ML19210A246

Abnormal Occurrence 50-289/75-31:on 750917,core Flood Tank Water Level Below Tech Specs Requirements.Caused by Incorrect Reading on Lower Reading Channel CF2-LT3.Channel Will Now Be Monitored & Personnel Informed on Procedures

ML19210A246
Person / Time
Site:	Three Mile Island
Issue date:	09/26/1975
From:	Arnold R METROPOLITAN EDISON CO.
To:
References
GQL-1547, NUDOCS 7910240957
Download: ML19210A246 (4)

Text

. . _ _ . .

NRC: T UTION FOR PART 50 DOCKE 1 !RI AL (TEMPORARY FORM)

CONTROL NO: 10'19 r LE: INCIDENT REPORT FIL' FROMyetropolitan Edison Co. DATE OF DOC DATE REC'D LTR TWX RPT OTHER Rading, PA.

R.C. Arnold 0-26-75 o-20 79 :CCC OTHER SENT AEC PDR ere TO: ORIG CC SENT LOCAL PDR ""v n:C 1 Siened 0 CLASS UNCLASS PROPINFO INPUT NO CYS REC'D DOCKET NO:

CCC 1- 50-289 DESCRIPTION: ENCLOSURES:

Atnornal Occurrence f 75-31, on 9-26-75, Concer- ing A Core Flood Tank.Found to Have a Lover Level ,

than required by Tech. Spec. . . . . . . . .

(1 Copy Enclosure Received) '

PLANT NAME: Three Mile Island # 1 FOR ACTION /INFORMATION SA3 10-1-75 BUTLER (L) SCHWENCER (L) ZIEMANN (L) REG AN (E)

W/ Copies W/ Copies W/ Copics W/ Copies CLARK (L) STOLZ (L) DICKER (E) / LEAR (L)

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^ " ' T"r4' 0VE PARR (L) VASSALLO (L) KNIGHTON (E) SPELS W/ Copies W/ Copies W/ Copies W/ Copies KNIEL (L)

W/ Copics PURPLE (L)

V// Copics YOUNGB LOOD (E)

W/ Copics W/ Copies ACKNOWLEDGED INTERNAL DISTRIBUTION MG FILD TECH REVIEW DENTON LIC ASST A/T IN D .

R. DIGGS (L) BRAITTTAN fiC PDH pSCHROEDER OGC, ROOM P-506A AAACCARY

% RIMES GAMMILL H. GEARIN (L) SALTZMAN GOSSICK/ST AF F KNIGHT K ASTN E R E. GOULBOURNE (L) MELTZ f CASE PAWLICKl BALLARD P. KREUTZER (E)

GIAMBUSSO SHAO SPANG LE R J. LEE (L) PLANS BOYD **p ST E t.LO M. RUSHER 0CK (L) MCDONALD MOORE (L) ENVIRO S. REED (E) CHAPMAN

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DENISE J. COLLINS REGAN KLECKER f .STEETS (L) EISENHUT REG OPR LAIN AS PROJECT LDR G. WILLI AMS (E)

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p1 - TIC (ABERN ATHY) (1)(2)(10) - N ATIONAL LABS 1 - PDR SAN /LA/NY 1 - W. PENNINGTON, Rm E-201 GT 1 - BROOKHAVEN NAT LA2 f 1 - NSIC (BUCHANAN) 1 - G. ULRIKSON, ORN L 1 - ASLB 1 - CONSU LTANTS 1 - Newton Anderson NEWM ARK /SLUME/AG 8 ASI AN 1 - AGMED (RUTH GUSSMx;i U-ACRS SE:T To LIC l.SST S. Teets /. Rm B-127 GT

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• /;llag powfR for PROGniss METROPOLITAN EDISON COMPANY - -- . m~.- r- -- -

PCST OFFICE BOX S42 REAclNG, PENNSYLVANI A 19603 TELEPHONE 215 - 929-3601 September 26, 1975 GQL 15h7

.fRegu.laterf_

.. - 1. .i i.13. Cy.

Directcr Division of Reacter Licensing , ~_

U.S. Iluelear Regulatcry Cc==ission .

