INES-event
INES 1

Disturbance of forced reactor coolant circulation in cold shutdown condition

On 16 May 1996 Unit 5 of Kozloduy NPP was in planned annual outage. The reactor core cooling was accomplished by the means of one train of the emergency and planned cooling system (pump 5TQ12D01). Main coolant pump no. 4 (MCP4) was disassembled for repair.
When the biological shield was placed inside of the MCP4, the suction pressure of the pump 5TQ12D01 rapidly decreased. The temperature increased to 70 deg. C. The redundant pump 5TQ22D01 was actuated in order to supply borated water in the reactor. The fuel assembly outlet temperature started to increase. The automatic step-by-step loading programme started and two trains of the safety systems were actuated by the signal delta t

Location: KOZLODUY-5
Event date: Thu, 16-05-1996
Nuclear event report
Legenda & explanation