TENNESSEE GAS PIPELINE COMPANY

Incident Narrative

ON 10/22/2021 AT 9:02AM CENTRAL TIME, AN ESD OCCURRED AT TENNESSEE GAS PIPELINE COMPANY, L.L.C. (TGP) COMPRESSOR STATION 550 IN HAMILTON, ALABAMA. AT APPROXIMATELY 9:04AM TGP PERSONNEL AT THE STATION BEGAN TO NOTICE THAT THE STATION WAS NOT ISOLATED. ESD VALVE 550-AD2 WAS FOUND IN THE OPEN POSITION ALLOWING GAS TO PASS THROUGH AND OUT OF THE VENT STACK. AT APPROXIMATELY 9:06AM THE VALVE WAS SHUT, ENDING THE EVENT. AT APPROXIMATELY 9:54AM, THE GAS RELEASE WAS DETERMINED TO EXCEED THE REPORTABLE THRESHOLD OF 3,000 MCF. THE EVENT WAS SUBSEQUENTLY REPORTED TO THE NRC AT 10:29AM. DURING THE INVESTIGATION, IT WAS FOUND THAT THE PILOT ON THE ESD VALVE CONTROLLER FOR VALVE 550-AD2 HAD FAILED DURING THE ESD AND DID NOT ALLOW ENOUGH GAS TO PASS THROUGH AND ACTUATE THE VALVE. THE PILOT WAS REPLACED AND THE STATION WAS RETURNED TO SERVICE AT 6:55PM ON 10/22/2021. THE ESD WAS TRIGGERED BY AN INADVERTENT KEY TURN IN THE CONTROL CABIN OF THE STATION, CAUSED BY CLOTHING ON A CONTRACTOR CATCHING AND TURNING THE KEY ON THE PANEL AS THE INDIVIDUAL WAS PASSING BY. THE INVESTIGATION INTO THE FAILURE OF THE PILOT ON VALVE 550-AD2 REVEALED THAT, PER THE MANUFACTURER, THE LIFE EXPECTANCY OF THE PILOT WAS ONE YEAR. THE PILOT HAD BEEN IN-SERVICE SINCE 2015. AT STATION 550, TGP WILL REVIEW THE LIFE EXPECTANCY OF ALL ESD PILOTS AND REPLACE ANY THAT ARE PAST THE LIFE EXPECTANCY STATED BY THE MANUFACTURER. TGP REVOKED OQ'S PERTAINING TO THE AUTOMATED VALVE MAINTENANCE TASK FOR THE INDIVIDUALS WHO SERVICED ESD VALVE 550-AD2. THOSE INDIVIDUALS WILL BE RETRAINED ON VALVE MAINTENANCE PROCEDURES. THE ANSWER TO QUESTION E1A WAS UPDATED AND THE ANSWERS TO A8 AND D7G WERE CORRECTED.