IR 05000413/1988038
| ML20236A224 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 02/25/1989 |
| From: | Lesser M, William Orders, Shymlick M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML20236A214 | List: |
| References | |
| 50-413-88-38, 50-414-88-38, GL-88-17, IEB-85-003, IEB-85-3, IEIN-87-062, IEIN-87-62, NUDOCS 8903160500 | |
| Preceding documents: |
|
| Download: ML20236A224 (23) | |
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION
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,/p REGION 11
,,.j 101 MARIETTA STRE ET, N.W.
e ATLANTA,CEORGIA 30323
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Report Nos. 50-413/88-38 and 50-414/88-38
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Licensee: Duke Power Company 422 South Church Street
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Charlotte, N.C.
28242 Docket Nos.:
50-413 and 50-414 License Nos.: NPF-35 and NPF-52 Facility Name: Catawba 1 and 2 Inspection Conducted:
November 27, 1988 - February 4, 1989 Inspector:M
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'h. T. Orders
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Inspector:
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'M. 5.1. Esser
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/Date/ Signed Approved by:
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7#4% @ 887 M. B. Shymlocl% Section Chief Date4igned Projects Branch 3 Division of Reactor Projects
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SUMMARY Scope:
This routine, resident inspection was conducted in the areas of review of plant operations; surveillance testing; maintenance observation; review of. licensee nonroutine event reports;. followup of previously identified items; and procedures review.
Results: One strength was identified with respect to the licensee's efforts to reduce the number of control room annunciators in alarm during normal operations, paragraph 3e.
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One weakness was identified in the area of overall maintenance and operation of the Control Room Area Ventilation system in that the licensee's incomplete understanding of and minimal maintenance on the system chillers has resulted in a recent history cf failures, paragraph Sc.
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One apparent violation is being considered for escalated enforcement concerning the inoperability of both trains of the Containment Air Return System on unit two due to incorrectly terminated electrical leads, paragraph 10.
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Within'the areas inspected, the following violations were identified:
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Inadequate measures to ensure cleanliness of VX. fan pit drains
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causing a potential inoperability of the. fans due~ to flooding : from containment spray, paragraph 3b.
Failure to' perform a safety evaluation required by 10CFR50.59 prior
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to removing 1RN244 from service, paragraph Sc.
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Failure to obtain permanent approval of a.. temporary charige,
paragraph 9.
Inoperable Auxiliary Building Ventilation train in excess of the
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-allowed action statement time (licensee identified), paragraph 6b.
Failure' to sample waste gas tank after an addition (licensee
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identified), paragraph 6b.
The following unresolved items were identified:
Gravity drain of FWST to refuel cavity, paragraph'3b.
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Turbine driven CA pump pressure seal failure, paragraph 4c.
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Valve stroke program inadequacies, limit to. limit testing,
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paragraph 4d.
Operational and maintenance problems with VC/YC, Sc.
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Valve 1 NF-233. testing method, paragraph 7.
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Post modification testing of VX dampers, paragraph 10.
Design engineering operability determination of VX, paragraph 10.
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REPORT DETAILS 1.
Persons Contacted Licensee Employees
- H. Barron, Operations Superintendent r
- W. Beaver, Performance _ Engineer
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R. Charest, Station Chemistry Supervisor T. Crawford, Integrated Scheduling -Superintendent W. Deal, Health Physics Supervisor
- J. Forbes, Technical Services Superintendent
- R. Glover, Compliance Engineer
- T. Harrall, Design Engineering R. Jones, Maintenance Services Engineer F. Mack, Project Services Engineer W. McCollough, Mechanical Maintenance Supervisor
- W. McCollum, Maintenance Superintendent
- T. Owen, Station Manager.
- J. Stackley, Instrumentation and Electrical Engineer D. Tower, Shift Operating Engineer R. Wardell,, Station Services Superintendent Other licensee employees contacted included technicians, operators,.
mechanics, security force members, and office personnel.
NRC Resident Inspectors
- W. Orders
- M.
Lesser
- Attended exit interview.
2.
Unresolved Items An Unresolved Item is a matter about which more information is required to determine whether it is acceptable or may involve a violation. There were 7 unresolved items identified in this report.
3.
Plant Operations Review (71707 and 71710)
a.
The inspectors reviewed plant operations throughout the reporting period to verify conformance with regulatory requirements, Technical Specifications (TS), and administrative controls. Control room logs, danger tag logs, Technical Specification Action Item Log, and the removal and restoration log were routinely reviewed. Shift turnovers were observed to verify that they were conducted in accordance with approved procedures.
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l The inspectors verified by observation and interviews, that' the measures taken to assure physical protection of the_ facility met
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current requirements. Areas inspected included the' security.
organization, the establishment and maintenance of gates, doors, and isolation zones in the proper conditions, and that access control and badging were proper and procedures followed.
One security related problem was identified.during the report period. At approximately 11:00 a.m. on Wednesday January 11, 1989, thefresident inspector-witnessed an unescorted visitor on the second floor of the "high rise" administration building. The resident followed the visitor to
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make sure she returned to the control of her escort. 'The matter was discussed with. licensee management and has been turned over to the-Region II Security Section for resolution.
In addition to the areas discussed above, the areas toured were observed for fire prevention and protection activities.. These included such things as combustible material control, fire protection
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systems and materials, and fire protection associated with maintenance. activities. The inspectors reviewed Problem Investigation Reports to determine if the licensee was appropriately documenting problems and implement 1,g corrective actions.
b.
Unit 1 Summary Catawba Unit 1 began the report period in Mode 5 having shut down.on November 24 to begin the cycle 3 (E0C-3) refueling outage.
The outage was scheduled to be 62 days in duration, but at the end of the report period, the unit was in Mode 4, approximately 5-7 days behind schedule.
Major activities accomplished during the outage included:
- Main turbine work
- S/G eddy current testing and plugging
- Refueling j
- S/G U-Bend Heat Treatment
- Retubing of 1B Component Cooling System (KC) heat exchanger
- Ice condenser work j
- MOVATS testing 40 valves The outage was nearly on schedule until the last few days when the retubed KC heat exchanger was found to be leaking and the turbine driven auxiliary feedwater pump seized when run for a performance test in preparation for unit startup.
