ML17326A866

Describes 810331 Incident Reported in LER 81-005/01T-0 Re Spray Additive Tank Level

ML17326A866
Person / Time
Site:	Cook
Issue date:	04/08/1981
From:	Shaller D INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML17326A865	List: ML17326A864 ML17326A866 ML17331A689
References
NUDOCS 8104170520
Download: ML17326A866 (2)

Text

IItVDIAIlfA8r NICHIGAA/ EIEC78IC CDNPANY DONALD C. COOK NUCLEAR PLANT P.o. Box 468, Bridgman. Mchigan 49106 (61Q 4664901 April 8, 1981 Mr. J. G. Keppler, Regional Director

'ffice of Inspection and Enforcement United States Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL 60137 Operating License DPR-74 Docket No. 50-316

Dear Mr. Keppler:

This letter is to inform you of an incident which occurred at the Indiana and Michigan Electric Company's Donald C. Cook Nuclear Plant on March 31, 1981 which was reported to Mr. E. Swanson of the NRC on the date of the occurrence and to your office in a letter dated March 31, 1981.

During a scheduled eighteen month surveillance of the Unit 2 Spray Additive Tank level magnetrol it was noted that the tank was only approximately one quarter full. Actual level measurements verified 1654 gallons of sodium hydroxide in the tank. This is in violation of Technical Specification 3.6.2.2 which requires a minimum volume of 4000 gallons. As previously stated at the time of discovery the low level alarm contacts were wired backwards precluding the low level alarm from annunciating.

Technical Specification verification of level had been performed by noting the absence of the low level alarm which is set to approximately 4190 gallons.

A review of this surveillance requirement, during an audit conducted by the American Electric Power Service Corporation Nuclear Safety and Design Review Committee had identified this as a potential problem. A change was to be initiated to satisfy the surveillance requirement by an actual level determi-nation using tygon hose. This change was never completed and surveillance remained as previously stated.

Investigation and review of all plant Iog books and data sheets indicate the sodium hydroxide left the Spray Additive Tank and entered the waste disposal system on or about December 21, 1979. Significant elevation of the waste evaporator concentrates pH occurred during this time with no manual caustic additions. The low level alarm on the. Spray Additive Tank was found to be wired backwards on March 31, 1981. At the previous surveillance, September 29, 1979 the tank level was not low and the Iow level alarm was wired pro-perly. Heavy construction activity in the Spray Additive Tank Room is

Mr. J. G. Keppler April 8,, 1981 Page Two suspected to have resulted in the determination of the level alarm wiring with a subsequent reconnection according to the wiring drawings. This pre-vented the loss of the sodium hydroxide to be detected by the tank's low level alarm.

The 1654 gallons of 32 percent sodium hydroxide leaves a volume of 1155 available for injection as, the low-low level alarm cutout leaves 499 gallons in the tank. Calculations by the American Electric'Power Service Corpora-tion Chemical Section indicate this would result in a final sump pH sump of 7.75.

As a result, the loss of Coolant Accident Iodine removal capability has been re-evaluated accounting for the as found tank condition. This evalu-ation shows that the containment spray system would have had an adequate amount of spray additive (NaOH) to minimi ze conQinment iodine and evolu-tion of iodine from the sump water in the event of a design basis accident.

The FSAR analyses were performed using. very conservative assumptions for the spray additive tank and resulted in our present Technical Specification limitations. Therefore, this event would not have any adverse effect on the health and safety of the public.

Completed plant actions to prevent reoccurrence include the revision of all applicable plant procedures to i ncorporate the actual level verification via tygon hose, the writing of a request for change (RFC) to correct wiring errors in the plant electrical drawings and the locking and chaining shut of the tank drain valves as per Operations STP 35 "Valve Position Logging".

Annunciator response procedures and sa'mpling procedures will be reviewed with the appropriate plant personnel by April 30, 1981.

Sodium hydroxide was received on-site and the Unit 2 Spray Additive Tank volume verified to be above Technical Specification minimum volume on April 4, 1981.

Sincerely,

0. V. Shaller Plant Manager

/pjv cc: J. E. Oolan R. S. Hunter R. W. Jurgensen R. F; Kroeger R. W. Kilburn E. Swanson/N. OuBry RO:III R. C. Callen MPSC J. M. Hennigan W. Lavallee EPRI PNSRC J. F. Stietzel E. L. Townley Oir., IE (40 copies)

Oir.,'MIPC (4 copies)