What we do at Blykalla

Blykalla is a Swedish deep-tech company at the forefront of the nuclear industry, pioneering the development of small modular reactors that provide clean, safe, and reliable energy. Thanks to lead-cooling, we achieve high safety in a very compact format, allowing for a simple and cost-effective design that can be mass-produced. Our unique reactor design will provide safe and green baseload energy that perfectly complements solar and wind power.

Help Us Prove a New Standard in Nuclear Fuel

Are you a technically sharp, self-driven engineer or scientist who understands how nuclear fuel really behaves - and how to prove it with credible models?

Join Blykalla and lead the fuel performance modelling effort that underpins development and qualification of a novel nuclear fuel in an advanced reactor. This role puts you at the center of predicting, validating, and defending fuel behavior for the western world’s first lead-cooled SMR.

You’ll own the fuel models and codes that allow for producing regulator-ready evidence that our fuel performs as intended.

What you’ll get to do

Your mission is to ensure that we can predict, explain and justify fuel behavior with confidence, using validated models, defensible assumptions and traceable data. 

Build and evolve fuel performance models

• Develop, extend, and adapt fuel performance models for nitride fuel in a fast-spectrum operation, with a focus on physical mechanisms rather than black-box use

• Understand and improve model behavior by analyzing why models work, where they break down, and what must be changed for lead-cooled operation

• Apply and benchmark models against other fuel types, including oxide and metallic fuels, to support comparison, validation, and fallback options

Shape data, experiments, and model credibility

• Define what experimental and operational data are needed to support, challenge, and improve fuel performance models

• Work closely with experimental and design teams to specify irradiation tests and pre- and post-irradiation examinations that generate data relevant for model validation or development

• Integrate data from experiments, literature, and historical programmes to calibrate models, assess validity ranges, and reduce key uncertainties

• Contribute to cross-disciplinary activities between reactor physics, thermal hydraulics, materials, backend, safety and licensing to ensure design coherence, manufacturability, and regulatory compliance.

Align modelling with fuel qualification and licensing

• Define, maintain and own the modelling basis used in fuel qualification, including scope, gaps, assumptions, acceptance criteria, and regulatory expectations

• Coordinate with international facilities to secure the knowledge and services (irradiation, transport, PIE) needed to reach fuel qualification and modelling needs

• Ensure consistent modelling assumptions across fuel design, materials, safety analysis, and licensing work

• Represent and support the company’s technical position on fuel performance in discussions with regulators, authorities, partners, and both national and international research organizations

• Establish modelling workflows, documentation, and quality practices that ensure traceability, reproducibility, and regulatory readiness
  

Where this role can take you

If you succeed in this role, you’ll become a cornerstone of Blykalla’s fuel and licensing strategy. Over time, this could grow into one of two directions:

• An expert path: Principal fuel performance authority coordinating modelling, experiments, safety analysis, and licensing through technical leadership across fuel types, materials, and operating conditions

• A strategist path: Technical lead for modelling and simulation across fuel and core-related R&D programmes, shaping longer-term modelling strategy and integration across the reactor programme

This is a core position with real influence over how advanced nuclear fuel is predicted, justified, and licensed not just at Blykalla, and potentially as a reference for future SMRs.

Who’ll you’ll get to work with

The Senior Nuclear Fuel Performance Engineer/Scientist sits in the Fuel management Team within Blykalla, and reports to the Fuel Manager. We are a diverse team that is passionate about our work and Blykalla. 

Who you are

You will be part of a highly skilled team with a can-do attitude. We value personnel chemistry and strive to create a workplace where you enjoy coming to. You think in mechanisms, not just results. You’re comfortable working where data is incomplete and uncertainty matters. You structure complex problems, make assumptions explicit, and know when a model is “good enough” versus when it isn’t. You challenge inputs, document decisions, and communicate clearly, especially when models drive high-stakes conclusions. You take ownership, flag risks early, and balance technical ambition with regulatory realism. You collaborate smoothly across disciplines and help raise the technical bar around you.

Qualifications

• Degree in nuclear engineering, physics, chemistry or a closely related field

• Over 5-years experience in fuel performance modelling for nuclear fuel, including development, modification, or critical assessment of models rather than black-box use

• Demonstrated ability to understand fuel behavior at the mechanism level and to diagnose why models work, where they fail, and how they must be improved

• Hands-on experience with fuel performance codes such as TRANSURANUS, FRAPCON/FRAPTRAN, BISON, or similar tools, including extending, adapting, or validating models

• Experience integrating experimental data from irradiation tests, post-irradiation examinations, literature, or historical programmes to support and improve modelling

• Ability to define what data and experiments are needed to support model credibility and uncertainty reduction, and to work effectively with experimental and qualification teams

• Understanding of how modelling contributes to fuel qualification, safety arguments, and regulatory submissions

• Ability to communicate and defend modelling assumptions, limitations, and results in technical discussions with regulators, authorities, and partners

• Fluency in English; Swedish is an advantage

• Willingness to travel within Europe, North America and occasionally beyond

• Eligibility to work with nuclear materials in Sweden
  

If you are not sure that you are 100% qualified but are up to the challenge, we encourage you to apply.

Location 

This position is for our office in Stockholm. Travel to partner sites and research facilities will be part of the role.

So, what do you think?

Don't miss the chance to be at the forefront of revolutionizing nuclear power. Join our team as Senior Nuclear Fuel Performance Engineer/Scientist and help shape the energy landscape of tomorrow. Apply today with your resume and a cover letter highlighting your relevant experience and achievements.

We are proud to foster an inclusive workplace free from discrimination. We strongly believe that diversity of experience, perspectives, and background will lead to a better environment for our employees and a better product. This is something we value deeply and we encourage everyone to be a part of changing the way the world thinks about power supply!

We offer competitive compensation aligned with our internal salary framework and growth potential in the role.

We do not accept applications via email. 

 We are not open to external help from recruitment agencies.