RELAP5-3D Code Developer

Idaho National Laboratory; Idaho Falls (ID); On-site; USD 79,000 - 195,000; Full time

Benefits offered by this job

Relocation package

401(k) with employer contribution

Job summary

Idaho National Laboratory is hiring a Modeling & Simulation Professional to join the Reactor Systems and Heat Transport team. The role centers on modernizing RELAP5-3D, improving code structure, readability, and maintainability, and integrating new features and tools.

You will perform thermal hydraulic analysis with RELAP5-3D and contribute to a high-impact nuclear safety software platform. The position requires a BS or advanced degree in a relevant field and 2–5 years of experience, with US

Qualifications

• Bachelor’s or advanced degree in a quantitative STEM field from an accredited institution.
• Level 2 or Level 3 prerequisites with specified years of relevant experience.

Responsibilities

• Update legacy Fortran code to modern standards and improve structure.
• Break down complex routines through refactoring and inline documentation.
• Develop new features and algorithms in Fortran and add Python scripts as needed.
• Apply automated documentation systems and streamline updates.
• Submit code updates via pull requests.
• Participate in the International RELAP5 User Group (IRUG) meetings.
• Collaborate with analysts and external partners to support development and integration.
• Perform thermal hydraulic design/safety analysis using RELAP5-3D or similar tools.
• Support strategic planning and performance reviews to align with long-term goals.

Skills

Excellent communication

Fortran programming

Python scripting

Education

B.S. in Mathematics, Engineering, Computer Science or related

Advanced degree in Mathematics, Engineering, Computer Science or related

Tools

RELAP5-3D

Fortran

Python

Job description

Job Description

INL is seeking a skilled and forward-thinking Developer to join the Reactor Systems and Heat Transport Department as part of the RELAP5-3D team in modernizing and expanding the capabilities of this critical nuclear safety analysis tool. This role involves improving code structure, readability, and maintainability, while also supporting the integration of new features and tools. The ideal candidate will be passionate about clean code practices and eager to contribute to a high-impact nuclear safety software platform. Additionally the developer will have the ability to perform thermal hydraulic analysis using RELAP5-3D to determine areas of improvement.

Essential Job Functions And Responsibilities

• Update legacy Fortran code to modern standards, including restructuring.
• Break down complex routines into manageable components through refactoring and enhancing inline documentation.
• Program new code features, capabilities, and algorithms in Fortran as assigned and use existing and new write Python scripts.
• Apply the automated documentation systems to streamline manual creation and updates.
• Submit code updates as pull requests to the repository.
• Participate in the International RELAP5 User Group (IRUG) Meetings.
• Collaborate with analysts, stakeholders, and external partners to support ongoing development and integration efforts.
• Perform thermal hydraulic design/safety analysis using RELAP5-3D or other thermal hydraulic tools.
• Participate in strategic planning and performance reviews to align development with long-term goals.

Required

• Level 2: Bachelor of Science in Mathematics, Engineering, Computer Science, or related discipline from an accredited institution and 2 years of relevant experience; or an Advanced degree in Mathematics, Engineering, Computer Science, or related discipline from an accredited institution.
• Level 3: Bachelor of Science in Mathematics, Engineering, Computer Science, or related discipline from an accredited institution and 5 years of relevant experience; or an Advanced degree in Mathematics, Engineering, Computer Science, or related discipline from an accredited institution and 2 years of relevant experience.
• Excellent verbal and written communication skills.
• This position is subject to export control restrictions per the Department of Energy. For this reason, you must be either a US Citizen or a US Green Card holder to qualify for the job.

The Ideal Candidate Will Possess

• Advanced degree from an accredited institution.

Physical Requirements

While performing the duties of this classification, the employee is frequently required to stand, walk, sit, stoop, kneel, bend, use hands to handle materials, manipulate tools, keyboard and type, reach with hands and arms, and operate job-related equipment. The employee must occasionally lift and/or move up to 25 pounds. Sufficient visual acuity and hearing capacity to perform the essential functions and interact with people is required. Reasonable accommodations may be made to enable individuals with disabilities to perform the essential functions.

Job Information

Idaho National Laboratory is hiring a Modeling & Simulation Professional to work on our Reactor Systems and Heat Transport team. Our team works a 9x80 schedule located out of our REC facility with every other Friday off.

• The pay range for this position is: Level 2 ($79,344 - $162,732) / Level 3 ($95,256 - $195,288). At Idaho National Laboratory compensation decisions are determined using factors such as education, relevant experience, and other credentials.
• Multi-Level: This is a multi-level posting and you will be placed at the appropriate level dependent on depth and breadth of proven experience and skills.

About Us

INL is a science-based, applied engineering national laboratory dedicated to supporting the U.S. Department of Energy's mission in nuclear energy research, science, and national defense. With more than 6,300 scientists, researchers, and support staff, the laboratory works with national and international governments, universities and industry partners to change the world's energy future and secure our nation's critical infrastructure.

Benefits and Relocation

• Medical, Dental, Vision, and Flexible Spending Accounts
• 401(k) with a 4.2% employer contribution and up to 4.8% match (regular positions) or self-contribute access (postdoctoral positions)
• Paid time off (personal leave)
• Employee Education Program (tuition assistance for eligible positions)
• Comprehensive Relocation Package
• Benefit eligibility subject to multiple factors, including employment status and position classification.

At this time, BEA will not sponsor any H1-B visas obtained outside of the United States of America (U.S.A.), including consular visas.

INL Mission

Our mission is to discover, demonstrate and secure innovative nuclear energy solutions, other clean energy options and critical infrastructure.

INL Vision

Our vision is to change the world's energy future and secure our nation's critical infrastructure.

Selective Service Requirements

To be eligible for employment at INL males born after December 31, 1959 must have registered with the Selective Service System (SSS). For more information see www.sss.gov.

Equal Employment Opportunity

Idaho National Laboratory (INL) is an Equal Employment Opportunity (EEO) employer. It is the policy of INL to provide equal employment opportunities to all qualified applicants without regard to race, color, religion, sex, sexual orientation, gender identity, national origin, age, protected veteran or disabled status, or genetic information.

Reasonable Accommodation

We will ensure that individuals with disabilities are provided reasonable accommodation to participate in the job application or interview process, to perform essential job functions, and to receive other benefits and privileges of employment. Please contact us to request accommodation.