IR 05000498/1997008
| ML20199D116 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 01/23/1998 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML20199D083 | List: |
| References | |
| 50-498-97-08, 50-498-97-8, 50-499-97-08, 50-499-97-8, NUDOCS 9801300142 | |
| Download: ML20199D116 (14) | |
Text
.
'
ENCLOSURE U.S. NUCLEAR REGULATORY COMMISSION
REGION IV
,
Docket Nos:
50-498,50-499 License Nos:
NPF 76, NPF 80 Report No:
50-498/97 08,50-499/97-08 Licensee:
STP Nuclear Operating Company Facility:
South Texas Project Electric Generating Station, Units 1 and 2 Location:
8 Miles West of Wadsworth on FM 521 Wadsworth, Texas 77483 Dates:
November 16,1997 through January 3,1998 Inspectors:
D. P. Loveless, Senior Resident inspector W. C. Sifre, Resident inspector W. J. Wagner, Reactor inspector Accompanying Personnel:
J. D. Hanna, Resident Inn,pector Trainee Approved by:
J. l. Tapia, Chief, Project Branch A Division of Reactor Projects Attachment:
Supplemental Information
.
9801300142 900123 gDR ADOCK0500g8
)
i l'
.
EXECUTIVE SUMMARY South Texas Project, Units 1 and 2 NRC Inspection Report 50-498/97 08; S0-499/97 08 This resident inspection included aspects of licensee operations, engineering, maintenance, and plant support. The report covers a 7 week period of resident inspection.
Operations e
Licensed operators performed in a professional manner and continuous awareness of plant conditions resulted from superior attention to control panelindications (Section 01.1).
The response of licensed operators and support organizations to a steam generator e
feedwater pump trip was very good (Section 01.1),
Plant equipment and licensed operators provided an excellent response to a failed e
closed main feedwater regulating valve. Emergency operating procedures were followed and control room supervision added value during the event response (Section 01.2).
The overall response to a main transformer oilleak was excellent. However, one e
operator error was observed (Section 01.3).
Material condition and housekeeping in the areas toured was very good. Minor
deficiencies observed were reported to control room personnel for documentation and repair (Section 02.1).
Maintenance Technician performance during corrective and preventive maintenance activities" e
observed was very good Work packages and instructions provided adequate detail and vendor information was properly incorporated (Section M1.1).
Surveillance testing observed was well conducted in accordance with approved (
e procedures and proper!y implemented the Technical Specification surveillance requirements (Section M1.2).
Enaineerina Engineering products reviewed were considered good, Condition report engineering e
evaluations were thorough and provided adequate detail to support the continued operability of the subject components. On one occasion, additional testing was appropriately recommended to support the operability determination (Section E1.1).
~
,
_ _..
...
-
.
-
-
.
,
!
'
'
Plant support
!
!
The ra(95gical controls, maintenance of emergency response facilities and equipment, o
,
and phy ecal security activities observed were considered to be excellent (Sections R1,1,
,
P2.1, and S1.1),
i e
General employee training courses were well conducted and properly supported open access to the NRC However, several minor procedural problems were noted (Section R5.1).
-
>
!
,i
.
I
>
f i
e f
,
!
o l
-
E
_-
._
_. _
-.
- -
..
....
. _. _
.
.
.
.
'
i l
Reno 1Dntaus Summary of Plant Stain
,
Unit 1 operated at essentially 100 percent power throughout this inspection period.
At the beginning of this inspection period, Unit 2 was operating at 100 percent power. On November 21, the unit was manually tripped from 100 percent power when a main feedwater regulating valve failed closed and resulted in decreasing Steam Generator 2D water level.
Following repairs, the unit was returned to 100 percent power on November 23. On
_
December 29, power was rapidly reduced to 9 percent reactor power and the turbine was removed from service ir' response to a large ollleak from Main Transformer 28. On January 2, the unit was returned to power following transformer repairs and testing. At the end of this inspection period, Unit 2 was operating at 100 percent power.
