DOMINION ENERGY QUESTAR PIPELINE, LLC

Incident Narrative

DOMINION ENERGY AND LOCAL EMERGENCY RESPONDERS WERE ALERTED TO AND MITIGATED A FIRE AT A COMPANY FACILITY ON 4/15/2020. THE FIRE WAS CAUSED BY AN ELECTRICAL ARC WHICH DAMAGED ACTUATOR POWER GAS TUBING AND IGNITED THE LEAK IT CAUSED. THIS INCIDENT OCCURRED AT A FACILITY LOCATED NEAR GREEN RIVER, WY ON ML001. INITIAL DAMAGE ESTIMATES WERE BELOW THE $50,000 INCIDENT REPORTING THRESHOLD; HOWEVER, SUBSEQUENT ANALYSIS THAT LED TO A DECISION TO REPLACE ADDITIONAL PIPING OUT OF AN ABUNDANCE OF CAUTION, INCREASED THE ESTIMATED REPLACEMENT COSTS ABOVE THE $50,000 THRESHOLD. THIS REPORTING CRITERIA WAS MET ON 4/20/2020 AT 14:30 AND A NRC REPORT WAS SUBSEQUENTLY MADE. ADDITIONAL TESTING DETERMINED THAT THE REPLACED EQUIPMENT WAS NOT ADVERSELY AFFECTED BY THE FIRE. NOTES ON SPECIFIC QUESTIONS: D2) THE PIR OF THE FAILED TUBING WOULD NOT CREATE AN HCA IN THE AREA; HOWEVER, THE FACILITY IS LOCATED WITHIN AN HCA ON ML001 D3) REPORTED PIR IS FOR ML001 DUE TO ML001 BEING USED IN QUESTION D2 E1A) REPORTED FLOW RATE IS FOR ML001 E2A) MAOP DETERMINATION METHOD REPORTED IN QUESTION E2A IS FOR THE TUBING THAT LEAKED. THE MAXIMUM SAFE OPERATING PRESSURE FOR THE TUBING IS DETERMINED PER 192.619(A)(4) TO BE THE MAIN LINE MAOP. MAIN LINE PIPING MAOP ON THIS SECTION OF ML001 WAS DETERMINED BY 192.619(A)(1). E6) LENGTH BETWEEN VALVES DOES NOT INCLUDE THE BLOCK VALVES LOCATED AT THE FACILITY INVOLVED IN THE INCIDENT