NORTHERN STATES POWER CO OF MINNESOTA — Liquefied natural gas (LNG) — incident on 2022-11-17

Liquefied natural gas (LNG) incident in MN. Reported cause: EQUIPMENT FAILURE. Reported consequences: 0 fatalities, 0 injuries, 50 NATURAL GAS WHILE BEING HANDLED IN GASEOUS PHASE released, $2,200 reported property damage. Operator-reported incident data submitted to PHMSA, generally within 30 days. Records may be supplemented or corrected and do not represent final agency causal findings.

Report number: 20220008.

Operator ID: 31636.

Reported incident date: 11/17/2022 16:16.

Cause detail: THREADED CONNECTION/COUPLING FAILURE

Cause detail: ON NOVEMBER 17, 2022, THE WESCOTT LNG FACILITY CONTROL ROOM RECEIVED A GAS ALARM IN THE C101 COMPRESSOR BUILDING. AFTER OPERATORS INVESTIGATED, THE PLANT EMERGENCY SHUTDOWN SYSTEM (ESD) WAS ACTIVATED. THE LOCATION OF THE LEAK WAS ON THE C-103 BOILOFF/FLASHBACK COMPRESSOR. THE LEAK WAS DUE TO FATIGUE FAILURE OF A CARBON STEEL THREADED COUPLING CONNECTION LOCATED ON THE 1-INCH PACKING VENT PIPE TO THE 1ST STAGE SUCTION DRUM. C-103 WAS TAKEN OUT OF SERVICE UNTIL PERMANENTLY REPAIRED BY REROUTING THE PIPING. NDE EVALUATION WAS PERFORMED ON OTHER SIMILAR THREADED CONNECTIONS ON C102 AND C103. THE INFORMATION RELATED TO THE LEAK WILL BE INCORPORATED INTO THE PLANT INTEGRITY MANAGEMENT PROGRAM.

PHMSA trend classification: not significant, not serious.

PHMSA standardized cause: EQUIPMENT FAILURE — THREADED CONNECTION/COUPLING FAILURE.

PHMSA indexed costs: $3,550 reported total cost, $1,582.745 in 1984 dollars, $3,649.318 in current-year dollars.

PHMSA trend flags, standardized causes, and indexed costs are analytical fields added to operator-reported incident data. They do not represent final agency causal findings.