Part 21 Report - 1998-290

LICENSEE: DRESSER-RAND SITE: DRESSER-RAND EN NUMBER:33958 DOCKET: EVENT DATE: 03-20-98 RX TYPE: EVENT TIME: 00:00 VENDORS: NOTIFY DATE: 03-25-98 EMERGENCY CLASS: N/A REGION: 1 STATE: NY TIME: 08:04 OPS OFFICER: LEIGH TROCINE 10 CFR SECTION: CCCC 21.21 UNSPECIFIED PARAGRAPH 10-CFR-PART-21 NOTIFICATION GOVERNOR VALVE STEMS MADE OF INCONEL-718 MATERIAL WILL EXPAND MORE THAN THE ORIGINAL 410 STAINLESS STEEL STEMS FOR THE SAME TEMPERATURE RISE. VALVE ASSEMBLIES THAT STROKE FREELY WHEN ASSEMBLED BIND OR DRAG AT OPERATING TEMPERATURES. THIS CONDITION RESULTS IN LOSS OF GOVERNOR CONTROL AND HAS BEEN REPORTED TO HAVE OCCURRED AT THE FOLLOWING THREE NUCLEAR POWER PLANTS: LIMERICK (S/N 36691), HOPE CREEK (S/N 37123), AND PERRY (S/N 38176). ALL REPORTED CONTROL PROBLEMS HAVE BEEN TRACED TO VALVE STEMS MANUFACTURED BY BW/IP. THE BW/IP MANUFACTURING DRAWING ALLOWS FOR A DIAMETER OF 0.4980/0.5000", AND THE DRESSER-RAND DRAWINGS ALLOW 0.4985/0.4990". ANY INCONEL STEM WITH A DIAMETER GREATER THAT 0.4988" IS SUSCEPTIBLE TO INTERFERENCE WITH THE CARBON WASHERS AT TEMPERATURES ABOVE 500�F AND COULD RESULT IN TURBINE CONTROL PROBLEMS. THE PERFORMANCE OF THE DRESSER-RAND INCONEL STEMS WITH THE CARBON SPACERS IS MARGINAL AT ELEVATED TEMPERATURES WITH THE MAXIMUM SAFE OPERATING TEMPERATURE BEING WELL BELOW 600�F.

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