Thermofluids Modelling Engineer (Reactor Faults)

Rolls-Royce SMR; East Midlands; Hybrid; GBP 42,000 - 55,000; Full time

Benefits offered by this job

Bonus 12.5%

Pension 12% + 6%

Private medical insurance

28 days holidays + buy/sell 4 days

Life assurance 6x

Home office support £250

Job summary

Rolls-Royce SMR is seeking a Thermofluids Modelling Engineer (Reactor Faults) to join the Performance & Analysis team. You will model fluid and thermal systems that extract power from the nuclear core, producing analyses that support safety cases and plant design optimisations.

The role requires building robust analysis routes, using Python on Linux HPC resources, and collaborating with test capability teams designing large-scale rigs for validation and benchmarking.

Qualifications

• Understanding of fluid dynamics and thermal processes with structured analysis.
• Experience with industry-standard fluids/thermal analysis software; nuclear hydraulics tools desirable.
• Ability to develop analysis methods, models, and Python-based solutions.

Responsibilities

• Model reactor systems and produce analyses demonstrating safe operation.
• Collaborate with system designers to optimise plant design and safety systems.
• Support development and authoring of safety case documentation.
• Communicate results across teams to define analysis requirements.

Skills

Fluid dynamics

Thermal analysis methods

Python

Analysis reports

Verification & validation

Safety-critical systems

Project delivery

Engineering degree

Chartered Engineer

Education

Engineering/Physics/Math/CS degree

Chartered Engineer preferred

Tools

RELAP

FLOMASTER

VIPRE

CTF

GOTHIC

Python tooling

Job description

Thermofluids Modelling Engineer (Reactor Faults)

We are Rolls-Royce SMR and we’re doing something that’s never been done before. We’re revolutionising an industry. That’s a once-in-a-career opportunity for those excited by such a challenge. This is more than just a job; this is a legacy.

We are now recruiting for a Thermofluids Modelling Engineer (Reactor Faults) to join our Performance & Analysis team, the centre of excellence for engineering analysis used to substantiate the performance and safety of the SMR power station.

About The Role

As a performance analyst, you will model fluid and thermal systems that extract power from the nuclear core and ensure safe operation of the reactor. This will involve producing models and analyses that demonstrate reactor operation and working closely with system designers to optimise the design of the plant and its safety systems to maximise safety, performance, and value for money.

Analysis outputs form a key input to the safety case and support the overall substantiation of the power station design. Performance analysts have a key role in supporting the development of and authoring analysis sections of the safety case.

The team uses a wide variety of tools and software to analyse key scenarios for the plant, including:

• Normal operations, when the reactor must produce power and respond to changes in demand from the grid
• Operating transients such as shutting down the reactor and then restarting it for refuelling
• Reactor faults, where passive safety systems are key to protecting the core and ensuring the integrity of the containment.

Due to the safety-critical nature of the modelling we undertake, excellent quality-management processes and code verification, validation and uncertainty quantification are essential. The development of robust and automated analysis routes around the analysis codes, primarily developed using Python on our Linux-based high-performance computing resources, is an important aspect of this.

The performance team collaborates closely with our in-house test capability team, who are building large-scale multi-megawatt test rigs to represent key aspects of the plant to support the validation of the performance analysis tools. There are opportunities within the team to work on benchmarking of our codes against test data and support the development of the test rig designs and associated test campaigns.

As performance analysis supports the development and substantiation of many aspects of the power station design, effective communication and collaboration with teams across a wide range of engineering and non-engineering disciplines is essential.

All performance engineers are responsible for planning their own work to ensure that objectives are met, quality processes are followed, and delivery is on schedule. Depending on your personal level of experience, there may also be the potential to apply your technical expertise to support the development of capability across the technical function, or take on leadership of technical areas or interfaces with other areas of the business.

We’ll Need You To

• Model reactor systems and produce analyses that demonstrate safe and efficient operation
• Work closely with system designers to optimise plant design and safety systems
• Support development and authoring of safety case documentation
• Collaborate across teams to define analysis requirements and communicate results

Key Skills Required

• An understanding of fluid dynamics and thermal processes, with experience applying structured, methodical analysis approaches
• Experience using industry-standard fluids and thermal analysis software; familiarity with nuclear thermal hydraulics tools (RELAP, FLOMASTER, VIPRE, CTF, GOTHIC desirable)
• Ability to develop analysis methods, models, and tools, including Python-based solutions, to support design and safety case development
• Skilled in writing clear, structured analysis reports and contributing to safety case documentation
• Experience in verification and validation of analysis models, including benchmarking, uncertainty quantification, and adherence to software QA processes
• Knowledge of safety-critical plant systems in industries such as nuclear, oil & gas, or aerospace; nuclear-specific knowledge desirable but not essential
• Track record of delivering analysis tasks to time, cost, and quality, with strong communication and leadership skills
• Degree-qualified in Engineering, Physics, Mathematics, or Computer Science; Chartered Engineer (or equivalent) preferred

Location:

Hybrid working with one of the following locations as your primary site: Derby, Manchester or Warrington

Salary And Package

The salary band for this will be between £42,000–£55,150 dependent on the skills, values, and knowledge you bring. There may be some flexibility with the starting salary in exceptional cases, and, in due course, there is the potential for you to develop the role further.

Benefits Include

• Bonus - Performance-related target opportunity 12.5%
• Benefits Allowance - £2,200 per annum for a bespoke package
• Pension - 12% employer and 6% employee contributions
• Holidays - 28 days (+ public holidays) with ability to buy or sell up to 4 days
• Private Medical Insurance - BUPA single cover
• Life Assurance - 6x pensionable pay
• Home Office Support - £250 one-off payment for new starters

Why Join Us?

You’ll be joining a forward-thinking organisation that values transparency, fairness, and innovation. We offer a flexible, inclusive, and supportive working environment, opportunities for career growth in a rapidly scaling business, and a culture that values diversity, innovation, and continuous learning.

• A flexible, inclusive, and supportive working environment.
• Opportunities for career growth in a rapidly scaling business.
• A culture that values diversity, innovation, and continuous learning.

We are an equal opportunities employer and welcome applications from all backgrounds. Inclusivity is important to us, and as a Disability Confident organisation, we are committed to fair, supportive, and continually improving recruitment practices that ensure everyone has the opportunity to thrive.

Confidence can sometimes hold us back from applying for a job. But we'll let you in on a secret: there's no such thing as a 'perfect' candidate. If you feel you meet 75% of the requirements for this role, we would love to hear from you.

Also, if you are considering a career move or a sector-jump, please get in touch – we welcome applications from people with transferable skills.

Selection Process

The closing date for this role is 30th March 2026. The process will then consist of an introductory call with the Talent Acquisition Partner, and then first-round interviews taking place straight away

Our Application Process

Due to the safety regulations within the nuclear industry, applicants will be required to participate in additional screening. These are: Obtaining Baseline Personnel Security Standard (BPSS) clearance Satisfactory completion of a Disclosure and Barring Service (DBS) check Satisfactory completion of a basic financial probity check