ML20127M600

Forwards Request for Addl Info Re Util Responses to Generic Ltr 83-28,Items 4.1,4.2.1 & 4.2.2 Concerning Reactor Trip Sys Reliability & Periodic Maint Program for Reactor Trip Breakers.Response Requested within 45 Days of Ltr Receipt

ML20127M600
Person / Time
Site:	Byron
Issue date:	06/24/1985
From:	Youngblood B Office of Nuclear Reactor Regulation
To:	Farrar D COMMONWEALTH EDISON CO.
References
GL-83-28, NUDOCS 8507010292
Download: ML20127M600 (7)

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Docket Nos.: STN 50-454 JW 2 41985 and STN 50-4i,5 Mr. Dennis L. Farrar Director of Nuclear Licensing Commonwealth Edison Company P. O. Box 767 Chicago, Illinois 60690

Subject:

Request for Additional Information - Items 4.1, 4.2.1, and 4.2.2 of Generic Letter 83-28 We have reviewed your responses to Generic Letter 83-28 dated November 5, 1983, February 29, 1984, June 1, 1984 and October 10, 1984 with respect 1 to Items 4.1, 4.2.1 and 4.2.2. Provide a response within 45 days of re-ceipt of this letter to the enclosed request for additional information.

Contact the Byron Project Manager, L. Olshan, at (301) 492-7070, if clarification is needed.

Sincerely, Oli1GINAL SIGNED BY:

B. J. Youngblood, Chief Licensing Branch No. 1 Division of Licensing

Enclosure:

As stated cc: See next page

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JUN 2 4 585 Mr. Dennis L. Farrar Director of Nuclear Licensing Commonwealth Edison Company Post Office Box 767 Chicago, Illinois 60690 cc: Mr. William Kortier Ms. Diane Chavez Atomic Power Distribution 5?9 Gregory Street Westinghouse Electric Corporation Rockford, Illinois 61108 Post Office Box 355 Pittsburgh, Pennsylvania 15230 Regional Administrator U. S. t;RC Region III Michael Miller 799 Roosevelt Road Isham, Lincoln & Beale Glen Ellyn, Illinois 60137 One First National Plaza 42nd Floor Joseph Gallo, Esq.

Chicago, Illinois 60603 Isham, Lincoln & Beale Suite 840 Mrs. Phillip B. Johnson 1120 Connecticut Avenue, N.W.

1907 Stratford Lane Washington, D. C. 20036 Rockford, Illinois 61107 Douglass Cassel, Esq.

Dr. Bruce von Zellen 109.N. Dearborn Street Department of Biological Sciences Suite 1300 Northern Illinois University Chicago, Illinois 60602 DeKalb, Illinois 61107 Ms. Pat Morrison Mr. Edward R. Crass 5568 Thunderidge Drive Nuclear Safeguards & Licensing Rockford, Illinois 61107 Sargent & Lundy Engineers 55 East Monroe Street Ms. Lorraine Creek Chicago, Illinois 60603 Rt. 1, Box 182 Manteno, Illinois 60950 Mr. Julian Hinds ,

U. S. Nuclear Regulatory Commission Byron / Resident Inspectors Offices 4448 German Church Road Byron, Illinois 61010 Mr. Michael C. Parker, Chief Division of Engineering Illinois Department of Nuclear Safety 1035 Outer Park Drive Springfield, Illinois 62704

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Enclosure BYRON STATION REQUEST FOR ADDITIONAL INFORMATION GL 83-28, ITEMS 4.1, 4.2.1 AND 4.

2.2 INTRODUCTION

Commonwealth Edison, the applicant for Byron Station, submitted their responses to Generic Letter 83-28 on November 5,1983, February 29, 1984, June 1, 1984, and October 10, 1984. The responses have been reviewed with respect to Items 4.1, 4.2.1 and 4.2.2 of the Generic Letter.

I. Item 4.1 - Reactor Trip System Reliability (Vendor-Related Modifications).

The applicant response states that Byron Station is proceeding with vendor recommendations for DS-416 breakers as delineated in the Westinghouse March 31, 1983 letter to Mr. R. C. DeYoung of the NRC. The applicant will replace the undervoltage attachments on DS-416 reactor trip switchgear prior to core load.

