United States Nuclear Regulatory Commission - Protecting People and the Environment

Bulletin 80-01: Operability of Ads Valve Pneumatic Supply

                                                            SSINS No.: 6870
                                                            Accessions No.:

                                UNITED STATES
                           WASHINGTON, D.C. 20555
                              January 11, 1980

                                                      IE Bulletin No. 80-01 


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 (ADS) pneumatic supply (either nitrogen or
air) may not be operable for all possible events because of a combination of
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 qualifications of the ADS pneumatic supply system: 

     (a) from accumulator system isolation check valve to ADS valve 

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

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 

IE Bulletin No. 80-01                                       January 11, 1980
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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 (ROO72); clearance expires July 31, 1980. Approval 
was given under a blanket clearance specifically for identified generic 

Sketch of ADS pneumatic supply 
Page Last Reviewed/Updated Friday, May 22, 2015