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Home NRC Library Document Collections Events, Reports Associated with Morning Reports 2003

Morning Report for February 21, 2003



                       Headquarters Daily Report

                         FEBRUARY 21, 2003

***********************************************************
                    REPORT             NEGATIVE            
                    ATTACHED           INPUT RECEIVED      

HEADQUARTERS                              X                   
REGION I                                  X                                      
REGION II              X                                      
REGION III                                X                   
REGION IV                                 X                   




PRIORITY ATTENTION REQUIRED  MORNING REPORT - REGION II  FEB. 21, 2003

Licensee/Facility:                     Notification:

Duke Power Co.                         MR Number: 2-03-0002
Mc Guire 1                             Date: 02/21/03
Cornelius,North Carolina                                                  
Dockets: 50-369
PWR/W-4-LP                            

Subject: FAILURE OF CONTAINMENT ISOLATION VALVE STEM - MCGUIRE UNIT 1    

Discussion:

On February 4, 2003, the stem of an auxiliary feedwater containment      
isolation valve at McGuire Unit 1 failed catastrophically while the valve
was being stroked open for post-maintenance testing.  The valve, 1CA-42B,
is a normally open 4-inch Atwood & Morrill parallel wedge gate valve that
is actuated by a Rotork 30NA1-21 model motor operator.  The licensee's   
investigation revealed a loose spring clip on the Rotork operator which  
caused the open limit switch to slip and prevented the operator motor    
from stopping.  In addition, the open torque switch was set incorrectly  
which allowed the valve operator to generate excessive loads in the open 
direction.  The incorrect torque switch setting resulted from an error in
the valve manufacturer's (Atwood & Morrill) "weak link" analysis         
calculation.  Because of this error, the licensee had set the valve's    
open torque switch setting significantly above the actual structural     
capability of the valve stem.                                            
                                                                         
The licensee and the vendor are currently assessing the potential generic
implications of this issue.  In the interim, the licensee has issued a   
nuclear network message concerning the loose spring clip and the valve   
manufacturer's stress analysis error.                                    

Regional Action:

The NRC evaluated the licensee's repair and testing activities for the   
valve and concluded that they were adequate.  The NRC staff is also      
following up on the potential generic implications of the loose spring   
clip on the actuator limit switch, as well as the error in the valve     
manufacturer's structural capability calculations.                       

Contact:  R. HAAG                    (404)562-4550

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