INES-event
INES 2

Leak from coolant channel K-05 at MAPS-2

Madras Atomic Power Station unit-2 was under shutdown. The coolant channel inspection program was in progress. Before inspection of channel, the special plug is installed, which has provision for connecting the extension tube, for moving the probe through the channel, remotely. Inspection of 25 channels was completed. At 0615 hrs, during inspection of the next channel, the seal plug got disturbed and developed leak, while connecting the extension tube. Shut down cooling pump was stopped to reduce rate of leak. D2O addition to PHT was initiated and light water addition was kept in poised state, which was added later. Emergency alert was declared at 0637 hrs. In the meantime plug was repositioned to its intended location, manually at 0645 hrs. The plant emergency alert was called off at 1420 hrs.
During the repositioning activity, one worker received tritium uptake of 1650 micro curie/litre, equivalent to a radiation dose of 33 mSv, which is more than the maximum allowed annual exposure limit of 30 mSv. The incident is rated at level on INES due to overexposure of a worker beyond annual regulatory limits, during the incident.

Location: KALPAKKAM-2
Event date: Fri, 26-03-1999
Nuclear event report
Legenda & explanation