These two issues will be discussed in detail in inspection report 413,414/89-05.
Catawba Unit 1 was the first Duke plant to implement enhancements requested in Generic Letter (GL) 88-17 " Loss of Decay Heat Removal" which was issued on October 17, 1988. These actions are designed to aid in correcting deficiencies in procedures, hardware and training related to loss of decay heat removal. Review of the implementation
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of these enhancements, and.a' review of' licensee's initial response to GL 88-17 revealed no apparent problems.
On January 6 Unit I experienced a loss of power on. Train A.
The unit was in Mode 5 and in the process of a Reactor Coolant (NC) System fill and vent. Train A Residual Heat Removal (ND) pump was'in service a
removing core decay heat.
Non-essential 6 9kV switchgear ITC was being powered through a normally open tie breaker ITC/7. When the IC Reactor Coolant-(NC) Pump was started, an overcurrent relay caused
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the tie breaker to trip after about 20 seconds. This resulted in a j
loss of power to 4.16kV essential switchgear 1 ETA and thus the loss I
of' the operating.ND pump.
The train A diesel generator had been
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removed from service, therefore, switchgear 1 ETA' could not be immediately re-energized.. Operators were, however, able to start the
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Train B ND pump. Although no heatup of the NC system. occurred, one pressurizer power operated relief valve which was aligned for cold overpressure protection opened several times due to the NC pump start transient. The licensee later determined that an incorrect circuit card had been installed in the non-safety related overcurrent relay which resulted in a reduced time delay overcurrent trip setting. The licensee was unable to determine when the installation occurred.
It should also be noted that the licensee's testing method for non-safety related relays did not detect the error. '
j On January 7, at approximately 4:00 p.m.
it was determined that the deep end of.the refueling canal had been overfilled allowing water to
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flow around the vertical missile shields to the reactor vessel.
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Water was approximately one inch deep at the vessel flange and flowed through the temporary nozzle covers and cavity seal to lower
containment. Water level was subsequently lowered in the deep end of the canal and the vessel. flange area was flushed with demineralized
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water. The cavity was cleaned / decontaminated and a visual inspection
of the vessel flange area showed areas of rust and slight traces of l
boron on five studs.
These areas were recleaned.
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Discussions with operations personnel indicated that the incident may have been caused by inadequate procedural guidance.
Procedure OP/1/A/6200/13 which controls the filling, draining and purification of the refueling cavity does not appear to adequately take into consideration the possibility of having the Refueling Water Storage Tank (FWST) in the purification mode. This in turn led the operators to overlook the fact that refueling water system valve FW-23 was open. This valve is a bypass around the Refueling Water System (FW)
pump and. provided a gravity drain flowpath from the FWST to the refueling cavity.
The review of this event is incomplete. An analysis of the interface between all applicable procedures in force at the time of the event, and an evaluation of the safety significance of the equipment which was wet by the event will be completed and documented in inspection report 413,414/89-05. Pending completion of that review, J.!: 4: sue l
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will remain an Unresolved Item (413/88-38-01): Gravity Drain of FWST j
To Refueling Cavity.
On January 26 the inspectors toured Unit i upper containment after the unit entered mode 3.
The inspectors observed excessive debris in j
the area of the Containment Air Return Fan (VX) pit drain. The drain
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is protected by a metal plate slightly raised and' supported above the i
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drain. Debris was allowed to accumulate under this plate.
If this drain were clogged there is a potential for flooding.the VX fans with containment spray af ter a LOCA thus rendering them inoperable.
The licensee declared both trains of VX inoperable after being informed by the inspectors and entered TS 3.0.3 until the VX fan pit drain L
could be cleaned.
The licensee also inspected and cleaned the fan pit drain of Unit 2.
The inspectors determined from discussions with licensee personnel that the quantity of debris removed from the Unit I drain would not have resulted in equipment inoperability.
Concerns remained, however, that the debris tas not discovered during the licensee's containment cleanliness inspections prior to entering
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mode 4 nor were measures in effect to remove the drain covers and
inspect / clean the area.
Due to the configuration of this drain, removal of the plate is essential in order to perform an adequate inspection. Station Directive 3.11.1, " Housekeeping and Cleanliness Levels in Safety and Non Safety Related Areas", defines the reactor building, including the VX pit area, as requiring Level IV clean-liness.
The station directive further specifies that Level IV cleanliness shall be obtained by removal of all dirt and debris from-the area.
Existing measures were apparently inadequate to meet this requirement.
This is identified as violation (413/88-38-02):
Inadequate Measures to Ensure Cleanliness Requirements for VX Fan Pit Drain, c.
Unit 2 Summary Unit 2 started the reporting period operating at about 98% power.
Continued problems with partial obstruction of the feedwater flow orifice and/or cages on the feedwater regulating valve to Steam Generator 2C forced the unit to reduce power to 94%. On January 12 the unit tripped from 94% power on low low SG 1evel when 2CF-55, Feedwater Regulating Valve to SG "D", failed shut. The cause was a blown fuse in the actuator's circuit (see paragraph 7). The reactor was restarted on January 13 and power escalated to 94%.
On January 21, the reactor was manually tripped from 23% after a turbine runback from 94%.
The failure of 4 stator cooling water heat exchanger discharge thermocouple caused the heat exchanger bypass l
valve to open and stator cooling water to overheat. This resulted in a loss of stator cooling water.
Subsequent to the runback both
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operating feedwater pumps were lost and the operators were forced to trip the reactor. The unit was restarted on January 22 and ended the period at power operation.
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d.
Operator Medical Records The inspector sampled medical records of licensed operators and compared them to the licensee's certification as documented on a copy of NRC Form 396.
The inspector verified that the guidelines of ANSI /ANS 3.4-1983 were. being followed. The following docket numbers were inspected:
55-20254 55-20258 55-20448 55-20637 55-20640
The licensee's copy of NRC Form 396 for docket number 55-20258 was inaccurate in that the block " corrective lenses be worn when performing licensed duties" was not checked. The inspector verified that the copy forwarded to the NRC had been previously corrected.
