Mechanical Engineer, Fluid Systems - 2026 New Graduate

Radiant

$75K — $95K *
Aerospace & Defense
Less than 5 years of experience
Job Overview by Ladders

Qualifications

  • Bachelor's degree in Mechanical, Materials, Aeronautical, Civil or Structural Engineering
  • Experience with fluid system architecture design
  • Experience in designing, building, and testing fluids systems
  • Proficient knowledge in fluid dynamics and thermodynamics
  • Proficient knowledge of heat exchanger design and analysis methods

Responsibilities

  • Own end-to-end engineering of fluid systems and components
  • Perform thermal and fluids analysis to guide design decisions
  • Conduct trade studies for system optimization
  • Develop and execute manufacturing/assembly instructions and test plans
  • Create and manage a Bill-Of-Materials (BOM)
  • Source and develop suppliers for components
  • Oversee subassembly design, manufacturing, and test schedules
  • Conduct risk analysis (FMEA) for subsystems

Benefits

  • Substantial incentive stock plan for all full-time employees
  • 100% coverage up to base silver level plan for employee medical plus 50% for dependents
  • Sponsored memberships in One Medical for employees and dependents
  • 100% coverage for vision plan plus 50% for dependents
  • 100% coverage for dental plan with orthodontia extra, plus 50% for dependents
  • Voluntary benefits including life, accident, and critical illness insurance
  • 8 weeks of paid parental leave for all parents
  • Daily catered lunch with free snacks and drinks
  • Flexible PTO policy and remote workday options
  • Company bonding events and camaraderie at headquarters
Full Job Description

About the Role

Radiant is seeking a highly motivated Mechanical Engineer, Fluids Systems to help own critical Kaleidos fluid systems from preliminary design through build and production. These systems include the primary loop subsystems and power conversion loop, serving to convert heat from the reactor core into electrical power. You will be responsible for the following: trade studies, component selection, thermal hydraulic analysis, piping design, vendor selection, assembly, and testing. You will have an instrumental impact of fueling the first new commercial reactor design in over 50 years by 2026.

Responsibilities & Duties:
  • Help own end-to-end engineering of fluid systems and components, including compressors, valves, and heat exchangers.
  • Perform thermal and fluids analysis to drive design decisions, verify system performance, and ensure structural integrity using first-principle hand calculations and finite element tools.
  • Perform trade studies to optimize system and meet program requirements.
  • Develop and execute manufacturing/assembly instructions and test plans.
  • Create and manage a Bill-Of-Materials (BOM).
  • Find and develop suppliers for all components.
  • Own subassembly design, manufacturing, and test schedules.
  • Own risk analysis (FMEA) for subsystems.
  • Collect requirements, provide expertise and feedback to engineers in other functional areas via clear, constructive communication.

Required Qualifications & Skills:
  • Bachelor's degree from an accredited institution in Mechanical, Materials, Aeronautical, Civil or Structural Engineering.
  • Experience with fluid system architecture design.
  • Experience in designing, building, and testing fluids systems.
  • Proficient knowledge in fluid dynamics and thermodynamics.
  • Proficient knowledge of heat exchanger design and analysis methods.

Desired Qualifications & Skills:
  • Knowledge of thermodynamic power cycles.
  • Prior experience with fluid system modeling via Matlab/Python.
  • Experienced in design for manufacturability and ramping up hardware build in a production environment.
  • Experienced in designing and operating test stands.
  • Takes extreme ownership of work and a high degree of responsibility.
  • Excellent communication across multidisciplinary teams.
  • Prior nuclear experience in not required for this role.
Benefits and Perks
  • Stock: Substantial incentive stock plan for all full-time employees.
  • Medical: 100% up to base silver level plan for employee + 50% dependents, offers up to Platinum plans.
  • One Medical: Sponsored memberships for employees and their dependents.
  • Vision: 100% top tier plan coverage + 50% for dependents.
  • Dental: 100% top tier plan coverage, orthodontia extra, 50% for dependents.
  • Voluntary life, accident, hospital, critical illness, commuter and FSA/HSA are offered as employee contributed benefits.
  • 8-weeks of paid parental leave for all parents. Additional paid pregnancy leave for CA employees.
  • Daily catered lunch. Free snacks and drinks.
  • Flexible PTO policy. Remote workday allocation.
  • Company and team-bonding events, happy hours and in-person camaraderie.
  • Beautiful El Segundo headquarters close to the Pacific Ocean.


Total Compensation and Benefits
Radiant compensates people for impact and invests in those who continue to raise the bar. Radiant's new hire compensation package includes base salary, substantial equity grants, and comprehensive health benefits. Total compensation and level are determined through a rigorous evaluation of interview performance, experience, education, and qualifications, and are designed to support continued growth as scope, responsibility, and impact expand at Radiant.

The best of today's advanced reactor builders don't wait for job postings. They join the winning team. If that's you, contact us directly for immediate opportunities: [redacted].

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