ANR PIPELINE CO

Incident Narrative

ON MARCH 15, 2024, THE MONITORING CENTER (MC) RECEIVED A CALL FROM A NEAR-BY RESIDENT THAT A VENT VALVE WAS ACTIVELY RELEASING GAS AT SOUTH CHESTER COMPRESSOR STATION (CS) IN OSTEGA COUNTY, NEAR THE CITY OF JOHANNESBURG, STATE OF MICHIGAN. SOUTH CHESTER CS IS CLASSIFIED AS A TRANSMISSION FACILITY OPERATED AND MAINTAINED BY ANR PIPELINE COMPANY, A TC ENERGY ENTITY. MC PERSONNEL DISPATCHED A TECHNICIAN TO THE SITE TO INVESTIGATE THE REPORTED EVENT. THE TECHNICIAN ARRIVED AT THE SITE AT 20:58 EDT, SHORTLY THEREAFTER, A SECOND TECHNICIAN ARRIVED TO SUPPORT THE FIRST RESPONDER. IMMEDIATE ACTIONS WERE TAKEN TO VERIFY THAT NO FIRE EXISTED IN LIEU OF THE UNINTENDED RELEASE OF MATERIAL INTO ATMOSPHERE, THEN ACTIONS WERE TAKEN TO CLOSE THE EMERGENCY SHUTDOWN (ESD) VALVE FV-153. AT 21:12 EDT, THE UNINTENDED RELEASE OF MATERIAL WAS STOPPED. THE UNINTENTIONAL GAS LOSS WAS CALCULATED AT 39,419MCF. A CALL WAS REPORTED OF THE INCIDENT TO THE NRC (REPORT NO. 1393986). THERE WAS NO PROPERTY DAMAGE, INJURIES, FATALITIES, OR MANDATORY EVACUATIONS WERE NEEDED. THE 48HR UPDATE REPORT TO THE NRC (REPORT NO. 1394062) WAS SUBMITTED ON MARCH 17, 2024. INVESTIGATION INTO THE SHAFER ACTUATOR DISCOVERED AN O-RING IN THE 3-WAY POPPET VALVE TO HAVE FAILED ALLOWING THE PILOT GAS TO VENT OFF WHICH CAUSES THE POWER GAS TO BE APPLIED TO THE ACTUATOR TO CYCLE THE VALVE OPEN AS DESIGNED. THE O-RING HAS BEEN REPLACED AND THE VALVE WAS RETURNED BACK INTO SERVICE ON APRIL 1, 2024.