The licensee stated they would correct their copy of NRC Form 396.
e.
Control Room Annunciators The licensee has initiated a program to reduce the number of annunciators that remain in an alarm condition in the control room.
The effort was started during the past summer with focus on Unit 1 and a goal for-the unit to achieve a " dark board" by the start of its refueling outage which began November 23.
The licensee was unable to reach their goal on Unit 1 and shifted emphasis towards-Unit 2.
Although a " dark board" has not yet been obtained - the inspectors consider licensee efforts to be effective and the
I licensee's program is considered a strength.
One violation was identified in paragraph 3b.
4.
Surveillance Observation (61726)
a.
During the inspection period, the inspector verified plant operations were in compliance with various TS requirements.
Typical of these requirements were confirmation of compliance with the TS for reactor coolant chemistry, refueling water tank, emergency power sy stems,
i safety injection, emergency safeguards systems, control room I
ventilation, and direct current electrical power sources.
The inspector verified that surveillance testing was performed in accordance with the approved written procedures, test instrumentation was calibrated, limiting conditions for operation were met, appropriate removal and restoration of the affected equipment was accomplished, test results met acceptance criteria and were reviewed by personnel other than the individual directing the test, and that
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any deficiencies identified during the testing were properly reviewed and resolved by appropriate management personnel.
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b.
The inspectors witnessed or reviewed the following surveillance:
PT/1/A/4200/02 Containment Closure IP/1/A/3620/01 1B Load Sequencer Timer Calibration
4358 SWR Quarterly Channel Calibration of j
Containment H2 Analyzer.
j PT/1/A/4200/06A Boration Flow Path Verification j
PT/1/A/4550/01C Refueling Communir tion fest
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PT/1/A/4600/19E Pre Mode 5 Survei.iance Items I
PT/1/A/4150/30 NC PORV and Block Valve Stroke Test IP/0/A/3710/21 D/G Battery Service Test IP/1/A/3200/03 Reactor Protection / ESF Time Response c.
. Turbine Driven Auxiliary Feedwater Pump On January 27, the licensee, to verify operability, attempted to start the turbine driven auxiliary feedwater pump (CAPT) on Unit 1 i
for the first time since the refueling outage. The unit had entered mode 3 at 2:41 a.m.
on January 26 and was in a 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> action statement per TS 3.7.1.2 until the CAPT could be tested. Operators stopped the pump when the turbine. reached 2000 rpm with no
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corresponding indicated flow.
A second start resulted in pump
seizure. After operators vented a large amount of gas from the' pump,
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the casing was removed and the impellar was inspected.
Results of the inspection indicated that the interstage pressure seal had seized.
The inspectors were concerned with the quality of system fill and vent.
Tagout Record 18-2411 was performed on January 16-which included a venting restoration ' sheet used to identify and sequence vents to be operated during the fill. The process appeared to be adequate. Portions of the system were, however, drained again on January 18 to perform a leak rate test of CAPT suction check valve ICA-8 using PT/1/A/4200/55.
The inspectors reviewed this procedure'
and determined that the system restoration, performed later that day, failed to vent the piping after filling it.
Specifically high point vents ICA-141 and ICA-195 were closed in steps 12.20.2 and 12.20.9 prior to the line being filled in step 12.20.10.
The inspectors requested the licensee to determine if the vents were operated under any.other mechanism prior to running the pump.
The licensee init4ated an investigation to include a metallurgical determination of the failure.
The licensee has indicated a concern over the possibility of hydrogen embrittlement of the pressure seal during the manufacturing process.
This is identified as Unresolved Item
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(413/88-38-03):
Turbine Driven CA Pump Pressure Seal Failure,
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pending licensee determination of adequacy of system venting and
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failure mode.
d.
Valve Stroke Timing
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i The licensee's valve stroke test program was reviewed in order to
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assess their current practice of testing motor operated valve stroke
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times from limit switch to limit switch.
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L The licensee requested 'and was granted relief from measuring full j
stroke time of these. valves.
The licensee's contention is. as i
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" Catawba's Operator Aid Computer Response Time Testing Program measures response time between limit switch actuations, rather than from the initiation of the actuating signal.
The only way to time the valve using the actuating signal as the initiating point is through the use of some manual means, such as a stop watch.
More consistent and repeatable results can be obtained by timing the valve from limit switch to limit switch."
In reality, the computer can be initiated by a test switch,
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coincident with the initiation signal for the valve thus timing the i
entire stroke.
More to the point however are the. apparent h
shortcomings of the current methodology.
First, when a valve is timed from limit switch to limit switch " full"
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stroke time is not measured as is required by 10CFR50.55 a(g).
Realistically, only 90 to 95% of valve stroke is measured.
Further, this method does not account for the time between initiation of the
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actuating signal and the start of valve motion.
Finally, the
licensee has in place, per procedure IP-0-A-3820-04, " Operating-
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Checkout of Limitorque and Rotorque Valve Actuators", a mechanism
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through which the OPEN limit switch can be adjusted to 95% of full stroke on motor operated gate / butterfly valves which do ' not meet
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response time requirements.
In essence, this shortens the stroke.
Identified on enclosure 11.5 of that procedure are 20 valves which have required the OPEN limit switch setting to be adjusted in order to meet response time requirements.
This matter will be. forwarded to NRR for review, and will remain
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Unresolved pending completion of that review and pending further NRC l
review of justification for adjustment of limit switches during maintenance / testing (413/88-38-04).
Valve Stroke Program Inadequacies.
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No violations or deviations were identified.
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Maintenance.0 observations (62703)
a.
Station maintenance activities of selected systems and components were observed / reviewed to ascertain that they were conducted in accordance with the requirements.
The inspector verified licensee conformance to the requirements in the following areas of inspection:
the activities were accomplished using approved procedures, and j
functional testing and/or calibrations were performed prior to returning components or systems to service; quality control records
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personnel; and materials used were properly certified. Work requests l
were reviewed to determine status of outstanding jobs and to assure that priority was. assigned to safety-related equipment maintenance which could effect system performance.
b.
The inspectors witnessed or reviewed the following maintenance activities:
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3085MNT 1B Diesel Piston Rod Assembly.
