ML20246N058

Forwards AEOD/E906, Failure of Steam Generator Isolation Check Valve, Technical Review Rept.Inservice Testing of Valves Should Be Conducted on Regular Basis for Both Forward & Reverse Flow Directions

ML20246N058
Person / Time
Site:	Calvert Cliffs
Issue date:	08/30/1989
From:	Novak T NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD)
To:	Rossi C Office of Nuclear Reactor Regulation
Shared Package
ML20246N050	List: ML20246N045 ML20246N058 ML20246N072 ML20246N093
References
AEOD-E906, GL-89-04, GL-89-4, NUDOCS 8909080027
Download: ML20246N058 (1)

Text

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AUG 3 0 W

- MEMORANDUM FOR: Charles E. Rossi, Director AEOD/E906

Division of Operational I

Events Assessment Office of Nuclear Reactor Regulation FROM: Thomas M. Novak, Director Division of Safety Progres Office for Analysis and Evaluation of Operational Data 308 ECT: FAILURE OF STEAM GENERATOR ISCLATION CHECK VALVE Enclosed for your information is a ecpy of an AEOD Engineering Evaluation Report on the failure of a steam generator isolation check valve at each unit of Calvert Cliffs.

The report suggests that successful operation of the steam generator isolation check valve may be necessary to prevent a more adverse condition than the FSAR analysis for a steam line break event. In this manner, these check valves serve a critical safety application.

The report indicates that licensees need to ensure that these check valves are capable not only of passing steam to drive the auxiliary feedwater pump turbines, but also of preventing a simultaneous blowdown of the steam generators. As a consequence, inservice testing of these check valves should be conducted on a regalar bas 's for both the forward and reverse flow directions. The issucnce of NRC Generic Letter 89-04, " Guidance on Developing Acceptable Intervice Testing Programs," which adaresses the need for back flow testing at check valves, woeld appear to be an appropriate step toward resolution of this concern. In addition to testing, the performance of periodic disassembly of check valves to inspect their internals ceuld provide valuable information for the prediction of valve failures.

If you shoulo have questions regarding this report, please do not hesitate te call either myself or Ted Cintula of my staff. Mr. Cintula tan be reached at x24493.

t _-.m __

h Thous A. Novak, Director k Division of Safety Programs Office for Analysis ard Evaluatirn of Operational Data

Enclosure:

As stated Distribution:

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