ML20012B778

Final Deficiency Rept CP-90-04 Re Holes in Innermost Containment Sump Screen.Initially Reported on 900208. Broken Wire Strand Corrected by Snugly Wrapping Strand of Stainless Steel Wire Around Broken Strand

ML20012B778
Person / Time
Site:	Comanche Peak
Issue date:	03/09/1990
From:	William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
CP-90-04, CP-90-4, TXX-90100, NUDOCS 9003160262
Download: ML20012B778 (2)

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-- Log # TXX 90100  !

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I L March 9, 1990 i winem J. CahiR. Jr.

Larcanhs Vkt hrsMent l

U. S. Nuclear Regulatory Commission l

[ Attn: Document Control Desk l

. Washington, D. C. 20555 i t  ;

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)  !

DOCKET NOS. 50 445 ,

b HOLES IN CONTAINMENT SUMP SCREEN l SDAR: CP 90-04 (FINAL REPORT FOR UNIT 1) i Gentlemen:

l l On February 8, 1990. TV Electric verbally notified the NRC of a deficiency ,

regarding holes found in the Unit 1 innermost Containment Sump screen.

TU Electric has concluded that this condition is reportable pursuant to .

10 CFR 50.55(e). This deficiency affects Unit 1 only.

Descriotion' During a walkdown by Operations personnel and the NRC, holes were observed in

< the fine wire mesh of the Recirculation Containment Sump screen. The largest ,

hole consisted of three broken vertical strands and four broken horizontal strands.

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Safety Sionificance The spacing of the fine wire mesh screen is based on the minimum size particle that could clog the Containment Spray nozzles, or grid assemblies in the-reactor core,< or interfere with Containment Spray or Residual- Heat Removal pump-clearances.

Had the holes gone uncorrected, material could have entered the sump'and interfered with these flow paths.

-Cause and Corrective Action The cause of this condition could not be conclusively determined; however, restricted access _to this. area during plant operations minimizes the potential '

for-future screen damage or the collection of sump debris. I o

Each broken wire strand _was corrected by snugly wrapping a strand of stainless steel wire around the broken strand and threading the wire around a minimum of '

7 undamaged strands on either side of the hole. The reworked mesh spacing is within the maximum permissible dimensions of the original screen

.(.115"x.115").

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TXX 90100 March 9, 1990 Page 2 of 2 Continued integrity of the screen is assured through Technical Specification surveillance requirements 4.5.2d.2 and portions of 4.5.3.1 which require Operations personnel to verify that containment recirculation sumps and subsystem suction inlets are clear of debris that would restrict flow and to check sump components (trash racks, screens, etc.) for structural distress or abnormal corrosion once per 18 months.

Sincerely,

/xk- AU.

William J. Cahill, Jr.

JLR/daj c - Mr. R. D. Martin, Region IV Resident inspectors, CPSES (3)