LOnorations
Conduct of Operations 01.1 Control Room Observations (Units 1 and.2)
a.
Insoection Scoce (71707)
Using Inspection Procedure 71707, the inspectors routinely observed the conduct of operations in the Units 1 and 2 control rooms. Frequent reviews of control board status, routine attendance at shift turnover meetings, observations of operator performance, and reviews of control room logs and documentation were performed, in addition to full power operations, the inspectors observed portions of the following evolutions:
response to a Unit 2 reactor trip on November 21.
o response to an inadvertent trip of Steam Generator Feedwater Pump 21 on
December 8.
.
response to a main transformer oilleak on December 29.
b.
Observations and Findings During routine observations, the inspectors noted that reactor operators were attentive at the control panels and effectively observed indications of plant parameters. Based on these observations and on interviews, the inspectors determined that the control room operators were continually aware of existing plant conditions. The control room supervisors remained cognizant of ongoing activities. The engineered safety features systems in both units were verified, by control panel observation to be aligned in
=
. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ - - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
_ _ - _ _ - _
.
.
accordance with Technical Specifications. Operators response to annaciator alarms was prompt, was in accordance with approved procedures, and appropriately dispositioned the clarm status. Licensed operators were observed utilizing self-verification techniques with one exception noted in Section 01.3 of this inspection report.
The inspectors routinely attended shift turnover and turnover meetings. The on shift operators provided clear and concise information to the oncoming operators. Oncoming operators routinely reviewed the controi room logs, discussed current plant conditions, and verified major equipment status. Plant managers and operations department managers were often observed in attendance at shift turnover meetings.
On December 8, the inspectors observed the control room operators respond to an inadvertent trip of Steam Generator Feedwater Pump 21, Operators properly implemented Plant Operating Procedure OPOP04 FW-0002, Revision 2, " Steam
,
Generator Feedwater Purnp Trip." During a subsequent investigation, maintenance personnel identified loose leads on the linear voltage differential transmitter for the pump turbine low pressure govemor valve. The inspec'or observed that the involvement of the
instrumentation and controls technicians and the system engineer was prompt, conservative, and resulted in proper diagnosis of the problem.
c.
Conclusions Licensed operators in the control room performed in a professional manner and were continuously aware of existing plant conditions. Superior attention to control panel indications was noted. Shift turnover activities were thorough, and turnover meetings were routinely attended by management. The response of licensed operators and support organizations to a steam generator feedwater pump trip was very good.
01.2 Resoonse to a Unit 2 ReactoLThp a.
la5DElion Scoce (92703. 7170Z)
On November 21, the Unit 2 Feedwater Regulating Valve 2D inadvertently closed.
Licensed operators attempted to reopen the valve without success. As the Steam Generator 2D water level approached 40 percent, operators manually tripped the reactor and entered emergency procedures. Resident inspectors responded to the site and observed the response of licensed operators and the stabilization of reactor parameters.
The following documents were also reviewed:
o Plant Operating Procedure OPOP05-EO E000, Revision 9, " Reactor Trip or Safety injection."
Plant Operating Procedure OPOP05 EO ES01, Revision 14, " Reactor Trip
Response."
.
.
l
Plant General Procedure OPGP03 ZO-0022 Revision 4," Post-Trip Review
Report."
e Post Trip Review 2 031, " Post Trip Review Report for Reactor Trip of Unit 2 on November 21,1997."
,
o Condition Report 9718760.
Event Review Team Report, " Unit 2 Manually Tripped Due to a Lowering Water e
Levelin Steam Generator 2D."
- Event Notification Worksheet.
Licensee Event Report 50-499/97-007, " Manual Reactor Trip Caused by a Loss
of Inventory in Steam Generator 2D."
b.
