Seaborg Technologies is a start-up on the forefront of advanced and innovative nuclear reactor technology working to provide abundant, affordable and sustainable energy to the world. We have grown to become the leading molten salt reactor start-up outside of North America with an international team of 20 employees from four continents. We are actively developing the design for our Compact Molten Salt Reactor, alongside licensing and experimental validation activities of key safety and performance claims, and are currently planning a multi-million salt lab to accelerate these efforts. We are engaged with multiple stakeholders in the growing advanced reactor supply chain, primarily in East Asia.


Our success is entirely due to our brilliant and passionate team of employees and experienced advisers - a team we are currently in the process of expanding with more world-class talent determined to create positive change in the world.


We are hiring a senior reactor physicist with advanced knowledge of thermal-hydraulics and/or neutronics to work with reactor development as a part of the core Seaborg team in central Copenhagen. The successful candidate will hold a leading position in Seaborg’s reactor physics group, and will be applying in-house and existing computational tools to simulate reactor behaviour and steer design activities of the reactor and experimental validation campaigns. The position will collaborate closely with the other design groups in Seaborg to ensure due consideration of all important physical phenomena and safety considerations across the different disciplines. Some international travelling should be expected.


Seaborg employees must be able to act proactively and independently to perform a wide variety of functions that do not always correlate with experience or expertise (such as writing job advertisements). That being said, the advertised position is expected to include at least some of the following responsibilities and tasks:

  • Plan, organise and execute computational reactor physics activities, including neutronics, thermal-hydraulics, multiphysics, etc., to guide the design of the reactor and experimental validation campaigns;

  • Plan, organise and execute validation and verification activities of computational reactor physics activities;

  • Project manage teams to succeed with R&D activities internally in Seaborg and in collaboration with external partners;

  • Analyse computational and experimental studies to suggest concrete solutions as a part of evidence-driven design development;

  • Prepare technical reports and specifications of SSC in accordance with Seaborg quality requirements;

  • Develop in-house computational tools and data analysis software;

  • Pursue compliance with regulatory requirements, including adhering to and further developing quality assurance schemes for software and design;

  • Review results, reports and software produced internally by other Seaborg teams;

  • Support IP development and acquisition activities;

  • Actively participate in the design of systems, structures, and components (SSC);

  • Support planning of R&D activities, including scheduling, costing and establishing decision criteria;

  • Train and supervise new employees and interns from around the world;

  • Interact with a diverse set of partners and stakeholders from around the world.


  • Desire to positively change the world by shaping the energy landscape of tomorrow;

  • Demonstrated ability to creatively and diligently approach and solve challenging tasks within time and budgetary constraints;

  • MSc or higher in nuclear reactor physics or nuclear engineering;

  • Proficiency with neutronics (stochastic and deterministic, preferably MCNP) and/or thermal-hydraulics/system analysis codes;

  • At least 5 years of relevant experience performing reactor physics simulations for use in design development and licensing activities;

  • Experience with computer clusters and high-performance computing;

  • Team player with effective communication and good interpersonal skills, including fluency in English;

  • Experience with (quality-controlled) software development preferred;

  • Experience with molten salt reactors preferred;

  • Ability to travel by plane and communicate outside of normal working hours when necessary.

At Seaborg we strongly value the combination of relevant experience, talent and personality traits that align with our team and overarching vision for a sustainable future. We therefore encourage applications from diverse backgrounds and are prepared to mould the job description to accommodate well-aligned candidates.


While our team is still small, our ambitions are not. Becoming a part of Seaborg presents a unique possibility to importantly impact and define the global energy landscape of tomorrow. We know that new ideas and influences are key to challenge the status quo and strive for continuous improvement, and so new hires can expect to importantly contribute to shaping both the technology and the future of the company.

We want to play an active role in enabling the personal and professional development of all employees so that they can evolve and grow to take on changing tasks and responsibilities. To give room for this development, we practice high work flexibility in an informal, merit-based environment without strict hierarchies. With time, we expect every employee to become an invaluable part of Seaborg and our success, and we underpin this expectation by offering all new employees stock options in the company.


We are based in Denmark, a country known for its high quality of life and extensive social welfare system. That means free health care and education, generous vacation arrangements, progressive maternity and paternity leave provisions, etc. More on this at


Our office is situated centrally in Copenhagen - a young and vibrant European capital on the Øresund coast with a thriving expat community and world-leading bicycle infrastructure.



Please note that we no longer accept applications for this position.

However, if you think you would be an outstanding candidate for a similar position in the future, feel free to let us know by sending an email to

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 © 2020  Seaborg Technologies

Titangade 11

2200 Copenhagen N