ML17254A643
| ML17254A643 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 11/19/1985 |
| From: | Kober R ROCHESTER GAS & ELECTRIC CORP. |
| To: | Zwolinski J Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML17254A644 | List: |
| References | |
| GL-83-28, NUDOCS 8511260262 | |
| Download: ML17254A643 (7) | |
Text
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ACCESSION VBR;8511260262'OC
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AUTHOR AFFILI AT'IONOBER RE WE Rochester Gas 8 Ele'ctr ic Gor p..
RECIP ~ NAME<
RECIPXE NT AFFIL'IAT'ION ZWULINSKIil'A.
Operat>ng, Reactors Branch 5
SUBJECT!'esponds to SER.re>> Generic-Ltr 83~28iltem 0 ~ 3 ~
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sys test interval will
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I liiZSZZZI ROCHESTER GAS AND ELECTRIC CORPORATION o 89 EAST AVENUE, ROCHESTER, EO IJS N.Y. 14649-0001 ROGER W. KOBER VICE PRESIDENT ElECTRIC 6 STEAM PRODUCTION TELEPHOHC ARKAcooc Tls 546.2700 November 19, 1985 Director of Nuclear Reactor Regulation Attention:
Mr. John A Zwolinski, Chief Operating Reactors Branch No.
5 U.S. Nuclear Regulatory Commission Washington, D.C.
20555
Subject:
RG&E Response to the Safety Evaluation of Generic Letter 83-28, Item 4.3 Reactor Trip Breaker Automatic Shunt Trip
Dear Mr. Zwolinski:
This letter is in response to the Safety Evaluation Report (SER) by the Office of Nuclear Reactor Regulation concerning RG&E responses to Generic Letter 83-28, Item 4.3 submitted by letter dated August 19, 1985.
This letter addresses compliance with NRC Staff positions regarding online testing, provision of test
- features, the provision of bypass breaker position indication, and bypass breaker interlocks.
On-Line Testin Ginna Station has the capability to perform on-line Reactor Trip (RT) breaker testing.
This capability is further discussed below.
- However, the RT breaker testing program has historically been performed each refueling outage except under special circum-stances when on-line testing was performed.
The test data accu-mulated over a
16 year period consists of 24 electrical trips on the two RT breakers each year.
In that period, no failures were recorded.
This indicates a high system availability.
In addition, during the 1985 refueling outage, acceptance testing was performed which verified the independent operation of both the Undervoltage Trip Attachment (UVTA) and the Shunt Trip Attachment (STA) on each RT breaker.
This independent operation testing and trending of parameters resulted in 46 additional electrical tests.
The addi-tional tests provide more reliability data but, more importantly, the trending will provide clear indications of impending component failure or "wear out" sufficiently in advance of any failure to permit repair or replacement.
Based on the historical data, which is presented more fully in the attached Design Analysis addressing
~
the Reactor Trip System Reliability,. there is no need to change the RT breaker test interval.
Decreasing the Reactor Trip System test intervals will not provide sufficiently greater system reli-ability to justify the potential added risks of spurious plant trips and increased challenges to safety systems.
~ 8511260262 851119 PDR ADOCH, 05000244 P
PDR.
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.ROCHESTER GAS AND ELECTRIC CORPORATION TO:
Mr. John A. Swolinski DATE:
November 19, 1985 SHEET NO.
2 Provision of Testin
.Features From the conclusions reached in the
- SER, the existence of test features necessary to perform independent testing apparently was not clear from the drawings provided by RGt'E.
The Staff concluded that since Ginna does not have test switches, on-line testing could not be performed to independently verify the oper-ability of both the STA and the UVTAs.
- However, independent testing can be performed.
Test switches can be used to directly trip the Shunt Trip Attachment independent from the Undervoltage Attachments.
Circuitry associated with the zirconium guide tube
- logic, a unique feature of the Ginna Reactor Protection System (RPS), is used to operate the UVTA independently from the STA.
The zirconium guide tube logic circuitry is not required for reactor protection but assures that the control rods are not engaged in the grippers during plant cooldown when different materials may experience different thermal contraction rates.
Interrupting the zirconium guide tube circuitry causes a
RT trip using only the UVTA coil.
Additional switches will be added to this circuitry during the 1986 outage to further facilitate this independent testing.
Following modification of the RT breaker logic during the 1985 outage to meet the requirements of Section 4.3 of Generic Letter 83-28, independent testing of the trip coils was performed using plant procedures.
In addition, Ginna Station procedure PT-32.0 has been modified to include the on-line testing requirements requested by your letter of August 19, 1985.
B pass Breaker Position Indication Included with the SER was the Staff's position on Reactor Trip Bypass Breaker Position Indication.
This document established a requirement tor separate breaker position indicating lights for each bypass breaker position.
The Staff requires that such lights be provided by the end of the 1986 refueling outage.
Ginna does not have indicatipg lights, however it does have a dedicated annunciator position which alerts the operator that a bypass breaker is closed.
RGGE will also modify the control circuitry associated with the two bypass breaker positions to provide direct red and green light indication on the Main Control Board.
Auxiliary position switches will be interlocked with appropriate cell switches to provide the required indication during the 1986 refueling outage.
The Staff's position on this subject was not included in generic letter 83-28 and therefore, was not part of RGEE's initial response.
The requirement was stated by the NRC Staff reviewers in telephone discussions related to the RGRE submittal, and documented in the position document attached to the SER.
B ass Breaker Interlocks The Staff's position requires that the two bypass breakers be interlocked with cell switches such that only one can be closed at a time.
This requirement also was not part of the generic letter
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'ROCHESTER GAS AND ELECTRIC CORPORATION TO:
Mr. John A. Zwolinski DATE:
November 19, 1985 SHEET NO.
3 arid consequently, not part of RGGE's original response.
These interlocks will be provided consistent with the Staff's requirement during the 1986 outage,,;even, though Ginna",has 'only,one bypass breaker.
The control>'schematics associated with th~
RT breakers will be modified to include the bypass breaker 'position 'indication and the interlocks.
I'evisions to the Ginna Sta'tion Technical Specification are not proposed at this time, consistent with the Design Analysis for on-line testing.
V truly yours,
.e/
R.
W. Kober
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