MAGELLAN AMMONIA PIPELINE, L.P.

Incident Narrative

AT 21:03:40 ON 10/17/2016, A RELEASE OCCURRED ON THE MAGELLAN AMMONIA PIPELINE, L.P. VALLEY TO MISSOURI RIVER PIPELINE SEGMENT. AT 21:14 MAGELLAN INITIATED A COMPLETE PIPELINE SHUTDOWN AND ISOLATION BASED ON SCADA AND THE CPM (PLM) SYSTEM INDICATIONS. WHILE COMPLETING THE PIPELINE SHUTDOWN AND ISOLATION, MAGELLAN RECEIVED A TELEPHONIC NOTIFICATION FROM A THIRD PARTY REGARDING A VAPOR CLOUD AND STRONG ODOR. MAGELLAN DECLARED A CODE RED AT 21:26:23, INITIATING A FULL EMERGENCY RESPONSE. FIELD OPERATIONS WERE NOTIFIED AND EMPLOYEES WERE DISPATCHED TO CLOSE MANUAL VALVES. THE PSAP (PUBLIC ACCESS SAFETY POINT) AND NRC WERE NOTIFIED AND PROVIDED WITH AN ESTIMATED RELEASE VOLUME OF AMMONIA. THE INITIAL NRC REPORT NUMBER WAS 1161809. ADDITIONAL NRC REPORTS (1161815 AND 116831) WERE MADE REVISING THE ESTIMATED AMOUNTS RELEASED AS ADDITIONAL INFORMATION BECAME AVAILABLE. RESULTS OF THE NATIONAL TRANSPORTATION SAFETY BOARD INVESTIGATION INDICATE THE PROBABLE CAUSE OF THE PIPELINE RUPTURE WAS CORROSION FATIGUE CRACKS THAT GREW AND COALESCED UNDER DISBONDED POLYETHYLENE TAPE COATING. CONTRIBUTING TO THE LOCATION OF THE CRACKING WAS EXTERNAL LOADING THAT CAUSED BENDING STRESS IN THE PIPE IN ADDITION TO THE CYCLIC STRESSES IN THE PIPE FROM THE INTERNAL PRESSURE OF THE AMMONIA TRANSPORTED. DECOMMISSIONING OF THE ANHYDROUS AMMONIA PIPELINE SYSTEM WAS SUCCESSFULLY COMPLETED ON APRIL 10, 2020. SUPPLEMENTAL/FINAL (5/19/2020): PART C6, D8D, D8G, G5-1,3,4, H