TEXAS EASTERN TRANSMISSION, LP (SPECTRA ENERGY PARTNERS, LP)

Incident Narrative

ON MARCH 9, 2023, TEXAS EASTERN TRANSMISSION, L.P. (TETLP) WAS CONDUCTING AN ANOMALY DIG ON LINE 14 CLIN-KOSC VS-4, M.P. 356.89, WHEN THE CREW IDENTIFIED INDICATIONS OF A LEAK (I.E., BUBBLING). A PIN HOLE LEAK WAS CONFIRMED WITH A SOAP SOLUTION AT APPROXIMATELY 12:07 CT. AT APPROXIMATELY 14:20 CT IT WAS CONFIRMED THAT REPAIRS WOULD LIKELY EXCEED THE PHMSA DAMAGE/REPAIR THRESHOLD, AND THE EVENT WAS SUBSEQUENTLY CALLED INTO THE NRC AT 14:47 CT. AT APPROXIMATELY 16:50 CT THE UPSTREAM VALVE WAS CLOSED, AND THE DOWNSTREAM COMPRESSOR STATION (CLINTON) WAS USED TO PULL THE PRESSURE IN THE LINE DOWN. AT 18:10 CT THE DOWNSTREAM VALVE WAS CLOSED, AND THE LINE WAS THEN COMPLETELY BLOWN DOWN TO MAKE THE REPAIR. THE LEAKING PIPE WAS CUT OUT AND REPLACED AND THE LINE WAS RETURNED TO SERVICE ON MARCH 12, 2023, 17:20 CT. THE REMOVED SECTION WAS SENT TO A LAB FOR FURTHER METALLURGICAL ANALYSIS. TETLP HAD ASSESSED THE LINE WITH AN MFL-A TOOL IN EARLY 2021. THE ANOMALY IN QUESTION WAS REPORTED AS HAVING A 66% DEPTH AND WAS ISSUED A DUE DATE OF APRIL 30, 2023. EXCAVATION BEGAN MARCH 8, 2023, AND DURING THE DIG PROCESS THE ANOMALY WAS FOUND TO BE LEAKING. FURTHER EXCAVATION VERIFIED THAT A NEGATIVE LEAD TO THE RECTIFIER HAD COME LOOSE RESULTING AN INCREASED CORROSION GROWTH RATE UNDER THE CONNECTION. 06/19/2023 THERE WERE NO CLEAR INDICATIONS OF A PROBLEM IN EITHER THE RECTIFIER READINGS OR THE TEST LEAD READINGS AT THE RECTIFIER, AND THERE WAS NO ADDITIONAL CORROSION DAMAGE IN THE AREA. THE CORROSION WAS CONCENTRATED UNDER THE LOOSE NEGATIVE GROUND BED LEAD WHERE CURRENT WAS LEAVING THE PIPE AND RETURNING TO THE GROUND BED.