ML20133G940

Forwards Response to 850624 Request for Addl Info Re Items 4.2.1 & 4.2.2 of Generic Ltr 83-28, Required Actions Based on Generic Implications of Salem ATWS Events

ML20133G940
Person / Time
Site:	Byron
Issue date:	08/06/1985
From:	George Alexander COMMONWEALTH EDISON CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
0472K, 472K, GL-83-28, NUDOCS 8508090131
Download: ML20133G940 (4)

Text

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(C ~1 Address Reply to. Post Office Box 767 gj Chicago, Illinois 60690 -

l- August 6, 1985 i s Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U~.S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

Byron Station Supplemental Response to Generic Letter No. 83-28,

" Required Actions Based on Generic Implications of Salem ATWS Events" NRC Docket-Nos. 50-454/455 l References (a): Generic Letter No. 83-28 D. G. Eisenhut letter to all OLS and CPS dated July 8, 1983 (NL-83-0003)

(b): B. J. Youngblood to D. L. Farrar letter dated June 24, 1985

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Dear Mr. Denton:

Reference (b) contained a request for additional infnrmation pertaining to Items 4.1, 4.2.1 and 4.2.2 of Generic Letter: 83-28.~ Attached are responses to each of those items.

Please address any questions that you or your staff may have concerning our responses to Generic Letter No. 83-28 to this office... Fifteen copies of this letter and attachment are being

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provided for your use.

Respectfully, G. L. Alexa der Nuclear Licensing Administrator bs Attachment cc: US~NRC Document Control Desk Washington DC .20555 L. N. 01shan - LB1 J. Stevens - NRR J.1G. Keppler --RIII 8g

• RIII Inspector - BY '

l 0472K 8500090131 850006 PDR ADOCK 05000454 P PDR

ATTACHMENT Item 4.1 Reactor Trip System Reliability (Vendor Related Modifications)

The staff states that the applicant did not refer to an April 21, 1983 Westinghouse letter concerning a modification to the undervoltage attachments on DS-416 reactor trip switchgear in its previous responses to Generic Letter 83-28.

. Response: Byron Station has confirmed that the undervoltage trip attachments referred to in the April letter have been installed on Unit 1.

Item 4.2.1 Periodic Maintenance Program for Reactor Trip Breakers.

The staff states the following 4 items were not addressed in previous responses:

1. Periodic maintenance frequency

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

3. Performance of UVTA trip force and breaker load checks

4. Performance of post maintenance functional checks Below are responses to each of the four items.

1. Periodic Maintenance Frequency Response: The station follows the staf f approved maintenance program outlined in the Westinghouse Manual for the DS-416 Reactor-Trip Circuit Breaker, Revision 0, October, 1984. The staff lists in the referenced letter seven items to be done on an increased frequency of 6 months or 500 breakers operations, whichever comes first. These 7 items listed are currently done on a refueling outage basis, or 500 breaker operations, whichever comes first (BHP 4200-016). This preventative maintenance is performed in accordance with the Westinghouse Maintenance Manual, therefore the current refueling outage maintenance schedule will be maintained.

With regard to the second group of 7 items, we concur with the staff recommendations to perform the preventative maintenance each refueling outage or af ter 500 breaker operations, whichever comes first.

2. Performance of Pre-cleaning Insulation Resistance Measurement-and Recording Response: The performance of pre-cleaning insulation resistance measurement and recording is included in station procedure BHP 4200-015 on a refueling outage basis.

3. Measurement of UVT A Trip Force and Breaker Load Checks Response: Measurements of UVTA trip force and breaker load check are currently performed after replacement of the UVTA.

BHP 4200-016 will be revised to include these two measurements on a refueling outage basis.

4. Performance of Post Maintenance Functional Checks Response: BHP 4200-015 provides for verification of breaker operation following inspection and lubrication. In addition, operating procedures 1805 3.1.1-10 and 1 BOS 3.1.1-11 provide for verification of operation of the trip breakers following maintenance. The two operating procedures perform the same functions on different trains.

The staf f also recommends the incorporation of a caution to avoid undocumented adjustments or '

modifications to the RTB's.

Response: The station's maintenance procedures for the Reactor Trip Breakers provide for only adjustments to the trip breakers. To perform additional changes to the breakers, actions would have to be specifically called out in the procedure. The procedures, therefore, do not need to be revised to add a caution statement.

Also, any modifications must follow the station's approved modification program.

Item 4.2.2: Trending of Reactor Breaker Parameters to Forecast Degradation of Operability.

The staff states that the following 4 items are identified as trendable:

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

.. 3 They go on to state that the applicant should identify the organization which will perform the trend analysis, how often the analysis will be performed, and how information derived from the analysis will be used to affect periodic maintenance.

Response:- For each refueling outage after reactor trip breaker maintenance, prior to unit start-up, the Byron Technical Staff will perform a trend analysis on the 4 parameters from item 4.2.2 above. Based on the results of the parameter review and trend analysis, the maintenance frequency may be increased, reduced, or remain the same for the reactor trip breakers.

0472K 9

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