ML19210A271

Forwards LER 77-005/04T.Provides Supplemental Info

ML19210A271
Person / Time
Site:	Three Mile Island
Issue date:	03/31/1977
From:	Arnold R METROPOLITAN EDISON CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19210A272	List: ML19210A271 ML19210A274
References
GQL-0431, GQL-431, NUDOCS 7910250557
Download: ML19210A271 (4)

Text

U.S. NUCLE AR REGULATORY C AISSION DOCKET NUMBER NRC PcR.4 195

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. N3C DISTRIBUTION FOR PART 50 DOCKET MATERIAL INCCIEb"TREPORT FROM: DATE OF OCCUMENT TO:

Metropolitan Edison Company 3/31/77 Mr. J. P. O'Reilly Reading, Pa. cars paesivso R. C. Arnold 4/12/77 ILETTER ONOTORIZED PROP tPePUT PORM NUMBER OF COPIES RECEIVED YORIGIN AL hNC LASSIFIE D OCOPY j / S / G /t./ 84 CESCRIPTION EN CLOSU RE Ltr. trans the following: Licensee Event Report (R0 50,289/77-05/4T) on 3/19/77 concerning change in river water

- discharge temperature exceeding 2 degrees F

.D0NOT REMOVE PLANT NAME:

Three Mile Island Unit No. 1 (3-P) (1-P)

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NOTE: IF PERSONNEL EXPOSURE IS INVOLVED ACKNOWLtDGED. SENo oIRECTtT TO xRECER/a. C0ttINS

_ , FOR ACTION /INFORMATION BRANCH CHIEF: R e.I d.

W/3 CYS FOR ACTION LIC., ASST.: 2 /1 4 p-e /v1 W/ / CYS , ,,

ACRS /(/ CYS ECLDftfG/SENT /.4-5 C M T_f $

, 2 INTERNAL DISTRIBUTION O E'M m PDR

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, f, EXTERNAL DISTRIBUTION CONTFtOL NUMBER LPDR: # A vesy Du g A '7-y/o S o / y J TIC:

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METROPOLliAN EDISON COMPANY POST OFFICE BOX 542 RE ADING. PENNSYLV ANI A 19603 TELEPHONE 215 - 929-0601 GQL Ch31 Erch 31,1977

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\v Mr. J. P. O'Reilly, Director \/ f.

Office of Inspections and Enforcement, Region 1 \,f _- s/

U. S. :iuclear Regulatory Cctmission 631 Park Avenue

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King of Frussia, P1. 19LC6

Dear Sir:

1 ,

)

Docket :io. 50-269 Operating License !?o JFR-50 In accordance with the Technical Specifications of our Three Mile Island

iuclear Station Unit 1 (TMI-1), we are reporting the following reportable occurrence.

(1) Report :Tumber: TT-05/hT (2a) Required Report Date: 0h-01-77 (2b) Date of Occurrence: 03-19-77 (3) Facility: Three Mile Island :iuclear Station - Unit I (k) Identificaticr. of Occurrence:

Title:

ChLnge in river water discharge temperature exceeded 2c? in one hour.

Type: A reportable occurrence ac defined by Environmental Technical Specification 2.1.b.(2) in that during reactor ccoldowr. ccnditions the discharge temperature changed by more than 2 F during a one hou/ period.

[47$648 y) / 0 30/ 4 3

}J."P.O'Reilly March 31, 1977 (5) Conditions Prior to Occurrence:

Pcver: Core: 0 MWt Elec: 0 MWe RC Flov 3000 gym Decay Heat Flev RC Pressure 300 psig RC Temp . 2290F FRZR Level 105 inches PRZR Temp -

h300F (6) Description of Occurrence:

The river water AT vas being maintained at Co? up to the time the Decay Heat Removal System was placed in service at 2100 hours0.0243 days <br />0.583 hours <br />0.00347 weeks <br />7.9905e-4 months <br />. As the Decay Heat Removal System was placed in service, the river vater discharge te=rerature began to increase causing an increase in the river water AT.

Since the Mechanical Draft Cooling TcVer was operating at its full available capacity, total river water flow was increased by starting additional river water pu=ps in order to reduce the river water AT. To ec=plement this acticn, steps were taken to reduce the primary plant cooldown rate by cutting back on the Decay Heat Closed Cccling water flow thru the Decay Heat Removal Cooler. The river water AT responded and returned to within the limit of a 2 F change in AT during any cne hour period. The operator then began to gradually increase the primary plant cooldown rate by throttling open the Decay Heat Closed Cocling vater flow thru the Decay Heat Removal Cooler. Because of control problems with DC-V-653 and DC-V-23, the above specification was again violated as the valve would initially only respond to large demand open/close signals. The tctal time elapsed was three (3) hours in which t'e maxi =u= change in AT in one (1) hour was 3.3 F.

(7) Apparent Cause of Cccurrence:

The apparent cause of the occurrence has been determined to be material in that during the above period the folleving equipment was either cut of service or not functioning properly:

1. SOCT "C" fan was out of service

2. DC-V-653 and DC-V-23 centrollers/ operators did not respond properly (8) Analysis of Occurrence This change in AT over any of the above three (3) hcurs did not adversely affect cur environment in that tha total river water te=perature was not significantly altered. Temperature surveys being conducted five (5)

=eters '4est and twenty-five (25) meters South or aur river water discharge point indicate a maximum 0.6 C (1.hhcF) increase . river water temperature during the above incident.

1476 549

J. F. O'Reilly March 31,1977 (9) Corrective Action:

IICEDIATE: Steps were taken to increase total river water flow and then to centrol the primary plant ecoldown rate to maintain the change in river water AT within the above specification.

LOIIG TERM: DC-7-653 and DC-V-23 shall be insnected and repaired as necessary to correct the respcnse 'racteristics.

. The

C" Mechanical Draft Cooling Tcver run is scheduled for repair during the current Refueling Cutage.

(10) Failure Data:

NA Similar Events EI Th-1 EI Th-8 EI 75-7 EI 75-8 EI 75-9 Sinc ere)'Y",

/ i

[' -

R. C. nrnc1d Vice President RCA:DGM:rk .

Attachment:

Licensee Event Report .

1476 750