PNO-II-91-074B, on 911123,unit Remained in Cold Shutdown,Per Declaration of Alert at 0214 Due to Leak in Rcs.As of 911126,total of 7,800 Gallons of Treated Water Released from Plant to Lake Hartwell

PNO-II-91-074B:on 911123,unit Remained in Cold Shutdown,Per Declaration of Alert at 0214 Due to Leak in Rcs.As of 911126,total of 7,800 Gallons of Treated Water Released from Plant to Lake Hartwell

ML20203C501
Person / Time
Site:	Oconee
Issue date:	11/26/1991
From:	Belisle A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:
References
PNO-II-91-074B, PNO-II-91-74B, NUDOCS 9712150324
Download: ML20203C501 (1)

FROM USm c RII DRP TO BiWta41xu P.W I 05-29-1992 09815ft1 PREt.ININARY NOTIFICATl_0N OF EVENT OR UNUSUAL OCCURRENCE PNO-!!-91-748 l

l  : preliminary notification constitutes CARLY notice of events of POSSIBLE safety or

,..elic interest significance. The information is as initially received without verifi-O cation or evaluation, and is basically all that is known by the Region li staff on this

( date.

FACit!TY: Duke Power Company Licensee Emergency Classification:

Oconee, Unit 3 Notification of Unusual Event Docket No. 50-287 Alert' Seneca, SC Site Area Emeroaacy General Ec -

X Not Applic SU8 JECT: REACTOR COOLANT SYSTEM LEAK UPDATE Unit 3 continues to remain in cold shutdown following the declarat' of > lert at 04'14 on November 23, 1991, due to a leak in the reactor coolant system (RC The reactor coolant system was Gepressurized and vented, and the total ..kage was approximately 70,000 gallons of radioactive water of which 47,800 gallons have been transferred to the adwaste building. The RCS leak was identified to be coming from a separated compressv.a fitting on a 3/4 inch reactor vessel level indication system pressure and level sensing line downstream of a flow restricting valve. The sensing line is located at the top of the *A' steam generator hot leg.

After reaching cold shutdown at 1720 on November 23, the licensee began evaluating the 9ditions inside the containment. During the first tery into containment at about 1530 November 25, 1991, the location of the leak was verN;ed.

Concentrations of airborna radioactive material in the containment continue to be reduced s by purging. Concentrations of noble gas and radiolodine have been reduced below 1.0 and 5.7 MPC respectively. Containment entry was mW by three separate licen,ee teams wearing appropriate protective clothing on the afternoon of November 25, 1991, to assess damage and evaluate areas needing decontamination. Preliminary evaluations show no significant internal radiation exposure as a result of the entry with the maximum external dose of approximately 40 milliram.

As of November 26, 1991, a total of 7800 gallons of treated water had been released from the plant to Lake Hartwell. As of this morning, an additional 27,000 gallons of contaminated water has been treated and is available for discharge. Preliminary '

calculations by licensee representatives show that discharges of all the water, after treatment, would result in wholebody radiation doses of less than 0.2 millirem.

Licensee and State of South Carolina off-site environmental monitoring teams have not detected any airborne radioactive material above background.

Throughout the purging, Region II has continued to consnunicate with the State of South Carolina. NRC resident and specialist inspectors have continued to monitor the licensee's activities throughout the event.

This information is current as of 11:00 a.m. on November 26, 1991. $

TACT

A. Belisle - 841-4196 E '&

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O!STRIBUTION: (See page 2) Es

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