ML18149A115

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Summary of 860407 Meeting W/Util & Westinghouse Re Reactor Trip Breaker Maint Program.Attendees List & Viewgraphs Encl
ML18149A115
Person / Time
Site: Surry, North Anna, 05000000
Issue date: 04/17/1986
From: Engle L
Office of Nuclear Reactor Regulation
To: Rubenstein L
Office of Nuclear Reactor Regulation
References
GL-83-28, NUDOCS 8604280066
Download: ML18149A115 (39)
v • d • e


Text

FROM:

SUBJECT:

==

Introduction:==

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 April 17, 1986 Lester S. Rubenstein, Director PWQ Proiect Directorate #2 Division ~f PWR Licensing-A Leon B. Engle, Project Manager PWR Project Directorate #2 Division of PWR Licensing-A

SUMMARY

OF MEETING WITH VIRGINIA ELECTRIC AND POWER COMPANY (VEPCO) REGARDING REACTOR TRIP BREAKER MAINTENANCE PROGRAM A meeting was held on April 7, 1986, in Bethesda, Maryland with representative~*

of the NRC staff, VEPCO, and the Westinghouse Owners Group (WOG) regarding the subject as noted above.

A listing of attendees is provided in Enclosure 1.

Background:

During the time period of January-February 1983, VEPCO requested Westinghouse to review the maintenance program for the DB-50 reactor trip switch gear.

In February 1983, the Salem ATWS event took place and the NRC staff's Generic Letter 83-28, "Required Actions Based on Generic Implications of Salem ATWS

Events, 11 was issued in ~luly 1983.

In October 1983, the WOG "Maintenance Program for DB-50 Reactor Trip Switch, 11 was issued and VEPCO responded to Generic Letter 83-28 in November 1983.

During May 1984, the WOG maintenance program was initiated at VEPCO, and during Fall-1984 through 1985, installation of Auto Shunt Trip and Trip Breakers took place at the Surry and North Anna Power Stations. During November 1984, VEPCO formed its own reactor trip breaker committee to assess the WOG maintenance program for reactor trip breaker trip reliability and presented the assessment of this program at the subject meeting as noted above.

It is noted that the NRC requires that reactor trip breaker testing be done in accordance with the WOG recommendations and any changes in the maintenance and testing frequency for reactor trip breakers does not affect present or oroposed specific plant Technical Specifications.

Discussion:

VEPCO's agenda and the salient points of VEPCO's presentation are provided in Enclosure?..

Presently, independent verification of operability is required for the undervoltage and shunt trip attachments as part of the monthly trip logic testing. Periodic maintenance is based on WOG "Maintenance Program for DB-50 Reactor Trip Switch Gear, 11 (October 14, 1983,.

The WOG""recom-mendations presently include:* (1) testing of the independent reactor trip breaker features, (2) the per~ormance of lubricating the UVTA and operating mechanism, (3) the performance of tests for trending parameters, (4) the performance of a trip margin test,.(5) the cleaning of the switchgear enclosure, and (6) a functional check (trip 10 cycles) prior to returning the breaker to service.

. ---8604280066 860417 PDR ADOCK 05000280, P

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Lester VEPCO's concerns with the current WOG Maintenance.Program include:

(1) excessive cycling, (2) excessive handling, and (3) reliability of unit

      • reactor.trip breakers. Regarding excessivP cycling, the breaker is required to trip 114 cycles for maintenance and 36 cycles for surveillance testing over an eighteen (18) month refueling interval.

In summation, this amounts to 150 cycles for a given fuel cycle period.

VEPCO stated that this cycling reduces the effectiveness of lubrication on UVTA and the operating mechanism as well as increasing the wear on breaker parts.

For excessive handling, VEPCO indicated this handling increases the probability of handling damage and may cause possible alignment problems.

Finally, unit reliability may be decreased because breaker operations on line as well as removing and reinstalling breakers increases the probability of a unit trip.

