ML19305B848
| ML19305B848 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 03/17/1980 |
| From: | Cavanaugh W ARKANSAS POWER & LIGHT CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 1-030-08, 1-30-8, NUDOCS 8003200478 | |
| Download: ML19305B848 (5) | |
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ARKANSAS POWER & LIGHT COMPANY POST OFFICE BOX 551 LITTLE ROCK, ARKANSAS 72203 [501)371-4422 WILLIAM CAVANAUGH 111 i
Vee President March 17, 1980 Generation a Constructon i
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Mr. H. R. Denton, Director.
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- Office of Nuclear Reactor Regulation i
U.S. Nuclear Regulatory Commission.
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- Washington, D.C.
20555
Subject:
Ark.snsas Nuclear One-Unit 1 Docket No. 50-313 License No. DPR-51 Evaluation of the Crystal Rive *r Unit 3 Event on February 26, 1980 (File:
1510)
Gentlemen:
In accordance with your letter of March 6, 1980, Arkansas Power & Light Company herein provides written responses to' Items 6 and 7 of Enclosure 3 to your letter.
Our responses pertain to Arkansas Nuclear One - Unit 1 (ANO-1) and are provided under 10 CFR 50.54(F).
4 ltem 6 Address each_CR-3 proposed corrective action in terms of applicability to your plant.
Question 6 - Address Crystal River proposed corrective actions A.
Immediate Actions 1.
Thorough testing of the NNI-X system to determine cause of initial failure.
Response
This item is not applicable to ANO-1 as no failure of the NNI-X has
-been experienced.
2.
Modify PORV so that NNI failure closes valve.
6 MEMBER MOOLE SOUTH U11uTIES SYSTEM
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Response
Immediate action will be taken via administrative controls to main-tain the PORV block valve ir. the closed position.
Modifications necessary to preclude the automatic opening of the PORV upon NNI failures are being investigated and implementation will be accomplished during the next outage (to shutdown condition) of suf-ficient duration following completion of engineering and equipment procurement, but not later than the next refueling outage.
3.
Modify pressurizer spray valve so that valve does not open on NNI. failure.
Response
i No immediate action is required.
The present ANO-Unit I actuation circuitry allows for timely operator intervention by closure of the pressurizer spray block valve in the event of the pressurizer spray valve opening on NNI failure.
Modifications necessary to preclude the automatic opening of the i
spray valve upon NNI failure are being investigated and implementation will be accomplished during the next outage (to a cold shutdown con-dition) of sufficient duration following completion of engineering and equipment procurement, but not later than the next refueling outage.
4.
Provide positive indication of all three relief or safety valves.
Response
Position indication for the PORV and two safety valves is currently installed and operable. This modification was made during our Jan-uary 1980 outage to comply with Item 2.1.3.a of NUREG-0578. The de-
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tailed method of implementation is described in our January 18, 1980 letter to Mr. Darrell G. Eisenhut.
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5.
Establish procedural control of NNI selector switches.
Response
During normal operations, administrative controls presently exist which define proper instrument selector switch positions so that the most reliable instrument configuration is always available to the oper-ators.
These controls consist of notations on the Control Room Log which give the preferred selector switch positions.
Emergency Procedures are being amplified to provide additional guidance to operators during transients on (1) which instruments to 4.
monitor in the event of various power supply failures and (2) corrective actions that can be taken.
Procedure revisions will be completed by March 31, 1980.
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6.
Train all operators in response to NNI failures.
Response
Simulator training, operator license training and requalification training include NNI/ICS failures and appropriate responses. Power supply failures can be identified via local descriptive drop panel alarms which.are repeated through a common alarm on the Main Control Room Ann'unciator.
4 Information on the Crystal River event has been provided to the operators and interim guidelines for operator action have been pro-mulgated. Upon completion of the procedural modifications discussed in item 5 above, training on the applicable Emergency Procedures will be given.
It is anticipated that this training will be completed by April 15, 1980.
7.
Move 120 VAC ICS "X" power to vital bus.
Response
No corrective action is necessary at ANO-1 since the DC power supplies (redundant plus and minus supplies with diode auctioneering) i for the ANO-1 ICS receive power from two (2) sources; i.e.,
a vital inverter supply and an instrument AC supply from the emergency bus.
Additionally, the external ICS AC loads are provided from the above sources via an automatic transfer switch with the inverter source pre-ferred.
6.
Initiate a more extensive (surveillance) program for the events recorder system.
Response
1.
No separate events recorder system presently exists at ANO-1.
Transient recording is accomplished by the plant computer via Sequence of Events, Post Trips Review, and Alarm Printout. All computer inputs are. verified on a yearly basis via the preventive maintenance program.
The Baily 855 mainframe was replaced in 1977 with a SEL 8600 pro-vided with inverter power.
Subsequently, no instances of transient data loss have '.een experienced due to hardware failures. Additionally, the plant is equipped with a NOVA computer which serves as a backup to the plant-computer for trane.ient data recording.
9.
Pra"~ _ the operator with redundant indication of main y r, parameters.
Response
Modifications necessary to enhance the availability of information concerning main plant parameters are being investigated and implemen-tation will be contingent upon completion of the design and equipment
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Based on equipment delivery, implementation will be accom-plished during the next outage (to a cold shutdown condition) of suf-
_ficient duration following completion of engineering and equipment pro-curement, but not later than the next refueling outage.
An interim report on the findings of our investigation will be provided by May 15, 1980.
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.B.
Actions at Next Refueling Outage 1.
Install indicating lights on vital bus panels.
Response
No corrective action is required. The 'iO-1 design provides for annunciation of vital bus status.
2.
Provide quick access to cabinet fuses.
Response
i No corrective action is required.
The ANO-1 design provides for quick access to cabinet fuses.
3.
Modify EFW circuitry.
Response
This modification was implemented on ANO-1 as a category A item of NUREG-0578 during the January 1980 outage. For further details, see our letter of January 15, 1980, and your letter of February 12, 1980.
C.
Long term Corrective Actions i
Response
A detailed assessment of the long-term corrective actions is not possible at this time.
The present list of possible areas of concern is preliminary in nature and further study is required.
AP&L intends to participate in any B&W generic studies and to review the applicability of any Crystal-River long-term action to ANO-1.
Any identified de-ficiencies will be corrected as necessary in a timely manner.
An in-terim report on the findings of our investigation will be provided by May 15, 1980.
Question 7 Expand your review under IE Bulletin 79-27 to include the implications of the CR-3 event. Inform us of your schedule for completion of this expanded review as discussed on March 4, 1980.
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Response
Our review of IE Bulletin 79-27 is continuing, and has been ex-panded to include the implicatiens of the Crystal River-3 event. As this review will be quite extensive, we estimate several weeks will be required to complete it.
Our submittal of March 12, 1980 to Mr. H. R.
Denton addressed some of the items included in IE Bulletin 79-27.
A partial. response to the Bulletin will be provided by April 1, 1980.
A schedule for submitting supplemental information will be provided at that time.
Ver truly yours, oMf
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William Cavanaugh, II WC:DGM:nak