using system-level codes
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• Analyze thermal-hydraulics performance under steady-state and transient conditions
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• Perform CFD modeling and simulation to support reactor and system design efforts
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• Collaborate cross-functionally with reactor design, systems, and safety teams
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• Contribute to the development and validation of modeling methodologies
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• Support design decisions through quantitative simulation insights
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Required Qualifications

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• Professional experience with system codes and accident modeling tools (RELAP, MELCOR, or equivalent)
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• Strong understanding of thermal-hydraulics and fluid dynamics principles
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• Professional engineering experience applying CFD and thermal-fluid analysis
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• Hands-on experience with CFD tools (Star-CCM+ preferred; other packages acceptable)
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• Ability to work onsite in a fast-paced, startup environment
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• Demonstrated ability to learn new technical domains and solve complex engineering challenges
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Preferred / Nice-to-Have Qualifications

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• Industry experience in nuclear engineering
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• Experience with nuclear-specific CFD applications
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• Experience coupling CFD and FEA analyses for thermal-mechanical design challenges
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• Experience modeling heat exchangers, steam generators, or similar thermal-fluid systems
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• Exposure to core design / reactor physics tools (CASMO, SIMULATE, or equivalent)
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• Experience with fuel performance modeling (FRAPCON, BISON, or similar)
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• Experience supporting work performed under NRC regulatory frameworks or licensing processes
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• Familiarity with cost modeling or techno-economic analysis
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• Broader systems-level understanding of reactor design
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• Experience working in startup, high-growth, or fast-paced engineering environments
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• Experience with both computational modeling and experimental/testing programs
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What We're Looking For (Culture & Mindset)

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• Strong communicator who collaborates effectively across highly technical teams
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• Proven grit, resilience, and determination —comfortable tackling ambiguous, high-difficulty problems
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• Strong interest in working on first-of-a-kind (FOAK) hard-tech projects
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• Curious, continuous learner who can quickly develop expertise in new technical areas
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• Builder mentality: takes ownership, moves with urgency, and thrives in early-stage environments
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• Committed to technical excellence while balancing speed, execution, and practical engineering outcomes
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• Motivated by the opportunity to help reshape the future of energy
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Compensation

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• Competitive salary based on years of experience
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• Healthcare & dental fully covered by the company. Vision Available.
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• Equity
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