IR 05000327/1993031

Insp Repts 50-327/93-31 & 50-328/93-31 on 930712-23.No Violations or Deviations Noted.Major Areas Inspected: Licensee Balance of Plant Equipment & Sys

ML20056E912
Person / Time
Site:	Sequoyah
Issue date:	08/12/1993
From:	George Macdonald, Shymlock M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:
Shared Package
ML20056E911	List: IR 05000327/1993031 ML20056E909
References
50-327-93-31, 50-328-93-31, NUDOCS 9308250285
Download: ML20056E912 (11)

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UNITED STATES

[pnec NUCLEAR REGULATORY COMMISSION i

l y- . REGION 11

Q 101 M ARIETTA STREET. N.W., SUITE 2900 {

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eE ATLANTA, GEORGLA 30323-0199

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j Report Nos.: 50-327/93-31 and 50-328/93-31 Licensee: Tennessee Valley Authority  ;

6N 38A Lookout Place  ;

1101 Market Street i Chattanooga, TN 37402-2801 i

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Docket Nos.: 50-327 and 50-328 License Nos.: DPR-77 and DPR-79 4 Facility Name: Sequoyah Units 1 and 2 Inspection Conducted: July 12 - 23, 1993 Inspector: 3 G. MacDonald Date Signed i

i Approved : f 6 $

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. ymlock, Chief Date Signed P) System Section Ehg eering Branch i Division of Reactor Safety j SUMMARY I

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Scope:

This special announced inspection was performed to assess the licensee's  !

balance of plant (BOP) equipment and systems. This inspection was a  :

continuation of inspection 93-26 on selected BOP electrical systems. The  :

licensee's backlog review process was reviewed and system walkdowns were  !

performed on the following systems: main feedwater control, main generator, i switchyard and transformers, 6900 volt electrical distribution, 480 volt i electrical distribution, and low voltage electrical distribution. Some of the ;

systems chosen for review contained both safety related and non-safety related l equipmen !

Results:

f In the areas inspected, violations or deviations were not identifie l The licensee review of system backlog and prioritization of items for restart i was generally adequate for the systems reviewe l The review and categorization of customer group routine testing, maintenance, and relay calibrations was inadequate. (paragraph 4)

9308250285 930812 PDR ADOCK 05000327- l G PDR j

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The licensee walkdown of main feedwater control system did not identify -

material condition discrepancies in the main feedwater pump turbine local control panels. This was considered a weakness (paragraph 2) ,

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Problem Evaluation Report (PER) SQPER930208 required an inspection of all safety related and unit reliability related Arrowhart motor starter auxiliary l switches. A ten percent inspection sample was planned for the remaining motor i starters. Of the approximately 600 motor starter auxiliary switches inspected i to date, 3 failed switches were identified and 11 % of the switches required l cleaning or refurbishment to ensure proper operation. (paragraph 6) j Inspection 93-26 raised a concern on wiring terminations for replacement ASEA !

Brown Boveri (ABB) current transformers (CT). Three additional cts were ;

identified which had been incorrectly terminated. All replacement CT wiring .

will be verified correct prior to restart. (paragraph 5) j

Fuse control discrepancies were identified in several B0P motor control !

centers and panels. (paragraph 6)

Licensee Event Report 92-018 was reviewed and remains open. This item will be !

further reviewed prior to Sequoyah Res, tar This balance of plant system review is not complete. Additional review of work status and system walkdowns are scheduled prior to Sequoyah restar I f

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REPORT DETAILS Persons Contacted Licensee Employees '

• J. Baumstark, Operations Manager

• L. Bryant, Maintenance Manager r

• M. Cooper, Sequoyah Restart Management

• R. Driscoll, Site Quality Manager

• Fenech, Vice President Sequoyah

• D. Keuter, Vice President Nuclea~r Readiness

• Lundy, Technical Support Manager

• Poage, Nuclear Assurance Audit and Assessment Manager

• J. Proffitt, Licensing Engineer

• K. Powers, Plant Manager

• J. Robertson, Independent Safety Engineering Manager

• R. Shell, Site Licensing Manager l *R. Thompson, Compliance Licensing Manager i *P. Trudel, Manager Design Engineering i l

• J. Ward, Manager Engineering and Modifications  !

