 INES 2 |
OVERFLOW OF A LIQUID EFFLUENT STORAGE TANK |
On the 21st of June, the operator noted an abonrmal continuous in-flow of water, from an eyewash located in the laboratory and connected to the tank. This had continued throughout the weekend.
Investigations undertaken showed that the tank overfill detection device had failed.
The tank overflowed into a barrel of insufficient capacity.
Its overfill alarm also failed to operate.
The water spilled over the floor of the room was collected in the room's sump, which had been fitted with a pump wrongly connected to the rainwater drain, and not to the industrial waste water drain.
A volume of water of less than 12 m2 was discharged into the rain water collector and collected outside the building in a hold-up pit.
The radioactivity detected in the hold-up pit was 5.10E4 Bq/m2 for alpha and 2.10E4 Bq/m2 for beta-gramme.
In view of the succession of operating and design anomalies at the facility and in view of the failure of items of equipment, this incident was graded level 2 on the severity scale.
(Please see also attached press release.)
Event date: Mon, 21-06-1993
