United States Nuclear Regulatory Commission - Protecting People and the Environment

LICENSEE: ANDERSON, GREENWOOD & CO (AGCO)    
SITE: ANDERSON, GREENWOOD & CO (AGCO        EN NUMBER:29066
DOCKET:                                  EVENT DATE: 07-14-95
RX TYPE:                                 EVENT TIME: 00:00
VENDORS:                                NOTIFY DATE: 07-14-95
EMERGENCY CLASS: N/A  REGION: 4 STATE: TX      TIME: 15:24
OPS OFFICER: JOSEPH SEBROSKY          
10 CFR SECTION: CCCC  21.21               UNSPECIFIED PARAGRAPH

ANDERSON, GREENWOOD & CO (AGCO) OF STAFFORD, TEXAS, CALLED TO    
REPORT A PROBLEM WITH RELIEF VALVES IN ACCORDANCE WITH 10 CFR    
PART 21.                                                         
                                                                 
AGCO HAS INFORMATION INDICATING THAT AGCO MODEL 81P RELIEF       
VALVES, IF ADJUSTED IN THE FIELD USING AIR AS THE TEST MEDIA, MAY
NOT EXHIBIT A SET PRESSURE WITHIN THE SPECIFICATION TOLERANCE.   
THESE RELIEF VALVES ARE DESIGNED FOR LIQUID THERMAL RELIEF       
APPLICATIONS AND ARE FACTORY SET AND SEALED TO THE SPECIFIED SET 
PRESSURE USING WATER AS THE TEST MEDIA.                          
                                                                 
AGCO RECOMMENDS USING WATER AS A TEST MEDIA WHEN ADJUSTMENTS ARE 
MADE IN THE FIELD; HOWEVER, THEY DO SUPPLY THEIR BUYERS WITH A   
PROCEDURE TO ADJUST THE SETPOINT OF THE VALVES WITH AIR.         
PRELIMINARY TESTS DONE BY AGCO SHOW THAT VALVES MAY EXHIBIT UP TO
A 40% SET PRESSURE DEVIATION WHEN THE AIR METHOD IS USED.  THESE 
TESTS ALSO INDICATE THE DEVIATION WILL BE LARGEST FOR LOW SET    
PRESSURES (100 PSI).                                             
                                                                 
AGCO HAS SUPPLIED MODEL 81P RELIEF VALVES TO THE FOLLOWING       
UTILITIES:  DUKE POWER COMPANY, NORTHEAST UTILITIES, VIRGINIA    
POWER, PENNSYLVANIA POWER AND LIGHT, BOSTON EDISON, CENTERIOR    
SERVICE, NEBRASKA PUBLIC POWER DISTRICT, VERMONT YANKEE, OMAHA   
PUBLIC POWER DISTRICT, GPU NUCLEAR CORPORATION, GEORGIA POWER,   
PUBLIC SERVICE ELECTRIC AND GAS, AND ENTERGY.                    
                                                                 
* * * * *  UPDATE RECEIVED BY FACSIMILE (SIGNED BY WEST) AT      
APPROXIMATELY 1534 ON AUGUST 10, 1995.  TAKEN BY TROCINE.  * * * 
* *                                                              
                                                                 
THIS CORRESPONDENCE PROVIDED THE RESULTS OF TESTING PERFORMED TO 
EVALUATE THE PROBLEM REPORTED BY AGCO ON JULY 14, 1995.  TESTING 
WAS PERFORMED TO ESTABLISH THE AMOUNT OF DEVIATION FROM NAME     
PLATE SET PRESSURE THAT COULD RESULT FROM AGCO'S MODEL 81P VALVE 
USING AIR AS THE TEST MEDIA INSTEAD OF WATER.  VALVES WERE       
ASSEMBLED AND SET PRESSURE ADJUSTMENTS WERE MADE FOLLOWING THE   
FACTORY PROCEDURE USING WATER AS THE TEST MEDIA.  THE VALVES WERE
THEN CHECKED USING AIR AS A TEST MEDIA.  IF THE AIR TEST METHOD  
DID NOT RESULT IN THE SAME SET PRESSURE VALUE, THEN FURTHER      
ADJUSTMENTS WERE MADE TO SATISFY THE AIR METHOD CRITERIA.  FOR   
VALVES WHERE ADJUSTMENTS WERE NECESSARY, THE FACTORY WATER
METHOD
WAS REPEATED, AND THE RESULTING SET PRESSURE WAS RECORDED.  THE  
DIFFERENCE BETWEEN THE FIRST WATER TEST SETTING AND THE SECOND   
WATER TEST READING REPRESENTED THE POTENTIAL DEVIATION FROM NAME 
PLATE SET THAT COULD RESULT FROM ADJUSTING THE VALVE USING THE   
AIR METHOD.                                                      
                                                                 
