ML17331A673

Responds to IE Insp Repts 50-315/80-15 & 50-316/80-14. Corrective Actions:Alarm Bistable Recalibr to Proper Setpoint & Design Change Initiated to Correct Indicator & Alarm Problems

ML17331A673
Person / Time
Site:	Cook
Issue date:	01/23/1981
From:	Hunter R INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML17331A670	List: ML17331A668 ML17331A671 ML17331A672 ML17331A673
References
AEP:NRC:00152, AEP:NRC:152, NUDOCS 8103100577
Download: ML17331A673 (7)

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P. O. BOX 18 BOWI-IHG GREEN STATION HEW YORK, H. Y. 10004 January 23, 198 AEP:NRC:00512 Donald C. Cook Nuclear Plant Unit Nos. 1 and 2 Docket Nos. 50-315 and 50-316 License Nos. DPR-58 and DPR-74 IE Insp ction Report Nos. 50-315/80-15; 50-316/80-14 Hr. James G. Keppler, Regional Director U.S. Nuclear Regulatory Commission Office of Inspection and Enforcement, Region III Glen Ellyn, Illinois 60137

Dear ter. Keppler:

This letter is our response to the Notice of 1/iolaticn attached as Appendix 'A'o t1r. R. F. Heishman's letter of January 2, 198'!. In accord-ance with Appendix 'A'o Hr. Heishman's letter this response is being submitted under oath and affirmation.

On July 28, 'I980, while Unit No. 2 was operating in Hode 'i, tne nitrogen cover pressure on one of the four accumulator tanks exceeded the upper limit of 644 psig specified in Technical Specification 3.5. !.d, for approximately ten minutes. The maximum pressure experienced was 650 psig.

This event was in fact the result of the failure of the high/low pressure alarm to clear during operator action to increase cover gas pressure. The transient nature of this event and the magnitude of the p. essure exc rsion

(+6 psi) coupled with the normal accuracy of the pressure ...on.itor (+ 14 psi) and the apparent lack of "dverse safety significance led to the Plant StaTf's request that personnel from American Electric Power Serv-ice Corporation (AEPSC) investigate the reportability of the event.

The results of the AEPSC review indicated that there was no reasonable adverse safety implications associated with the subject event. it was recognized that the apparent nitrogen overpressure did constitute entry into the 'Action Statement'f Specification 3.5.1.d., however, the re.iewers felt that the reporting criteria of Specification 6.9.1.9.b, "...operation 8 1 031085%'

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ATTACHMENT TO LER NO. 80-039/03L-0 SUPPLEMENT TO CAUSE DESCRIPTION

1. Investigation into this event determined that the cause can be attributed to several factors:

1. The normal procedure the operator uses when restoring the accumulator pressure is to use the annunciator alarm that is received when the low pressure condition clears as a notification to shut off the nitrogen supply. The annunciator used for this alarm is a common high/low pres-sure alarm. The alarm did not clear due to a drift in the setpoint for the high pressure alarm bistable which energized this bistable prior to the low pressure alarm bistable clearing. Failure of this alarm/bistable contributed to the nitrogen pressure exceeding the high pressure limit; Cause Code E - Component Failure.

2. A second contributing cause was the fact that the pressure indicator used for reading the accumulator has a very wide range, 0-700 psig. This, coupled with an approximate 2C gauge accuracy, (+ 14 psi,), makes it very difficult to read the gauge accurately; Cause Cole .B - Design.

3. Also contributing to the apparent overpressure condition was operator failure to pay close attention to the operation at hand, thus permitting the indicated pressure to exceed the high pressure limit; Cause Code A-Personnel Error.

The following corrective actions have been taken:

1. The overpressure condition was corrected within approximately 10 minutes.

2. The alarm bistable was re-calibrated to the proper setpoint.

3. A design change has been initiated to correct the indicator and alarm problems.

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Mr. James.B. Keppler AEP: t/RC: 00512 in a degraded mode...", had not been fulfilled as the apparent cover gas overpressure did not impair the abiliLy of the affected accumulator to perform its safety function. The AEPSC response to the Plant Staff's request failed to provide clear guidance as tc t!>e'repo> tabil:ty of the subject event.

Effective corrective action by the operators") returned the accumulator cover gas pressure to within the limits of Specification 3.5.l.d. in ap-proximately ten minutes; well wi.hin the time period of one hour allowed by the 'Action Statement'f the Specification. The reportability of this event has been discussed with those members o the AEPSC staff involved with the aforementioned review. Particular emphasis was placed on the

- need for the AEPSC office to provide clear and concise guidance to the Plant Staff in matters such as the one discuss..d h rein. These actions should be suffi'cient to prevent reoccurrence of similar events.

Yery truly yours, R. S. "Hun7er Yance Pr esident cc: John E. Dolan R. C. Callen G. Charnoff R. W. Jurgensen D. Y. Shaller Region III Site Inspector

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STATE OF NEV, YORK )

COUNTY OF fi'Esi YORK)

R. S. Huni'er, being duly sworn, deposes and says he .is the Vice Pres-.den'f Licensee 'Indiana and Nschigan Electric Company, ihat he has read the foregoing response to the NRC Notice of Violation contained in IE Inspection Reports No. 50-315/80-15 and No. 50-316/80-14 and I:no;>s the contents thereof, and the said contents are true to he best of his I nowledge and belief.

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pd Subscribed and sworn to be>ore me this ~~ ~ day of

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