INES-event
INES 1

HEAVY WATER SPILL FROM MODERATOR SYSTEM

During unit shutdown, a flange joint in Moderator heavy water line started leaking resulting in spillage of heavy water and resulted in tritium in air concentration in Moderator room (inside containment) going up. Plant emergency had to be declared. Heavy water was drained below the level of the flange and the leak was attended.
BASIS FOR RATING: Rating selected is level 1. Categorised under A-IR of Table 1. (defence in depth). Safety functions were fully available. Since the corrective action (repair of leak) had to be delayed due to restriced access to the area due to high tritium in air concentration as per guidelines under paragraph 4.1, higher rating of 1 is selected.
DIFFICULTIES IN RATING:

Location: KALPAKKAM-1
Event date: Thu, 07-03-1991
Nuclear event report
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