ML20085D137

Ro:On 720709,steam Line Isolation Valve B Malfunctioned During Periodic Test.Caused by Sheared Pin in Linkage Between Valve Stem & Disc.Valve Repaired

ML20085D137
Person / Time
Site:	Robinson
Issue date:	07/18/1972
From:	Utley E CAROLINA POWER & LIGHT CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085D140	List: ML20085D137
References
NUDOCS 8307200566
Download: ML20085D137 (1)

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Carolina Power & Light Company /

Raleigh, North Carolina 27602 July 18, 1972 Mr. John F. O' Leary, Director Directorate of Licensing U. S. Atomic Energy Commission ,

Washington, D. C. 50545 H. B. ROBINSON PLANT LICENSE DPR-23 MALFUNCTION OF "B" STEAM LINE ISOIATION VALVE

Dear Mr. O.' Leary:

In accordance with Paragraph 6.6.3.a, Technical Specifications, it is reported that on July 9,1972, the "B" steam line isolation valve did not function properly during a periodic test. Instead of cycling closed for approximately 2" of stem travel and then re-opening to the fully open position as expected when the valve controls were put in test mode, the valve closed completely. The resulting transient ini-tiated a reactor trip on steam generator "Lo-Lo" Icvel and caused the power operated relief valve to operate.

The reactor was placed in a cold shutdown condition, the cause of the shutdown investigated, and repairs made. With the assistance of the valve manufacturer's representativc, repairs were made to the affected valve and the controls on all three valves carefully checked and adjusted.

1 Disassembly of the valve operator and valve internals revealed that a pin j had v.sheared

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in the linkage-_ between the valve stem and the disc.

All repairs and adjustments to the valve were completed, all three isolation valves tested for proper operation, and the plant re-turned to operation on July 13, 1972.

Yours very truly, "f /

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EEU:HH E. E. pUtley -<)

e Manager c: Mr. C. D. Barham Bulk Power Supply p Mr. N. B. Bessac (i Mr. B. J. Furr IDg[fh#

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