Skip Content

Emergency

 

Emergency Classification at Nuclear Power Plants

The International Atomic Energy Agency's four-category system is generally adopted for classifying nuclear emergencies at nuclear power plants :-

 
Emergency Classification

Radiological Impact

Description

Emergency Standby
A prescribed situation or external event which may affect the safety of the plant.
Events are in process or have occurred which indicate a potential degradation of the level of safety of the plant. Release of radioactivity which necessitates any off-site emergency response actions (e.g. radiation monitoring) is not expected.
Plant Emergency
The radiological consequences of the emergency situation are confined to a section of the plant.
Events are in process or have occurred which involve an actual or a potential for substantial degradation of the level of safety of the plant. Radiological consequences, which resulted or may result from the emergency, are confined to a section of the plant. Off-site radiological exposure is far below the lower limit of the intervention level for sheltering.
Site Emergency
The radiological consequence of the emergency situation are confined to the site.
Events are in process or have occurred which involve actual or likely major failure of plant functions needed for protection of the public. Radiological consequences, which resulted or may result from the emergency, are confined to the site. Apart from the area near the site boundary, the off-site radiological exposure is below the lower limit of the intervention level for sheltering.
General Emergency
(Off-site emergency)
The consequence of the emergency situation extends beyond the site boundary.
Events are in process or have occurred which lead to actual or projected damage to the reactor core, or resulted in core melting, and potential loss of containment integrity. Radiological consequences of the emergency extend beyond the site boundary. (Note 2)
 
   
Note 1 : Measures in dealing with the above categories of nuclear emergency are covered in the emergency plans for GNPS/LNPS.

Note 2 : GNPS/LNPS are located far away from the urban areas of Hong Kong (about 50 km). Given this distance, it is highly unlikely that HKSAR would be affected significantly following any accidental release of radioactivity from the nuclear power stations.

The above content and graphics are provided by EMSD

Previous page
Nextpage