421740PS Repair 2A Delta T Channel PT/1/A/4400/01 ECCS Flow Balance Retest 284780PS Replace Mechanical Seal on 2A1 Component Cooling Pump c.
Control Room Ventilation System On November 30, 1988 during Train
"B" ESF testing the associated Control Room Ventilation (VC/YC) chiller failed to properly start due to low oil level. Operations personnel monitor the oil level daily.
The inspectors determined that on November 7, 1988 operations personnel had noted the level to be low. Work Request 41958 was written to add oil but was later cancelled due to an apparent misunderstanding between Maintenance Engineering Services (MES) and
operations personnel.
MES is aware of the phenomenon where at low i
loads, oil is carried over from the sump with the refrigerant and collects in the evaporator.
In some cases, therefore, MES does not desire to add oil to the chiller, but reclaims the oil from the evaporator.
For this reason the work request to add oil was cancelled.
The chiller was then operated routinely from
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November 15-20 and again on November 28 with no apparent problems
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until the failure on November 30.
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On January 11, 1989 further problems with the chiller occurred.
Train "A" chiller had been removed from service.
Train "B" chiller had apparently been overfilled with oil.
Maintenance technicians were in the process of attempting to reclaim the oil under the misconception that the level was low. Another misunderstanding had taken place and level was actually high.
During the reclaiming process sump level was allowed to become too high and the chiller tripped.
The licensee entered TS 3.0.3 twice as a similar trip occurred a few hours later, j
The licensee was also forced to enter TS 3.0.3 on October 25, 1988, when the only operable chiller tripped on high bearing lube oil temperature.
These events appear to be indicative of underlying, programmatic problems associated with the operation and maintenance of the system.
The inspectors reviewed the chiller preventive maintenance program and found it to be lacking with respect to many of the manufacturer's recommended maintenance items.
The licensee
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has not developed standing work requests (SWR) on the following. items
as suggested in CNM 1211.00-0345, " Operating Instructions for Carrier
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. Centrifugal Refrigeration Machines":
- change refrigerant filter
- change oil and filter l
- inspect refrigerant float system
- calibrate safety controls
- inspect economizer damper The licensee also lacks many wiring diagrams depicting electrical connections of components on the chillers such as the hot gas bypass valve and the safety relays.
The inspectors expressed concern in this area and were told t' hat SWRs are being. developed and assistance from the vendor is being requested to in: prove maintenance on the chillers.
A station problem report had been generated to develop a.
wiring diagram for the hot gas bypass valve but not for relays or other components.
On January 26 during a routine plant tour, the inspectors observed that the valve actuator had been removed for 1RN-244 (automatic flow control valve for condenser cooling to Train "A" VC/YC Chiller). The valve was fully open. The chiller had been idle since January 19 and was considered operable by the licensee.
Section 9.2.1.2.3 of the FSAR states that these control valves are aligned to the Class 1E emergency diesel generators from either unit and are designed to
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ensure continued operation, maintaining control room area-habitability by controlling chiller condenser head pressure af ter a loss of offsite power, LOCA, ~ and earthquake.
The inspectors voiced concern to the licensee with respect to the operability of. the chiller in that 1RN-244 would be unable to perform its intended safety function of modulating to control condenser pressure. With condenser pressure too low, the chiller is susceptible to trip on low chill water or refrigerant temperature after an ESF actuation.
Contributing to the concern was the seasonally related low heat sink temperature of approximately 50 degrees.
The inspectors determined that the actuator had failed on December 18, 1988 and was removed on January 20, 1989 for maintenance under work request 29788 OPS.
Problem Investigation Report (PIR) 0-C89-0046 was generated in response to NRC concerns to address the operability of the chiller.
On January 30, Design Engineering (DE) evaluated the use of 1RN-244 or its bypass valve in a non modulating mode and stated the chiller was operable.
However, DE cautioned that there was a potential for the chiller to trip on evaporator low chilled water temperature or evaporator low refrigerant temperature.
DE further stated that if the hot gas bypass valve (1YC-362) was not open a trip could occur due to refrigerant build up in the condenser and subsequent low refrigerant temperature. (The funtion of the hot gas bypass valve is to allow high pressure refrigerant gas to bypass the condenser to prevent surging at low refrigerant temperatures). It should be noted
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'that the licensee..had also obtained information from the vendor indicating toat the chiller might not start after being idle for a few days due to the this build up. DE had assumed the hot gas bypass-
' valve was being maintained open, however, it had not been opened on -
the idle chiller and had not been functioning properly since December
19. The station had not previously. considered the possibility of the
L chiller malfunctioning in these various manners.
Based on' this information and associated documentation, the inspectors concluded
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that the. licensee failed to perform a safety evaluation as required by 10CFR50.59 to evaluate for the increased probability of occurrence of a malfunction to the chiller prior to removing 1RN-244 from service.
This is identified as a violation (413,414/88-38-05):
Failure to Perform A Safety Evaluation Required by 10CFR50.59 Prior to Removing 1RN-244 From Service.
On January. 31 the inspectors again became concerned with the.
operability of Train "A" chiller when they observed that the chiller was operating with the hot gas bypass valve' closed.
The condition was discussed with the MES system expert who was also concerned that the excess condenser cooling water flow coupled with the closed hot gas bypass valve was causing condenser pressure to. be.' too low (pressure was approximately 70 psig, the normal pressure band is.
l 95-120 psig).
Refrigerant was collecting in the condenser and the machine was more susceptible to tripping on low refrigerant'
temperature.
Apparently the station had elected to reject the
caution by. DE to maintain the hot gas bypass valve open. At this point the station consulted with DE and decided to open the valve.
The inspectors questioned whether Train "A" VC/YC Chiller had in fact i
been inoperable and unable to perform its intended safety function i
during the period of December 18, 1988 to January 31, 1989 considering the aforementioned inoperable components 'and the increased potential for failure to start or trip after starting.
Design Engineering was also concerned with the increased potential to trip but concluded that the chiller was, and had been operable based upon a single successful start which had occured during the time in question.
The inspectors question the basis for the operability
conclusion in that the single successful start may have been
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fortuitous, the conclusion did not consider worst case conditions, and did not appear to be indicative of the system's ability to perform it's intended safety function.
