Nuclear Alert Declared at Two Catalonia Plants Just 24 Hours After Trial Alarm

Two Fires, One Morning — Just 24 Hours After a Drill

Two separate fires broke out simultaneously at two of Catalonia's nuclear power plants on the morning of April 22, 2026 — just 24 hours after civil protection agencies had conducted a large-scale trial of the ES-Alert emergency notification system. Both incidents were at facilities in the province of Tarragona: the Ascó nuclear plant and the Vandellós II nuclear plant.

Emergency response teams successfully contained both fires. There were no radiological leaks and no danger to the public — but the timing, coming so soon after a rehearsal of the very same emergency protocols, has drawn significant attention.

What Happened at Ascó

At the Ascó plant, a fire broke out at 9:35am and lasted approximately 40 minutes. The incident prompted the activation of the plant's Internal Emergency Plan (PEI) at Level 1 — the lowest category on the emergency scale. Authorities briefly escalated to the PENTA exterior plan, the protocol designed to protect nearby residents in the event of an incident at a nuclear facility, before standing it down once the fire was under control.

What Happened at Vandellós II

At Vandellós II, a ventilation unit in an electrical housing building began releasing smoke. This was classified as a "pre-alert" — one level below a formal emergency declaration. On-site fire brigades intervened rapidly, and the Nuclear Safety Council (CSN) — Spain's nuclear regulator — classified the incident at Level 0 on the international scale, meaning it had no safety significance beyond the site itself.

No Radiation Risk

Both the CSN and the plant operators confirmed that neither incident involved any radiological release. The fires were contained within non-nuclear areas of both facilities, and radiation monitoring at and around both sites showed no elevated readings. All safety protocols functioned as intended.

The public in the surrounding areas — including the towns of Ascó, Vandellós, and the broader Tarragona region — was never at risk.

The Awkward Timing

What has made these incidents particularly noteworthy is the timing. Just 24 hours earlier, civil protection agencies across Catalonia had run a large-scale test of the ES-Alert system — the national emergency notification platform that sends mass alerts to mobile phones in a given area. The drill was conducted to test the readiness of the system to notify the population near nuclear facilities in the event of a real incident.

The fact that real emergency plans were being activated at both sites within a day of that drill is, at minimum, a striking coincidence — and has given critics of Spain's nuclear energy policy fresh ammunition.

Reigniting the Nuclear Debate

Spain has seven operating nuclear reactors, and the government of Prime Minister Pedro Sánchez has maintained a plan to close all of them between 2027 and 2035 as part of Spain's transition to renewable energy. The closures are designed to be phased, with the plants taken offline sequentially rather than all at once.

Critics of the closure plan — including local leaders in Catalonia and energy industry representatives — argue that nuclear currently provides around 60% of Catalonia's electricity, and that shutting down the plants before sufficient renewable capacity is in place risks blackouts and energy price spikes. They have seized on the Ascó and Vandellós incidents as evidence that ageing plants require careful management.

Supporters of the closure timeline counter that the incidents, while dramatic in timing, were contained exactly as they should be — demonstrating that the safety systems work.

What to Know About Nuclear Safety in Spain

Spain's nuclear plants are regulated by the Consejo de Seguridad Nuclear (CSN), which publishes regular reports on plant safety and incident classification. The international scale used to classify nuclear events runs from Level 0 (no safety significance) to Level 7 (major accident — the level assigned to Chernobyl and Fukushima). Both of Wednesday's events were at the very bottom of that scale.

The ES-Alert system, which was being tested the day before, is the same platform used for other civil emergencies including flooding and extreme weather — its use is not specific to nuclear incidents.

This article is based on reporting from Euro Weekly News, published April 22, 2026.