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• K. Whittenburg, Public Relations Manager Other licensee employees contacted during this inspection included engineers and administrative personne Other organizations NRC Personnel

• B. Bonser, Senior Resident Inspector (Region II)

• B. Crowley, Reactor Inspector (Region II)

• A. Gibson, Director, Division of Reactor Safety (Region II)

• Holland, Senior Resident Inspector (Sequoyah)

• Kellogg, Section Chief, Division of Reactor Projects (Region II)

• L. Moore, Reactor Inspector (Region II)

l *C. Ogle, Resident Inspector (Region II)

• D. Roberts, Resident Inspector (Region II)

• R. Schin, Project Engineer (Region II)

• S. Shaeffer, Resident Inspector (Sequoyah)

• M. Thomas, Reactor Inspector (Region II)

• Denotes those individuals that attended the exit meetin Acronyms and abbreviations used throughout this report are listed in the last paragrap . Main Feedwater Control System (System 46)

The function of the Main Feedwater Control System was to provide a signal to control MFPT speed in response to inputs from feedwater and steam header pressures and steam flow inputs from all 4 steam generators. The Main Feedwater Control System consisted of the setpoint

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calculators, differential pressure controllers, the MFP manual / auto  !'

control stations, and the high pressure oil system components. The oil system components controlled the high pressure oil to the MFPT HP and LP  !

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stop valves and governor valves for each MFPT. The major oil system components consisted of two AC oil pumps, a DC emergency oil pump, l hydraulic positioners, a hydraulic controller and an oil reservoi The l'

hydraulic controller contained a hand speed changer, an electric speed changer and the governor valve positioner motor. Additional equipment  !

consisted of hydraulic oil lines, solenoid valves and various

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indicator ;

The inspector reviewed the Main Feedwater System backlog review notebook  ;

to determine if reliability significant work backlog items were '

classified as restart items. The inspector determined that emergent work items were being evaluated in accordance with the licensee's t '

backlog review proces The backlog of identified work for system 46 consisted of open work l requests and work orders, conditions adverse to quality, master issues  !

list items, design change notices, and obsolete equipment items. The  ;

total work backlog included fifty five items and forty eight were l classified as restart items. The prioritization of work activities was >

considered adequate. The items identified in the licensee's reliability study which had caused plant transients had been addresse Major activities completed or scheduled as restart items for the ' system consisted of replacement of Foxboro 62H controller auto / manual transfer relays, replacement of solenoids for the HP and LP stop valves for all MFPTs, HP and LP stop valve limit switch repairs, repairs to governor '

valve positioners and indicator lights, repairs to drain valve limit switches and indicator lights, pressure controller calibration, oil  ;

l cleaning, and various oil leak repair !

l Significant post restart work items included Foxboro 62H controller '

i replacement and overvoltage at the MFPT solenoids and relay The inspector performed a preliminary walkdown of the system to ensure that significant problems had been identified in the rest rt o list and to verify an acceptable material condition existed prior to plant restar System engineer and third party walkdowns had been completed and many additional work request tags were noted on system components. The MFW control system was not energized and the oil system was not pressurize The inspector noted several material discrepancies that had not been identified by the previous walkclown effort The MFPT IB local control cabinet was missing its cover hardwar Inside the control cabinet the inspector observed six' cracked indicator light sockets which showed heat damage. Corrosion was present on several switches and terminal blocks. This had not been identified by )

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f 3 i The 2A MFPT local control cabinet had surface corrosion and several broken indicator light lens covers. The lens colors did not match the  !

drawing requirements. These deficiencies were identified by the i license !

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The inspector noted 2 burned indicator light sockets, a cracked switch  ;

and missing cable bundle supports inside the 2A MFPT local control  ;

cabinet. The 2A MFPT governor valve positioner switch was incorrectly  :

labelled as the switch for 1A MFPT governor valve positioner. These i

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deficiencies were not identified by the licensee. Work requests were  :

written for the identified deficiencie From the review of outstanding work / design items and the preliminary i

system walkdowns, the inspector considered that appropriate work items  ;

j were scheduled to be completed prior to restart.

l l Main Generator Electrical (System 57) l The main generator system consisted of the generator, exciter, voltage

! regulator and associated protective circuits and monitoring  !

