Nuclear Primary Systems and Thermal-Hydraulics Engineer

The ocean is the largest undeveloped frontier on earth — and the next chapter of abundant energy will be written at sea. We're building the infrastructure to power it.

About Ocean Atomics (OA)

Ocean Atomics is an American company designing, licensing, and assembling a standardized nuclear electric power plant and the surrounding support systems for maritime applications. We will install these plants on any vessel built to our nuclear-ready standards, and will provide end-to-end sustainment in our planned nuclear lifecycle dockyard. We will help develop the licensed operators to unlock this new capability for your energy intensive application at sea. To move fast and to lead the creation of this new market, we are leveraging the compact, proven systems enabled by water-cooled reactors.

Our mission

Scale nuclear energy. Power generations.

Our vision

A maritime commons thriving with abundant, economical, modern, and safe nuclear-powered activity — built, serviced, and staffed by re-industrialized American shipyards and people.

Role Summary

As Nuclear Primary Systems & T-H Engineer, you define the arrangement of the primary system and build the thermal-hydraulic models that prove it works in all design basis conditions. Your analysis is the throughline between arrangement decisions, safety margins, and the licensing case that lets a reactor operate at sea.

This is a role we're hiring at multiple levels (L1 through L4). The work is shared across levels; scope and accountability scale with experience.

What You'll Do

At all levels, you will:

• Define and maintain the arrangement of the primary system and its interfaces with supporting systems

• Build, run, and maintain system thermal-hydraulic models spanning steady-state, transient, and accident design basis scenarios

• Analyze decay heat removal architectures and demonstrate adequate cooling for design basis events, accounting for the maritime environment

• Couple system models with neutronics and structural inputs to support multiphysics and transient studies

• Document analysis results and V&V methodology in support of the licensing process

• Provide primary system and accident-response information to our safety analysis, simulator, and operations teams

At more senior levels you will additionally:

• Lead trade studies that balance arrangement, component sizing, and safety margins across the primary system

• Own the licensing basis documentation and justify methodology

• Mentor newer engineers and review their thermal-hydraulic analyses

• Drive cross-team coupling decisions with our neutronics and structural teams on multiphysics studies

What You Bring

Required at all levels

• Bachelor's degree in Nuclear or Mechanical Engineering, or equivalent practical experience

• Experience building and running system thermal-hydraulic models of nuclear plants, with working knowledge of one or more reactor systems codes (e.g. RELAP5-3D, TRACE)

• Strong understanding of primary system behavior: natural circulation, two-phase flow, and the tradeoffs between active and passive cooling

• Working knowledge of decay heat removal design and the design basis events that size it

• Ability to work on a close, rapidly iterative design team and translate analysis into arrangement decisions

Preferred

• Familiarity with multiple system and subchannel/CFD tools (e.g. RELAP5-3D, TRACE, GOTHIC, COBRA, STAR-CCM+) and with coupling system models to neutronics

• Experience supporting safety analysis and licensing basis development (DBAs, LOCA/non-LOCA, station blackout)

• Strong technical writing skills, particularly for regulator-facing documentation

Don't meet every bullet? We'd still like to hear from you. If you're excited by the mission and most of this resonates, apply.

Export control notice

This role involves access to information subject to U.S. export control laws, including unclassified nuclear technology governed by the U.S. Department of Energy under 10 CFR Part 810. Depending on a candidate's status, access may require DOE authorization, which Ocean Atomics may apply for. Any offer is contingent on your ability to work in compliance with these requirements. We evaluate all applicants regardless of citizenship or national origin, except where required by law.

Why this matters

Every industry on Earth needs scalable, clean energy, and the ocean is the ideal place to unlock it. Joining Ocean Atomics means building real, lasting infrastructure — the kind that powers generations. The world needs abundant energy. Let's make it happen.

Ocean Atomics LLC is an equal opportunity employer.

We are committed to a workplace free of discrimination and do not discriminate on the basis of race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability, genetic information, veteran status, or any other characteristic protected by applicable law. We are committed to providing reasonable accommodations; if you need an accommodation during the application process, contact [email protected].