Headquarters Daily Report

                         OCTOBER 10, 1997

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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 - HEADQUARTERS OCTOBER 10, 1997

MR Number: H-97-0126

                           NRR DAILY REPORT ITEM
                           GENERIC COMMUNICATIONS



NRC Information Notice 97-77, "Exemptions From the Requirements of       
Section 70.24 of Title 10 of The Code of Federal Regulations," dated     
October 10, 1997.                                                        
                                                                         
The NRC is issuing this information notice to inform addressees about    
actions the staff plans to take regarding enforcement actions and the    
granting of exemptions from the requirements of Section 70.24 of Title 10
of the Code of Federal Regulations (10 CFR 70.24).                       
                                                                         
Technical contact:  G. Wunder, NRR                                       
                    301-415-1494                                         
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REGION III  MORNING REPORT     PAGE  2          OCTOBER 10, 1997

Licensee/Facility:                     Notification:

Commonwealth Edison Co.                MR Number: 3-97-0102
Byron 1                                Date: 10/09/97
Byron,Illinois                         LICENSEE VIA ENS & RI VIA PHONE &PC
Dockets: 50-454
PWR/W-4-LP                            

Subject: REACTOR SHUTDOWN REQUIRED BY TECHNICAL SPECIFICATIONS           

Discussion:

On October 10, 1997, at 4:48 a.m. (CDT), Unit 1 completed a shutdown     
required by Technical Specifications and entered Mode 3 (Hot Standby.)   
During an ECCS venting surveillance on 10/9/97, the licensee identified  
that a Reactor Coolant System Pressure Isolation Valve (1SI8819C, SI Cold
Leg Check Valve) was leaking. The licensee calculated that the leak rate 
was approximately 5 GPM at 7:14 p.m. on 10/9/97. Technical Specification 
3.4.6.2.f allowed a maximum of 1 GPM leakage with RCS pressure at 2235   
psig. Action C required the leak rate to be reduced within 4 hours or be 
in hot standby within the next 6 hours and in cold shutdown within the   
following 30 hours. The licensee was unable to reduce the leak rate and  
began the shut down at 10:08 p.m. on 10/9/97.                            
                                                                         
The licensee identified the excessive leakage after a safety injection   
system venting surveillance indicated more gas coming out of solution    
than normally expected. Also, during the SI cold leg injection header    
venting, the 1C safety injection accumulator level dropped, indicating   
back leakage through the SI cold leg check valve and the source of the   
water was the 1C SI accumulator. No additional leakage from the Reactor  
Coolant System was identified.                                           
                                                                         
Currently the licensee is formulating repair plans.                      

Regional Action:

The resident inspector observed the shutdown and will monitor repairs of 
the check valve and the subsequent startup.                              

Contact:  T. M. TONGUE               (630)829-9613
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