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L The inspector reviewed the Main Generator System backlog review notebook ,

to determine if reliability significant work backlog items were

, classified as restart items. The inspector determined that emergent l l work items were being evaluated in accordance with the licensee's t backlog review proces The backlog of identified work for system 57 consisted of open work .

requests and work orders, master issues list items, design change 1 notices, operator aides,and obsolete equipment items. ' Thirty seven )

total items were identified for system 57, and thirty were classified as i restart items. The items identified in the licensee's reliability study which had caused plant transients had been corrected or were scheduled as restart items.

! Restart items scheduled for system 57 included installation of digital l fault recorders, installation of an additional volts / hertz relay for l Unit 2, replacement of obsolete thermoverters, minor repairs to hydrogen l coolers, replacement of exciter cooling water piping, extensive cleaning l and testing of the automatic voltage regulators, and various repairs to main generator monitoring instrumentatio The inspector performed a preliminary walkdown of the system to ensure-that significant problems had been identified in the restart list and to verify an acceptable material condition existed prior to plant restar l The system engineer and third party walkdowns had been completed for the  !

system. The inspector did not find material condition discrepancies which had not been identified by the license ,

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From the review of outstanding work / design items and the preliminary system walk <iowns, the inspector considered that appropriate work items ,

were scheduled to be completed prior to restar I 4. Transformers and Switchyard (System 241) j System 241 consisted of the main transformers, unit auxiliary l transformers, common station service transformers, the 161 kV switchyard <

! components, the 500 kV switchyard components, and monitoring and j protective instrumentation.

l l The inspector reviewed the System 241 backlog review notebook to determine if reliability significant work backlog items were classified as restart items. The inspector determined that emergent work items were being evaluated in accordance with the licensee's backlog review process. There were several restart items in system 241 which had been '

rescheduled for post restart implementation. The inspector determined that the bases for downgrading the prioritization for these items was l acceptabl The backlog of identified work for system 241 consisted of open work requests and work orders, condit, ions adverse to quality, master issues list items, design change notices, and obsolete equipment items. Of the 185 total items identified for system 241, 102 were classified as restart item .

The inspector had previously identified that customer group protective  !

relay calibrations and certain customer group switchyard routine testing and routine preventive maintenance activities were not reviewed as part of the backlog review process. The inspector attended the Backlog i Review Committee (BRC) meeting held to review these customer group work l items. The system engineer was not present at the meeting. The meeting *

performed a review of the work activities and schedule status for the work items which were due or overdue. Certain work activities were  ;

planned for completion prior to restar ,

A backlog review evaluation was prepared for each of the three work area i databases. The inspector reviewed the evaluations and concluded that '

the documentation of the review was inadequate. The items were ,

evaluated as categtry 8 (not required for restart). A single  ;

justification was provided encompassing all items listed in each of the >

three databases. Additional detail was required to properly evaluate ]

and document the work status and justify post restart work item Common station service transfornier (CSST) A automatic load tap changer had a high number of operating cycles (approximately 240,000). The ,

vendor manual recommended an inspection of the load tap changer when the  !

operating cycles reached 200,000 cycles. This item was previously not scheduled as a restart item but the inspection has been rescheduled to be completed prior to restar l l

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Items identified in the licensee's reliability study which had caused i plant transients had been addressed or were scheduled as restart item l Major work activities completed or scheduled as restart items included installation of a new 500 kV main generator power circuit breaker, new l transformer gas sensing relays, transformer bushing believille washers, ;

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and transformer maintenance.

l L The inspector performed a preliminary walkdown of the system from )

l June 14-25, 1993 documented in Inspection Report 93-26. The system '

L engineer wal? downs for tne system were not complete and additional l

[ walkdowns of the system will be performed prior to restar j From the review of outstanding work / design items and the preliminary system walkdowns, the inspector considered that appropriate work items i were scheduled to be completed prior to restar . 6900 Volt Electrical Distribution System (System 202)

i System 202 consisted of the 6900 volt start boards, unit boards, I shutdown boards, common boards and cooling tower board l The inspector reviewed the System 202 backlog review notebook to determine if reliability significant work backlog items were classified I as restart items. The inspector determined that emergent work items were being evaluated in accordance with the licensee's backlog review process. System 202 contained several restart items which had been j rescheduled as post restart. The inspector reviewed the items and 3 determined that the licensee had performed an appropriate review to '

