Grid Fluctuations at Chashma Nuclear Power Generating Station Affecting C-1, C-2, C-3 and C-4

Print View Posted on: 02 March 2021

Event Date: 09 January 2021 Event Type: Power Reactor
Event Location: Pakistan, Chashma Nuclear Power Generating Station INES Rating: 0 (Final)

On January 09, 2021, C-1, C-2, C-3 and C-4 situated at Chashma Nuclear Power Generating Station faced severe grid fluctuations during operation at around 2341 hrs due to country wide power breakdown. C-1, C-2 and C-4 tripped on 'Reactor Coolant Pump (RCP) Bus Under Frequency' while C-3 tripped on ‘SRC Loop-A Coolant Flow Low’. Both offsite power sources (220 kV and 132 kV) were also lost and both Emergency Diesel Generators (EDGs) of each C-1, C-2 and C-4 started automatically and successfully connected to provide power to emergency buses. While one of the EDGs (EEG-001DG) of C-3 could not start on auto and it had to be manually started after some time. Hot shutdown was maintained at C-1, C-2, C-3 and C-4.
Standby (SB) was declared at 2356 hrs on January 09, 2021 at C-1, C-2 and C-4 while Plant Emergency (PE) had to be declared at C-3 due to unavailability of one of the EDGs (EEG-001DG). Being responder plants, C-1, C-2 and C-4 also declared Plant Emergency. At C-3, EEG-001DG became available at 0004 hrs on January 10, 2021 and Plant Emergency was downgraded to Standby while other plants also responded.
Later, Standby was terminated at C-1 (1510 hrs), C-2 (1310 hrs), C-3 (1335 hrs) and C-4 (1510 hrs) after restoration of offsite power sources on January 10, 2021.

INES Rating: 0 - Below scale (Final) as per 02 March 2021
Release beyond authorized limits? No
Overexposure of a member of the public? No
Overexposure of a worker? No

Contamination spread within the facility? No
Damage to radiological barriers (incl. fuel damage) within the facility? No

Degradation of Defence In-Depth Yes

Person injured physically or casualty? No
Is there a continuing problem? No

Muhammad Usman
Pakistan Nuclear Regulatory Authority (PNRA)
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