Event
- Event ID
- 521
- Quality
- Description
- A technical failure in the High-Pressure turbine blades caused high vibrations in lubricating oil pipes. Some pipes broke off and the oil leak caught fire from hot surfaces. Also the generator's hydrogen leaked out and exploded.
The fire caused the loss of control air and electrical power of several safety-related components: for instance, two turbo-blowers and main heat exchanges were inoperable The fire also affected a main circulation water pipe expansion joint causing outpouring of sea water which caused the flood of the lower levels of the turbine and reactor buildings - Event Initiating system
- Classification of the physical effects
- Hydrogen Release and Ignition
- Nature of the consequences
- Macro-region
- Europe
- Country
- Spain
- Date
- How was it involved?
- Rupture & Formation Of A Flammable H2-Air Mixture
- Initiating cause
- Conventional Component Failure (Turbine-Generator)
- Root causes
- Root CAUSE analysis
- The explosion was caused by turbine vibrations which led to rupture of a fastener beating of the turbine shaft.
Facility
- Application
- Power Plant
- Sub-application
- Nuclear power plant
- Hydrogen supply chain stage
- All components affected
- generator, HP turbine, turbine blades, oil, hydrogen
- Location type
- Confined
- Location description
- Industrial Area
- Operational condition
- Pre-event occurrences
- A technical failure in the HP turbine blades caused high vibrations in lubricating oil pipes. Some pipes broke off and the oil leak caught fire from hot surfaces.
Emergency & Consequences
- Number of injured persons
- 0
- Number of fatalities
- 0
- Currency
- $
- Property loss (onsite)
- 100000000
- Post-event summary
- Fire damaged one of the 2 turbine generators.
The turbine vibrations also led to rupture of a condenser intake pipe, with an ensuing flood that unlashed an estimated total of 4000 cubic meters of water in lower floors of the turbine and reactor buildings.
The extent of the damage is estimated at $ 100 million.
Lesson Learnt
- Lesson Learnt
- Generic lesson learnt from major Nuclear Power Plants accidents can be found in
IAEA, Experience gained from fires in nuclear power plants: , IAEA-TECDOC-1421
Available at https://www-pub.iaea.org/MTCD/publications/PDF/TE_1421_web.pdf
Event Nature
- Release type
- gas-liquid mixture
- Involved substances (% vol)
- H2,
oil - Actual pressure (MPa)
- 0.4
- Design pressure (MPa)
- 0.4
- Presumed ignition source
- Not reported
References
- Reference & weblink
IAEA, Experience gained from fires in nuclear power plants: Lessons learned, 2004, IAEA-TECDOC-1421<br />
Available at https://www-pub.iaea.org/MTCD/publications/PDF/TE_1421_web.pdf<br />
(accessed July 2024)WIKIPEDIA page dedicated to the accident https://en.wikipedia.org/wiki/Vandell%C3%B2s_I_nuclear_incident<br />
(accessed October 2025)WISE International
This event is listed in From T. VIROLAINEN, J. MARTTILA, H. AULAMO, "TURRBINE GENERATORS AT VVER-440 NUCLEAR POWER PLANTS”, in "Upgrading of fire safety in nuclear power plants", IAEA-TECDOC-1014, Proceedings of an International Symposium, Vienna (Austria), 18-21 November 1997<br />
https://www.iaea.org/publications/5310/upgrading-of-fire-safety-in-nucl… <br />
(accessed July 2024)
JRC assessment
- Sources categories
- IAEA
