INES-event
INES 0

Manual shutdown for repairing the steam generator tube leak

Yonggwang unit 2 was operated at the rated power. On July 19, 1996 radioactive material Xe-135 was detected when condenser off-gas was monitored. Continuing surveillance was carried out to detect the leakage rate from the primary side. Leakage rate from primary to secondary side increased gradually.
When the leakage rate reached around 9 l/hr, the plant started manual shutdown to repair the S/G tubes on August 7, 1996.
Investigation revealed that one tube leaked because of wear induced by foreign material. After removing foreign materials and plugging the damaged tubes, plant was returned to normal operation.
During the event no safety system operation was required and there were no abnormal releases of radioactivity to the environment.
Justification: As full safety functions were available, the event is rated at level "0" as per User's manual Part III, Table II, A1.

Location: YONGGWANG-2
Event date: Wed, 07-08-1996
Nuclear event report
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