Senior Mechanical Engineer-Codes, Standards & Design Frameworks

Shape the rules before the rules are fixed. We’re supporting a leading organisation in advanced nuclear technologies developing a next-generation reactor concept.

This is a design-led engineering company, not a utility and not an EPC contractor, and they are strengthening their mechanical capability at the point where codes, standards, quality frameworks, and real engineering decisions intersect. This role sits early in the design lifecycle. It is about judgement as much as calculation.You may currently be working in a high-integrity environment where the rulebook is already written.

The codes are set. The pathways are established. Your role is to apply them. But what if you could help define how those rules are interpreted for an advanced reactor?

Here, mechanical design philosophy is not inherited, it is shaped. You would take ownership of how applicable codes and standards are interpreted, adapted, and justified in the context of a novel system. You would perform structured gap analyses between established industrial or nuclear standards and what an advanced reactor genuinely requires. Where strict compliance is not straightforward, you would help define defensible alternative approaches, technically rigorous and regulator-legible. This is collaborative, senior engineering work.

You would work closely with systems, thermal, materials, safety, and quality colleagues to ensure design coherence. You would contribute to substantiation strategy, governance material, and internal technical decision-making as the design matures from concept toward early detailed design.

The background we are looking for:

Strong mechanical engineering fundamentals with clear evidence of personal design ownership.

Experience navigating codes, standards, and quality frameworks in high-integrity environments.

Exposure to pressure systems, structural integrity, thermal-mechanical behaviour, fatigue/creep, or safety-class components

Comfort working in early-phase engineering, where ambiguity exists and frameworks are still evolving.

Experience within nuclear reactor or plant design is valuable.

Equally, candidates from aerospace, defence, or oil & gas design environments-particularly those used to regulated, safety-critical systems-would be highly relevant.

This is an office-first role based in Stockholm.

Regular in-person collaboration is important, and relocation is expected for core team members.

If you are technically rigorous, comfortable challenging assumptions, and motivated by helping define credible compliance pathways for a next-generation reactor-we would be glad to speak with you.

Capax Mundi supports advanced nuclear and energy-transition organisations across Europe.

We approach each conversation with care, discretion, and long-term perspective.