Moreover, the ultimate l
conclusion appears to contradict previous determinations.
These
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questions remain unresolved pending further investigation.
l The licensee's recent history of operational and maintenance problems on the chillers is considered a weakness and is identified as Unresolved Item (413/88-38-06): Operational and Maintenance Problems i
Associated With VC/YC Chillers, pending programmatic improvements by I
the licensee and further review by NRC.
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The licensee recognizes and discussed these general concerns with the l
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inspectors ;in a meeting on February 3 and intends to implement
changes to improve in this area.
The changes are to include
i reassignment of resources, increased attention to preventive maintenance, an increased sensitivity towards operability issues and l
increased assistance from the vendor. Progress in this area will be
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followed under the above mentioned unresolved item.
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One violation was identified in paragraph Sc.
6.
Review of Licensee Non Routine Event Reports (92700)
a.
The below listed Licensee Event Reports.- (LER) were reviewed to determine if the information provided met NRC requirements.
The determination included: adequacy of description, verification of compliance with Technical Specifications and regulatory requirements, corrective action taken, existence of potential generic problems, reporting requirements satisfied, and the relative safety significance of each event.
Additional inplant reviews and discussion with plant personnel, as appropriate, were conducted for those reports indicated by an (*).
The following LERs are closed:
- 413/88-24 Additions Made to Waste Gas Storage Tank Without Technical Specification Required Analysis Due to Management and Procedural Deficiencies
- 413/88-25 Inoperability of Auxiliary Building Ventilation System Train Due to Personnel Errors and Design Deficiencies 414/88-07 Actuation of Auxiliary Feedwater System Due to Loss of Main Feedwater Pump Turbine Condenser Vacuum 414/88-29 Containment Valve Injection Water System
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Inoperable Due to Procedural Deficiency and i
Management Error i
- 414/88-30 Inoperability of All Power Range Channels Due to Inadequate Procedure b.
The licensee reported in LER 413/88-24 an event where a waste gas decay tank was not sampled after an addition in violation of Technical Specification (TS) 4.11.2.6.
The inspectors reviewed corrective action as documented in the LER. This violation meets the criteria specified in Section V of the NRC Enforcement Policy for not issuing a Notice of Violation and is not cited. This is documented as Licensee Identified Violation (LIV 413/88-38-07):
Failure to i
Sample Waste Gas Tank After An Addition.
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The licensee reported in LER 413/88-25 an event where Train 1A of the Auxiliary Building Ventilation (VA) System was inoperable in excess of the allowed action statement of TS 3.7.7.
The licensee determined the inoperability on November 15 after the tailure of a surveillance test.
The licensee determined however that the train should have been declared inoperable on November 6 af ter cracks were discovered in some duct work.
The inspectors reviewed corrective action as documented in the LER.
This violation meets the criteria specified in Section V of the NRC Enforcement Policy for not issuing a Notice
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of Violation and is not cited.
This is documented as Licensee l
Identified Violation (LIV 413/88-38-08):
Inoperable VA System In
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Excess of the Allowed Action Statement Time.
l Two licensee identified violations were identified in paragraph 6b.
7.
Follow-up on Previous Inspection Findings (92702)
(Closed)
Violation 414/88-15-07:
Failure to Follow TS for Pressurizer Safety Valve Position Indication: The licensee provided a response to the violation in correspondence dated June 6,1988. The inspector reviewed Station Direction 3.1.14 which now requires approval of compensatory measures by the Operations Superintendent, Station Manager or Duty Station Manager.
Based on this the item is closed.
(Closed) Violation 414/88-18-04:
Failure to Retest Valve 2BB-61B after maintenance.
The licensee responded to the violation in correspondence dated July 15, 1988. The licensee stated that an evaluation of program enhancements was being conducted including the need for a station retest manual.
In correspondence dated November 16, 1988 in response to a different violation, the licensee committed to the NRC to have a retest manual issued by June 1, 1990. Based upon these actions and followup to other items this violation is considered closed.
(Closed)
Unresolved Item 413,414/87-05-02:
Potentially Inadequately Sized Valve Actuators.
The licensee reviewed valve stroke time design calculations for motor operated containment isolation valves to determine adequacy of actuator size. The results of the review were documented in a letter dated December 8,1988 from D. L. Rehn and D. L. Ward of Design Engineering to T. B. Owen. The review assumed worse case conditions such as the valve being back seated and reduced synchronous motor speed.
Six valves were identified which theoretically would exceed Technical Specification Stroke Time limits of 10 seconds:
1 & 2 NF-233, 1 & 2 BB-8, and 1 & 2 NC-56.
The inspector reviewed data from all tests done in 1988 on each valve to determine the actual performance.
The values of stroke times were as follows:
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i IBB-8 7.1 - 7.8 sec j
2BB-8 6.2 - 7.0 sec
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1NC-56 7.6 - 8.8 see i
2NC-56 8.0 - 8.4 sec
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1NF-233 8.3 - 10.0 sec 2NF-233 7.6 - 7.8 sec
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The inspector was concerned with valve INF-233, Glycol Return Containment Isolation Valve, which had a stroke time of 10.0 seconds when tested on
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November 30, 1988. The inspector determined that when the valve is timed
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from limit switch to limit switch, results have been typically about 8.3
seconds. When timed from initiation of the actuating signal to the closed
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limit switch, as was done on November 30, 1988, the result was 10 seconds.
The licensee committed to revise the method of timing INF-233 to time it from initiation of the actuating signal to the closed limit switch in order to ensure operability.
The licensee recently tested the valve in l
this manner and obtained a stroke time of 9.4 seconds. The licensee also t
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decided to conduct a review of test data to identify any valves which also have large differences in timing using the two methods and to adjust their testing program accordingly.
Based upon this the unresolved item is closed and an inspector followup item is opened,(IFI 413/88-38-09):
Revision of 1NF-233 Testing Method and Licensee Review of Stroke Time Test Data Pending Completion of the Licensee's Review.
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Inspector Followup Item 413,414/87-36-02: Long Term Corrective i
Action for Post Modification and Post Maintenance Testing.