Qbservations and Findinas During the initial investigation into the event, maintenance personnel identified that the primary power supply to Process Control Cabinet 08 was tripped and the breaker to the secondary power supply was in the "OFF" position.- Troubleshooting results disclosed that a capacitor had failed on the voltage to pulse converter circuit card, in addition, a capacitor mounting strap in the primary power supply had caused an intomal short. The fault protection system of the cabinet caused the loss of both the primary and secondary power supplies from the single circuit card failure.
Process Control Cabinet 08 was part of the 125 vde system that provided power to the feedwater regulating valve control circuitry, Loss of the power caused the valve to fall closed and also caused a failure'of the steam dumps to actuate, complicating plant recovery, Operators responded well to the event. Licensed operators followed emergency operating procedures and plant operating procedures throughout the recovery Controls were manipulated in a careful and methodical manner, Shift supervision provided appropriate levels of oversight in ensuring that plant parameters were maintained. Annunciator alarms were observed and quickly acknowledged.
The inspectors evaluated the quality of the event review team response and the posttrip review. These evaluations were properly conducted and provided valuable insights. The plant had responded well to the event, with only minor deficiencies noted. This was indicative of an outstanding material condition of plant systems and equipment prior to the reactor trip.
c.
Conclusions.
- Licensed operators responded well to a failed closed main feedwater regulating valve.
Emergency operating procedures were carefully followed and control room supervision
=
added value during the event response. The material condition of plant systems and equipment was outstandin,
.
01.3 Raoid Unit 2 Power Reduction uoon Main Transformer 2B Oil Leak a.
Inspection Scooe (93702)
On December 29,1997, a contractor reported a large oilleak issuing from the top of the Unit 2 Main Transformer 29. At 1:33 p.m., operators began a rapid power reduction in accordance with station off normal operating procedures. At 2:38 p.m., reactor plant operators rer d that the leak had stopped. During that time, reactor power had been reduced from 100 percent to 26 percent. The resident inspectors responded to the main control room and observed the rapid down power and stabilization of the reactor coolant system. The following procedures related to the event were reviewed:
o Plant Operating Procedure OPOP03 ZG 0000, Revision 7 " Plant Shutdown from 100 percent to Hot Standby "
Plant Operating Procedure OPOP04 TM-0005, Revision 1, " Fast Load Reduction."
b, Qbservations and Findinas Operators transitioned from Procedure OPOPO4 TM-0005 to Procedure OPOP03-ZG-0006. After the oil leak had stopped, the power reduction was continued at a normal rate until the reactor was at 9 percent power. The main generator output breakers were opened at 7:48 p.m. While performing operations necessary to properly remove Steam Generator Feedwater Pump 21 from service, a licensed operator attempted to trip the pump without completing the proceduralized prerequisites. These included placing the startup feedwater pump handswitch in the " Pull-to-Lock" position.
Another licensed operator detected the error and prevented a procedural violation. A condition report was not written to document this occurrence until the inspectors inquired why one had not been wntten. Condition Report 97-20369 was subsequently written on December 31 to address the operator error, it was determined that the oil had been issu ng from a sudden pressure relief valve on top of the main transformer housing. Approximately 300 gallons had relieved from the valve and were contained within a berm surrounding the transformer. The relief valve was removed and tested satisfactorily; oil samples indicated that particulates and gases were within normal specifications; and a core efficiency test indicated that the windings had not sustained damage. Licensee craftsmen identified an oilleak on the suction side of the recirculation pump. An excessive volume of oil found in the oil surge tanks and low levels found in the transformer housing indicated that air intrusion had occurred.
Workers also identified a bad temperature switch that failed to actuate one half of the transformer cooling fans when required. Plant engineers surmised that air entering the system and heated by the core had caused the pressure to rise and lift the relief valve.
Following replacement of the oil coolers, repair of system fittings, and vacuum testing for leak tightness of the system, the plant was returned to power operation. -. - _. - _..
_
-_
-
_-
- - -. _. _ -
_ - _ -. - -. - - _..
.
.
.
.
