ML19326A763

Forwards Deficiency Rept Re Cavitation Problems During Last Three Stages of Letdown Orifice in Rcs.Revision to Makeup Pump Recirculation Orifice Prone to Cavitation.Orifice to Be Returned to Manufacturer for Mod

ML19326A763
Person / Time
Site:	Crystal River
Issue date:	10/08/1974
From:	Rodgers J FLORIDA POWER CORP.
To:	Knuth D US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML19326A755	List: ML19326A754 ML19326A763 ML19326A767
References
NUDOCS 8003030893
Download: ML19326A763 (1)

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Power Co m po n a t oo m october 8, 1974 Donald F. Knuth, Director

'lhe Directorate of Regulatory Operations

• U. S. Atomic Energy Commission Washington, D. C. 20545

Subject:

50-302

Dear Mr. Knuth:

In accordance with Federal Regulation 10CFR50.55(e), we wish to report that we have been advised by Babcock 6 Wilcox Company of the results '

of an investigation they undertook regarding the letdown orifice  ;

installed-in the reactor coolant system. Reir investigation revealed -

that cavitation and subsequent erosion would occur in the last three stages of the letdown orifice. Additionally, their investigation indicated that the revision to the make-up, pump recirculation orifice also was subject to cavitation. He later' item is covered by a previous report. At the direction of BGW. we are returning the subject orifice v/ to the manufacturer for modification. It is expected that this modifica-tion will assure that the problem will not occur at Crystal River Unit #3.

I am enclosing a summary report that delineates the identification of the problem, it s effect on the system, and the corrective action.

If you have any further questions, please advise us.

Very tnily yours, Idh J. T. Rodgers Og Assistant Vice President Attachment cc: M. H. Kleinman N. C. Moseley, Director Region II, AEC/DRO O'

8008030 3 General Office 32o inirty-rourtn street soutn . P O Box 14042, st. Petersburg, Florida 33733 e 813-866-5151