The licensee l
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has enhanced installation of modifications by writing implementation procedures which outline isolation boundaries and their effects, a work sequence, and a retest and/or functional verification description.
l Retests conducted by the Performance Engineering Group are intended to overlap the isolation points to assure operability.
The licensee's response to violation 413,414/88-33-01 dated November 16, 1988 committed to the NRC that a Retest Manual will be issued by June 1,1990. The manual will consolidate all requirements for retesting plant equipment following maintenance or modifications.
Based upon the licensee's corrective actions taken to date and continued followup of the above mentioned violation this item is closed.
(Closed)
Inspector Followup Item 414/88-30-01:
TS Interpretation of i
Containment Isolation Valves.
The licensee provided additional guidance for inoperable safety related power operated valves and methods to comply with the action statements of TS 3.6.3.
The guidance is included in enclosure 2 of Station Di rective 3.1.14, " Operability Determination".
Based on this the item is closed.
(Closed) Inspector Followup Item 414/88-35-02: Applicability of Equation 2.2-1 to PRNI Errors Incurred by Power Changes. The inspector completed l
discussions with T. G. Dunning of NRC:NRR concerning the use of equation 2.2-1 in Technical Specifications for determining nuclear instrument
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operability during power changes. The use of equation 2.2-1 is acceptable i
although it was initially intended for use during instrument calibration
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e checks..The licensee will use the equation for power changes until an equivalent analysis'may be justified for use. Followup of the licensee's.
. actions will continue under Violation 414/88-35-01 and this item is closed.
(0 pen) - Unresolved Item ' 413/86-27-01, 414/86-30-0:
Followup of Analysis of Bussman Type FNA Fuses for Reliability.
On January 12,1989 Unit 2 tripped from 94'4 power on Steam Generator Low Low Level after the feedwater regulating valve -(2CF-55) to "0" Steam Generator failed shut.
The cause was determined to be a loss of electrical power to a non-safety related solenoid valve which vented the air actuator allowing. 2CF-55 to fail shut.
A 2 amp FNA-2 Bussman fuse was determined to have failed mechanically causing the loss of power.
The licensee has experienced previous mechanical failures of these fuses and the inspectors have been following licensee actions under Unresolved Item 413/86-27-01, 414/86-30-01. ' Based on previous failures of these fuses the licensee committed in a l Confirmation : of Action letter dated July 3, 1986 to replace, modify or perform visual surveillance on Bussman FNA safety related fuses.
The licensee's experience was also used to generate Information Notice 87-62 on the issue.
The licensee completed the replacement of affected fuses-located in mild environments with Little Fuse FLQs, however, those located in harsh environments needed to be environmentally qualified.
The qualification ' testing was completed in November 1988. At the time of the trip on January 12, harsh environment fuse replacement had not commenced nor had the replacement of non-safety related fuses been addressed.
The licensee has appraised the inspectors of 6 mechanical failures discovered during the weekly fuse surveillance over a period of approximately 2 and 1/2 years.
Af ter. the recent trip, however, the insper: tors became aware of over 70 mechanically failed FNA fuses discovered as a result of maintenance work requests on both safety and non safety equipment.
The licensee has decided to accelerate and upgrade the implementation of the Little Fuse FLQ according to the following plan:
Unit 2 safety related fuses will be replaced during the refueling outage in March, followed by replacement of Unit i fuses. Non-safety related fuses will be identified and replaced afterwards.
This item remains open pending NRC review of licensee actions to replace the fuses.
No violations or deviations were identified.
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8.
Follow-up On NRC Bulletins (92721)
As requested by Action Item e. of Bulletin 85-03, " Motor-0perated Valve Common Mode Failures During Plant Transients Due to Improper Switch Settings", the licensee identified the required safety-related valves, the valves' maximum differential pressures and a progaram to assure valve operability in their letters dated May 16, 1986, November 20, 1986, and February 18, 1987.
Review of these responses indicated the need for
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additional information' which' was requested' in NRC Region 'II. letter dated March 23, 1988.
Review of the licensee's April 22, 1988, response to the request for
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additional information idicates that the licensee's selection of the -
applicable safety-related valves to be addressed and the valves' maximum differential pressures meets the requirements of the bulletin and that the
. program to assure valve operability requested by Action Item e.
of the~
bulletin is now acceptable, with the exception of providing justification in cases where. testing with maximum differential pressure cannot practicably be-performed.
Differential ' pressure testing of valves to demonstrate operability for Catawba was discussed in Inspection Report Nos. 50-413/88-05 and 50-414/88-05.
The results of the' inspections to verify proper implementation of this program and the review of the final response required by Action Item f. of the bulletin will be addressed in additional inspection reports.
9.
Plant Procedures (42700)
The inspector reviewed the licensee's program for implementing temporary changes to procedures. Guidance procedures and a sampling of temporary changes were reviewed to ensure the requirements of Technical Specification 6.8.3 were being met.
The licensee allows temporary approval of changes. by a qualified reviewer and an SRO licensed-individual, Final approval must be made by a Superintendent within seven days as required by Station Directive (SD) 4.2.1, " Development, Use and Approval of Station Procedures".
The inspector was concerned that the directive lacked guidance with respect to the use of temporary approvals and assurance that the intent of the procedure is not altered. A change in intent may be taken to mean a change to what is accomplished by the basic procedure or a change to the method by which it is accomplished in a manner which has safety significance.
The licensee agreed to revise SD 4.2.1 to provide additional guidance in this area.
The inspector also reviewed Operations Management Procedure (OMP) 1-4,"Use of Procedures," where authority is given to the Shift Supervisor to deviate from a procedure under abnormal or emergency conditions provided the intent is clearly not changed. The inspector pointed out that TS 6.8.3 requires these changes to be documented, reviewed and approved by a Superintendent within 14 days, and that OMP 1-4 had no such requirement.
The licensee agreed with the inspector's observation and will revise the procedure. This is identified as Inspector Followup Item (413/88-38-10):
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Additional Guidance For Temporary Changes Pending Revisions to SD 4.2.1 l
and OMP 1-4.
l The inspector reviewed selected temporary approvals to changes and concluded that the licensee is meeting the requirements of TS 6.8.3.