Determination of the root cause of the failure and of the adequacy of corrective maintenance on the main transformer were ongoing at the end of this inspection period.
Therefore, review of the licensee's root cause determination and the associated corrective actions sa well as a review of the licensea's investigation of the operator error will be tracked as an inspection followup item (499/97006-01).
- c.
Conclusions The overall response to a main transformer oilIcak was excellent. Investigative actions were well designed and properly validated the condition of the main transformer.
,
Operator response during the rapid load reduction was considered very good, however, t
one operator error was observed (Soction 01.3).
O2 Operational Status of Facilities and Equipment 02,1 Plant Tours (Units 1 and 2)
a.
Insoection Scone (71701)
The inspectors routinely toured the accessible portions of plant areas in Units 1 and 2.
Areas of special attention during this inspection period included:
Units 1 and 2 turbine-generator buildings, e
Units 1 and 2 fuel handling buildings.
e
Units 1 and 2 electrical auxiliary buildings.
e Standby Diesel Generator Rooms 12,13, and 21.
e Unit 2 Isolation Valve Cut,1cle.
b.
Observations and Findinas
'
The inspectors observed that systems and components had been maintained in good
,
material condition in both units in general, housekeeping was very good. Licensee management wan routinely observed in the plant monitoring ongoing activities.
I During a tour of the Standby Diesel Generator 21 room, the intpectors noted that both starting air compressors were leaking oil. Through discussions with the shift supervisor, the inspectors determined that one of the leaks had not been documented. The shift supervisor took action to ensure that both oil leaks were documented on Condition
Report 97-18398 and would receive corrective maintenance.
c.
Conclusions
Material condition and housekeeping in the areas toured were very good. A minor deficiency related to not documenting all leaks associated with the starting air compressor for Standby Diesel Generator 21 was reported to control room personnel.
Subsequent documentation of the observed leaks was sufficient to assure repair of all leaks.
. _
_
__
__ _
._
_
._
-
- - -.. - _ -.
.. -
_ _ -
-. _ -.
_ - - - - - -
-..
-
. -- -..
.
'
08 Miscellaneous Operallons issues (92901,92700)
08.1 (Closed) Licensee Event Reoort 50-499/97-007: Manual Reactor Trip Caused by a Loss
,
of Inventory h Steam Generator 2D This report addressed the November 21,1997, Unit 2 reactor trip. The review of this event is documented in Section 01.2 of this inspection report. Maintenance personnel
,
replaced the failed circuit card and the primary power supply to the subject process control cabinet. Since no similar events have occurred at South Texas Project within the last 3 years, the event was considered isolated. Although, further reviews and inspections associated with the event continued to be conducted by licensee personnel,
,
no further NHC review was required.-
a 11. Maintenance M1 Conduct of Maintenance
,
M1.1 General Comments on Field Maintenance Activities
a.
insoection Scoos (62707)
The inspectors observed portions of the following ongoing maintenance activities identified by their Work Authorization Number, e
96965 Standby Diesel Generator 13 Diagnostic Test e
121865 Control Room Air Handling Supply Unit 36 Temperature Controller Repair
,
b.
Obtenations and Findinas The overall performance obsorved during the preventive and corrective maintenance activities was very good. Technicians and mechanics demonstrated strong knowledge and familiarity with equipment and assigned work. Work was performed with appropriate supervision involvement. System engineers provided good support for the data collection and analysis during diagnor. tic testing. Work packages and instructions provided adequate detail and vendor information was properly incorporated into work packages and data analyses.
c.
Conclusioni Technician performance during the correctiva and preventive maintenance activities observed was very good. Work packages and instructions provided adequate detail and vendor information was properly incorporated. System engineers provided good support
_ during diagnostic testing.
.
.
- -,.. - _..
,.
.. _ -
.m-,
..,-,-
-- - -,.. _,.,
.
M1.2 General Comments on Surveillance Testina i
'
Insoection Scooe (61723)
a.
