ML17254A512
| ML17254A512 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 08/12/1985 |
| From: | NRC |
| To: | |
| Shared Package | |
| ML17254A511 | List: |
| References | |
| GL-83-28, NUDOCS 8508140098 | |
| Download: ML17254A512 (5) | |
Text
ENCLOSURE
'AFETY EVALUATION R.
E.
GINNA POWER PLANT REACTOR TRIP SYSTEM RELIABILITY ITEMS 4.2.1 AND 4.2.2 OF 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 l'icensees and applicants 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:
GL, Item 4.2.1 A planned program of periodic maintenance, including lubrication, housekeeping, and other items recommended by the equipment supplier.
0'L, Item 5.2.2 Trending of parameters affecting operation and measured during testing to forecast degradation of operation.
Rochester Gas and Electric Corporation, the licensee for Ginna, submitted responses to the Generic Letter on November 4, 1983, and
/
February 28, 1985.
This report presents an evaluation of the adequacy of those responses and of the licensee's preventive maintenance and surveillance programs for RTBs.
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2.
EVALUATION CRITERIA
- 2. 1 Periodic Maintenance Pro ram The primary s'ource for periodic maintenance program criteria is Westin house Maintenance Pro ram for DB-50 Reactor Tri Switch ear, Rev.
0.
This document is the breaker manufacturer's recommended maintenance program for the DB-50 breaker and provides specific direction with regard to schedule, inspection and testing, cleaning, lubrication, corrective maintenance and record keeping.
The document was reviewed to identify those items that contribute to breaker trip reliability consistent with the generic letter.
Those items identified for maintenance at six
.month intervals that should be included in the licensee's RTB maintenance program are:
2 ~
30 ~
4.
5.
6.
7.
8.
9 10.
12.
13.
14.
15
'erification of trip bar freedom Verification of operating mechanism alignment and freedom Retaining ring verification Verification of nut and bolt tightness Verification of pole bases physical condition Verification of arcing and main contacts physical condition Verification of insulating link's physical condition Verification of wiring insulation and termination physical condition Verification of arc chute physical condition Verification of breaker cleanliness Undervoltage Trip Attachment (UVTA) dropout voltage test and lubrication Shunt Trip Attachment (STA) operation verification Verification of operation of auxiliary switches Inspection of positioning lever condition Functional test of the breaker prior to returning it to service.
The licensee's RTB periodic maintenance should also include, on a
refueling interval basis:
16, Verification of cell interlock operation 17.
Examination and cleaning of breaker enclosure 18.
Measurement of trip force required 19.
Functional test of the breaker prior to returning it to service 20.
Breaker response time for undervoltage trip.
All of the items listed above are recommended by the manufacturer except Item 20.
This item is the breaker trip response time measurement which is implied by the IEEE Standard 279-1971.
2.2 Trendin of Parameters 9~~o~'~
~ etter 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 force, and breaker response time for undervoltage trip..
The staff position is that the above three parameters in addition to the breaker, insulation resistance are acceptable and recommended trending parameters to forecast breaker operation 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.
EVALUATION 3.1 Evaluation of the Licensee Position on Item 4.2.1 The licensee states that his preventative maintenance program for RTB's has been revised and will have been approved and implemented by the completion of the scheduled 1985 refueling outage.
He further states that
his procedures will conform in intent to the referenced Mestinghouse maintenance program; however, the licensee has neither included hi's revised procedures nor affirmed that they include each of the elements detailed in Section
- 2. 1 of this SER.
The staff finds that the licensee has not provided a reviewable description of his preventative maintenance program..
The licensee performs RTB preventative maintenance on a 12-month
- interval, based on prior acceptable RTB maintenance performance.
The staff finds this interval acceptable provided the licensee confirms that 200 RTB trips are not exceeded during the interval.
The staff considers Item 4.2. 1 of Generic Letter 83-28 to be open pending receipt of a reviewable description of an acceptable maintenance
- program, and confirmation that 200 RTB trips are not exceeded during a
12-month interval.
3.2 Evaluation of the Licensee's position on Item 4.2.2 The licensee has committed to performance of trend analysis of trip force, undervoltage trip dropout voltage and insulation resistance; the licensee performs response time testing, but does not trend breaker response time.
The licensee has identified the organization which will perform trend analysis, how often it will be performed and how the information 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.
4.
CONCLUSIONS The staff considers Item 4.2.1 of Generic Letter 83-28 to be open pending receipt of a reviewable description of an acceptable maintenance
- program, and confirmation that 200 RTB trips are not exceeded during a
12-month interval.
The staff finds the licensee position on Item 4.2.2 to be acceptable.