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reschedule the items and concluded that the bases for the schedule l changes were adequate.

l The backlog of identified work for system 202 consisted of open work requests and work orders, conditions adverse to quality, master issues l list items, design change notice's, justification for continued operation and obsolete equipment items. Of the 177 total items identified for system 202, 102 were classified as restart item Inspection Report 93-26 described a concern regarding incorrect wiring i of replacement cts. The licensee conducted an incident investigation of ;

the issue. Three additional cts were identified with incorrect  !

secondary wiring connections. The licensee will. . verify that all i replacement cts are properly wired prior to plant restart. The '

inspector will review this item on subsequent inspections prior to i restar i l

Major restart work activities included implementing the start board fast l transfer scheme, board outages for. the start boards, . turbine building common boards and shutdown boards, breaker maintenance, CT inspections, ,

extended trip pushbuttons for the 7.5 HK switchgear and installation of !

the shutdown board 80% undervoltage relay I

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Significant post restart work items included overduty of the unit boards and CSST C start bus feeder cable replacemen The system review was not complete. The system engineer walkdowns were not complete for the system. The inspector performed a preliminary walkdown of Unit Board 2A and Common Board The material condition of the equipment inspected was acceptabl I From the review of outstanding work / design items and the preliminary l system walkdowns, the inspector considered that appropriate work items <

were scheduled to be completed prior to restar . 480 Volt Electrical Distribution System (System 201)

The system consisted of the safety related and the non-safety related *

480 volt boards and motor control centers (MCCs). The plant reliability study did not identify any plant trips attributable to system 201 equipmen The inspector reviewed the System 201 backlog review notebook to determine if reliability significant work backlog items were classified as restart items. The inspector determined that emergent work items l were being evaluated in accordance with the licensee's backlog review i process. There were no system 201 restart items which had been reschedule ;

i The backlog of identified work for system 201 consisted of open work l requests and work orders, conditions adverse to quality, master issues '

list items, design change notices, and obsolete equipment items. Of the 196 total items identified for system 201, 73 were classified as restart item '

The Arrowhart MCCs were obsolete and the motor starter auxiliary ,

switches had demonstrated poor reliability. PER SQPER930208 on ,

Arrowhart MCC motor starter auxiliary switches was reviewed. A safety i related motor starter failed due to a failure of the starter auxiliary i switch contacts. The probable cause of the initial failure was the use of the incorrect cleaning solvent. The licensee tested various cleaning ;

agents present onsite and found one cleaning agent that caused the same ;

reaction to the plastic parts that was observed on the failed motor '

starter. When sprayed with 111 trichloroethane the plastic switch cover !

turned a cloudy white color. The solvent caused the plastic switch  ;

plungers to adhere to the switch housing. Review of the MCC board and j MCC motor starter cleaning PM procedures indicated that only vendor ,

approved cleaning agents were allowed by the procedur i SQPER930208 corrective action consisted of verifying proper auxiliary

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switch response when manually actuated. Sluggish response required cleaning or refurbishment. All safety related and unit reliability

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related motor starters would be inspected. A 10% sample of the remaining motor starters would be inspected. The motor starter l inspection was ongoing. Approximately 600 motor starter auxiliary i

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7 switches.had been inspected and 3 were identified which appeared to have the same failure mechanism as the initial failure described in l SQPER930208. Approximately 11% of-the starter auxiliary switches l inspected have required cleaning or refurbishment. The inspector will 1 perform additional followup inspection of this issue on subsequent '

inspections prior to restar Significant post restart work items included qualified alternate feeder circuits to boards and MCCs, coordination of 480 V BuP Westinghouse DS j switchgear, and qualification for Westinghouse DS-206 480 V breakers i with disabled discriminator circuit ;

i The system review of System 201 was not complete. The system engineer -

had not completed his system walkdowns. 'The inspector performed a l preliminary walkdown of the system to ensure that significant problems  ;

had been identified in the restart list and to verify an acceptabl !

material condition existed prior to plant restar l i

Fuse control discrepancies were noted in' Turbine Building Common MCC A  ;

and B, CVC Boards A and B, Auxiliary Building Common MCC B, and 480 Volt Auxiliary Building Common Board. Noisy starters were identified in CV Board B and Auxiliary Building Common MCC B. A starter with grease ,

coating the auxiliary switch was identified on Auxiliary Building Common  !

