Do you want to contribute to the future of nuclear safety through advanced research in thermal hydraulics? We offer a fully funded doctoral researcher position that allows you to develop strong expertise in analytical, experimental and numerical modelling while supporting next‑generation nuclear safety analysis.
The LUT School of Energy Systems is looking for a doctoral (junior) researcher in nuclear thermal hydraulics system modelling.
The position is located at LUT's Laboratory of Nuclear Engineering. LUT University is Finland's leading institution in energy technology research. LUT's nuclear engineering laboratory has been conducting nuclear power plant thermal hydraulics experiments and modelling since 1974, focusing on large light-water reactors, small modular reactors, gas-cooled reactors, advanced measurement techniques, and nuclear regulations. The laboratory has longstanding expertise in both modelling and experimental evaluation of factors that influence the safety of nuclear power plants.
What you'll do
We are seeking a curious individual interested in pursuing an academic career and enhancing state-of-the-art safety analysis methods. This position focuses on the fundamental study of counter-current flow limitations (CCFL). Your work will involve analytical, experimental, and numerical analyses of the CCFL phenomenon, with the aim of improving physics modelling in computational fluid dynamics (CFD) and system thermal-hydraulic (SYS-TH) codes commonly used in nuclear safety analysis. CCFL modelling currently relies on simplistic empirical correlations in SYS-TH codes used for nuclear safety assessments. These correlations often struggle to accurately predict CCFL in complex flow scenarios and intricate geometries.
The goal of your doctoral research will be to advance understanding of CCFL by developing models based on first principles, supported by a combination of well-instrumented separate-effects tests conducted at LUT University and detailed CFD modelling. You will perform detailed CFD simulations, implement CCFL models into a selected thermal-hydraulic system code, verify the implementation, and validate the code's performance using data from previous system tests. Through realistic physics modelling, your research will aim to advance existing methodologies, deepen our understanding of the CCFL phenomenon in nuclear power plants, and ultimately promote nuclear safety.
You will pursue independent and original research within the nuclear engineering laboratory, submit publications to peer-reviewed journals, and collaborate with international research groups working on nuclear thermal hydraulics.
As a doctoral (junior) researcher, your main task will be to complete your doctoral degree within four years. This includes preparing a dissertation, which typically consists of four peer-reviewed publications and a summary, and completing 30 ECTS credits of doctoral studies. In addition, you will participate in teaching bachelor's and master's students and in academic duties such as seminars, conferences, presentations, and scientific discussions.
What we expect from you
You must have a master's degree (M.Sc. or equivalent) in a relevant field (energy technology, nuclear engineering, mechanical engineering) and the ability and motivation to complete the doctoral studies within their normative duration (i.e., four years).
You should have knowledge of fluid mechanics, nuclear thermal hydraulics, thermodynamics, numerical methods, applied mathematics, and related areas. Previous experience in and knowledge of mathematical modelling and fluid flows - particularly two-phase flow dynamics - are an advantage, as is a background in conducting experiments and CFD and system thermal-hydraulic codes (e.g., APROS, TRACE, RELAP5).
We expect fluency in English - both written and spoken. In addition, you must submit an application for the right to complete doctoral studies to the LUT Doctoral School within the first two months of the employment relationship.
What we offer
At LUT, we offer you the opportunity to become an expert in the field of your dissertation and will support your learning, training, and professional development. You will receive guidance from Professor Juhani Hyvärinen and Associate Professor Giteshkumar Patel, and you will have the chance to participate in international research collaborations. We encourage you to pursue your research independently, explore innovative approaches, and develop your scientific expertise.
This position is based in Lappeenranta and requires regular on-site presence.
Your goal is to finish the doctoral degree within the given timeframe. The work will start as soon as possible, preferably in February-March 2026 and will include a six-month trial period. The contract is initially for one year and may be extended for three additional years, depending on the progress of your studies and research.
The hours are flexible and support work-life balance. The position follows a system of 1,612 annual working hours in accordance with the collective agreement for Finnish universities.
The salary aligns with the Finnish university salary system's pay scale for teaching and research staff (requirement level 1). The starting salary is approximately EUR 2,780 per month, depending on experience and qualifications.
How to apply
The deadline for applications is 10 February 2026 at 23:59 Finnish local time (UTC + 2 h). Fill out the online application form and attach the following documents in English and in PDF format:
- A motivation letter: an account of your merits and activities of significance to the vacancy (max. 2 pages)
- A curriculum vitae (CV) following the guidelines of the Finnish Advisory Board on Research Integrity
- Scanned copies of your bachelor's and master's degree certificates and transcripts of records; if the documents are not in English or Finnish, include certified translations, and if your degree is unfinished, include an official estimate of the completion date
- Your master's thesis or its draft or abstract or other significant research work
- A one-page statement describing your research interests and how they align with the project
- Contact details of at least two references (or letters of recommendation if available)
Only applications that include all required documents will be considered.
We will review applications on a rolling basis.
For more information about the position, please contact Associate Professor Giteshkumar Patel, [email protected], +358 40 152 9413.
Read more about LUT as an employer and the LUT Doctoral School.
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LUT University | LUT University seeks solutions to global issues with its expertise in technology, business, and social sciences. LUT is a trailblazer in promoting the energy transition and the regenerative use of natural resources and helps build resilient communities, industry, and businesses through data, research, and education. LUT's campuses are in Lappeenranta and Lahti, Finland, but its impact is global. Lut.fi/en
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Application period starts: 2026-01-20 08:00Application period ends: 2026-02-10 23:59