ML20205T530

SER Supporting Responses to Generic Ltr 83-28,Items 4.2.1 & 4.2.2 Re Reactor Trip Sys Reliability

ML20205T530
Person / Time
Site:	Crystal River
Issue date:	06/09/1986
From:	NRC
To:
Shared Package
ML20205S958	List: ML20205S955 ML20205T530
References
GL-83-28, NUDOCS 8606130344
Download: ML20205T530 (4)

Text

.

o .

\

SAFETY EVALUATION REPORT CRYSTAL RIVER UNIT 3 REACTOR TRIP SYSTEM RELIABILITY -

ITEMS 4.2.1 AND 4.2.2 0F GENERIC LETTER 83-28

1. INTRODUCTION On July 8,1983, the Nuclear Regulatory Commission (NRC) issued Generic 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 to submit a'descr.iption 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:

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

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

Florida Power Corporation, the licensee for Crystal River 3, submitted responses to the Generic Letter on November 11, 1983, September 25, 1985, and October 11, 1985. This report presents an evaluation of the adequacy of those responses and of .he licensee's preventive maintenance and l

surveillance programs for RTBs.

gDR606130344 860606 p ADOCK 05000302 )

PDR I

l . _ .

^

2. EVALUATION CRITERIA 2.1 Periodic Maintenance Program The primary criteria for an acceptable periodic maintenance program are contained in Maintenance Instruction GEI-50299EI*, Power Circuit Breakers, Tyoes AK-2/2A 15, AK-2/3/2A/3A-25, AKU-2/3/2A/3A-25," and Service Advice 175-9.35 and 175-9.20, by General Electric. The NRC Staff, Eauipment Qualification Branch, has reviewed these items and endorsed the maintenance program they describe. The criteria include those items in the General Electric instructions and advisories that relate to the safety e

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 licensee's RTB maintenance program are:

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 different potential;

2. Verification of breaker physical condition, including wiring insulation and termin'ation, all retaining rings, Dole 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, operatina mechanism alignment and freedom, and undervoltage trip (UVT) device armature freedom; 4 Verification of the optimum freedom of the armature;

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

l 2

. o O

6. Verification of undervoltage pick-up setting, as specified in Service Advice 175-9.35, Item #53, and drocout voltage;

7. Verification that the trip torque required on the, trip shaft is less than 1.5 pound-inches, as specified in Service Advice 175-9.3S, Item #54; "Before" and "After" maintenance torque values should be recorded;

8. Verification of positive tripping by checking the adjustment between the UVT device and trip paddle as specified in Service Advice 175-9.35, Item #55;

9. Verification of proper trip response time as specified in Service

~

Advice 175-9.35, Item #S6;

10. Shunt Trip Attachment (STA) operation verification;

11. Examination and cleaning of breaker enclosure;

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

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 degradation of operation. The parameters measured during the maintenance 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 Dosition is that the above three parameters in addition to the breaker insulation resistance are acceptable and recommended trending oarameters to forecast breaker ooeration degradation or failure. If subsequent 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.

3

I e o.

3. EVALUATION 3.1 Evaluation of the Licensee Position on Item 4.2.1 The licensee states that his preventative maintenance program for RTBs contains all the elements detailed in Section 2.1 of the SER. The licensee states that periodic maintenance is performed on an annual basis, with a functional test performed monthly. The staff finds that the licensee's extended maintenance interval is acceptable. This acceptance is based on GE's recommendation that maintenance on RTBs located in mild environments 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 RTBs because of their location in a mild environment and reduced service duty at Crystal River (less than 200 RTB cycles annually).The staff finds the licensee position on Item 4.2.1 to be acceptable, provided the licensee confirms that the UVT device roller-rivet clearance is measured with the UVT armature down in the energized positio.n, as recommended in IE Notice No. 85-58.

3.2 Evaluation of the Licensee's Position on Item 4.2.2 The licensee states that he will compile and submit to B&W trend data for RTB trip response time, trip shaft torque, and UVT device pickup and dropout voltage. The B&W Owners Grouo Reactor Trip Breaker Reliability Monitoring Program is attempting to identify the most effective parameters to forecast breaker degradation or failure. The staff finds the licensee position on Item 4.2.2 to be acceptable.

4. CONCLUSIONS Based on a review of the licensee responses, the sta#f finds the licensee responses on Items 4.2.1 and 4.2.2 of Generic Letter 83-28 to be acceptable, provided that the licensee confirms that the UVT device roller rivet-armature clearance is measured with the VVT armature down in the energized position, as recommended in IE Notice No. 85-58.

Principal contributor: E. Rowney Dated: June 9, 1986 4