United States Nuclear Regulatory Commission - Protecting People and the Environment

IEB 80-01 Operability of ADS Valve Pneumatic Supply (Generic Letter 80-04)



GL80004                                                     SSINS No.:  6870
                                                            Accessions No.: 
                                                            7912190652 

                                 UNITED STATES 
                         NUCLEAR REGULATORY COMMISSION 
                     OFFICE OF INSPECTION AND ENFORCEMENT 
                            WASHINGTON, D.C. 20555 

                               January 11, 1980 

                                                    IE Bulletin No.  80-01 

OPERABILITY OF ADS VALVE PNEUMATIC SUPPLY 

On January 10, 1980, the NRC was informed by Philadelphia Electric Company 
that engineering evaluation for Peach Bottom 2 and 3 has disclosed that the 
Automatic Depressurization System (ADS0 pneumatic supply (either nitrogen or
air) may not be operable for all possible events because of a combination 
misapplication of check valve, a lack of leak testing of the accumulator 
system backing up each ADS valve operator and questions about the continued 
operability of the pneumatic supply in a seismic event.  Attached is a 
simplified schematic of the pneumatic supply.  The check valve nearest to 
the accumulator is a PAL, three-quarter inch, stainless steel, socket welded 
check valve with a hard seat (valve identification-B-1376 on the upper 
flange). Plant information at Peach Bottom shows substantial supports for 
the pneumatic supply inside the drywell, but seismic qualification has not 
been verified. The licensee has stated that the pneumatic supply is not 
seismically qualified outside  the drywell. 

Unit 2 was shutdown on 1/10/80 because of questions of ADS operability and 
Unit 3 has been provided a seismically qualified nitrogen supply at the 
containment penetration pending confirmation of seismic qualification of 
piping inside Unit 2 containment.  The licensee is changing their valve to 
one with a soft seat to reduce leakage. 

Actions to be taken by Licensees of GE BWR facilities with an operating 
license which use a pneumatic operator for ADS function: 

1.   Determine if your facility has installed hard-seat check valves to 
     isolate the ADS accumulator system from the pneumatic supply system. 

2.   Determine if periodic leak tests have been performed on your ADS 
     accumulator systems to assure emergency pneumatic supply for the FSAR-
     required number and duration of valve operations. 

3.   Review seismic qualification of the ADS pneumatic supply system: 

     (a)  from accumulatory system isolation check valve to ADS valve 
          operator, 

     (b)  from isolation valve outside containment up to ADS accumulator 
          check valve. 
.

IE Bulletin No.  80-01                                     January 11, 1980 
                                                           Page 2 of 2 

4.   Based upon determination of items 1, 2, and 3 above, evaluate 
     operability of the ADS for the conditions under which it is required to 
     be operable including a seismic event.  If operability cannot be 
     established adhere to appropriate Technical Specification action 
     statement. 
     
5.   Provide an immediate notification to the NRC in the event the ADS is 
     found to be inoperable. 

6.   Provide a response in writing by January 18, 1980, for those facilities
     which use a pneumatic operator for ADS function. 

Reports should be submitted to the Director of the appropriate NRC Regional 
Office and a copy should be forwarded to the U.S. Nuclear Regulatory 
Commission, Office of Inspection and Enforcement, Division of Reactor 
Operations Inspection, Washington, D.C. 20555. 

Approved by GAO, B180225 (R0072); clearance expires July 31, 1980.  Approval
was given under a blanket clearance specifically for identified generic 
problems. 

Attachment: Sketch of ADS pneumatic supply 


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