TENNESSEE GAS PIPELINE COMPANY

Incident Narrative

AT 2:20 PM TENNESSEE GAS PIPELINE COMPANY, L.L.C. (TGP) CONTROL ROOM RECEIVED AN ALARM OF AN EMERGENCY SHUTDOWN (ESD) AT STATION 110 IN MOREHEAD, KENTUCKY. AT 2:32 PM, AN OPERATOR ARRIVED ON SITE TO BEGIN ASSESSING THE ESD SYSTEM. THE RELEASED WAS STOPPED AT 2:45 PM AND AT 4:30 PM, WHILE ATTEMPTING TO RESET THE ESD SYSTEM, IT WAS DISCOVERED THAT VALVE 1D7, WHICH IS ON A SUCTION LINE COMING OFF OF LINE 100-7, DID NOT CLOSE AS DESIGNED DURING THE ESD. BECAUSE THE VALVE DID NOT CLOSE DURING THE ESD, GAS FROM THE MAINLINE WAS MAKING ITS WAY THROUGH THE SUCTION SIDE OF THE STATION AND OUT OF THE STATION SILENCER, VENTING TO ATMOSPHERE. AN EMERGENCY RESPONSE CALL WAS HELD AT 5:00 PM TO DISCUSS THE EVENT. BECAUSE THE 1D7 VALVE DID NOT CLOSE IT WAS FORECASTED THAT THE GAS LOSS QUANTITY WOULD EXCEED 3,000 MCF. AS A RESULT OF THIS FORECAST THE EVENT WAS REPORTED TO THE NRC. THE INITIAL ASSESSMENT DISCOVERED THAT A LIGHTNING EVENT CAUSED THE STATION TO ESD. AFTER FURTHER INVESTIGATION, IT WAS FOUND THAT THE VALVE OPERATOR ON VALVE 1D7 HAD RECENTLY BEEN REPLACED WITHOUT A MANAGEMENT-OF-CHANGE (MOC). THE VALVE OPERATOR HAD A DEFAULT CONFIGURATION FOR ""PRESSURE-UP"" ACTIVATION ON AN ESD SYSTEM; HOWEVER, THE ESD SYSTEM AT STATION 110 FUNCTIONS AS A ""PRESSURE-DOWN"" ESD SYSTEM. INSTALLATION OF THE VALVE OPERATOR WITHOUT AWARENESS OF ITS DEFAULT DESIGN CONFIGURATION, CAUSED VALVE 1D7 NOT TO CLOSE DURING THE ESD AT THE STATION. AS A CORRECTIVE ACTION, TGP REVIEWED ITS MOC PROCEDURE WITH OPERATORS AT STATION 110. OPERATORS WERE RETRAINED TO RECOGNIZE THAT A MOC IS NEEDED FOR MAKING CHANGES TO THE NORMAL DESIGN CONDITIONS OR DESIGN PARAMETERS OF PIPELINE OPERATIONS.