ST-HL-AE-1118, Final Deficiency Rept Re Rear Brackets for Snubbers Supplied by Nuclear Power Svcs.Initially Reported on 840706.B Rear Brackets Will Be Replaced within 6 Months

Final Deficiency Rept Re Rear Brackets for Snubbers Supplied by Nuclear Power Svcs.Initially Reported on 840706.B Rear Brackets Will Be Replaced within 6 Months

ML20094L563
Person / Time
Site:	South Texas
Issue date:	08/03/1984
From:	Oprea G HOUSTON LIGHTING & POWER CO.
To:	Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
ST-HL-AE-1118, NUDOCS 8408150389
Download: ML20094L563 (5)

Text

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The Light NE%f flouston Lighting & l'ower !!O. Ilox 1700 llouston, Texas 7700! (713) 228-9211 Au 1984 STgust 3'1118 HL-AE-File Number: G12.204 Mr. John T. Collins -@ 2 0W2 3 Director, Region IV U. S. Nuclear Regulatory Commission  ! M =$g 611 Ryan Plaza Drive, Suite 1000 -l Arlington, Texas 76102 -

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Dear Mr. Collins:

South Texas Project Units 1 & 2 Docket Nos. STN 50-498, STN 50-499 Final Report Concerning NPSI Snubber Assembly Rear Brackets On July 6, 1984, pursuant to 10CFR50.55(e), Houston Lighting & Power Company (HL&P), notified your office of an item concerning rear brackets for snubbers supplied by Nuclear Power Services, Inc. (NPSI). Attached is the final report concerning this item.

If you should have an questions concerning this matter, please call Mr. Michael E. Powell (713 993-13?8.

Very truly yours, uw A h.T. W. (prea, Jr.

Executive Vice President MEP/mg

Attachment:

Final Report Concern *ng NPSI Snubber Assembly Rear Brackets 8408150389 840803 A gDRADOCK05000 /

W2/NRC2/a p j

August 3, 1984 Ifouston Lighting & Power Company ST-HL-AE-1118 File Number: G12.204 Page 2 cc:

Darrell G. Eisenhut, Director Brian E. Berwick, Esquire Division of Licensing Assistant Attorney General for Office of Nuclear Reactor Regulation the State of Texas U.S. Nuclear Regulatory Comission P. O. Box 12548, Capitol Station Washington, DC 20555 Austin, TX 78711 Victor Nerses, Project Manager. Lanny Sinkin U.S. Nuclear Regulatory Comission Citizens Concerned About Nuclear Power 7920 Norfolk Avenue 114 W. 7th, Suite 220 Bethesda, MD 20016 Austin, TX 78701 D. P. Tomlinson Robert G. Perlis, Esquire Resident Inspector / South Texas Project Hearing Attorney c/o U.S. Nuclear Regulatory Comission Office of the Executive Legal Director P. O. Box 910 U.S. Nuclear Regulatory Comission Bay City, TX 77414 Washington, DC 20555 M. D. Schwarz, Jr., Esquire Charles Bechhoefer, Esquire Baker & Botts Chairman, Atomic Safety & Licensing Board One Shell Plaza U.S. Nuclear Regulatory Comission Houston, TX 77002 Washington, DC 20555 J. R. Newman, Esquire Dr. James C. Lamb, Ill Newman & Holtzinger, P.C. 313 Woodhaven Road 1025 Connecticut Avenue, N.W. Chapel Hill, NC 27514 Washington, DC 20036 Judge Ernest E. Hil Director, Office of Inspection Hill Associates and Enforcement 210 Montego Drive U.S. Nuclear Regulatory Comission Danville, CA 94526 Washington, DC 20555 E. R. Brooks /R. L. Range William S. Jordan, III, Esquire Central Power & Light Company Harmon & Weiss P. O. Box 2121 1725 I Street, N.W.

Corpus Christi, TX 78403 Suite 506 Washington, DC 20006 H. L. Peterson/G. Pokorny City of Austin Citizens for Equitable Utilities, Inc.