TWO SERIES OF TESTS WERE PERFORMED:  ONE USING KEL-F SEAT        
MATERIAL AND ANOTHER USING PEEK SEAT MATERIAL.  SET PRESSURES    
RANGING FROM 100 PSI TO 2,000 PSI WERE TESTED.  THE POTENTIAL SET
PRESSURE DEVIATION ABOVE NAME PLATE WAS DETERMINED TO BE 4% TO   
15% FOR MODEL 81P VALVES WITH KEL-F SEAT MATERIAL AND A SET      
PRESSURE RANGE OF 100 PSIG TO 750 PSIG.  THE POTENTIAL SET       
PRESSURE DEVIATION ABOVE NAME PLATE WAS DETERMINED TO BE 20% TO  
40% FOR MODEL 81P VALVE A WITH PEEK SEAT MATERIAL AND A SET      
PRESSURE RANGE OF 100 PSIG TO 750 PSIG.  THERE WAS NO IDENTIFIED 
POTENTIAL SET PRESSURE DEVIATION ABOVE NAME PLATE FOR MODEL 81P  
VALVES WITH EITHER KEL-F OR PEEK SEAT MATERIAL AND A SET PRESSURE
RANGE GREATER THAN 750 PSIG.                                     
                                                                 
SINCE THE AIR TEST METHOD WAS BASED ON THE VALVE'S FIRST LEAKAGE 
ON INCREASING PRESSURE, RESULTS WERE VERY DEPENDENT ON THE       
EFFECTIVENESS OF THE VALVE SEAT.  PEEK IS A VERY HARD PLASTIC    
RELATIVE TO KEL-F AND REQUIRES MORE SEATING LOAD TO EFFECT A     
SEAL.  THEREFORE, THE POTENTIAL DEVIATION FOR PEEK SEAT MATERIAL 
IS GREATER THAN FOR KEL-F SEAT MATERIAL.  FOR BOTH MATERIALS, THE
HIGHER SET PRESSURES (GREATER THAN 750 PSIG) SHOWED NO DEVIATION 
BETWEEN WATER AND AIR TEST METHODS.  FOR THE LOWER SET PRESSURES,
THE RANGE OF DEVIATIONS SHOWED NO SIGNIFICANT TREND.             
                                                                 
AGCO STATED THAT THE REFERENCED DEVIATIONS ARE ONLY APPLICABLE TO
AGCO'S MODEL 81P LIQUID RELIEF VALVES THAT HAVE HAD SET PRESSURES
ADJUSTED AFTER SHIPMENT FROM THE FACTORY USING AIR AS THE TEST   
MEDIA AND FIRST CRACK (LEAK) AT 95% OF SET PRESSURE AS THE       
CRITERIA.  ANY VALVE THAT HAS AGCO'S FACTORY LEAD SEAL UNBROKEN  
OR HAS BEEN ADJUSTED USING THE WATER TEST METHOD IS UNAFFECTED.  
                                                                 
AGCO ALSO STATED THAT THE MODEL 81P VALVE SHOULD ONLY BE SET     
PRESSURE ADJUSTED USING THE WATER TEST METHOD DESCRIBED IN       
PROCEDURE NO5.9040.180, REVISION F, FOR SET PRESSURES BELOW 750  
PSIG AND THAT EITHER THE WATER OR AIR TEST METHOD MAY BE USED FOR
SET PRESSURES ABOVE 750 PSIG.  AGCO IS CURRENTLY IN THE PROCESS  
OF PREPARING LETTERS EXPLAINING THESE FINDINGS AND RECOMMENDED   
PROCEDURES TO ALL CUSTOMERS WHO HAVE PURCHASED THIS MODEL VALVE. 
                                                                 
THE NRC OPERATIONS CENTER NOTIFIED NRR/RVIB (HODGE).             

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