VTT Summer of Changemakers: Research Trainee / Thesis Worker, Nuclear energy

Do you want to start changing the world for the better next summer? Are you all about science and technology? Would you like to develop your skills and use them to tackle the greatest challenges of our time? VTT might be just the place for you. Apply now for VTT Summer of Changemakers 2023 traineeships. Together, we can turn these challenges into a hopeful future.

VTT is one of the leading applied research organisations in Europe. What unites us are curiosity, a passion for learning and a purpose: to solve the biggest challenges of our time and turn them into sustainable growth and well-being. Our cross-disciplinary community of over 2100 brilliant minds from 50 different nationalities is focused on creating impact through science-based innovation. In recent years, we have created ground-breaking innovations such as the world's fastest and most accurate radiation detector, a cancer-sniffing sensor device for smartphones, and a headphone set entirely made of microbial materials. Now, we are looking for passionate changemakers – you – to join us as summer trainees.

Do you want to model an advanced nuclear reactor with state-of-the-art tools?  Join us - and let’s make science work for hope next summer!

VTT is preparing for the nuclear decarbonization of high-temperature industrial processes by building up the modelling capabilities for high-temperature gas-cooled reactors (HTGRs). As part of VTT’s reactor analysis team, your task is the steady state modelling of an HTGR core at different power levels with VTT’s computational reactor analysis framework Kraken.

As electricity production in Finland and the Nordic countries are already largely free of CO2 emissions, industrial processes that require high-temperature heat (chemical processes, hydrogen production, etc.) are an important next target for decarbonization. HTGRs are designed as a nuclear heat source for such processes. 
Kraken is a modern collection of solvers for reactor core physics: Neutronics, thermal hydraulics, and nuclear fuel behaviour. Kraken has been developed for the safety analyses of  Finnish nuclear power plants and the evaluation of new reactor concepts since 2017.

What your responsibilities would include:

  • Your main responsibility is the modelling of zero power and full power physics tests for a high-temperature gas-cooled reactor core
  • The analyses are repeated using: 
    • high-fidelity neutronics based on VTT’s Serpent Monte Carlo code
    • reduced order neutronics based on VTT’s Ants nodal neutronics program with coolant flow modelled using the OpenFOAM CFD toolbox
  • The computational analyses will be conducted on a Linux computational cluster using command line-based analysis codes
  • Your analysis will provide the initial estimation of the accuracy of the reduced order sequence compared to the high fidelity sequence in HTGR full power modelling
  • The results of the work can be reported as a Bachelor’s thesis or a special assignment.

Who we are looking for?

  • We expect you to have at least 3 years of studies in a relevant field (physics, mathematics, energy technologies, or similar)
  • Familiarity with Python will be an advantage when working with Kraken
  • Familiarity with OpenFOAM or other similar CFD tools may be an advantage in the analyses. 

As a person, we hope that you are:

  • Capable of independent work, but also a team player
  • An innovative problem-solver, not afraid of new challenges
  • Passionate about technology. 

The ideal VTT Changemaker is a curious mind, who is eager to develop and take on new challenges. We appreciate ambition and willingness to learn over having all the answers or skills ready when you start. You are also a team player with strong collaboration skills who wants to drive positive impact in the world.

What would we offer you?

  • Impactful work for the future. As a leading applied research organisation, we are on a mission to bring exponential hope to the world by joining together people, businesses, science and technology. We tackle the biggest challenges of our time – from climate change and resource sufficiency to industrial renewal and smart healthcare – and turn them into sustainable growth. Read more about our strategy – the path of exponential hope.
  • Career opportunities, top-level mentors. At VTT, your skills are appreciated and supported with the opportunity to learn from the top experts in their field. You’ll get to discover our community of over 2100 experts representing more than 50 nationalities working across cutting-edge fields of science and technology.
  • Meaningful projects, real responsibility. With us, you get to take on meaningful projects and create innovative scientific and technical solutions as part of our Reactor analysis team. We treat all employees as equals and give you real responsibility from the start. VTT is a caring employer that supports your growth and work–life balance and offers a range of well-being services.

What is like to work with us solving the biggest challenges of our time? Check from the video what kind of experiences Aymara, Daniil, Eric and Isabella had from their summer traineeships and what kind of change did they drive.

Apply now and join our community of brilliant minds!

Come, curious minds and clever changemakers! Prepare your CV and cover letter, and send in your application with your transcript of records via our recruitment system as soon as possible but at the latest by 5 February 2023. Let’s change the world for the better next summer.

All VTT Summer of Changemakers traineeships are paid and the duration is usually between 3 and 6 months. The exact starting date and length of the traineeship can be discussed. We will process applications as they come in, and fill in the position as soon as we find the right candidate.

Please read more of VTT Summer of Changemakers from here: https://www.vttresearch.com/en/summer-changemakers

Interested and want to hear more?

For further information, please contact Senior scientist Ville Valtavirta, Ville.Valtavirta@vtt.fi.

For more information on the Kraken framework, see: Introduction to the Kraken framework

We look forward to hearing from you!

Apply between and
Employment type: Full-time, Fixed-term (Summer traineeship / Thesis position)


VTT is one of Europe's leading research organisations, a visionary innovation partner for businesses and society. We bring hope to the world by turning the greatest challenges of our time into sustainable growth with cutting-edge science and technology. We employ a community of over 2100 world-class problem-solvers across fields of science and business. You can familialise yourself with VTT's research infra from here.

VTT – beyond the obvious

Location: Kivimiehentie 3, Espoo

Currently, we have over 40 truly meaningful and versatile traineeship positions open! See other summer trainee position from VTT Summer of Changemakers 2023 pages.


VTT Summer of Changemakers: Research Trainee / Thesis Worker, Nuclear energy

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