Pakistan
 INES 1 |
Leakage of Heavy Water from Feeder Pipe |
Plant was in shutdown state since October 05, 2011 because of maintenance activities. As per normal procedure during shutdown state, Standby Cooling System (SH) was in service to remove decay heat from the reactor core while Primary Heat Transport (PHT) system was in depressurized state. On October 19, 2011, inspection of channel S-11 grayloc seal was carried out to find out any foreign material in the orifice. During normalization of the system, Boiler Room (B/R) floor beetle alarm received in control room. Later, 'Tritium in Air High' alarm also annunciated.
INES 0 |
Fire incident in boiler room |
While monitoring boiler room through CCTV during plant start-up, flames were observed in the vicinity of one of the main coolant pumps. Reactor was immediately shut down, and primary heat transport system crash cooled to 300 deg. F. Shift fire fighting crew rushed to the affected area to extinguish the fire. At the fire site it was observed that the insulating material of the piping close to the main coolant pump was burning.
INES 0 |
Power excursion and subsequent plant trip |
Due to problems in the Process Salt water heat exchangers, the performance of control room air-conditioning chillers (which is cooled by the process salt water) was affected, resulting in rise of the control room temperature (up to 87.5 deg. F). this rise in control room temperature adversely affected the satisfactory operation of the two regulating computers. At 0153 hrs controlling computer B started internal initialization frequently, while controlling computer A stalled at 0200 hrs. without any alarm.
INES 1 |
Release of iodine-131 from 131 production plant of nuclear chemistry division Pakistan Institute of Nuclear Science and Technology |
On August 5, 20 and 21, unusual high activity up to 2203 Bq/m3 was reported by the Health Physics surveyor in the I-131 plant room during routine air sampling. Investigations revealed that the ventilation of the building was shut down during off-working hours. Due to the closure of exhaust/ventilation system, the negative pressure in I-131 cell was lost and the pressure in the cell became in equilibrium with room pressure, thereby by un-utilized Iodine-131 vapors in the fume hoods diffused and escaped the cell causing spread of radioactivity in the plant room.
INES 0 |
STICKING OF SHIELD PLUG IN THE FUEL CHANNEL |
Fuelling machine failed to unlock and remove the shield plug. The shield was manually removed by draining the fuel channel. During the operation, no person was exposed to high radiation fields.
Event Description:
