Junk plant Ginna: Failure of 46 Year Old Transformer and Plant Trip

Basically a run to failure philosophy. They are make believing they are the coal power industry. Those guys were into run to failure big time.

The failed transformer was model Westinghouse serial number RBR-6831 and had been in service for 46 years. There was no indication or warning of impending failure.

LER 2016-001 

Loss of Station Auxiliary Transformer 12A Resulting in Automatic Start of Emergency Diesel Generator A due to Undervoltage Signals to Safeguards Buses 14 & 18

On 02/11/2016 at 2305, Ginna Station experienced a loss of Station Auxiliary Transformer 12A, causing Emergency Diesel Generator A to automatically start due to undervoltage signals to safeguards buses 14 and 18. Station Auxiliary Transformer 12A failed due to a high side phase to phase internal fault with relays for overcurrent and differential current actuated. All plant systems responded as designed. Control room operators stabilized the plant per abnormal operating procedures. The plant was placed in 100/0 electrical lineup on the off-site circuit 767 with Emergency Diesel Generator A secured. Station Auxiliary Transformer 12A was replaced with a spare and the plant was restored to normal off-site power line-up on 02/20/2016 at

0018.

The failed transformer was model Westinghouse serial number RBR-6831 and had been in service for 46 years. There was no indication or warning of impending failure.

Look at how long they were in a less safe plant electrical line up. Check out their risk determination, they had a replacement sitting on site. They didn't want to wait for a new order at the time of the event. But they never found the time to install the new transformer in the plant before the 46 year old Aux transformer failed. 

I was waiting for them to say, replacing transformers proactively wasn't in their procedures. Blame it on the procedure writers???  

February 11, 2016:

• 2305 hours - Operations received indication of loss of off-site power circuit 7T. Emergency Diesel Generator A started and loaded safeguards buses 14 & 18. Station Auxiliary Transformer 12A was determined to be the failed component with indication from overcurrent and differential relays tripped. Technical Specification LCO 3.8.1 was entered.

• 2306 hours - Operators entered Emergency Operating Procedure AP-ELEC.1 for loss of 12A Bus.

• 2325 hours - Operators started Equipment Restoration Procedure ER-ELEC.1 for restoration of off-site power, in order to supply all loads from off-site circuit 767.

February 12, 2016:

• 0032 hours - Station Auxiliary Transformer 12A was removed from service and the electric plant was placed in 100/0 lineup. In this lineup, off-site power circuit 767 provides service to all four of the 480 volt safeguards buses via Station Auxiliary Transformer 128.

• 0052 hours - Technical Specification LCO 3.8.1 was exited with power to safeguards buses 14 and 18 restored from off-site power circuit 767.

• 0053 hours - Emergency Diesel Generator A was secured.

• 0127 hours - Abnormal Operating Procedure AP-ELEC.1 was exited after transferring all loads to off-site circuit 767 via ER-ELEC.1.

• 0351 hours - Notification of Emergency Diesel Generator A start, event# 51730 was made per 1OCFR50.72(b)(3)(iv)(A)

February 12-19, 2016:

• Activities performed by the station to replace Station Auxiliary Transformer 12A with a spare transformer.

February 19, 2016:

• 1813 hours- Replacement transformer energized.

February 20, 2016:

• 0018 hours: Operations established the Normal off-site power lineup (two off-site power feeds), as was the pre-event condition, by completing procedure 0-6.9.2.