IEB 80-01 Operability of ADS Valve Pneumatic Supply (Generic Letter 80-04)
GL80004 SSINS No.: 6870
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
(b) from isolation valve outside containment up to ADS accumulator
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
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
Attachment: Sketch of ADS pneumatic supply
Page Last Reviewed/Updated Friday, May 22, 2015