IR 05000254/1993012
| ML20044G169 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 05/25/1993 |
| From: | Hiland P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20044G160 | List: |
| References | |
| 50-254-93-12, 50-265-93-12, NUDOCS 9306020112 | |
| Download: ML20044G169 (7) | |
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i U.S. NUCLEAR REGULATORY COMMISSION
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REGION III
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i Repoit Nos. 50-254/93012(DRP); 50-265/93012(DRP)
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Docket Nos. 50-254; 50-265 License Nos. DPR-29; DPR-30 i
Enforcement Action No.93-127
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Licensee:
Commonwealth Edison Company Executive Towers West III 1400 Opus Place, Suite 300 Downers Grove, IL 60515
Facility Name:
Quad Cities Nuclear Power Station, Units 1 and 2 Inspection At: Quad Cities Site, Cordova, Illinois
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L Inspection Conducted:
March 29 through May 11, 1993
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Inspectors:
E. A. Plettner l
S. G. DuPont
D. M. Liao
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Approved By:
O Pat Hiland, Chief Date Reactor Projects Section IB
Inspection Summary
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h Jnspection from March 29 throuch May 11. 1993. (Recort Nos. 50-254/93012(DRP):
50-265/93012(DRP))
Areas Inspected: A special, unannounced safety inspection by the reactor
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engineer, and senior resident inspectors from Big Rock Point Station and i
Braidwood Station. The areas inspected were maintenance and surveillance, engineering and technical support.
Results: Of the two areas inspected, two apparent violations were identified
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in paragraphs 2 and 3.
In the area of maintenance and surveillance, the
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apparent violation regarded the inoperability of the Unit 2 emergency diesel generator (EDG) due to inadequate maintenance performed on the Unit 2 EDG
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cooling water pump. -In the area of engineering and technical support, the i
apparent violation regarded the inoperability of the Unit 1/2 EDG due to a i
design error (associated with the undervoltage rel:ys) that existed since i
original construction.
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9306020112 930525 PDR ADOCK 05000254 l
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DETAILS 1.
Persons Contacted Commonwealth Edison Company (CECO)
R. Bax, Station Manager D. Craddick, Assistant Superintendent - Maintenance D. Gibson, Master Mechanic H. Hentschel, Operations Manager D. Kanakares, Regulatory Assurance, NRC Coordinator M. Jackson, Regulatory Performance C. Moerke, Supervisor Modification Design A. Misak, Regulatory Assurance Supervisor B. Strub, Assistant Superintendent - Operations G. Tietz, Executive Assistant R. Dammann, Technical Staff J. Schrage, Nuclear Licensing Administration U. S. Nuclear Reculatory Commission P. Hiland, Section Chief T. Taylor, Senior Resident Inspector P. Prescott, Resident Inspector E. Plettner, Senior Resident Inspector, Big Rock D. Liao, Reactor Engineer The above attended the exit interview conducted on May 11, 1993.
The inspectors also talked with and interviewed several other licensee employees, including members of the technical and engineering staff; and electrical and mechanical maintenance personnel.
2.
Maintenance and Surveillance Event Descriotion On March 29, 1993, while Unit 2 was on a refueling outage, an operator identified that the oilers on the Unit 2 emergency diesel generator (EDG) cooling water pump were not sufficient in height to lubricate the pump bearings during a routine oil change of the pump bearings. After disassembly of the pump, the as-found condition showed that'the retainers to both the inboard and outboard bearings were completely destroyed. The spacing between the balls to the bearings was irregular.
The balls were permanently damaged. The pump was close to failure, but-had not failed at the time of discovery.
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Insoectors Review The inspectors reviewed training materials, maintenance history on EDG cooling water pumps, and the EDG cooling water pump work request (WR)
procedure; interviewed personnel involved; and inspected the physical condition of the Unit 2 EDG cooling water pump.
The following is a chronology of oiler problems:
July 16.1985 (WR #43381)
Adjusted oiler level to proper height due to a problem keeping oil in the bulb while the Unit 1/2 EDG cooling water pump was running.
January 26. 1988 (WR #62957)
The oil level was found set too high on the Unit 1/2 EDG cooling water pump.
January 26. 1988 (WR #62956)
The oil level was set too high on Unit 1 EDG cooling water pump allowing oil to run out of the pump shaft.
