Onkalo

Design Project • December 2025

The human race has a fascination to reach out to those beyond our time and space in an attempt to be acknowledged or remembered. Whether it be time capsules we place in the ground or satellites we launch into space to attempt to make contact with an extraterrestrial species; humans have had an interest with reaching into the unknown. Perhaps we have developed this interest from the ancient relics we find on our planet to this day.

Anthropologically speaking, conscious humans are so new to Earth that there are few relics left behind by those who came before. Every so often, ancient scrolls, pottery, or architecture is discovered - hearkening to a past society. Who can say exactly what relics we will end up leaving for civilizations millennia from now. Concerningly, one of those inevitable relics will be the many decaying nuclear waste vessels that have the potential to create ecological disaster. Due to their extremely long life, they remain deeply toxic for many thousands of years. This has caused humanity to ultimately settle on burying them deep underground so that they are never touched again.

The first step in this field is being conducted in the coastal South of Finland at what has been named the Onkalo spent nuclear fuel repository. It is a 1,700-foot deep tunnel intended to be the world’s first facility for spent nuclear fuel. For the last twenty years, this tunnel has been in the process of being excavated. Next year, the final stage of this development will kick off; where trenches are dug for the final burial pits of spent fuel. It is this grand effort which has awarded Onkalo with its name, which translates to “hiding place” in Finnish.

Despite the deep tunnel that is the Onkalo facility, the question remains, how do you keep future humans - unaware of the danger - away from the nuclear waste for thousands of years? It is almost inevitable that our language will be entirely lost in that time, and our meaning of symbolism forgotten. What if future humans interpret this site as a religious burial ground, or a treasure pit, much like how the western civilization reacted to discovering the Egyptian pyramids? Who is to say that any form of messaging, incomprehensible to the future people, would deter them from unearthing spent nuclear repositories?

Onkalo, built as a seal over the nuclear waste tunnel, is an architectural solution intended to last for millenia. It is only composed of black-dyed structural concrete for lasting endurance. It is built in a spiked cantilever form to convey danger to humans and protect the entrance from any kind of weather conditions. Inside, conditions are even less hospitable for humans. Dark and windy, Onkalo presents temporary physical pain to the future human. Through a series of channels far above their head, wind rushes into the cavity, blowing through a grating whistle system and echoes off the large walls. Not far into the chamber is a sheltered plinth with engravings simply depicting the danger that this place is guarding. These hieroglyphs are paired with inscriptions in every major language currently utilized on the planet to give us the best chance at being understood.

Ultimately, the people of the future will inherit a world with our destructive and toxic chemicals sealed under the Earth. We, as their ancestors, have an obligation to protect them by informing them of the danger, as well as doing our part to look after the planet today.