The applicant did not refer to the vendor recommendations for the DS-416 breakers that supercede those of March 31, 1983, specifically the Westinghouse April 21, 1983 letter to Mr. R. C. DeYoung. In this letter, Westinghouse committed to replace UVTAs on 05-416 breakers. The new attachments have modified (widened) grooves to accommodate the new retaining rings. Quality control and field installation procedures are also provided to ensure proper critical design dimensions and alignment. The applicant is to submit to the NRC either:

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A statement confirming that all vendor-recommended 1.

D5-416 modifications have been implemented; or I

, 2. A written evaluation of the technical reasons for

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. not implementing any vendor recommended f modification. 1 II. Item 4.2.1 - Periodic Maintenance Program for Reactor Trip Breakers. .(

II.1 Criteria for Evaluating Compliance with Item 4.2.1 The Byron Station Units 1 and 2 Reac, tor Trip Systems

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utilize, Westinghouse 05-416 circuit breakers. The e,

prfurycriteriaforanacceptablemainter,epceprogram for the DS-416 Reactor Trip Breaker (RTB) are contained 3

in Westinghouse Maintenance Manual for the DS-416 ,

, Reactor Trip Circuit Breaker, Revision 0, October 1984. The NRC' staff, Equipment Qualification Branch, has reviewed this document and endorsed the maintenance' program described in it. More specifically, thecriteriausedtoevaluadecomplianceincludethose items in this document that relate to the safety function of the breaker, supplemented by those measures

/ that must be taken to acadulate data for trending.

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'II.2 Issues Relating >t.(. g , M I

l The applicant response states that their maintenance procedure (BHP 4200-015) for the DS-416 RTBs incorporates lubrication, housekeeping and other items recommended by the Westinghouse technical man')al a

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supplied with the original equipment. The applicant procedure was included as part of the submittal and has been reviewed.

The Byron Station periodic maintenance program for the reactor trip ~

breakers should include, on a six-month basis (or when 500 breaker operations have been counted, whichever comes first):

' 1. General inspection to include checking of breaker's cleanliness, all bolts and nuts, pole bases, arc chutes, insulating link, wiring and auxiliary switches;

2. The retaining rings inspection, including those on the undervoltage trip attachment (UVTA) and shunt trip attachment (STA);

3. Arcing and main contacts inspection as specified by the Westinghouse Maintenance Manual;

4. UVTA check as specified by the Westinghouse Maintenance Manual, including replacement of UVTA if dropout voltage is greater than 60% or less than 30% of rated UVTA coil voltage;

5. STA check as specified by the Westinghouse Maintenance Manual;

6. Lubrication as specified by the Westinghouse Maintenance Manual;

7. Functional check of the breaker's operation prior to returning it to service.

The Byron Station periodic maintenance program for the reactor trip breakers should include, on a refueling interval basis (or when 500 breaker

-operations have been counted, whichever comes first):

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1. Pre-cleaning insulation resistance measurement and recording;

2. RTB dusting and cleaning;

3. Post-cleaning insulation resistance measurement and recording, as specified by the Westinghouse Maintenance Manual;

4. Inspection of main and secondary disconnecting contact's, bolt tightness, secondary wiring, mechanical parts, cell switches, instruments, relays and other panel mounted devices;

. 5. UVTA trip force and breaker load check as specified by the Westinghouse Maintenance Manual;

6. Measurement and recording RTB response time for the undervoltage trip;

7. Functional test of the breaker prior to returning to service as specified by the Westinghouse Maintenance Manual.

The maintenance procedure should include a c'aution to the maintenance personnel against undocumented adjustments or modifications to RTBs.

The applicant's responses to date address most of the items detailed above. Those items not addressed are:

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1. Periodic maintenance frequency

2. Performance of pre-cleaning insulation resistance measurement and recording f

3. Performance of UVTA trip force and breaker load checks t

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4. Performance of post-maintenance functional tests.

III. Item 4.2.2 - Trending of Reactor Trip Breaker Parameters to Forecast Degradation of Operability.

III.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 (a) undervoltage trip attachment dropout voltage, (b) trip force, (c) breaker response time for undervoltage trip, and (d) breaker insulation resistance.

III.2 Issues Relating to Item 4.2.2 The applicant states that the Byron Station Maintenance History Program will trend breaker response times.

The applicant is to commit to inclusion of trip force, breaker response time and dropout voltage for undervoltage trip and breaker insulation resistance as 1

trending parameters. The applicant 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.

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