05000259/LER-1979-003-01, /01T-1 on 790120:during Cold Shutdown,Local Leak Rate Test Indicated Excessive Total Leakage.Caused by Leaking Valve Seating Surface in Eight Valves.Valves Repaired & Retested

/01T-1 on 790120:during Cold Shutdown,Local Leak Rate Test Indicated Excessive Total Leakage.Caused by Leaking Valve Seating Surface in Eight Valves.Valves Repaired & Retested

ML19282C190
Person / Time
Site:	Browns Ferry
Issue date:	03/16/1979
From:	TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19282C188	List: 05000259/LER-1979-003, Forwards LER 79-003/01T-1 05000259/LER-1979-003-01, /01T-1 on 790120:during Cold Shutdown,Local Leak Rate Test Indicated Excessive Total Leakage.Caused by Leaking Valve Seating Surface in Eight Valves.Valves Repaired & Retested
References
LER-79-003-01T, LER-79-3-1T, NUDOCS 7903210175
Download: ML19282C190 (3)

LER-1979-003, /01T-1 on 790120:during Cold Shutdown,Local Leak Rate Test Indicated Excessive Total Leakage.Caused by Leaking Valve Seating Surface in Eight Valves.Valves Repaired & Retested

Event date:
Report date:
2591979003R01 - NRC Website

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. N 4C b ;.M 366 UPDATE REPORT - PREVIOUS REPORT DATE 2/14/79 (7 77)

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2 While in cold shutdown for refueling, local leak rate testing was performed in accord-1 l ance with T.S. 4.7. A.2.2,h. and 1. The total leakage (6,042.0179 SCFH) exceeded the al-j o

a lo l4 l lowable 60 percent La per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (707.1 SCFH). There was no hazard to the public

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50-259/7723, 50-260/789 and 50-296/7825.

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40 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h lThere was excessive leakage by the valve seating surface.

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Form BF-17 BF 15.2 6/09/78 LER SUPPLEMENTAL INFORMATION BFRO 259 /

793 Technical Specification Involved 4.7.A.2.g, h..and i Reported Under Technical Specification 6.7.2.a(2)

Date of Occurrence 1/20/79 Time of Occurrence 0430 Unit 1

Identification and Description of Occurrence:

The total as found leakage for containment penetrations was found to exceed the allowable 60% La or 707.1 SCFH. Total leakage was 6,042.0179 SCFH.

Conditions Prior to Occurrence:

Unit 1 shutdown for refueling.

Action specified in the Technical Specification Surveillance Requirements met due to inoperable equipment. Describe.

None Apparent Cause of Occurrence:

There was excessiye leakage by the seating surfaces.

Analysis of Occurrence:

None

Corrective Action

The seating surfaces were repaired and retested to demonstrate operability.

(Refer to the attached sheet for va'lve data and leakage paths.)

Failure Data:

50-257/7723, 50-260/789,and 50-296/7825.

Tennessee Valley Authority - Browns Ferry Nuclear Plant

VALVE DATA BFRO-50-259/793 1-14 1-15 64-17 64-18 76-24 Valve No.

1-37 64-19 l-38 Mfg.

Atwood & Morrill Rockwell Rockwell Fisher Controls Size 26 inch 20 inch 20 inch 10 inch Type Globe Butterfly Butterfly Butterfly Model A&M 20851 H Low-2284W 225498 P98537-02 Valve Rating 1250 psig @ 575 'F 125 psig ANS 125 psig ANS 150 psig Mode of Operation Air operated Air operated Air operated Air operated Normal Operating Pressure 1150 psig @ 562 F Test @ 50 psig Test 0 50 psig 56 psig @ 160 F TOTAL "AS FOUND" LEAKAGE - 6,042.0179 SCFH for Isolation Valves Leakage Path Isolation Valve No.

As Found Path Leakage Per Cent of Total X-7A 1-14/15 2196.000 SCFH 36.35%

X-7C 1-37/38 2807.7569 46.47 X-25 64-17/18/19/

793.2256 13.13 76-24 5796.9825 95.95%

As can be seen f rom the above tabulation, these three leakage paths (X-7A, X-7C, and X-25) were responsible for 96 percent of the total "as found" leakage. The leakage for the remaining isolation valves total 245 SCFH which is well below our allowable 60% La or 707.1 SCFH. However, all valves that exceeded their individual reference leak rates were repaired and retested to ensure the "as left" leakage was as low as attainable.

JGD:JHT 3/7/79