It is 12 p.m. on Sunday, April 26, 2026, when Pope Leo XIV steps onto the balcony of St. Peter's Basilica for the Regina Caeli prayer. His calm voice resonates over a crowd-filled square. "Atomic energy must be used only for peaceful purposes." The statement came at the precise moment when, 2,100 kilometers from Rome, Ukrainian and Belarusian families commemorated in Slavutych the 40th anniversary of the explosion of Reactor No. 4 at the Chernobyl Lenin power plant. On April 26, 1986, at 1:23 a.m., a failed safety test blew off the reactor's lid, releasing an estimated 400 times the radioactivity of Hiroshima into the atmosphere. Four decades later, the memory remains vivid – and the warning more relevant than ever.

The Pope's Solemn Appeal

In his address, broadcast by Vatican News, the successor to Francis called "for the responsibility of states" and "for the remembrance of the victims." Leo XIV, the first American pope in history, elected in May 2025, particularly emphasized the distinction between the civil use of atomic energy – "which can be a gift, provided it is regulated" – and any form of military use. He evoked the "thousands of liquidators" sent in 1986 to the plant site, many of whom died in the following months or years from radiation exposure. The papal ceremony concluded with a minute of silence, followed by a prayer in Ukrainian, Russian, and Belarusian – a rare gesture, praised by several diplomats.

Slavutych, City of Memory

In Slavutych, the city built after the disaster to relocate the plant's personnel, commemorations brought together nearly 3,000 people. Mayor Yuri Fomichev laid a wreath at the liquidators' stele, in the presence of representatives of the Ukrainian government and some foreign diplomats. The context is heavy: Slavutych was briefly occupied by Russian forces in March 2022, and the historical Chernobyl plant, under a sarcophagus since 2017, is now under the control of the Ukrainian State Nuclear Regulatory Inspectorate after several alerts linked to the war. A Greenpeace delegation conducted radiation measurements in the exclusion zone, confirming the stability of the containment structure, completed at great expense by the international community.

Zelensky: "The Danger Is Still There"

In a recorded statement broadcast Sunday morning, Volodymyr Zelensky used the anniversary to point to Russian responsibility. "Forty years after Chernobyl, it is Moscow again that is bringing the world to the brink of a man-made nuclear catastrophe," he stated, alluding to the Zaporizhzhia power plant, Europe's largest nuclear facility, occupied by the Russian army since March 2022. The Ukrainian president recalled that IAEA personnel present on site had repeatedly reported power outages and military maneuvers in the immediate vicinity of the reactors. The issue of demilitarizing the site, requested by Kyiv and supported by the UN agency, remains unanswered by Moscow.

A Memory That Transcends Ukraine

Around the world, ceremonies were held to mark the anniversary. In Brussels, the European Commissioner for Energy issued a statement recalling that "Europe must learn the lessons" from Chernobyl to regulate the growth of civil nuclear power – an issue revived since the SMR (small modular reactors) compromise adopted in March 2026 by the EU Council. In Tokyo, where the memory of Fukushima remains just as present, a silent march brought together several thousand people. In the United States, the Department of Energy released a declassified timeline of the American response to the Soviet catastrophe for the first time. In Minsk, however, no official ceremony was held – Belarus, which received nearly 70% of the radioactive fallout in 1986, remains aligned with the Russian position.

Editorial Opinion

Forty years later, Chernobyl is not just a commemoration: it is a reference point for thinking about the contemporary relationship with technology. Pope Leo XIV's words, in their simplicity, avoid the pitfall of moralizing discourse: they set a condition – peaceful purpose – as a prerequisite for any use of atomic energy. At a time when Europe and the United States are reviving their civil nuclear sectors, when the United Kingdom has announced a new generation of SMRs, and when the war in Ukraine poses an unprecedented threat to civilian power plants, the Vatican's voice serves to recall an often-forgotten truth: technical mastery never dispenses with ethical responsibility. Chernobyl not only contaminated a territory; it established, for centuries, the precedent of an irreversible technological catastrophe. That, fundamentally, is what must be passed on.

Key Takeaways

• April 26, 1986: Explosion of Reactor No. 4 at the Chernobyl Lenin power plant (1:23 a.m.).
• Pope Leo XIV (first American pope) calls for strictly peaceful use of atomic energy.
• Ceremonies in Slavutych, a city built for plant personnel.
• Zelensky accuses Moscow of threatening the safety of Zaporizhzhia (occupied since March 2022).
• Chernobyl containment sarcophagus completed in 2017, still stable according to Greenpeace.