January 30. 1992 (WR #92333)
The Unit 2 EDG cooling water pump overhaul was completed.
The elbows of the oiler piping were installed incorrectly.
February 4. 1993 During the last documented in-service testing (IST) of the Unit 2 EDG cooling water pump, no sign of excess vibration or degradation of the pump was detected.
liarch 20. 1993 (DVR NO. 04-01-93-024)
The outboard pump bearing of IA residual heat removal service water (RHRSW) pump was damaged during surveillance testing due to insufficient lubricant.
The licensee determined the event was due to a shorter than required sightglass which could not supply adequate oil to the bearing.
March 29. 1993 During a lubrication oil change, an operator identified the Unit 2 EDG cooling water pump oiler level was too low to supply lubricant to the pump.
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The Unit 2 EDG cooling water pump was overhauled in January 1992 in
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accordance with WR Q92333. During the overhaul, piping. elbows were i
incorrectly assembled and the critical knife edge of the oiler was set
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at the bottom of the bearing housing. This incorrect configuration of
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the oiler and piping resulted in no lubrication to the pump bearings.
The only oil available for lubrication was the residual oil left from the pump overhaul. This degraded condition of Unit 2 EDG cooling water pump existed from January 1992 until the time of discovery in March
1993.
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Licensee Response
'j The licensee's short term corrective action was to replace the Unit 2 EDG cooling water pump and conduct in-shop training for mechanical
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maintenance personnel.. All safety related pumps in both units were
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verified to have oilers properly installed. The licensee's long term
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corrective action was to mark the side of the new bearing housing to
indicate the proper level of oil for all similar type pumps. The bench j
marking will be accomplished through routine preventive maintenance
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activities.
Insoectors Conclusion i
The correct orientation of the Unit 2 EDG cooling water pump oiler was i
not identified in training materials or work request procedures. Work l
request Q92333, required maintenance personnel to " match-mark" parts
'l prior to and during disassembly of equipment for proper orientation during reassembly. Apparently, maintenance personnel failed to match-i mark the oiler piping which resulted in an incorrect oiler
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configuration. Maintenance personnel also failed to recognize that the
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oil level was adjusted by the knife edge of the oiler not the level i
shown in the oil bulb.
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The Unit 2 EDG cooling water pump is a required support system supplying.
l cooling water to the Unit 2 EDG and Unit 2 emergency core cooling system l
(ECCS) room coolers.
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It was evident, given the amount of damage observed, that the pump was j
degraded to a condition that it would not have performed its intended
function for the time required in the design basis accident. Technical
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Specification (TS) 3.9.E.1 stated that the unit EDG.is required for
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continued reactor operation with allowable limiting condition for
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operation for seven days. The inability to. supply cooling water to Unit 2 EDG constituted an entry into a seven-day limiting condition for operation (LC0) for continued reactor operation of Unit 2.
The licensee-l exceeded the LCO.
This is an apparent Violation (50-265/93012-01(DRP))
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Enoineerino and Technical Support Event Description On April 22, 1993,- while Unit 2 was in a refueling outage and Unit I was
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at 100% power, an operator was performing an undervoltage surveillance t
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test required by the TS on the Unit 1/2 EDG. While performing the test, the Unit 1/2 EDG cooling water pump failed to automatically start. When the Unit 1/2 EDG was selected to Bus 28 (Unit 2 Bus), the anti-pump logic stayed energized which prevented closure of the Unit 1/2 EDG j
cooling pump breaker onto Bus 28.
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Inspectors Review The inspectors reviewed engineering electrical prints, engineering modification packages, and procedures used for surveillance testing and
equipment operation; and interviewed personnel involved with the Unit
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1/2 EDG and the Unit 1/2 EDG cooling water pump. The following is a chronology of the events.
September 26. 1983 (Modification No. M-4-1/2-83-14)
I Appendix R modification process was started.
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May 14. 1985 (Modification No. M-4-1/2-83-14)
l Appendix R installation and testing completed.
l April 24. 1989 (Modification No. M-4-1/2-83-14)
Appendix R modification final close out completed.
March 25. 1992 (Project No. 9048-37)
Modification requested by engineering for undervoltage/ loss of coolant accident signal.
April 8. 1992 (Project No. 9048-37)
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Request to Sargent and Lundy from the Quad Cities Site to review i
the Engineering thange Notice 04-00760E for.the modification.