MCC B. The general condition of the Auxiliary and Turbine building B0P

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MCCs was judged to be marginal and in need of preventive maintenanc l i

from the review of outstanding work / design items and the preliminary i system walkdowns, the inspector considered that appropriate work items l were scheduled to be completed prior to _ restar )

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7. Low Voltage AC and DC Distribution System (System 250)

System 250 consisted of the vital 125 VDC batteries, battery chargers, inverters, and the 250 VDC station batteries, battery chargers, and inverter The backlog of identified work for system 250 consisted of open work requests and work orders,- conditions adverse to quality, master issues  ;

list items, design change notice ~s, and obsolete equipment items. Of the i 107 total items ' identified for system 250, 35 were classified as restart  ;

items. The items identified in the licensee's reliability study which I had caused plant transients had been corrected or were scheduled as i restart item The inspector reviewed the System 250 backlog review notebook to determine if reliability significant work backlog items were classified as restart items. The inspector determined that emergent work items were being evaluated in accordance with the licensee's backlog review process. There were no system 250 restart items which_had been reschedule ___ _ _ _ . . . . . _ _ _ _ . _ _ _ _ _ _ _

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A major item for system 250 was 'the age of the vital and station batteries. Both station batteries and vital batteries 1 through 4 were !

nearing their 20 year life. The inspector reviewed the test results of .

the last performance discharge test for all the station and vital t

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batteries. All test results indicated greater than 90 %. The inspector l reviewed the replacement schedules for the vital batteries and noted !

that vital battery 4 was not scheduled for replacement until after it f had passed the 20 year point. Vital battery 4 was scheduled for replacement by January 1995 but would reach its 20 year life on  !

July 1994. This schedule did not meet the replacement criteria of IEEE standard 45 ;

Major restart work items included replacement of the preferred '

inverters, vital inverter maintenance, and replacement of vital ,

instrument power board transfer switche l l

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The system 250 review was not complete. The systent engineer had not i completed his system walkdowns. The inspector performed a preliminary walkdown of the system to ensure that significant problems had been i identified in the restart list and to verify an acceptable material ;

condition existed prior to plant restar ,

The inspector noted a breaker racking tool inside breaker compartment 102 of the fifth vital battery switchboar ,

The vital battery board ;

ammeter selector switches were inadequately labelle ;

From the review of outstanding work / design items and the preliminary !

system walkdowns, the inspector considered that appropriate work items were scheduled to be completed prior to restar . Licensee Event Report 92-018 The inspector reviewed LER 92-018 which described a reactor trip as a result of a high steam generator level condition caused by a failure of the feedwater regulating valve controller auto / manual transfer rela Failures in the plant air systems caused poor operation of the air operated valves and a failure of the controller auto / manual transfer relay prevented manual control. The auto / manual transfer relays in the controllers were replaced. All corrective actions for the LER have not been varified as complete therefore the item remains open. This item will be further reviewed by the inspector on subsequent inspections prior to plant restar . Exit Interview The inspection scope and results' were summarized on July 23, 1993, with those persons indicated in paragraph 1. The inspector described the areas inspected and discussed in detail the inspection finding Dissenting comments were not received from the license Proprietary information is not contained in this repor _

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i Acronyms and Abbreviations ABB ASEA Brown Boveri AC Alternating Current L B0P Balance of Plant *

! BRC Backlog Review Committee l CSST Common Station Service Transformer  ;

, CT Current Transformer  !

! CVC Chemical and Volume Control

'DC Direct Current ,

l EDG Emergency Diesel Generator Electrical Distribution System

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EDS FCV Flow Control Valve  ;

HP High Pressure .

JC0 Justification for Continued Operation ,

kV Kilovolt +

LP Low Pressure l

[ MCC Motor Control Center  ;

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MFP Main Feedwater Pump .

MFPT Main feedwater Pump Turbine l MFW Main Feedwater  !

M0V Motor Operated Valve  :

NRC- Nuclear Regulatory Commission i PCB Power Circuit Breaker  :

PER Problem Evaluation Report l PMT Post Maintenance Test *

TVA Tennessee Valley Authority -

UFSAR Updated Final Safety Analysis Report  !

VAC Volts Alternating Current j VDC Volts Direct Current i

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