Washington, D.C. 20555

Dear Sir:

Docket :ic. 50-289 Operating License :ic. DPR-50 In accordnnee with the Technical Specifications of cur Three Mile Island

?!uclear Station Unit 1 (T'*I-1), we are reporting the fclicvi- ;g r. p .4 '

cccurrence. g V 'h (1) Report Iiumber: A0 50-289/75-31 g jfg,, p (2a) Report Date: September 26, 1975 k h (2b) Cccurrence Date: September 17, 1975 CH g g,,,,,

I9? S

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,+ ..,

(3) Facility: Three Mile Island IIuclear Station Unit '.'.x/ %s s u.-c ,/.' x i (h) Identification of Occurrence:

Title:

a Ccre Flced Tank Fcund to Have a Lcuer Level Than Recuired by Technical Specifications Type: An abnormal occurrence as defined by the Technical Specificaticns, paragraph 1.Sb, in that the lev level in the Core Flood Tank constituted violation of a limiting condition fcr cperation established in Technical Specification 3.3.1.2a.

(5) Conditions Prior to Occurrence:

Power: Core: 100",

Elect.: 845 MWe (3ross) 6 RC Flow: 138 x 10 lb/hr 7 1, 03" RC Fress: 2155 psig 0

RC Temp. ST9 F FR:R level: 220 Inches

,'v- ~ O FR R Temp. 655 F 1

(6) Lescription of Cccurrence:

On September 17, 1975 Core Flocd Tank level transmitter calibratien was being conducted due to differences in indication between redundant level channels. The lever reading channel (CF2-LT'c) was checked first since the other channel (CF2-LTh) had been indicating that level was ccnstant and proper. After mincr transmitter adjustments, CF2-LT3 indicated that actual water level was 12.2 feet.

This is a violaticn cf Technical Specification 3.3.1.2a since a level of 12.55 ft. * **"*" **"*** 0"* 1*

volume of 1010 ft .3. * #*4" #*

Ennediately borated water was added to restore the volume of bcrated water in the B Core Flood Tank within Technical Specification limits.

(7) Designaticn of Apparent Cause of Cccurrence:

The apparent cause of this occurrence is material in that initially it .as believed that the CF2-LTh indicaticn was correct and that the "B" Core Flced Tank was within allevable limits. Upon calibration and minor adjustment of the CF2-LT3 transmitter, it was found that CF2-LT3 was reading correctly and the tank volu=e was actually lov.

When the CF2-LTh transmitter was calibrated, it was found to be within specification. Blovdcun of the lev side sensing line indicated that there was partial bIcekage in the line, since after blevdown the CF2-LTk indication corresponded with the CF2-LT3 indication.

A ccntributing cause was also personnel in that earlier checkout of the CF2-LT3 transmitter =ay have identified the problem pricr to the tank being cut of limits.

(8) Analysis of Occurrence:

It has been deternined that the cut-of-limit volume for B Core Flccd Tank did not constitute a threat to the health and safety of the public since

s. all other engineered safety features were operable and,

b. the "A" Core Flced Tank had greater than the minimum equivalent level of 12 55 ft. which indicates that the combined inventory of both core flood tanks vculd have been sufficient to reficed the ccre.

(9) Corrective Action:

In addition to the immediate corrective actions listed abcve other corrective actions are:

a. Perscnnel have been instructed to troubleshcct differences in redundant level channels as scen as such differences occur.

b. The level channels assceirted with the Ccre Flecd tank:

vill be renitored for trends indicating problems which might "equire further evaluaticn.

1476 306

. -The Plant Cperations Review Cc=mittee and Station Superintendent have reviewed and approved the above ccrrective actions and have taker steps to assure ccepletien of the yet to be ecmpleted corrective actions.

(10) Failure Eata:

Ucne Similar Cccurrences:

None Sincerely, A i

q! /,

y cu(1 R. C. Arnold Vice President RCA:CWS:ilm File: 20.1.1/7 7.3 5 1 cc: J. P. O'Reilly Office of Inspection and Enforcement, Regicn 1 07 T A76