The salient points of VEPCO's proposed maintenance program for reactor trip *

  • breakers would include:

(1) revised maintenance procedure to reduce the number of cycles or trips during maintenance, (2) extend the maintenance frequency from 6 to 12 months, and (3) trend breaker parameters and perfonnan*ce

  • to determine the effectiveness of the maintenance program. Actual revisions to the present program include the reduction in maintenance procedure for breaker tripping from 38 to 27 cycles. Additionally, maintenance would be performed on an annual basis instead of the present 6 month interval. Also, vendor refurbishment (off-site vendor program to return breaker to "as new" condition) would be perfonned for at least 3 refueling cycles. Finally, the proposed program would reduce breaker cycles for maintenance from 114 to 37 per unit cycle.

VEPCO's justification for extending the maintenance period to 12 months is based on WOG criteria which states the maintenance period may be extended to 9-12 months based on experience and trending data and provided 200 breaker cycles are not exceeded.

Also, unit breaker reliability would be increased by reducing the risk of on-line maintenance.

In addition, trend data collected

  • by VEPCO does not indicate any adverse trends in breaker performance over the past two years.

The proposed maintenance program would reduce both the amount*

of handling and the amount of wear on breaker parts. And, reducing breaker operations increases the effectiveness of lubrication on UVTA and the operating mechanism.

==

Conclusions:==

Based on the above, VEPCO in summar.Y indicated that:

(1)

(2)

(3)

(4)

Excessive cycling reduces the effectiveness of lubrication and increases wear on breaker parts.

On-line maintenance increases the probability of reactor trip.

The proposed maintenance program reduces the number of breaker cycles by 67.5% while continuing to satisfy the WOG maintenance program requirements.

~*

The proposed 12 month maintenance frequency reduces breaker hijndling and probability of reactor trip.

Lester (5) Trending of past breaker performance coupled with breaker refurbishments for each refueling cycle justifies a 12 month maintenance frequency interval.

(6)

Improved maintenance program increases unit breaker reliability.

In conclusion, it is noted that the VEPCO proposal to change the maintenance frequency from 6 months to 12 months does not affect present proposed plant specific Technical Specification requirements.

VEPCO will be submitting a supplemental response to Generic Letter 83-28 which addresses a periodic 12 month maintenance interval.

For other Westinghouse plants, these matters will be handled on a generic basis between the WOG and specific utilities.

Enclosures:

As stated cc:

See next page DISTRIBUTION Docket File PAD#2.Rdg L. Engle D. Miller NRC PDR Local PDR

~

PM~

LEngle:hc 4/q/86 Isl Leon B. Engle, Project Manager PWR Project Directorate #2 Division of PWR Licensing-A Office of Nuclear Reactor Regulation

Mr. W. L. Stewart Virginia Electric & Power Company cc:

Richard M. Foster, Esq.

Cockrell, Quinn & Creighton 516 Cherry Tower 920 South Cherry Street Denver, Colorado 80222 Michael W. Maupin, Esq.

Hunton, Williams, Gay and Gibson P. 0. Box 1535 Richmond, Virginia 23?.12 Mr. W. T. Lough Virginia Corporation Corrnnission Division of Energy Regulation P. 0. Box 1197 Richmond, Virginia 23209 Ellyn R. Weiss, Esq.

Harmon, Weiss and Jordan 2001 S Street NW Washington, DC 20009 Mr. J. T. Rhodes Senior Vice President - Power Virginia Electric and Power Co.

