NRC Generic Letter 80-04, IEB 80-01 Operability of ADS Valve Pneumatic Supply

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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.

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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