ML20085D495

Ro:On 720514,primary to Secondary Leak Determined to Exist in Steam Generator A.Caused by Plugged Tubes in Steam Generators A,B & C.Mods to Improve Recirculation Rate Made

ML20085D495
Person / Time
Site:	Robinson
Issue date:	06/09/1972
From:	Utley E CAROLINA POWER & LIGHT CO.
To:	Block E US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085D492	List: ML20085D489 ML20085D495
References
NUDOCS 8307250712
Download: ML20085D495 (1)

Text

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Carolina Power & Light Company . YI @jx A.' .c g\

Raleis, North Carolina 27602

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Mr. Edward J. Bloch, Director Directorate of Licensing (

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U. S. Atomic Energy Commission 4 17 3j'/

Washington, D. C. 50545 "

H. B. ROBINSON UNIT NO. 2 50-261 LICENSE DPR-23 PRIMARY TO SECONDARY LEAK IN "A" STEAM GENERATOR

Dear Mr. Bloch:

In accordance with paragraph 6.6.1 C., Technical Specifications, it is reported that a primary to secondary leak was determined to exist in the "A" steam generator. While performing a plant startup on May 14, 1972, af ter a week's scheduled outage, an abnormal leak rate was observed. The Icak ,,f approximately 12 gpm was confirmed to be in "A" steam generator by an increase in water level and an increase in the count rate on the radia-tion monitor, R-19, located in the steam generator blowdown flow path. The plant was returned to a cold shutdown condition for steam generator inspec-tion and repairs.

When primary side of "A" steam generator was opened, a tube leak was confirmed. Subsequent evaluation of the incident and eddy current inspection of selected tubes indicated that steam generator tubes on all three steam generators had been attacked. As a result thirty tubes were plugged in "A" steam generator, two in "B", and four in "C". Under the technical direction of Westinghouse, several modifications to improve the recirculation rate in the secondary side of the steam generators were made.

Additionally, Westinghouse recommended modifications in the secondary water chemistry to increase the phosphate concentration.

A complete report covering this incident, including an evaluation of the cause and the corrective action taken, is in preparation and will be forwarded in the near future. ,

The unit was returned to service on June 9, 1972.

Yours very truly, f i , ,

j , JC6 ?h NBB/rb1 E. E. Ut ey Manager ,,gl ,

cc: Mr. C. D. Barham Bulk Power Supply c[j - C,,f Mr. G. P. Beatty /y;a Mr. N. B. Bessac O

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