ML18092A748
| ML18092A748 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 08/19/1985 |
| From: | Corbin McNeil Public Service Enterprise Group |
| To: | Varga S Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML18092A749 | List: |
| References | |
| GL-83-28, NUDOCS 8508290131 | |
| Download: ML18092A748 (5) | |
Text
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Public Service Electric and Gas Company Corbin A. McNeill, Jr.
Vice President -
Public Service Electric and Gas Company P.O. Box236, Han cocks Bridge, NJ 08038 609 339-4800 Nuclear August 19,' 1985 Director of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission 7920 Norfolk Avenue Bethesda, MD 20014 Attention:
Mr. Steven A. Varga, Chief Operating Reactors Branch, No. 1 Division of Licensing
Dear Mr. Varga:
REQUEST FOR ADDITIONAL INFORMATION CONCERNING MPA B-81, ITEMS 4.2.l AND 4.2.2 -
PREVENTIVE MAINTENANCE PROGRAM FOR REACTOR TRIP BREAKERS/
MAINTENANCE AND TRENDING (GENERIC LETTER 83-28)
SALEM UNITS 1 AND 2 DOCKET NOS. 50-272 AND 50-311 Pursuant to the subject request for additional information dated June 17, 1985 concerning Reactor Trip Breakers, PSE&G herewith submits its response in the attachment to this letter.
Should you have any questions do no hesitate to contact us.
Attachment C
Mr. Donald c. Fischer Licensing Project Manager Mr. Thomas J. Kenny Senior Resident Inspector Sincerely,
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. 6506290131 850819
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SALEM UNITS l AND 2 REQUEST FOR ADDITIONAL INFORMATION GENERIC LETTER 83-28 ITEM 4. 2.1 """. Periodic. Maintenanc.e.Program for. Reactor.. Tri2 Breakers NRC REQUEST:
1.1 Criteria for Evaluatin_Sl.Com2liance with Item 4.2.l The Salem Units 1 and 2 Reactor Trip Systems utilize Westinghouse DB-50 circuit breakers.
The primary criteria for an acceptable maintenance program for this breaker are contained in Maintenance.Pro.s:i:ram for DB-50 Reactor Tri_£ Switch2ear, Rev. O, dated October 14, 1983, by Westinghouse.
The NRC Staff, Equipment Qualification Branch, has reviewed and endorsed the Westinghouse Maintenance Program for DB-50 Switchgear.
Specifically, the criteria used to evaluate compliance includes those items in the Westinghouse program that relate to the safety function of the breaker, supplemented by those measures that must be taken to accumulate data for trending.
1.2 Issues Relating to Item 4.2.1 Does the current Salem Units 1 and 2 periodic maintenance program for the reactor trip breakers inclu9e, on a six month basis:
- 1.
Verification of trip bar freedom;
- 2.
Verification of operating mechanism alignment and freedom, using the procedure identified in the Westinghouse program;
- 3.
Retaining ring verification, 33 places;
/
- 4.
Verification of nut and bolt tightness;
- 5.
Verification of pole bases physical condition;
- 6.
Verification of ar6ing and main contacts physical condition, using the procedure identified in the Westinghouse program; 7
- Verification of insulating link's physical condition;
- 8.
Verification of wiring insulation and termination physical condition;
- 9.
Verification of arc chute physical condition;
- 10.
Verification of breaker cleanliness;
- 11.
Undervoltage Trip Attachment (UVTA) dropout voltage test and lubrication, using the procedure identified in the Westinghouse program;
- 12.
Shut Trip Attachment (STA) operation verification;
- 13.
Verification of operation of auxiliary switches;
- 14.
Inspection of positioning lever condition, using the procedure identified in Westinghouse progr*am;
- 15.
Functional test of the breaker prior to returning it to service, using the procedure identified in the Westinghouse program; Does the current Salem Uni ts 1 and 2 p.eriodic maintenance program for the reactor trip breakers include, on a refueling interval basis:
- 1.
Verification of cell interlock operation;
- 2.
Examination and cleaning of breaker enclosure;
- 3.
Measurement of trip force required, using the procedure identified in the Westinghouse program;
- 4.
Breaker response time for undervoltage trip;
- 5.
