Bulletin 80-01: Operability of Ads Valve Pneumatic Supply
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 (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
operator,
(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
statement.
.
IE Bulletin No. 80-01 January 11, 1980
Page 2 of 2
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
problems.
Attachment:
Sketch of ADS pneumatic supply
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