Headquarters Daily Report

                         JUNE 11, 1998

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                    REPORT             NEGATIVE            NO INPUT
                    ATTACHED           INPUT RECEIVED      RECEIVED

HEADQUARTERS                           û                   
REGION I            û                                      
REGION II                              û                   
REGION III                             û                   
REGION IV                              û                   
PRIORITY ATTENTION REQUIRED  MORNING REPORT - REGION I  JUNE 11, 1998

Licensee/Facility:                     Notification:

Peco Energy Company.                   MR Number: 1-98-0033
Limerick 2                             Date: 06/10/98
Philadelphia,Pennsylvania              RI PC                              
Dockets: 50-353
BWR/GE-4                              

Subject: RESULTS OF INVESTIGATION INTO UNIT 2 SPURIOUS SBLC INJECTION    

Discussion:

Limerick staff determined electromagnetic interference (EMI) caused the  
spurious standby liquid control (SBLC) injection that occurred on June 3.
At the time of the SBLC injection, technicians in the auxiliary equipment
room (AER) were cycling the 2M safety relief valve (SRV) hand switch as  
part of a post maintenance test for the SRV.  This activity induced a    
pulse that actuated the redundant reactivity control system (RRCS) output
to the 2C SBLC injection logic.  The interaction was possible because the
2M SRV wiring is in the same cable tray as the wiring for the RRCS-to-2C 
SBLC logic.                                                              
                                                                         
In response, LGS personnel installed ferrite EMI suppression beads on    
selected wiring terminated in the Unit 2 RRCS cabinet to shield the      
wiring.  For example, technicians put beads on the wiring leading to the 
2A,B, and C SBLC initiation relays, as well as the leads to the feedwater
runback logic.  Subsequent testing showed this modification suppressed   
EMI sufficiently to prevent logic actuation.  Long term, the facility    
will review this event for generic implications concerning other         
EMI-sensitive logic.                                                     
                                                                         
Cleanup of the reactor water was completed.  In addition, plant          
management completed their evaluation on the consequence of the SBLC     
boron injection event on vessel internals, on the fuel, and on           
reactivity.  There was minimal effect.  NRC staff agrees with this       
assessment as well as the root cause determination.  Startup is expected 
to occur on Thursday.                                                    

Regional Action:

The resident staff is monitoring these activities.                       

Contact:  Todd Fish                  (610)327-1344
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