P. O. Box 1088 c/o Ms. Peggy Buchorn Austin, TX 78767 Route 1, Box 1684 Brazoria, TX 77422 J. B. Poston/A. vonRosenberg City Public Service Board P. O. Box 1771 San Antonio, TX 78296 Revised 07/13/84 i

Au 1984 STgust 3*1118 HL-AE-Attachment Page 1 of 3 South Texas Project Units 1 and 2 Final Report Concerning NPSI Snubber Assembly Rear Brackets I. Suninary In some cases, a forged rear bracket (i.e., version B rear bracket) for l

use in snubber Inc. (NPSI) applications rather has been than a Pachined rear supplied bracket by(Nuclear i.e., versionPower Services, A rear bracket). The version 8 blacket is not an acceptable substitute due to interferences which will occur in angular applications of the snubber. ,

The potential exists that s ubbers which move into the area of  !

interference may be renderea inoperable due to damage or binding at the j rear bracket thus preventing the snubber from performing its intended {

function.  !

II. Description of Deficiency On July 6, 1984, pursuant to 10CFR50.55(e), Houston Lighting and Power Company (HL&P) notified the NRC Region IV, of the above item concerning rear brackets for snubber assemblies supplied by NPSI.

The problem was discovered during an installation fit-up hold point for material verification prior to welding of the rear bracket. Rear brackets supplied for use in snubber applications are required to be a machined rear bracket (SMRB version A per NPSI catalog change notice 81-STP-2, Sheets 18B). The strut rear bracket (SRRB version A) is identical and may be used in a snubber assembly. However, forged rear brackets (SRRB version B) were supplied with the snubber assemblies by '

NPSI.

The version B rear bracket is not an acceptable substitute due to interference which takes place for sizes SRRB-06, 08,10,12, and 14 when used on a snubber up to snubber sizes PSA 10 or A/D 1600. This interference takes place when the snubber assembly is at an angle of about 30"to 90* from the normal, when viewed from one ear of the bracket. The interference is between the snubber body at the forward bracket end for short center-to-center dimension snubbers and between the snubber body and the paddle end for any length of fixed snubber (see figure 1).

Snubbers which move into the area of interference may be rendered inoperable due to damage or binoing at the rear bracket, thus preventing the snubber from performing its intended function. This will limit free movement of the piping system thereby inducing additional stress into the piping which may cause an overstressed condition.

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w August 3 1984

=ST-HL-AEI 1118'

. . Attachment Page 2 of 3 III. Corrective Action

-A corrective action work plan has been initiated which consists'of the, E

following main elements.

n 1.- NPSI has issued a blanket NCR on the rear brackets supplied to date. In addition, shipments of additional version'B rear brackets were put on hold by NPSI.

l 2. NPSI has provided a final list of 275 snubber assembl.ies L supplied to STP containing version B rear brackets.

t Version B rear brackets on snubber assemblies will be replaced

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i 3.

with version A brackets for those snubber sizes identified in Section II.

4. The Bechtel Procurement Supplier Quality Inspection Plan has been revised to include an in-process verification that rear brackets are in compliance with supplier approved drawings.

We anticipate completion of replacement of the version B brackets within the next six (6) months.

IV. Recurrence Control Measures have been taken to improve the effectiveness of. inspections by NPSI and the Bechtel Supplier Quality Representative (SQR). NPSI will verify at their final inspection hold point that the fabricated item is consistent with shop drawing / catalog data sheet requirements for the rear brackets. The Bechtel SQR will verify on a sample basis (approximately 5%) that the proper bracket is included.

V. Safety Analysis A detailed safety analysis was not performed. However, assuming a conservative worst case scenario, the interference problem with the version B rear brackets could possibly cause an overstressing of safety-related piping and supports.

( August 3, 1984

,. ST-HL-AE-1118 Attachment Page 3 of 3 i

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