ML20137F858

Forwards Responses to 850624 Request for Info Re Items 4.1, 4.2.1 & 4.2.2 of Generic Ltr 83-28, Required Actions Based on Generic Implications of Salem ATWS Events. Undervoltage Trip Attachments Will Be Installed Prior to Fuel Load

ML20137F858
Person / Time
Site:	Braidwood
Issue date:	08/21/1985
From:	George Alexander COMMONWEALTH EDISON CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
0534K, 534K, GL-83-28, NUDOCS 8508270109
Download: ML20137F858 (4)

Text

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s Commonwealth Edison

/ one First Nrtion11 Plaza, Chicago, liknoss C Address Reply to. Post Office Box 767

- Chicago. Illinois 60690 August 21, 1985 Mr. - Harold R.- Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington,- DC 20555

$9t@n t Ord13 wood Station

. Supplemental Response to Generic Letter ta, m gA,

" Required Actions Dr. ad wh Geaur1<

Implications of Salem ATWS Events" NRC Docket Nos. 50-456/457 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

Dear Mr. Denton:

Reference (b) contained a request for additional information pertaining to Items 4.1, 4.2.1 and 4.2.2 of Generic Letter 83-28 for Byron Station. Attached are responses to each of those same questions for Braidwood. Station.

Please address any questions that you or your staff may have concerning our-responses to Generic Letter No. 83-28 to this o f fice . Fif teen copies of this letter and attachment are being provided for your use.

Respectfully, f

G. L. Alex nder Nuclear Licensing Administrator bs Attachment cc: US NRC Document Control Desk Washington DC 20555 J. Stevens'- LB1

.J. G. Keppler - RIII RIII Inspector - BW O[g

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E l ATTACHMENT Item 4.1 - Reactor Trip System Reliability (Vendor-Related Modifications).

The applicant is to submit to the NRC either:

1. A ststempat confirming that all vendor-recommended D5-416 modifications have been implemented; or

2. A written evaluation of the technical reasons for not implementing any vendor recommended modification.

Response: Braidwood Station has confirmed that the undervoltage trip attachments referred to in the April letter will be installed on l Units'l and 2 prior to fuel load.

Item 4.2.1 - Periodic Maintenance Program for Reactor Trip Breakers.

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

l. 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. It should be noted that BwHP 4002-010 is in draft form, with an On-site review ' scheduled for the week of August 26, 1985.

1. Periodic Maintenance Frequency Response: The station will follow the staff approved maintenance program outlined in the Westinghouse Manual for the DS-416 Reactor Trip rircuit Breaker, Revision 0,.0ctober, 1984. The staff lists in the referenced letter seven items to be done on an m.__-

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1 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 (BwHP 4002-010). 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 after 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 BwHP 4002-010 on a refueling outage basis.

3. Measurement of UVTA-Trip-Force and Breaker Load Checks Response: Measurements of UVTA trip force and breaker load check will be performed.

BwHP 4002-010 includes these two measurements on a refueling outage basis.

4. Performance of Post Maintenance Functional Checks m

Response: BwHP 4002-010 provides for verification os breaker operation following inspection and lubrication. In addition, operating procedures 1Bw0S 3.1.1-10 and 18w0S 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 staff also recommends the incorporation of a caution to avoid undocumented adjustments or modifications to the RTB's.

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Response: The station's maintenance procedure for the Reactor Trip Breakers provides 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 procedure, therefore, does 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.

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, the Braidwood 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 'requency may be increased, reduced, or remain the same for the reactor trip- breakers.

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