A small but significant leak of radioactive water has occurred at a decommissioned nuclear power station in Japan, raising fears that workers may have been exposed.
Incident Details at the Fugen Plant
The incident took place at the Fugen nuclear plant in Fukui Prefecture, which is currently undergoing a lengthy decommissioning and dismantling process. During work on December 23, 2025, approximately 20 millilitres of water containing a high concentration of the radioactive isotope tritium is believed to have leaked.
Japanese broadcaster NHK reported that detailed investigations are now focused on determining whether any personnel were splashed with the contaminated liquid. Authorities have stated that the possibility of internal exposure through inhalation has been ruled out.
Containment and Ongoing Monitoring
Citing the country's Nuclear Regulation Authority, officials confirmed a crucial point: no radioactive material escaped outside the plant's controlled area. Measurements of radiation levels both within the facility and in the surrounding environment have shown no deviation from normal readings.
The plant's operator, the Japan Atomic Energy Agency, is expected to provide a further update in a scheduled press conference.
Understanding the Risk: What is Tritium?
Tritium is a radioactive form of hydrogen, but it is considered one of the weakest forms of radiation. It cannot penetrate human skin unless introduced through a cut or graze. The primary health concern arises if it is ingested or inhaled, a scenario which plant authorities insist has not happened in this incident.
Nevertheless, the management of tritium at decommissioned nuclear sites remains a significant issue for Japan. The country has been engaged in a controversial, long-term process of releasing treated and diluted water containing tritium from the Fukushima Daiichi plant since 2023. That facility was the site of a catastrophic meltdown following the 2011 earthquake and tsunami, which forced the evacuation of over 150,000 people.
The leak at Fugen, while contained, underscores the ongoing challenges faced in safely dismantling Japan's retired nuclear infrastructure.