The inspectors observed portions of the following surveillanta activities:
Plant Surveillance Procedure OPSP03 AF-0007, Revision 10. " Auxiliary I
e Feedwater Pump 14 Inservico Test."
Plant Surveillance Procedure OPSP03 DG 0003, Revision 10. " Standby Diesel
Generator 13 Operability Test."
b.
Observations and FindiDSS The observed smaillance tests were well performed. The tests utilized approved procedures and properly implemented Technical Specification surveillance requirements.
Plant operators were observed performing detailed walkdowns of equipment during testing activities. System engineers provided good support during the collection of data for equipment performance trending.
c.
Conclusions Observed surveillance testing was well conducted in accordance with approved procedures and properly implemented the Technical Specification surveillance requirements. Good involvement by plant operators and system engineers was noted during surveillance testing.
Ill. Engineering E1 Conduct of Engineering E1.1 Review of Ooerability Evaluations for Electrical Deficiencies a.
Insoection Scoce (3755_1)
Using inspection Procedure 37551, the inspectors periodically reviewed engineering problems and plant incidents for their root cause. Engineering products were evaluated
to determine the effectiveness of the 'icensee's controls for identifying, resolving, and preventing problems. The following specific Condition Report Engineering Evaluations were selected for indepth review:
97-19385-3 Operability Report: Water Intrusion into Components on Standby Diesel Generator 12 Local Operating Panel.
- 97-20070-1 Operability Report: Overvoltage Condition on Class 1E 125 vde Bus E1D1.
_.
-
.
- - -
.
-
.-_
_
_
.
.
.
b.
Observations and Findinas Condition Report Engineering Evaluation 9719385-3 was developed by the system engineer to determine the impact of water intrusion into the local operating panel on the operability of Standby Diesel Generator 12. The water intrusion resulted from condensation on the emergency ventilation system dripping down onto the local panel.
The evaluation identified the affected components as Non Class 1E relaying and metering devices. Through review and discussion with the system engineer the inspector determined that failure of the affected devices would not impact the diesel generator's ability to perform its safety function. The inspector also toured the affected area with the system engineer and independently determined that the water could not have reached the Class 1E equipment because of their physicallocations.
Condition Report Engineering Evaluation 97 20070-1 was developed to determine the impact of an overvoltage event on the operability of the battery and service loads connected to the Class 1E 125 vde Bus E1D11. The overvoltage event occurred when the amplifier board on the Number 2 battery charger failed as it was placed in service.
The charger output voltage immediately jumped to approximately 170 yde and remained high until the charger was removed from service. The voltage gradually decayed over a 2 minute interval to the normal voltage of 130 vde as the Number 1 charger was returned to service.
As part of the operability evaluation, engineering personnel identified and evaluated each affected component utilizing component history, industry experience, and vendor specifications and consultation. The evaluation was thorough and effectively identified potentially impacted devices. The only devices identified as potentially sensitive to the high voltage were the Reactor Coolant Pump 18 undervoltage and underfrequency relays. The engineers recommended calibration of the relays to ensure operability. The relays were calibrated in accordance with Plant Surveillance Procedures OPSP06 RC 0003, Revision 5, "Undervoltage RCP Relay Channel Calibration /TADOT" and OPSP06 RC 0004, Revision 5,"Underfrequency RCP Relay Channel Calibration /
TADOT."
c.
Conclusions The engineering evaluations reviewed were considered good. Condition report engineering evaluations were thorough and provided adequate detail to support the continued operability of potentially affected components. On one occasion, additional testing was appropriately recommended to support the operability determination.
l
_,
_
.__
._
.
.
lE.PjanLSusand R1 Radiological Protection and Chemistry Controls RI.1 Iours of RadiologicklCQDirolled Areas (71750)
Routine tours of the radiological controlled areas wer' conducted throughout the inspection period. Doors and gates required to be locked in accordance with Technical Specifications or the licensee's radiation protection program were venfied to be properly secured. Ongoing work observed in these areas was performed in accordance with approved radiation work permits.
