United States Nuclear Regulatory Commission - Protecting People and the Environment


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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