Post Office Box 26666 Richmond, Virginia 23261 Mr. Anthony Gambardella Office of the Attorney General Suoreme Court Ruildinq 101 North 8th Street -

Richmond, Virginia 23219 Resident Inspector/North Anna c/o U.S. NRC Senior Resident Inspector Route 2, Box 78 Mineral, Virginia 23117 Mrs. Margaret Dietrich Route 2, Box 568 Gordonsville, Virginia 22042 Mr. Paul W. Purdom Environmental Studies Institute Drexel University 32nd and Chestnut Streets Philadelphia, Pennsylvania 19104 e

North Anna Power Station Units 1 and 2 Atomic Safety and Licensing Appeal Board Panel U.S. Nuclear Regulatory Corrnnission Washington, DC 20555 Regional Administrator, Region II U.S. Nuclear Regulatory Corrnnission Office of Executive Director for Operations 101 Marietta Street N.W.,. Suite 2900 Atlanta, Georgia 30323 Mr. E.W. Harrell P. 0. Box 402 Mineral, Virginia 23117 Old Dominion Electric Cooperative c/o Executive Vice President Innsbrook Corporate Center 4222 Cox Road, Suite 102 Glen Allen, Virginia 23060 Mr. Richard C. Klepper Board of Supervisors Louisa County Courthouse P. 0. Box 27 Louisa, Virginia 23093

t ENCLOSURE 1 LIST OF ATTENDEES FOR MEETING WITH VIRGINIA ELECTRIC AND POWER COMPANY ON "NRC J. T. Bea rd V. Benaroya P. Boehnert S. Brown F. Burrows L. Engle J. Knight

0. Parr C. Patel F. Rosa E. Rossi N. Romney L. Rubenstein P. Shemanski S. Weiss APRIL 7, 1986 Westinghouse Corporation A. Deb J. Mesmeringer Houston Lighting & Power T. G. Roberson VEPCO R. Beger N. Clark J. DeMarco H. Fonteci 11 a R. Hardwick R. Nicholls G. Panne 11 W. L. Stewart J. Wilson Commonwealth Edision L. D. Butterfield (WOG) p-

Virginia Power Reactor Trip Breaker Presentation April 7, 1986 r

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r 0 VI C

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Agenda I. Introduction and Background e

II. Current Requirements III. Description of Breaker Components W. Demonstration of Selected Procedural Steps V. Concerns wiJb Current Maintenance Program VI. Proposed Maintenance Program VII. Licensing Actions e

VIII. Conclusions IX Hands-on Breaker Familiarization

Virginia Power Reactor Trip Breaker Progra,n Introduction and

  • Background e

.* e

  • 1 History 1983 Jan-Feb --

Westinghouse Reviews Breaker Programs at Virginia Power's Request Feb --

Salem A 1WS Event July --

Generic Letter 83-28, "Required Actions Based on Generic Implications of Salem AlWS Events Oct --

WOG "Maintenance Program from DB-50 e

Reactor Trip Switch Gear" Nov --

Virginia Power Response to Generic Letter 83-28

History 1984 May --

WOG Maintenance Program Initiated at Virginia Power 1985 Fall'84 --

Installation of Au~o Shunt Trip and Trip thru '85 Breaker Counters at Virginia Power Plants Nov --

Virginia Power Reactor Trip Breaker Maintenance Committee Formed e

1986 April --

Meeting with NRC

Virginia Power Reactor Trip Breaker Prograni f,

I' Curr~ntRequiremen~

Regulatory Requirements

  • Independent verification of operability of undervoltage and shunt trip attachments as part of monthly trip logic testing
  • Periodic maintenance based on Westinghouse Owners Group "Maintenance Program for DB-50 Reactor Trip Switch Gear" ( 10-14-83) e

Regulatory Requirements

  • Maintenance performed at 6 month intervals -

may be extended to 9-12 months as maintenance and test trends indicate

  • Trending of lN trip attachment dropout voltage, trip force, breaker response time 91 ei

Vendor.Recommendations

  • Test Independent Trip Features
  • Perform Lubrication Procedure on lNTA & Operating Mechanism
  • Perform Tests for Trending Parameters

Vendor Recommendations

  • Perform Trip Margin Test
  • Clean Switchgear Enclosure
  • Functional Check Prior to Returning to service

Virginia Power Reactor Trip Breaker Program Description of Breaker Components

Virginia Power Reactor Trip Breaker Program Demonstration of Selected Procedural Maintenance Steps