April 10. 1992 (Project No. 9048-37)
Sargent and Lundy responded to the Quad Cities Site with a letter
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stating that it was acceptable to do the modification. The
modification was being done under the emergency change process.
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Phone approval was given to the plant to start the modification process.
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f April 30. 1992 (Project No. 9048-37)
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Installation was completed and engineering performed the walkdown I
of the system.
l May 2. 1992 (Project No. 9048-37)
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Phone approval was given for the first modification test which was l
unsuccessfully performed.
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Phone approval was given for the second modification test which
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was unsuccessfully performed.
Phone approval was given for the l
third modification test waich was successfully performed.
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April 22. 1993 (Q0S 6500-4)
i Inoperable condition was identified while performing a 4 KV i
i undervoltage Technical Specification surveillance test.
April 27. 1993 (Modification No. M-04-0-93-003A)
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The 1993 modification to correct the 1992 design error was
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completed.
i Licensee Response
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l The licensee's short term corrective action was to modify the circuit on j
April 27, 1993, to ensure the Unit 1/2 EDG would perform its intended i
design function for an Unit 2 design basis accident. The licensee's
long term corrective action is to complete the root cause analysis and l
formulate additional corrective actions as needed.
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t Inspectors Conclusion i
Root cause investigation identified that the problem (a design error.
l involving the undervoltage relays) had existed since original
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construction. Given the design basis accident of a loss of all offsite j
power and a loss of coolant accident for Unit 2, a. simplified sequence
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of the problem is as follows
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When the power loss on Bus 18 (Unit 1) and 28 (Unit 2) was sensed,
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the undervoltage protection circuitry would send a trip signal to the Unit 1/2 EDG cooling water pump supply breakers from Bus 18 l
and Bus 28.
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The circuitry associated with the Unit 1/2 EDG cooling water pump supply breaker from Bus 28 would sense the power loss on Bus 18, l
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undervoltage condition on Bus 28.
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The Unit 1/2 EDG would start and load, to supply power to Bus 28.
l However, the Unit 1/2 EDG cooling water pump would fail to start because of the anti-pump protection circuitry associated with Bus
28. The circuit would prevent the supply breaker from (Bus 28)
closing because of the lock out restart feature.
The licensee had four opportunities since original construction to
discover the design error. The first was during the Appendix R
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modification installed in 1985. The second was Information Notice 88-75 1'
issued September 16, 1988. The third was Information Notice 88-75 Supplement 1 issued April 17, 1989. The fourth was during the
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undervoltage/ loss of coolant accident modification installed in 1992.
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integrated tests to ensure the operability of the system for the
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expected operatinnal conditions like the design basis accident for
Unit 2.
In the second and third cases, a review of the Information i
Notice failed to identify the logic problem. The Zion Station (a Commonwealth Edison Company Plant) was identified in Supplement 1 of
Information Notice 88-75 as having an anti-pump logic problem.-
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From construction of the plant in 1971 to April 1993, the Unit 1/2 EDG cooling water pump was unable to perform its intended function during a
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design basis accident for Unit 2.
A design basis accident as defined in the Quad Cities Updated Final Safety Analysis Report Revision 1,1992, is a loss of all normal offsite power and a loss of coolant accident for
Unit 2.
TS 3.9. A.1 stated in part that the reactor shall not be made
critical unless all the following requirements are satisfied: The Unit 1/2 diesel generator shall be operable. TS 3.9.E.1. stated that
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the unit EDG is required for continued reactor operation with allowable
limiting condition for operation for seven days. Without the Unit 1/2 i
EDG cooling water pump the Unit 1/2 EDG would fail as would the unit ECCS room coolers lined up to receive cooling water from the Unit 1/2 i
EDG cooling water pump. This is an apparent Violation (50-265/93012-02(DRP)) of TS 3.9.A.] and TS 3.9.E.1.
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Exit Interview
t The inspectors met with the licensee representatives denoted in l
paragraph I during the inspection period and at the conclusion of the-j inspection on May 11, 1993._ The inspectors summarized the scope and
results of the inspection and discussed the likely content of'this j
inspection report. The licensee acknowledged the information and_did
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not indicate that any of the information disclosed during the inspection
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could be considered proprietary in nature.
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