Nuclear Mechanical Engineer

Summary

We are looking for an Experienced Nuclear Mechanical Engineer to join the Transmutation Reactor Unit at Transmutex, contributing to the design, analysis, and qualification of critical components for the START transmutation reactor.

Transmutex is a Geneva-based start-up founded in 2019. We aim at reinventing nuclear energy by designing START (Subcritical Transmuting Accelerated Regenerative Technology) to optimize the transmutation of long‑lived nuclear waste. The innovative combination of particle accelerators and fuel, based on existing long‑lived radioactive waste, will let us develop energy process that will be intrinsically safe, will reduce the stockpile of long‑lived waste, is resistant to proliferation, and will be cost competitive.

We are seeking an Experienced Nuclear Mechanical Engineer with experience in the design and analysis of critical nuclear reactor components. You will be part of the Reactor Unit based in Geneva and will report to the Reactor Unit Head.

As an Experienced Nuclear Mechanical Engineer you will take part in the design and assessment of nuclear critical components for the START Reactor such as fuel assemblies, fuel handling equipment, reactor core components and reactor pressure vessels. Your tasks will consist of:

• Design and analyse reactor internals according to thermomechanical, fluid and neutronic requirements.
• Detailed analysis of critical components using finite elements tools (ANSYS or similar codes) and designed using Solidworks/CATIA.
• Support the design and prototyping of critical components of the fuel handling and storage equipment to demonstrate functionality and performance in representative conditions.
• Define experimental requirements for qualification, verification and validation of material and mechanical models.
• Define material and component failure limits based on established standards and postulated safety events.
• Coordinate with other Units to define interfaces and integration requirements.
• Engage with suppliers and manufacturers and contribute to drafting and manufacturing first‑of‑a‑kind and series production of components complying with system requirements.

The candidate we are looking for must have:

• Master's degree or PhD in mechanical/nuclear engineering or equivalent,
• 5‑10 years of experience in mechanical design of nuclear components,
• Minimum 5 years experience in 3D CAD design (preferably in Solid Works),
• Deep understanding of finite element analysis (preferably using Ansys) applied to structural and failure assessments, advanced material model implementation and thermomechanical behaviour.
• Knowledge of nuclear design codes such as ASME BPV Section 3 and/or RCC‑M.
• Strong communication skills in English (French is a plus).

• Prior knowledge of fast reactor designs and/or Accelerator Driven Reactor Systems (ADS)
• Experience in advanced manufacturing methods for prototyping and series production.
• Knowledge of vibration analyses including flow induced vibrations.
• Experience of materials for operation in fast reactors and tailored material model implementation within finite elements analyses.
• Knowledge of nuclear safety principles, design for safety and failure modes.
• Ability to work collaboratively across multi‑disciplinary environment with experience in interfacing with suppliers, manufacturers, designers, technicians and engineers.

Start date:

Q1 2026

Location:

Vernier, GE, Switzerland

Contract:

Full‑time, permanent employment contract

Package:
We offer competitive remuneration and social security, accident/disability insurance and pension plans; one day per week work from home, as well as five weeks paid vacation (+ office closure in between Xmas and New Year).

One to two technical interviews with the hiring manager and other Transmutex team members;
Interview with HR for retained candidates, final interview with Management for shortlisted candidates.