ML19209A519

First Deficiency Rept Re Qualification of Steam Generator & Pressurizer Power Operated Relief Valve Control Sys & Main Feedwater & Automatic Rod Control Sys.Next Rept Will Be Submitted in Approx Three Months

ML19209A519
Person / Time
Site:	Wolf Creek, Callaway, Sterling
Issue date:	09/28/1979
From:	EMVSNUPP
To:
Shared Package
ML19209A517	List: ML19209A516 ML19209A519
References
NUDOCS 7910040280
Download: ML19209A519 (2)

Text

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Enclosure SNUPPS REPORT ON POTENTIAL SIGNIFICANT DEFICIENCY:

QUALIFICATION OF CONTROL SYSTEMS Westingnouse identified the following four control systems for generic consideration of non-safety grade / safety grade interface interactions:

a. Steam generator power operated relief valve control system

- A piping failure in the vicinity of the steam generator relief valves could be assumed to cause the valves to stick open. The combination of the pipe failure, an assumed single failure, and the stuck valve (s) may re-sult in inadequate auxiliary feedwater flow.

b. Pressurizer power operated relief valve control system

- A failure of secondary system piping inside the contain-ment is assumed to cause pressurizer power operated re-lief valves (PORV) to open. The resultant secondary break coincident with PORV opening may have more severe consequences than those accidents previously analyzed,

c. Main feedwater control system

- A small secondary system break could affect normal feedwater flow control causing low steam generator levels prior to protective actions for the break.

d. Automatic rod control system

- An intermediate size high energy line break is assumed to affect the rod control system such that the initial con-ditions previously assumed for tne break may not be valid.

The status of each of these matters, as they pertain to the SNUPPS design is summarized below.

a. The SNUPPS control sA h and main steam line atmospheric relief valves have been pr n , ed es Class IE devices and are environ-mentally qualif'M M .ithstand the effects of a high energy line break. ' > r; no unreviewed safety questions exist for SNUPPS in th 3 regard.

b. This matter is still under revie.4 for the SNUPPS design. One possible resolution is the qualification of pressurizer PORVs to the environment caused by high energy line breaks. SNUPPS is investigating this possibility.

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Enclosure Page Two

c. This matter is still under review for the SNUPPS design.

d. This matter is still under review for the SHUPPS design.

For items b, c, and d above, a supplemental report will be submitted when the review is complete. This additional information should be available in approximately three to four months.

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