ML20212C627

PNO-OSP-88-003:on 880310,licensee Determined That B Concentration in Loop 3 Cla Was 2,102 Ppm.Increase Outside TS 3.5.1.1 Limits of 1,900 - 2,100 Pp,Caused by in-leakage from RCS

ML20212C627
Person / Time
Site:	Sequoyah
Issue date:	03/15/1988
From:	Richardson S NRC OFFICE OF SPECIAL PROJECTS
To:
References
PNO-OSP-88-003, PNO-OSP-88-3, NUDOCS 9710300057
Download: ML20212C627 (1)

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(~3 PRELIMINARYNOTIFICATIONOFEVENTORUNUSUALOCCURRENCEPMO-0SP-88-Oh This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The infonnation is as initially received without verification or evaluation, and is all that is known by the OSP staff on this date.

FALILITY: Tennessee Valley Authority Licensee Emergency Sequoyah Unit 2 Classification:

DocketNo.50-3fS n ., X Notification of Unusual Soddy-Daisy, Tennessee, Event Alert 26 Site Area Emergency General Emergency N' /S Not Applicable 4/O feg

SUBJECT:

PLANT C00LDOWN INITIATED UNDER TECHNICAL SPECIFICATION 3.5.1.2 On March 10, 1988 at 4:54 p.m., the licensee determined that boron concentration in the loop 3 Cold Leg Accumulator was 2,102 ppm. This increase outside Technical Specification (TS) 3.5.1.1 limits of 1,900 - 2,100 ppm was caused by in-leakage from the Reactor Coolant System. The licensee immediately began action to return the accumulator concentration to within TS limits. At 8:25 p.m., operators began cooling the Unit down in accordance with I the TS action statement. A Notification Of Unusual Event (NOUE) was made because the licensee initiated a " shutdown required by TS". At 9:40 p.m.,

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following a dilution of its concentration, a sample was taken from the loop 3 Cold Leg Accumulator. This sample indicated that the adjusted concentration was 2,079 ppm. A second sample showed 2,080 ppm. Accordingly, the cooldown and the NOUE were teminated at 10

10 p.m. The Unit was taken from 527 degrees F/1750 psig to 483 degrees F/1650 psig during this event. It has since returned to its previous plant conditions.

This information is current as of 8:00 a.m. (EST) on March 11, 1988.

CONTACTl S. Richardson, 492-3286 hfW r/

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i Chm, Cmrs,  !

e . t 'i R C/R Distribution:

9710300057 880315 GPA, GC, CA, PDR, Historian, b '

-O 90-003 PDR o