Thermal-Hydraulics Engineer

Bluecore Energy HQ; Long Beach (CA); On-site; USD 140,000 - 210,000; Full time

Job summary

BlueCore Energy in Long Beach, CA, is developing floating pressurized-water reactors and seeks a Thermal-Hydraulics Engineer to model and size reactor cooling systems in a hands-on startup environment.

You will contribute to safety analyses, DNBR evaluations, and cross-functional collaboration with engineering teams. Advanced degrees and experience with RELAP5-3D, VIPRE, and ASME NB are valued. On-site work near the harbor supports real-world impact.

Qualifications

• MS or PhD in Nuclear or Mechanical Engineering
• Experience with system thermal-hydraulics codes (RELAP5-3D, TRACE, ATHLET).
• Experience with subchannel codes (VIPRE-01, COBRA-TF/CTF) for MDNBR and hot-channel evaluation.
• Knowledge of ASME Boiler & Pressure Vessel Code NB (Section III).
• Ability to size steam generators and heat exchangers from heat balances.
• Experience sizing reactor pressure vessel walls using membrane hoop thickness formulas.

Responsibilities

• Own system thermal-hydraulics modeling (nodalization, LOCA, natural circulation) and DNBR/hot-channel analysis.
• Perform mechanical sizing for RPV, steam generator, pressurizer, and reactor coolant pumps.
• Establish primary/secondary/tertiary heat balances and flows, including seawater heat rejection support.
• Author transient/accident TH evaluations and coordinate with the safety case.
• Set minimum-DNBR using SAFDL and validate CHF correlation basis.
• Manage fatigue and fracture margins in mechanical component design.
• Coordinate neutronics-thermal hydraulics feedback with Core Physics team.

Skills

Thermal-hydraulics modeling

DNBR analysis

Subchannel analysis

Reactor pressure vessel sizing

Steam generator sizing

Heat exchanger sizing

Code familiarity (ASME NB)

Coupled neutronics-thermal hydraulics

Education

MS or PhD in Nuclear or Mechanical Engineering

Tools

RELAP5-3D

TRACE

ATHLET

VIPRE-01

COBRA-TF/CTF

ANSYS

ABAQUS

Job description

Our Mission Is Simple: Democratize Access To Clean Energy

Welcome to BlueCore Energy! We are on a relentless mission to democratize access to clean energy. By designing and building advanced floating Pressurized Water Reactors (PWRs) on barges right here in Long Beach, CA, we are bringing scalable, clean, and reliable power to the world. Joining our team means getting in on the ground floor of a revolution in marine small modular reactors (SMRs). If you are passionate, driven, and ready to tackle some of the most exciting challenges of our time, we want you on our team!

Our Values

• Humility — We hold strong opinions loosely, say "I don't know," ask for help early, and let the best idea win regardless of who it came from.
• Inclusivity — The best engineering comes from many perspectives. We build a team where everyone is heard, and we mean it.
• Pragmatism — We solve the real problem in front of us, reuse what already works, and value a tested answer over an elegant one.

About the Role

The Thermal-Hydraulics Engineer operates at the critical intersection of fluids, structural mechanics, and safety. You will convert the reactor heat source into a safe, sized coolant system by wearing multiple hats. In this role, you will model system thermal-hydraulics, perform mechanical sizing for the primary, secondary, and tertiary loops, and help author the Chapter 15 safety analyses for our Preliminary and Final Safety Analysis Reports (PSAR/FSAR).

Responsibilities

• Own system thermal-hydraulics modeling (nodalization, LOCA, natural circulation) and subchannel Departure from Nucleate Boiling Ratio (DNBR) and hot-channel analysis.
• Perform mechanical sizing for the reactor pressure vessel, steam generator, pressurizer, and reactor coolant pumps.
• Establish primary, secondary, and tertiary heat balances and flows, including seawater heat rejection support.
• Author the Chapter 15 transient and accident thermal-hydraulic evaluations and coordinate them with the broader risk-informed safety case.
• Set the minimum-DNBR using 95/95 Specified Acceptable Fuel Design Limits (SAFDL) and validate the CHF correlation basis.
• Manage fatigue and fracture margins in mechanical component design.
• Manage coupled neutronics and thermal-hydraulics feedback in close coordination with the Core Physics team.

Required Qualifications & Skills

• MS or PhD in Nuclear or Mechanical Engineering with a specialization in reactor thermal-hydraulics or pressure-vessel design.
• Demonstrated hands-on experience running system thermal-hydraulics codes (e.g., RELAP5-3D, TRACE, or ATHLET).
• Experience running subchannel codes (e.g., VIPRE-01, COBRA-TF/CTF) for MDNBR and hot-channel factor evaluation.
• Deep understanding of ASME Boiler & Pressure Vessel Code, Section III, Division 1, Subsection NB (Class 1) for primary component design-by-analysis.
• Ability to size a steam generator and heat exchangers from heat balances using formulas.
• Experience sizing reactor pressure vessel walls utilizing membrane hoop thickness formulas.

Desired Qualifications & Skills

• Experience designing primary, secondary, and tertiary loop components for marine or compact-PWR environments.
• Familiarity with ANSYS or ABAQUS structural FEA to evaluate components under dynamic marine loads.
• Deep understanding of 10 CFR 50 Appendix G fracture-toughness requirements and embrittlement shifts over vessel life.
• Familiarity with applying shock and wave dynamic loading constraints to primary component mounts and structures.

Working at BlueCore Energy

On-Site Requirement:

Our team works together at our Long Beach facility, right next to our barge.

Highly Cross-Functional:

Startups move fast! You must possess the ability to seamlessly collaborate across multiple teams to rapidly solve problems and keep production moving.

Physical & Machinery Requirements:

Because we are a hands-on startup, this role may require the ability to perform physical labor, navigate active construction/manufacturing zones, and/or operate heavy machinery and specialized manufacturing equipment as needed.