The inspector identified, however, that temporary change
to IP/1/A/3222/158, " Calibration Procedure for Reactor Coolant Flow Channel II", was not properly approved within the seven day requirement of SD L_'_
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The licensee initiated corrective action which included obtaining approval and methods to prevent recurrence. This item is an isolated case with minor regulatory concern and is identified as a violation (413/88-38-11):
Failure to Obtain Permanent Approval of a Temporary Change. This violation meets the criteria specified in Section V of the NRC Enforcement Policy for not issuing a Notice of Violation and is not cited.
The inspector also reviewed the general condition of the licensee's operating, maintenance and test procedures.
Some. procedures appeared to have an excessive number of changes which had not been incorporated into a retype and readability was difficult. Specific examples were pointed out to the licensee for correction. It appeared to the inspector that there is an excessive backlog of Instrumentation and Electrical (IAE) procedures needing retypes.
SD 4.2.1 recommends retypes after five changes.
The inspector determined that over 160 IAE procedures had five or more changes not incorporated into the typed version. Although the licensee is in the process of retyping some of these and most are useable, many of the examples had over 20 changes not incorporated.
The inspector discussed these concerns with the licensee. The licensee agreed that the backlog is too high'and is developing a plan to reduce it within 12 months. This is identified as Inspector Followup Item (413/S8-38-12):
Excessive Backlog of IAE Procedures Needing Retype Pending Reduction of the Backlog to a Manageable Size.
One violation was identified.
10. Containment Air Return System Inoperability Event On December 20, 1988, the Resident Inspection Staff was notified (received a copy of the cover sheet for station problem investigation report (PIR)
2-C88-0151) that on March 31, 1988, during the performance of an auxiliary safeguards periodic test, the Unit 2, train A Containment Air Return and Hydrogen Skimmer System (VX) fan damper had failed to open. Train A of VX was declared inoperable and a work request was written to investigate and repair the damper. It was discovered that two wires in the damper control circuit were incorrectly terminated (reversed) which effectively removed the interlocks which open the damper automatically on a safety system actuation.
It was subsequently determined that the manual actuation circuitry of the damper had also been rendered inoperable by the wiring error.
After the wiring error was corrected, a functional test of the damper was performed which consisted of simulating a containment high high pressure signal and observing that the damper opened. It should be noted
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I that damper position is " verified" by observing indicating lights in the l
control room which are not confirmed to indicate actual damper position.
After the functional test was performed, the damper was declared operable
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The licensee hypothesizes that these wires were incorrectly terminated
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during the installation of station modification NSM CN-20223, a
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local panels in the auxiliary building.
This modification was completed by approximately January 3, 1988.
PT/2/A/4450/05A, " Containment Air Return Fan 2A and Hydrogen Skimmer Fan 2A Performance Test", was subsequently conducted to satisfy retest requirements of the modification.
The test was completed on January 24, 1988 and damper response was timed with a stop watch by observing damper indicating lights in the control room.
Computer alarm summa y data however does not indicate that the damper cycled.
Unit 2 operated in all modes while the damper and thus train A of VX, was inoperable. The unit began a routine refueling outage in December 1987 and by the middle of February, 1988 was in the process of start-up. Of pH ma ry concern, however, is the time wnich spans the period between Fat ruary 19, 1988, when the unit entered Mode 4, where the system is required by technical specification, until April 1,1988 when the wiring error was corrected and the system was returned to an operable status.
Sequence Of Events i
Date Time Event 12/25/'i 1147 Unit 2 Mode status change from mode 4 to l
mode 5, for refueling outage Wiring changes completed for NSM CN-20223 1/3/88
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1/24/88 0515 PT/2/A/4450/05A post mod test performed, damper cycled, verified by lights in control r om, computer data does not show damper i
r... veme n t 2/19/88 1653 Unit 2 mode change from mode 5 to mode 4, start-up from refueling PT/2/A/4200/09A Auxiliary Safeguards Test 3/31/88
performed, damper fails to cycle Work request 6375 pRF written to investigate
and repair damper malfunction 4/1/88 0400 Incorrect wiring found and corrected 1905 Functional test performed on damper / declared operable PIR 2-C88-0151 initiated 4/6/88
r Design Engineering concludes damper operable 4/15/88
with incorrect wiring
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8/16/88 Station requests Design Engineering.
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re-evaluate operability evaluation i
i Design Engineering concludes that damper' was i
9/14/88
inoperable Conclusion finally reached on 12/19/88-
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operability / deportability NRC resident staff becomes aware of event 12/20/88
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LER 414/88-33 issued 1/27/89
System Description The VX system is located entirely within Containment with the two air return fans located-in.the upper compartment. Each fan has a capacity of 40,000 cfm and is capable of performing the design function of displacing air from the upper compartment to the lower compartment, returning' air which was displaced by the loss-of-coolant blowdown to the lower
compartment.
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Both fans are started by the containment spray actuation signal 9. minutes after the containment pressure reaches 3 psig.
After discharge.into the lower compartment, air flows with steam produced by residual heat through the ice condenser doors into the ice condenser compartment where the steam portion of the. flow is condensed.
T,he air flow returns to the upper compartment through the vents in the ' upper portion of the ice condenser compartment. The air return fans operate continuously after actuation, circulating air through the containment volume provided that containment pressure is above 0.25 psig. When the' containment pressure falls below i
0.25 psig, the air return and hydrogen skimmer fans are de-energized and tre cycled by the 0.25 psig pressure permissive signal.
The normally closed isolation damper is provided on the discharge of each air return fan acting as a barrier between the upper and lower compartments.
This damper remains closed during the initial blowdown to prevent ice condenser bypass following a postulated loss-of-coolant ar.cident.
The isolation damper is actuated by the containment spray actuation signal 10 seconds after containment pressure reaches 3.0 psig l
but is prohibited from opening until the pressure differential between the
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upper and lower compartments is less than 0.5 psig with the lower compartment positive to the upper compartment.
L The air return fans have sufficient head to overcome the divider barrier differential pressure (a maximum of 11.55 psf) resulting from residual heat steam flow and fan air flow entering the ice condenser through the
lower inlet doors. Each air return fan is provided with both normal and emergency Class IE power.
