Event
- Event ID
- 278
- Quality
- Description
- The explosion occurred in the condenser area of a steam turbine, two hours after the unit tripped due to a stator earth fault.
The stator earth fault had damaged two hydrogen cooler tubes, which allowed hydrogen to pass from the stator casing into the condenser via the condensate system.
The ignition source was thought to be either via a contact with the hot metal of the steam chests or due to an electrostatic spark. - Event Initiating system
- Classification of the physical effects
- Hydrogen Release and Ignition
- Nature of the consequences
- Macro-region
- Europe
- Country
- United Kingdom
- Date
- How was it involved?
- Internal Explosion (H2-Air Mixture)
- Initiating cause
- Conventional Component Failure (Electricity, Power)
- Root causes
- Root CAUSE analysis
- The INITIATING cause the leak of damaged hydrogen pipes.
Nothing can be said on the root cause, but the fact that the stator earth fault was able to damage the hydrogen pipe may be attributed to a design failure and/or shortcoming in the risk assessment.
Facility
- Application
- Power Plant
- Sub-application
- unspecified
- Hydrogen supply chain stage
- All components affected
- hydrogen pipe
- Location type
- Confined
- Operational condition
- Pre-event occurrences
- A stator earth fault had occurred two hors before the incident and damaged the hydrogen coolant system.
- Description of the facility/unit/process/substances
- DESCRIPTION OF A "STEAM CHEST"
The steam chest serves as a distribution point for the high-pressure steam coming from the boiler.
Emergency & Consequences
- Number of injured persons
- 0
- Number of fatalities
- 0
Event Nature
- Release type
- gas
- Involved substances (% vol)
- H2 100%
- Presumed ignition source
- Hot surface
- Deflagration
- N
- High pressure explosion
- N
- High voltage explosion
- N
References
- Reference & weblink
Event description provided by HSE, original source confidential
JRC assessment
- Sources categories
- HSE
