Principal Thermal-Hydraulics & Safety Analysis Engineer

Voiceflow; Long Beach (CA); On-site; USD 150,000 - 190,000; Full time

Job summary

BlueCore Energy in Long Beach, CA is seeking a Principal Thermal-Hydraulics & Safety Analysis Engineer to model thermal-hydraulics, size loops, and author safety analyses for PSAR/FSAR. You will own DNBR and subchannel analyses, coordinate with core physics, and ensure primary components meet ASME NB requirements through rigorous design-by-analysis.

This on-site, hands-on role requires collaboration across teams, interfacing with marine reactor design and safety case development to deliver

Qualifications

• MS/PhD in Nuclear or Mechanical Eng with reactor thermo-hydraulics specialization.
• Hands-on experience with system thermo-hydraulics codes (RELAP5-3D, TRACE, ATHLET).
• Experience with subchannel codes (VIPRE-01, COBRA-TF/CTF).
• Deep understanding of ASME Boiler & Pressure Vessel Code NB (Class 1) Sect 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 and DNBR analysis.
• Mechanical sizing for RPV, SG, pressurizer, and RCPs.
• Establish heat balances for primary/secondary/tertiary loops.
• Author Chapter 15 safety analyses and coordinate with risk assessments.
• Set minimum DNBR per 95/95 SAFDL and validate CHF basis.
• Manage fatigue and fracture margins in design.
• Coordinate neutronics-thermal-hydraulics feedback with Core Physics.

Skills

Thermal-hydraulics

Reactor design

System modeling

Code NB NB (ASME NB)

VIPRE-01

RELAP5-3D

CFD tools

Education

MS/PhD in Nuclear/Mechanical Eng (Thermal-Hydraulics/Pressure Vessel)

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.

Principal Thermal-Hydraulics & Safety Analysis Engineer

About the Role

The Principal Thermal-Hydraulics & Safety Analysis 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 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.

• Experience integrating deterministic Chapter 15 safety results with a broader Probabilistic Risk Assessment (PRA).

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.