R5 Staff Training and Qualification in RP&C RS.1 General Emoloy2 Land Radiation Worker Trainina (71750)
During this inspection period, the inspectors reviewed and observed General Employee Training Courses 1 and 2. Both the computerized version of the courses and the handouts for the lecture series wire reviewed. Both versions provided appropriate levels of information, were well conducted, and included multiple examples of staticn management supporting open access to the NRC.
The inspectors also reviewed Plant General Procedure OPGP03 ZT 0133, Revision 4
" General Employee Training Program ' Section 10.1 of this procedure stated that,
" Personnel who believe that they possess the knowledge cor,tained within the (Plant Access Training), [ Radiation Worker Training), or LWRT courses may challenge a course by taking an examination based on course objectives." On several occasions different instructors strongly encouraged personnel attempting to requalify to take the challenge examination instead of the full course without due consideration as to whether the employees felt that they possessed the required knowledge to do so. The inspectors noted that the computerized course referenced NRC Form 3. The picture was unreadable because of the size. Form 3 was not posted in the training area, nor could instructors produce a copy for viewing. The inspectors noted that Form 3 is required to be posted in work areas, but is not specifically required to bo presented as part of instruction to emoloyees. These findings were presented to the Staff Training Division Manager who stated that they would be reviewed and addressed as appropriate.
Condition Report 98-233 was written to track the issues.
P2 Status of EP Facilities, Equipment, and Resources P2.1 insoection of Emeroency Resoonse Facilities (71750)
During routine plant tours, the inspectors observed that the technical support centers and operations support centers in both units and the emergency offsite facility were all readily available and maintained for emergency operatio.
Q
Si Conduct of Security and Safeguards Activities S1.1 Daily Phvalcal Security Activity Observations (71750)
On a daily basis, the inspectors observed the practices of security force personnel and the condition of security equipment. Protected area barriers were in good condition.
Personnel access measures and equipment searches were properly conducted.
Security officers were alert and fully aware of the responsibilities of their respective posts.
V. Management Meetinga X1 Exit Meeting summary The inspectors presented the inspection results to inembers of licensee management at
' the conclusion of the inspection on January 6,1998. Management personnel acknowledged the findings presented. The inspectors asked whether any materials examined during the inspection should be considered proprietary. No proprietary information was identifed.
l
-
.,
.
Ie ATTACHMENT SUPPLEMENTAL INFORMATION PARTIAL LIST OF PERSONS CONTACTED Licensee G. Childers, Manager, Instrumentation and Controls, Unit 2 T. Cloninger, Vice Preeldent, Nuclear Engineering W. Cottle, President and Chief Executive Officer J. Crenshaw, Manager, Mechanical Fluids Division B. Dowdy, Manager, Operations, Unit 2 J. Groth, Vice President Nuclear Generation E. Halpi,1, Manager, Maintenance, Unit 2 S. Head, Licensing Supervisor C. Lunsford, Program Supervisor, Maintenarice B. Masse, Plant Manager, Unit 2 G. Parkey, Plant Manager, Unit 1 M. Ruvalcuba, System Engineer G. Weldon, Manager, Staff Training Division jNSPECTION PROCEDURES flP) USED IP 37551: Onsite Engineering IP B1726: Surveillance Observations IP 62707: Maintenance Observation IP 71707: Plant Operations IP 717S0: Plant Support IP 92700: Onsite Followup of Written Reports at Power Reactor Facilities IP 92901: Followup - Operations IP 93702: Prompt Onsite Response to Events at Operating Power Reactors ITEMS OPENED AND CLOSED
,
QDetOnd 50-499/97008-01 IFl Review of the Root Cause Determination, the Operator Error, and the Associated Corrective Actions Related to a Loss of Main Transformer Oil
'
C101td 50-499/97-007 LER Manual Reactor Trip Caused by a loss of Inventory in Steam Generator 2D
.