From the Physics Olympiad in Mexico to the commissioning of OL3 – Aku Ansio’s career has been built at the intersection of theory and practice

A 19-year-old upper secondary school student from Juva boards an airplane for the first time in his life. This is no ordinary holiday trip, but a journey to Mexico for the International Physics Olympiad. Young Aku Ansio has excelled in physics throughout upper secondary school and has also achieved success in national physics competitions. Now he is heading into a situation where the foundations of Finnish upper secondary school physics are no longer enough on their own—he is stepping directly into the company of the world’s most talented young physics students.

The Physics Olympiad in Mexico did not bring Aku a third-place finish like the national competition had, but the experience left a lasting mark. It showed how far expertise can be taken when physics is approached with determination and ambition. At the same time, it was Aku’s first real trip abroad and a leap from South Savo onto the international stage.

That journey marked the beginning of a path that has since taken him to studies in engineering physics, annual outages at nuclear power plants, international summer jobs, and eventually into reactor instrumentation and radiation measurements at OL3. Today, Aku works at Platom as an automation specialist and an expert in reactor instrumentation and radiation measurements.

From a farm to the world of engineering physics

Aku comes from Juva in South Savo, where he spent his childhood on a farm surrounded by nature and domestic animals. Although farm life was a strong presence in his early years, he sensed from an early age that his own future would most likely lie elsewhere.

Aku’s brothers were interested in continuing the farm, while his own academic success clearly pointed him in another direction. Upper secondary school and university studies felt like the natural next step. The cows and the farm were left in his brothers’ care, while Aku set his sights on technology and physics.

During upper secondary school, his thoughts were for a long time focused on Lappeenranta and studies in energy technology. Renewable energy in particular interested him. However, physics came so naturally to him that his success in competitions opened doors more broadly. In the national physics competition, he placed third in his year group, which in practice meant he could choose his place of study almost anywhere he wanted.

In the end, he chose Otaniemi and engineering physics.

From renewable energy to reactor physics

Although Aku’s original interest lay in renewable energy, his direction began to change during his studies. After his first year at university, he decided to specialize in reactor physics.

The decision was practical, but also far-reaching. A great deal was happening in the nuclear energy sector: the commissioning of OL3 was ahead, OL4 was being planned, and the Fennovoima project was underway. The field seemed to have a need for experts, and Aku saw in it an opportunity to build a career in carbon-free energy production.

One of his first jobs in the field was as a radiation protection officer during the annual outage at the Loviisa power plant in 2012. Among his later summer jobs, one at GE Hitachi in Wilmington, USA, stood out in particular. The international experience also gave him perspective on Finnish working life.

There, Aku realized that Finnish work culture is valuable and effective in many ways, even if salary levels do not always compare favorably internationally.

When theory turns into practice

What has particularly fascinated Aku in the nuclear energy field is how demanding theory is transformed into concrete solutions at the plant. In courses, students calculate how fuel behaves and how reactor physics phenomena are modeled. At a power plant, you can see how that same theory is applied in practical work—for example in core loading design and in the safe operation of the plant.

Annual outages and working at plant sites have been important learning experiences. Seeing a power plant both in operation and up close during maintenance gives the whole picture a completely different scale.

One of the most tangible experiences has been visiting the steam generator at the Loviisa power plant. The horizontal steam generators used in Loviisa are easy to enter, and moments like these make the technology feel concrete and real. They serve as a reminder that a nuclear power plant is not just calculations, systems, and documentation, but a vast technical entity in which every detail matters.

The commissioning of OL3 as the greatest learning experience of Aku’s career

Aku’s career in the nuclear energy sector truly began in Olkiluoto in 2016. He worked at TVO for five years as the system engineer responsible for radiation measurement systems and reactor instrumentation. After that, his path led him to Platom—first briefly to the Fennovoima project, and later back to OL3 to work once again with familiar systems and equipment.

Among the achievements of his career so far, Aku highlights in particular the successful qualification of OL3’s radiation measurements, as well as the commissioning of reactor instrumentation and radiation measurement systems. At the same time, the commissioning of OL3 was the greatest learning experience of his career so far.

The commissioning combined intense schedule pressure, a broad technical scope, and the need to prioritize correctly. When progress is driven by a critical overall schedule, you have to be able to identify what is most important at that particular moment, Aku sums up.

Aku says he learned to follow a clear principle: tasks related to the critical commissioning schedule had to be prioritized regardless of what else was happening around them. This experience is also reflected in his current work. He still works with the same systems and equipment, now from the perspective of maintenance.

Working with safety as the guiding principle

In his current role, Aku works within the client organization on the maintenance of reactor instrumentation and radiation measurement systems. His primary workplace is OL3, and he meets his Platom colleagues from time to time at the Rauma office.

The work is very much expert work carried out within the client organization, which means that day-to-day collaboration with other Platom employees is more limited than in many other roles, Aku says.

Aku takes a practical view of this: his job is to work for the client and ensure that his expertise serves the plant’s needs in the best possible way.

He describes Platom as a flexible employer that looks after its employees’ interests. For example, in situations involving travel for work, the starting point is always a discussion about whether the employee is able and willing to go. Aku also feels that he receives support in practical matters, such as relocating to another locality for work.

In his working life decisions, safety is his foremost guiding principle. In the nuclear energy field, it is not a separate value but the foundation of everything. Safety is visible in the systems, operating practices, prioritization, and in the way expert work is carried out day after day.

Experience that can be applied to future projects

In the future, Aku hopes to be involved in the commissioning of a new nuclear power plant. The commissioning of OL3 taught him a great deal, and the experience accumulated over the years would be valuable to apply from the very early stages of a new project.

The most likely future opportunity, in my view, is the construction of district heating reactors in Finland. The need for carbon-free energy production is growing, and nuclear energy can be a significant part of future energy solutions in new applications as well, Aku sums up.

Aku’s own career path has been built largely through practical experience, technical expertise, and the right opportunities. He describes his career as having partly drifted in a certain direction, but throughout there has always been a strong technical orientation and an interest in how energy can be produced safely and without emissions.

Hands-on work teaches a great deal about the plant

For young people or those considering the field, Aku offers concrete advice:

It is worth applying for annual outage work at nuclear power plants, even for very practical hands-on jobs. You can learn a surprising amount about the plants that way. When you see up close how a power plant operates, how maintenance is carried out, and how different systems are connected to one another, your understanding develops in a very different way than it does only in a lecture hall or while reading documents.

This combination of practice and theory also describes Aku’s own career well. He has come a long way from the abstract problems of the Physics Olympiad: to radiation measurements, reactor instrumentation, commissioning, and maintenance. Yet the same basic idea remains in the background as it did already in his upper secondary school years—the desire to understand how things work.

Cottage life, nature and balance outside work

Outside work, Aku values spending time at the cottage, being in nature, and going for runs. In addition, he takes part in Local Defence companies training exercises a few times a year.

His wife and cat also bring joy and energy to everyday life. In his free time, the focus is on things that are far removed from schedule pressure and technical systems: nature, loved ones, and the opportunity to recover through time outdoors.

Perhaps that is one of the strengths of Aku’s career story. It brings together the calm rural roots of Savo, exceptional talent in physics, international experience, and demanding expert work in the nuclear energy sector. The journey from the Physics Olympiad in Mexico to the commissioning of OL3 has not been a straight, carefully planned path, but it has been built step by step on expertise, curiosity, and a professional pride grounded in safety.