Event
- Event ID
- 813
- Quality
- Description
A release of hydrogen and steam occurred in the battery room of a nuclear power plant around 21 h. Site agents neutralised the batteries. Noting the failure of the smoke extractor, public firefighters ventilated the room.
- Event Initiating system
- Classification of the physical effects
- Unignited Hydrogen Release
- Nature of the consequences
- leak no ignition
- Macro-region
- Europe
- Country
- France
- Date
- Component involved
- battery
- Failure mode
- rupture, no ignition
- Initiating cause
- over-heating
- Root CAUSE analysis
The INITIATING CAUSE was the overheating of batteries, which produced the release of water of the electrolyte and hydrogen.
The ROOT CAUSE is not provided. The fact that a fume detector, which had the obvious function to detect this type of events, was not function suggests inadequacy of inspection and maintenance.- Root causes
- Date entry in HIAD
- 01/01/2020
Facility
- Application
- Power plant
- Sub-application
- Nuclear power plant
- Hydrogen supply chain stage
- All components affected
battery room, smoke extractor
- Location type
- Confined
- Location
- industrial area
- Operational condition
- UNKNOWN
- Description of the facility/unit/process/substances
DESCRIPTION OF THE SYSTEM
The report does not mention the type of batteries used and their functions. It can only be said that it was an energy storage system, possible as alternative or additonal power supply in case of emergency. The mentioned accidental production of steam and hydrogen could be possibly suggest a lead-acid battery system.
Emergency & Consequences
- Number of fatalities
- 0
- Number of injured persons
- 0
- Post-event summary
The property loss was related to the need to replace (partially) the battery storage system.
- Emergency action
Site agents neutralised the batteries. Public firefighters ventilated the room with their own means. Normal operation was restored at 22:50.
In-depth data
- Release type
- gas mixture
- Involved substances (% vol)
- H2,
steam - Probable IGNITION SOURCE
References
- Sources categories
- ARIA
- Reference & weblink
ARIA data base event no. 42040
https://www.aria.developpement-durable.gouv.fr/accident/42040_en/?lang=…
(accessed October 2025)