Functional test of the breaker prior to returning it to service, using the procedure identified in he Westinghouse program; The licensee is to confirm that the periodic maintenance program includes these 20 items at the specified intervals or commit to their inclusion.
PSE&G.RESPONSE:
The periodic maintenance program for the Salem reactor trip breakers was revised to include all of the inspection and testing requirements which were identified in the Maintenance Proj;iram for DB~SO Reactor Trip Switchgear, Revision O
- Although the PSE&G procedure may differ from the Westinghouse procedure, it presently addresses all 20 items {and will continue to do so) identified above.
The PSE&G procedure prescribes additional maintenance activities beyond the Westinghouse procedure as described below:
- 1.
The preventiv~ maintenance performed at the 6 month intervals is the same as that performed during refueling outages except during refueling the switchgear cabinet components are maintained and the undervoltage trip attachments (UVTA) are replaced.
- 2.
The Westinghouse procedure requires measurement of breaker trip force only during refueling outages.
PSE&G performs this measurement during each 6 month maintenance interval and performs 3 "as found" and 3 "as left" measurements.
Additionally, the PSE&G method of measuring trip bar force utilizes calibrated weights and a pulley system.
- 3.
The Westinghouse procedure requires that breaker response time for undervoltage trip be measured during each refueling outage.
The PSE&G procedure requires that this measurement be made during each 6 month maintenance interval, with 3 "as found" and 3 "as left" measurements performed.
In addition to undervoltage trip timing, PSE&G performs shunt trip timing and breaker closure timing.
These measurements are also performed during each 6 month maintenance interval, with 3 "as found" and 3 "as left" measurements.
- 4.
The Westinghouse functional check prior to returning to service requires the breaker be closed and tripped both electrically and manually to demonstrate that all functions including closing, shunt tripping and undervoltage tripping (10 UV trips) are normal and a visual inspection of the positioning lever.
The PSE&G functional test of the breaker after cleaning, lubrication, and inspection not only includes the 10 UV trip test but also consists of gathering "as left" data on breaker trip bar forces, and UVTA and shunt trip timing consisting of 3 measurements each.
The functional test also includes a test of the cell interlock lever.
In addition, PSE&G performs a final functional test from the Solid State Protection System.
All of the above tests are performed at each 6 month interval.
Attached is a copy of M3Q-2 (Revision 8), which is the procedure presently in use for the reactor trip breakers.
Also attached is M3Q-3 which is utilized for the reactor trip breaker cubicle cleaning and inspection
- Item.4. 2. 2
~. Trending.. of Reactor TriE Breaker. Parameters to Forecast Degradation of.012erabilit,.y NRC REQUEST:
J 2.1 Criteria for Evaluating Compliance with Item~ 4.2~2 Four parameters have been identified as trendable and are included in the criteria for evaluation.
These are (1) undervoltage trip attachment dropout voltage, (2) trip force, (3) breaker response time for undervoltage trip, and (4) breaker insulation resistance.
2.2 Issues Relatin_g.. to Item 4.1.2 The licensee is to commit to inclusion of trip force, breaker response time and dropout voltage for undervoltage trip and breaker insulation resistance as trending parameters.
The licensee should also identify the organization which will perform trend analysis, how often the analysis will be performed and how the information derived from the analysis will be used to affect periodic maintenance
- PSE&G RESPONSE:
PSE&G presently trends the four parameters identified in 2.1 (and will continue to do so) and, in addition, trends breaker closure timing, shunt trip timing, UVTA output force margin, shunt trip bar clearance, UVTA trip bar clearance, shunt trip coil resistance and UVTA coil resistance.
The data is initially reviewed by the Salem Maintenance Department for acceptance to the predefined acceptance criteria.
Nuclear Engineering plots the data and analyzes the trends to gage the acceptance of the maintenance performed.
The data analysis has been used to modify the measuring techniques to eliminate human error and provide consistency in measuring the required forces.
Presently, PSE&G performs three measurements each of "as found" and "as left" breaker data.
This data collection requires breaker cycling which will affect breaker life.
PSE&G will use the data to propose elimination of breaker operations in areas where three measurements are not warranted.
Additionally, data analysis is being used to verify the adequacy of the 6 month maintenance interval *