Procedural Maintenance Steps

  • Manually close and trip breaker
  • Point out areas of lubrication
  • Illustrate how lNTA and shunt trip attachment trip breaker
  • Restrain lNTA, close breaker, release lNTA to trip breaker

Procedural Maintenance Steps

  • Attach a 20 ounce weight to trip bar and repeat above step
  • Point out trendable data parameters and points of measurements
  • Cycle breaker 10 times for final check

~

Concerns

  • Excessive Cycling
  • Excessive Handling
  • Unit Reliability

Excessive Cycling

  • 114 cycles/ refueling for maintenance 36 cycles/ refueling for sutveilance testing 150 cycles/ refueling total
  • Reduces effectiveness of lubrication on lNf A and operating mechanism
  • Increases wear on breaker parts

1 Excessi.ve Handling

  • Probability Of handling daniage
  • Possible alignment problems
e.

Unit Reliability

  • Breaker operations on line increases probability of unit trip
  • Removing and reinstalling breakers increases probability of a unit trip

. I e

Virginia Power Reactor Trip Breaker Prograni Virginia Power's Proposed Maintenance Program/or Reactor Trip Breakers

Major Goals of Program

  • Revise maintenance procedure to reduce number of cycles during maintenance
  • Extend maintenance frequency from 6 to 12 months
  • Trend breaker parameters and performance to determine if future extensions are justified
r

Proposed Program Revision

  • Reduce maintenance procedure from 38 to 27 cycles
  • Perform maintenance procedure annually
  • Perform vendor refurbishment every refueling for at least 3 refueling cycles
  • Proposed program reduces breaker cycles for maintenance from 114 to 3 7 I refueling

( two thirds reduction)

-1

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Justification for 12 Month Maintenance

  • WOG states "maintenance period may be extended to 9-12 months if experience indicates and providing 200 breaker cycles are not exceeded"
  • Increases unit reliability by reducing risk of on line maintenance
  • Trendable data has not indicated any adverse trends in breaker performance during the last 2 years of testing

Proposed Maintenance Program

  • Reduce the amount of handling on the breaker
  • Reduce the amount of wear on breaker parts
  • Reducing breaker operations increases effectiveness of lubrication on lNT A and operating mechanism e

Westinghouse Refurbishment Program

  • Initially every refueling
  • Future adjustments possible based on breaker performance
  • Tolerance check on operating parts
  • Test_ed to new breaker specifications
  • Return breaker to "as new" condition

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  • 1

Proposed Maintenance Program Virginia Power Proposed*

Maintenance Schedule

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e

Proposed Maintenance Program Phase 1 Phase 2 Phase 3 6 Month Maintenance Intervals 12 Month Maintenance Intervals with Westinghouse Refurbishment Program every refueling Lengthen Maintenance Intervals and reduce Refurbishment Program when justified e*

e*

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f Virginia Power e

Reactor Trip Breaker Program Licensing Actions

Licensing Actions

  • Suppleinental response to Generic Letter 83-28 addressing periodic maintenance at 12 month intervals

...

  • 1 e

Virginia Power Reactor Trip Breaker Program Conclusions C

e e

Conclusions

  • Excessive cycling reduces effectiveness of lubrication and increases wear on breaker jJ*

parts

  • On-line maintenance increases the probability of reactor trip

Conclusions

  • Proposed maintenance program reduces number of breaker cycles by 67.5% while continuing to satisfy WOG maintenance program requirements
  • Proposed 12 month maintenance frequency reduces breaker handling and probability of reactor trip

~

e

Conclusions

  • Trending of past performance coupled with breaker refurbishments each refueling justifies 12 month maintenance frequency
  • Change in maintenance frequency from 6 months to 12 months does not affect present or proposed Technical Specification requirements

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Conclusions*

  • Trended breaker parameters and performance from Phase 2 will be used to determine if further extensions are justified
  • Improved maintenance program increases unit reliability e

el

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