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

Incident Narrative

ORIGINAL REPORT: ON FRIDAY, NOVEMBER 23, AT 4:24 PM EST LILLY STATION HAD A STATION EMERGENCY SHUT DOWN (ESD). THE ESD WAS CAUSED BY A COMMERCIAL POWER DISRUPTION. THE EMERGENCY GENERATOR STARTED THOUGH A CIRCUIT BREAKER TRIPPED CAUSING A LOSS OF ELECTRICAL POWER WHICH RESULTED IN FULL STATION ESD ACTIVATION. WHEN THE ESD OCCURRED, GAS VENTED THROUGH THE THREE STATION ESD BLOW DOWN VALVES BECAUSE 30""X 24"" (VALVE 19-149) FAILED TO CLOSE AUTOMATICALLY. OPERATOR PERSONNEL MANUALLY CLOSED VALVE 19-149 AT 5:01 PM EST. TOTAL GAS LOSS THROUGH THE THREE ESD BLOW DOWN VALVES WAS CALCULATED TO BE 23.24 MMSCF. WHEN THE ESD SYSTEM ACTIVATED, THE CONTROL PILOT ASSEMBLY IN THE SHAFER ACTUATOR FOR VALVE 19-149 FROZE DUE TO THE PRESENCE OF WATER (EXTERNAL TO THE CONTROL) AND COLD AMBIENT TEMPERATURES WHICH CAUSED THE VALVE TO REMAIN OPEN. SUPPLEMENTAL REPORT: 48 HR NRC REPORT 1231234 PRIOR TO THE NOVEMBER 23, 2018 INCIDENT AT TETLP'S LILLY COMPRESSOR STATION, TETLP HAD CALCULATED THE ESTIMATED GAS LOSS FOR A NORMAL ESD EVENT AT LILLY STATION TO BE 1.23 MMSCF. BASED ON THIS CALCULATION, AN ESD OPERATING AS ANTICIPATED WOULD NOT BE REPORTABLE, SINCE THE GAS RELEASE WOULD BE WELL UNDER THE 3 MMSCF THRESHOLD FOR REPORTING. HOWEVER, ONE OF THE ESD ISOLATION VALVES UNEXPECTEDLY DID NOT CLOSE PROPERLY, SO THE ACTUAL GAS LOSS WAS GREATER THAN THE ESTIMATED 1.23 MMSCF, AND GREATER THAN THE 3 MMSCF REPORTING THRESHOLD. ON NOV. 24, THE ESTIMATED GAS LOSS WAS CALCULATED TO BE MORE THAN 3 MMSCF, AND THEN WAS REPORTED TO NRC. THIS EVENT HAS IDENTIFIED THE NEED FOR ADDITIONAL TRAINING AND AWARENESS OF THE REQUIREMENT TO IMMEDIATELY REPORT SUCH EVENTS TO INTERNAL PERSONNEL RESPONSIBLE FOR NRC NOTIFICATIONS. THE TRAINING WILL BE DEVELOPED AND IMPLEMENTED SYSTEM-WIDE IN 2019.