 INES 1 |
Small leakage from Residual Heat Removal System. |
Temelin Unit 2 (VVER 1000 Reactor type) was in shutdown from June 2, 2004 for replacement of main output transformer (2AT3). The reactor heat removal was established by the residual heat removal system (2TQ32). Spontaneous step increase in flow indication (2TQ32F001) was detected in the morning hours on June 6, 2004, complemented by a slight decrease in pressure indication on respective residual heat removal pump suction. The immediate inspection on the pump (2TQ32D01) identified a pipe leakage on the impulse pipeline of the referenced flow measurement. Immediately after, the redundant residual heat removal system was started up (2TQ12), and the pump 2TQ32D01 was shutdown and isolated in order to stop the leak.
Before the pump isolation, approximate volume of 3 cubic meters of primary water were directed to the containment waste system (YZ) for further treatment by the plant technological systems. Leakage resulted in the contamination of two containment rooms. Surface contamination (in the room A 123/3 - 3 Bq/cm2 and in the room A 036/3 - 8 Bq/cm2) was below existing action levels.
No persons were contaminated during this event, and no leakage outside the containment and into the environment occurred. Currently the impulse pipeline repair is finished.
The event is preliminary rated as level 1 on the INES upon consideration of additional factors
(INES Manual, chapter IV-3.3.3.), i.e., the repetition of the event.
Event date: Sun, 06-06-2004
