ML20034F298
| ML20034F298 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 02/23/1993 |
| From: | Gardner R, Pegg W, Shembarger K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20034F295 | List: |
| References | |
| 50-254-93-05, 50-254-93-5, 50-265-93-05, 50-265-93-5, NUDOCS 9303030005 | |
| Download: ML20034F298 (4) | |
See also: IR 05000254/1993005
Text
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U. S. NUCLEAR REGULATORY COMMISSION
REGION III
Reports No: 50-254/93005(DRS);50-265/93005(DRS)
Docket Nos: 50-254; 50-265
Licenses No:
Licensee: Commonwealth Edison Company
Opus West III
1400 Opus Place
Downers Grove, IL 60515
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Facility Name: Quad Cities Nuclear Plant
Inspection At: Quad Cities Nuclear Plant
Inspection Conducted:
February 9-11, 1993
Inspectors: NbMM4
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K. Shembarger
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W. Pegg
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Approved:
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R. Gardner, Chief,
Date
Plant Systems Section
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Insoection Summary
Insoection on February 9-11. 1993 (Recort No. 50-254/93005(DRS):
50-265/93005fDRS).
Areas Insoected:
Special inspection of matters associated with the Unit I and
Unit 2 HPCI systems being inoperable due to check valve leakage within the
HPCI systems.
Results: The inspectors determined that the HPCI systems were in a degraded
condition for several years as a result of the check valve leakage, which
could have prevented the systems from performing their function during a small
break LOCA event. Three violations were identified during the inspection
pertaining to inadequacies in 1) the inservice testing program, 2) test
control, and 3) a maintenance procedure. ' One weakness was identified-
regarding the lack of guidance in the emergency operating procedures to ensure
the HPCI pump discharge volume was maintained full during an event.
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DETAILS
1.0
Exit Meetina Attendees
Commonwealth Edison Company (CECO)
D. Bax, Station Manager
J. Burkhead, Quality Verification
D. Crannick, Maintenance Superintendent
H. Hentschel, Operations Manager
D. Kanakares, Regulatory Assurance, NRC Coordinator
J. Leider, Technical Services
A. Misek, Regulatory Assurance Supervisor
M. Nools, Quality Control Supervisor
C. Smith, Mechanical Maintenance
J. Wethington, Assistant Technical Staff Supervisor
U. S. Nuclear ReaulatorY Commission (NRC)
T. Taylor, Senior Resident Inspector
The NRC inspectors also contacted and interviewed other licensee personnel
during the inspection.
2.0
Inspection Results
2.1
Purpose of the Inspection
The purpose of the inspection was to review the matters associated with the
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HPCI system inoperability on February 5,1993, due to check valve leakage
within the HPCI systems.
2.2
Descriotion of Event
On February 5,1993, the licensee determined, after aligning 1) the HPCI
system suction to the torus and 2) the ECCS keep fill system to the HPCI
system, that the check valves located in the pump suction line were leaking.
This was identified as a result of the ECCS keep fill system's inability to
maintain adequate system pressure while aligned to-the HPCI system. The.
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licensee disassembled the check valves and identified that the hinge and disc
assembly for both valves were misaligned, allowing water to. flow from the HPCI
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system piping through the check valves to the torus. The licensee realigned
the hinge and disc assembly for each valve, performed a visual and pressure
check to ensure the valves seated adequately, and returned the HPCI systems to
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service.
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2.3
Sianificance of Event
Between at least January,1982 for Unit I and March,1990 for Unit 2, and
February,1993, the HPCI systems at the Quad Cities Nuclear Plant were in a
degraded condition as a result of misaligned hinge and disc assemblies in the
torus suction check valves. The valve leakage that occurred as a result of
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the hinge and disc assembly misalignment could have prevented the HPCI systems
from performing their intended function during a small break LOCA event.
