ML20236C000

Safety Evaluation Re Generic Ltr 83-28,Items 4.1,4.2.1 & 4.2.2 Concerning Preventive Maint Program for Reactor Trip Breakers/Maint & Trending.Licensee Position on Items Acceptable

ML20236C000
Person / Time
Site:	Waterford
Issue date:	10/20/1987
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20236B987	List: ML20236B985 ML20236C000
References
GL-83-28, NUDOCS 8710260452
Download: ML20236C000 (4)

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UNITED STATES

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I SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION-GENERIC LETTER 83-28, ITEM 4.1, 4.2.1 AND 4.2.2 ,

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PREVENTATIVE MAINTENANCE PROGRAM FOR REACTOR TRIP BREAKERS / MAINTENANCE A1 WATERFORD STEAM ELECTRIC' STATION, UNIT 3  !

i DOCKET NO. 50-382

1.0 INTRODUCTION

On July 8, 1983, the Nuclear Regulatory Commission (NRC) issued Generic t Letter (GL) 83-28. This letter addressed intermediate-term actions to be  ;

taken by licensees and applicants aimed at assuring that a comprehensive program of preventive maintenance and surveillance testing is implemented for the reactor trip breakers (RTBs) in pressurized water reactors. In particular, Item 4.2 of the letter required the licensees and applicants i to submit a description of their preventive maintenance and surveillance program to ensure reliable reactor trip breaker operation. .The description of the submitted program was to include the following: 4 GL, Item 4.1 All vendor-recommended reactor trip breaker modifica-tions shall be-reviewed to verify that either: each  ;

modification has, in fact, been implemented, or i a written evaluation of the technical reasons for not-implementing a modification exists.

GL, Item 4.2.1 A planned program of periodic maintenance, including lubrication, housekeeping, and other items recommended j by the equipment supplier.

GL, Item 4.2.2 Trending or prameters affecting operation and measured during testing to forecast degradation of operation.

Louisiana Power and Light, the licensee for Waterford-3, submitted responses to Items 4.1, 4.2.1 and 4.2.2 of the Generic Letter on November 4,1983, )

November 30, 1984, and September 2, 1987. This report presents an evalua- I i

tion of the adequacy of those responses and of the licensee's preventive maintenance and surveillance programs for RT8s.

j 2.0 EVALUATION CRITERIA 2.1 Periodic Maintenance Program f i

The primary criteria for an acceptable periodic maintenance program 1 are contained in Maintenance Instruction GEI-50299EI*, " Power Circuit l Breakers, Types AK-2/2A-15, AK-2/3/2A/3A-25, AKU-2/3/2A/3A-25," and

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8710260452 871020

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Service Advice 175'-9.3S and 175-9.20, by General Electric (GE),'and.

NRC IE1Information Notice No. 85-58. The NRC staff, the former -

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s Equipment Qualification Branch (the NRC was re-organized on April 13, 1987), reviewed these items and endorsed the maintenance program they- ,

describe. -The criteria include 1those items in the General Electric '

instructions 'and advisories that relate to the safety ' function of the breaker, supplemented by those measurements which must be taken to accumulate data for trending. Those items identified for maintenance

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at six month intervals that should be included in the licensee's.RTB J maintenance' program are: l c

1. Verification of breaker cleanliness and insulation structure; all foreign materials, such as paint, dust, or oil, should be .

removed to prevent electrical breakdown between points of l l

different potential;-

'2. Verification of breaker physical condition, including wiring insulation and termination, all retaining rings, pole bases, arc ,

quencher, stationary and movable contacts, and tightness of nuts and bolts;

3.  : Verification of proper manual operation of the-breaker, including checks for excessive friction, trip bar freedom,. latch engagement, i o

d freedom, and undervoltage trip l

.(perating UVT) devicemechanism alignment an armature freedom; l

4. Verification of the optimum freedom of the armature;

5. Verification of proper trip latch engagement as specified in Service Advice.175-9.35, Item #S2;

6. Verification. of undervoltage pick-up setting, as specified in Service Advice 175-9.35, Item #S3, and dropout voltage;

7. Verification that the trip torque required on the trip shaft is less than 1.5 pound-inches, as specified in Service Advice l 175-9.3S, Item #S4; "Before" and "Af ter" maintenance torque l values should be recorded; l

8. Verification of positive tripping by checking the adjustment between the UVT device and trip paddle as specified in Service Advice 175-9.3S Item #S5;

9. Verification of proper trip response time as specified in Service Advice 175-9.3S, Item #S6;

10. Shunt Trip Attachment (STA) operation verification; I

11. Examination and cleaning of breaker enclosure;

12. Functional test of the breaker prior to returning it to service.

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2.2 Trending of Parameters

' Generic Letter Item 4.2.2 specifies that the licensee's preventative  ;

maintenance and surveillance program is to include trending of parameters affecting operation and measured during testing to forecast degradati_on of operation. The parameters measured during the main-tenance program described above which are applicable for trending are undervoltage trip attachment dropout voltage, trip torque, and breaker response time for undervoltage trip. The staff position is l that the above three parameters in addition to the breaker insulation resistance are acceptable and recommended trending parameters to i forecast breaker operation degradation or failure. If subsequent l experience indicates that any of these parameters is not useful as a tool to anticipate failures or degradation, the licensee may, with

' justification and NRC approval, elect to remove that parameter from  ;

those to be tracked. .1 3.0 EVALUATION 3.1 Evaluation of the Licensee's Position on Item 4.1 )

The licensee has confirmed that the Reactor Trip Breakers have been ,

l refurbished in accordance with vendor-recommendations. We find the licensee position on Item 4.1 meets the staff requirements and is acceptable.

3.2 Evaluation of tne Licensee's Position on Item 4.2.1 The licensee's responses confirmed that the periodic maintenance 1 program for the Reactor. Trip Breakers used at Waterford-3 includes all of the items listed in Paragraph 2.1 of this safety evaluation, j The licensee's responses also stated that periodic maintenance on the RTBs will be performed annually, and that a six month interval is too short given the frequency of breaker operation. l 1

We find that the licensee'r extended maintenance interval meets tne staff requirements and is acceptable. This acceptance is based on l i

GE's recommendation that maintenance on RTBs located in mild environ-ments should be performed annually. The vendor recommendation that RTBs located in harsh environments or experiencing severe load conditions be maintained more frequently is not applicable to these i RTBs because of their location in a mild environment and reduced service duty at Waterford-3. We find the licensee's position on Item 4.2.1 meets the staff requirements and is acceptable.

3.3 Evaluation of the Licensee's Position on Item 4.2.2 The licensee will trend undervoltage trip attachment dropout voltage, l trip force, and breaker response time. They do not trend breaker insulation resistance. The licensee will perform any appropriate  !

j preventive or corrective maintenance if the analysis of the trend d.ita indicates need for such action. We find that the licensee's  !

position on Item 4.2.2 is acceptable.

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4.0 . CONCLUSIONS Based on its review of the licensee's responses, the staff finds the licensee's position on Items 4.1, 4.2.1 and 4.2.2 of Generic Letter 83-28 to be acceptable. <

Principal Contributor: A. Toalston Dated: October 20, 1987 l i

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