Back-up power line restored to Europe’s largest nuclear plant during ceasefire in Ukraine

FEARS of a nuclear accident at Europe’s largest atomic power plant have eased after a back-up power line connecting the site to an external electricity source was restored.

Off-site power lines at the Zaporizhzhia nuclear power plant (ZNPP) have repeatedly been damaged since Russia launched its invasion of Ukraine in February 2022. The latest repairs took place after a temporary, local ceasefire brokered by the International Atomic Energy Agency (IAEA) – the fifth such truce in the Zaporizhzhia region since the conflict began. 

Connections to external electricity supplies are essential to maintain safety and cool fuel at nuclear power plants. Although the ZNPP, under Russian control since March 2022, has not generated electricity for more than three years, its reactor cores and spent fuel still require continuous cooling. 

Before the latest repairs, earlier this month, the plant had relied on a single external power line for more than three weeks after military activity reportedly damaged key components in a switchyard at a neighbouring fossil fuel power station. 

Before the war, the ZNPP had ten connections to off-site power. Since the start of the conflict, the plant has lost all external supply on 12 occasions, including twice in the past three months. 

Russian shelling in the first weeks of the war prompted the IAEA to establish its “five concrete principles” to ensure safety at the ZNPP, urging against military strikes targeting the plant and storing heavy weapons or personnel at the site. 

However, fighting has continued close to Ukraine’s nuclear sites, including at the New Safe Confinement structure at Chernobyl, where electrical fluctuations triggered automatic startup of an emergency diesel generator after substations were damaged. 

Rafael Mariano Grossi, director general of the IAEA, said the repeated external power outages at Zaporizhzhia “underline the importance of maintaining secure off-site power under the five principles”. 

The latest repair work began with demining activity on 27 February, when the ceasefire came into effect. IAEA workers then replaced and refurbished damaged switchyard components, including breakers, disconnectors, current transformers and cable sections. 

While the work “strengthens nuclear safety and security”, Grossi said the restored line offers “reduced independence” as the IAEA has not been able to return it to its original configuration. The agency is looking to complete a full restoration in due course.