Specifically, during a small break LOCA event, with HPCI saction aligned to
the torus and the HPCI pump cycling on and off as designed to maintain reactor
vessel level, multiple water hammer events could have affected the ability of
HPCI to perform its intended function.
2.4
Inspection Findinos
2.4.1
HPCI Check Valve Classification
The inspectors determined that the licensee had incorrectly classified the
HPCI system check valves (1-2301-39 and 2-2301-39) in the IST program (Section
XI of the ASME Code). Specifically, the licensee classified the valves as
category "C", with an open only safety function. The valves should have been
classified as category
"C", with an open and closed safety function, since the
check valves must close to prevent draining of the HPCI pump discharge piping
to the torus while the system is idle following a HPCI turbine trip.
Failure
to classify the valves correctly is considered a violation of 10 CFR 50.55a
(254/93005-01(DRS); 265/93005-Cl(DRS)).
2.4.2
HPCI Check Valve Testina
The inspectors determined that the licensee was not testing the HPCI system
check valves (1-2301-39 and 2-2301-39) as required by Subsection IWV (IWV-
3522) of Section XI of the ASME Code. Specifically, the Code requires, in
part, that valves that are normally open during plant operation, and whose
function is to prevent reversed flow, be tested. Since the valves are
normally open during HPCI system operation with suction from the torus, and
are required to close to prevent reversed flow with the system idle following
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a HPCI turbine trip, testing was required.
Failure to perform required
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testing is considered a violation of 10 CFR 50, Appendix B, Criterion XI
(254/93005-02(DRS); 265/93005-02(DRS)).
2.4.3
HPCI Check Valve Disassembly and Testina Procedure
The inspectors determined that the licensee's procedure to disassemble and
test the HPCI system torus suction check valves (QCMMS 2300-1, "HPCI Torus
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Suction Check Valve () (2)-2301-39) Disassembly and Testing - Test Every Third
Refueling Outage, Rev. 0) did not provide guidance to ensure the valves were
seated properly.
Specifically, the acceptance criteria in the procedure was
limited to ensuring smooth operation of the valve from closed to open and back
to closed, and failed to include a method to ensure proper valve seating.
Failure to have procedures that include appropriate quantitative and
qualitative acceptance criteria is considered a violation of 10 CFR 50,-
Appendix B, Criterion V (254/93005-03(DRS); 265/93006-03(DRS)).
2.4.4
fmeroency Operatina Procedure Guidance Associated with Operation
of the HPCI System
The inspectors determined that guidance did not exist in the emergency
operating procedures (DGAs) to manually align the ECCS keep fill system.in the
event that 1) CCST level decreased below that required to maintain adequate
HPCI discharge volume (9.5 feet), or 2) HPCI suction automatically transferred
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from the CCST to the suppression pool. Although a control room alarm existed
to alert the operators of an automatic transfer in HPCI suction from the CCST
to the suppression pool, and the associated alarm response guidance directed
the operator to manually align the ECCS keep fi n system to the HPCI system,
the alignment may not have been performed in a timely manner or at all during
implementation of the emergency operating procedures.
(This is due to the
fact that control room annunciators are not safety related, and during a ; mall
break LOCA event,1) a large number of alarms would be annunciating in the
control room, making it difficult to identify a specific annunciating alarm,
and 2) emergency operating procedure implementation would take precedence over
responding to annunciatorr.)
Lack of guidance in the emergency operating
procedures (DGAs) to ensure the ECCS keep fill system is aligned when
required, to prevent water hammer events in the HPCI system, is considered a
weakness.
3.0
?;1t_ heetiw
The inspectors met with the licensee staff (denoted in Paragraph 1) at the
site on February 11, 1993, for an exit meeting to summarize the purpose,
scope, and findings of the inspection. A verbal summary of the inspection
findings was provided to the licensee at that time.
The inspectors discussed
the likely informational content of the inspection report with regard to
documents or processes reviewed by the inspectors during the inspection.
The
licensee did not identify any such documents or processes as proprietary.
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