ML20138R343

SER Accepting Licensee Position on Generic Ltr 83-28,Items 4.2.1 & 4.2.2 Re Reactor Trip Sys Reliability,Provided That Licensee Confirms That Undervoltage Trip Device Roller rivet-armature Clearance Measured W/Armature Down

ML20138R343
Person / Time
Site:	Rancho Seco
Issue date:	12/17/1985
From:	NRC
To:
Shared Package
ML20138R340	List: ML20138R338 ML20138R343
References
GL-83-28, TAC-53144, NUDOCS 8512310197
Download: ML20138R343 (5)

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. SarETY E'lAUJATIC'l PEPOPT

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REACT 9? ??!3 9YSTiu CELIMI'.!TY ITEMS 4.2.1 AN3 1.2.2 0F GENEPIC LETTER 43-23 1

1. INT 2000CTION On July 8,1983, the Nuclear Regulatory Ccemission (NRC) issued Generic Letter (GL) 83-28. This letter addressed intermediate-term actions to be taken by licensees and applicants airned at assuring that a comprehensive program of preventive maintenance and survat11ance testing is implemented for the reactor trip breakers (RTSs) in pressurized water reactors. In particular, Item 4.2 of the letter required the licensees and appilcants to submtt a description of their preventive maintenance and surveillance program to ensure reliable reactor trip breaker operation.

The description of the submitted program was t.o include the following:

GL, Item 4.2.1 A planned program of periodic maintenance, including lubrication, housekeeping, and other items recommenced by the equipment ;upplier.

GL, Item 4.2.2 Trending of parameters affecting operation and r n:ured during testing to forecast degradation of operaticn.

Sacramento Municipal Utility Olstrict (SMU3), the licensee for Rancho Seco, submitted responses to the Generic Letter on November 4, 1983, and May 3 '1985. This report presents an evaluatten of the adequacy of those responses and of the licensee's preventive maintenance and surveillance programs for RTBs. '

1 0512310197 851217 h'DR ADOCK OD000312 '

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2. EVALUATION CRITERIA 2.1 Periefle !'iint+11nc? Pr >1 ram The primary criteria for an acceptable pertoalc maintenance program are contained in Maintenance Instruction GEI-50299EI, Power Circuit j Breakers Types AK-2/2A-15. AK-2/3/2A/3A-25, AKU-2/3/2A/3A-25,* and Servt:e

! Advice 175-9.35 and 175-9.20, by General Electric, and t;RC !! Infor ation

) Notice No. 85-58. Tha NRC Staff Equipment Qualification Branch, has

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reviewed these items and endorsed the maintenance program they describe.

j The criteria include those items in the General Electric instructions and advisortes thJt 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 at six month intervals that should be included in the Itcensee's RTS maintenance program are:

1. Vertftcation 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 different potential; - '

2. Verification of breaker physical cendition, including wiring insulation and termination, all retaining rings, pole bases, are quencher, stationary and movable contacts, and tightness of nuts and bolts;

3. Vertf tcation of proper manual operation of the breakra, including checks for excessive friction, trip bar freedom, latch engagement, operating mechanism alignment and freedom, and undervoltage trip (UVT) device armature freedom:

l 4. Verification of the optimum freedcm of the armature;

5. Vertf tcation of proper trip latch engagement as specified in Service Advice 175-9.3S, Item #S2.

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6. 'lerification of undervoltage pick-up sosting. Js speelf ted in r l Service Advice 115-9.35. Iten #33, and dropout voltage; 7.

Verification that the trip torque required on the trip shaft is l

1ess than 1.5 pound-inches, as specified in Service

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Advice 175-9.3S, Item #S4; "Before" and "Af ter" maintenance

! torque values should be recorded; I t

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Verificat1on of positive tr1pping 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 175-9.35, Item dS5;

10. Sh_unt Trip Attachment (STA) operation vertftcation; I i

11. Examination and cleaning of breaker enclosure;

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

1' 2.2 TreMinn of para ?ters t

Generic l.etter Item 4.2.2 specifies that the Itcensee's preventative '

maintenance and surveillance program is to include trending of parameters affecting operation and measured during testing to forecast degradation of .

operation. The parameters taasured during the maintenance program g

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described above which are appitcable for trending are undervoltage trip attachment dropout voltage, trip torque, and breaker response time for >

undervoltage trip. The staff position is that the above three parameters

' l in addition to the breaker insulation resistance are acceptable and

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] recomended trending parameters to forecast breaker operation degradation  !

or failure. If subsequent experience indicates that any of these l

l 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.

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3. EVALUATION 3.1 Evaluation of th+ Licensee Position en item 4.2.1 The Itcensee states that his preventative m31ntenance program for Rias i is being revised and will contain all the elemants detailed in Secticn 2.l' l of this SER. The licensee states that they will perform maintenance at

) six-month intervals for one refueling cycle. At th3t time, the licensee is I

confident that the results of the S&W Owners Group reliability monitoring program will indicate that a maintenance interval of twelve (12) months or 1 more is appropriate. The staff finds the licensee position on Item 4.2.1 l

to be acceptable, provided the licensee confirms that.the UVT device roller

{ rivet-armature clearance is measured with the UVT armature down in the l energtred position, as recomended in IE Notice No. 85-58.

3.2 Evaluation of the Licentee's Posttien on item 4.2.2 The Itcensee measures trip torque, breaker response time and undervoltage trlp pic'k'up and dropout voltage; the licensee has elected not to monitor insulation resistance on the grounds that SMUD has no expertence to indicate that breaker insulation resistance variation has ever caused unacceptable oper3tten of the Rias or prevented them from performing their safety function. The staff recor rends that all four of the para.aeters identified in Section 2.1 of this SIR be monitored, but finds the licensee l position acceptable, based on Rancho Seco's experience of no insulation resistance-related problems on RT85. The Itcensee is a participant in the

]j 8&W Owners Group Reliability Monitoring Program, which is attempting to o

1 identify the most effective parameters to forecast breaker degradation or failure. The licensee is providing these data to the B&W Owners Group Availability Group, which will perform trend analysis. The Itcensee has identtfled how often data will be collected and how the informJtion derived

! from the analysis will be used to affect periodic maintenance. The staff

finds the licensee position on Item 4.2.2 to be acceptable.

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4. CONCLUSIONS -

Based on a review of the licensee responses, the staff finds the licensee positions on Items 4.2.1 and 4.2.2 of Generic Letter 33.23 to be acceptable, provided the licensee confirmi that the UVT davice roller rivet-armature clearance is measured with the UVT armature down in the energized position, as recommended in IE Notice No. 85 da.

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