Fan design is compatible with operation in a post-accident containment environment.
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Safety Concern Both ' trains of VX are required for Modes 1 through 4.
Train A of VX was inoperable for a period of approximately 42 days while the unit was in modes 1 through 4, spanning the period from February 19, 1988 to April 1, 1988 as discussed above.
In determining the time VX Train B was inoperable simultaneously with Train A, it was found that Train B Solid State Protection System was 'out of service on March 3, 1988 for two hours; testing of Train B Containment Pressure Control System was performed on March 7 for one. hour 'and twenty-two minutes; diesel generator 2B Operability Testing was performed on February 29 thru March 1, March 15, March 21 thru March 22, and March
29, 1988 which resulted in the diesel being inoperable for approximately
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four hours.
Cumulatively, VX Train B was inoperable due to various reasons for.approximately seven and one half hours during the time VX Train A was inoperable.
The VX fans are designed to displace air from the upper compartment to the lower compartment, returning air which was displaced by the LOCA blowdown in the lower compartment, and operate continuously after actuation until containment. pressure decreases below 0.25 psig.
One obvious safety concern is containment pressure and temperature response to the worst case accident scenario with both trains of VX inoperable.
System Requirements l
Technical Specification 3.6.5.6 requires in modes 1 through 4, that two l
independent Containment Air Return and Hydrogen Skimmer Systems be OPERABLE.
With one Containment Air Return and Hydrogen Skimmer System i!'
inoperable the inoperable system shall be restored to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or the unit is to be in at least HOT STANDBY within the I
next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
Train A of VX was inoperable for 42 days while the unit operated in modes 1-4.
Train B of VX was also inoperable during that 42 day period for a cumulative time of approximately 7 1/2 hours.
This event constitutes an apparent violation of the requirements of TS 3.6.5.6, and is identified as apparent violation 414/88-38-13, Containment l
Air Return Damper Inoperability Due to Incorectly Terminated Electrical I
Wires.
Since this incident is under consideration for escalated enforcement, no Notice of Violation will be issued with this report.
Post Modification Testing post modification testing did not appear to be adequate in this incident.
j As stated in Incident Investigation Report (IIR) C88-092-2, on January 24, l
1988, Performance personnel completed PT/2/A/4450/05A and timed the damper l
with a stop watch by observing damper indicating lights. The report also l
states, however, that computer alarm summary data does not indicate that the damper cycled.
It should be noted that currently available information indicates that the damper indicating lights are not verified to indicate actual damper position.
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Subsequently, on March 31 when PT/2/A/4200/09A, " Auxiliary Safeguards
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Test Cabinet Periodic Test", was performed the damper did not open,
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the incorrectly terminated wires were found'
From the evidence, it
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appears that the test performed on January 24 was inadequate.
The
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licensee indicated that the wiring may have been altered subsequent to the test of January -24, however, there is no evidence to support that'
hypothesis.
Notwithstanding, there should have been testing performed after that manipulation to prove system / component operability.
This issue will remain Unresolved pending the completion of continued inspection in the area of the adequacy of the. post modification tests -
performed (414/88-38-14):
Post Modification Testing of VX Dampers.
I Design Engineering Operability Determination When this problem was discovered, (April 1988) station personnel requested that Design Engineering evaluate past operability of Train A of VX.
Design Engineering responded on April 15, 1988, indicating that VX was operable with the incorrect circuitry in place.
On August 16, however, Station Compliance requested a revised operability evaluation based on
'further evaluation at the site. On September 14, 1988, Design Engineering concluded that the subject damper, along with its test circuit, was indeed inoperable during the time the circuit error was in place.
.i The concern here is two-fold. The first concern is over the quality of the operability evaluation. Design Engineering's first attempt appears to have been inadequate.
An in depth review of the process Design Engineering employed in performing this evaluation will be performed by the resident staff and will be documented in inspection report 413/89-05.
In as much as station personnel rely heavily on Design Engineering conclusions, it is of great importance that these conclusions be accurate, conservative and sound.
The second area of concern is the timeliness of reporting this event. The event occured on April 1,1988.
After a number of discussions between station personnel and Design Engineering, it was concluded on September 14, 1988 that the subject damper was inoperable. This was re-confirmed on December 19, 1988 and yet the LER was not issued until January 27, 1989, i
almost 10 months after the event date. This issue will remain Unresolved pending the completion of continued inspection in the areas of Design Engineering's operability evaluation process and the events leading up to the ultimate filing of LER 414/88-33. (414/88-38-15):
Design Engineering Operability Determination and Reporting of VX Inoperability.
11.
Exit Interview (30703)
The inspection scope and findings were summarized on February 3, 1989,
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with those persons indicated in paragraph 1.
The inspector described the areas inspected and discussed in detail the inspection findings listed below.
No dissenting comments were received from the licensee.
The
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Item Number Description and Reference j
413/88-38-01 Gravity Drain of FWST To Refueling Cavity
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k 413/88-38-02 Inadequate Measures to Ensure Cleanliness Requirements for VX Fan Pit Drains.
413/88-38-03 Turbine Driven CA Pump Pressure Seal Failure 413/88-38-04 Valve Stroke Program Inadequacies.
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l 413,414/88-38-05 Failure to Perform A Safety Evaluation Required by 10CFR50.59 Prior to Removing l
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1RN-244 From Service 413/88-38-06 Operational and Maintenance Problems Associated With VC/YC Chillers 413/88-38-07 Failure to Sample Waste Gas Tank After An Addition.
413/88-38-08 Inoperable VA System In Excess of the Allowed Action Statement Time 413/88-38-09 Revision of INF-233 Testing Method and Licensee Review of Stroke Time Test Data 413/88-38-10 Additional Guidance For Temporary Changes 413/88-38-11 Failure to Obtain Permanent Approval of a Temporary Change 413/88-38-12 Excessive Backlog of IAE Procedures Needing Retype 414/88-38-13 Containment Air Return Damper Inoperability Due to Incorectly Terminated Electrical Wires 414/88-38-14 Post Modification Testing of VX Dampers.
414/88-38-15 Design Engineering Operability Determination of VX l
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