ML19211C124

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Forwards IE Circular 79-25, Shock Arrestor Strut Assembly Interference. No Written Response Required
ML19211C124
Person / Time
Site: South Texas  STP Nuclear Operating Company icon.png
Issue date: 12/20/1979
From: Seyfrit K
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To: Eric Turner
HOUSTON LIGHTING & POWER CO.
References
NUDOCS 8001100104
Download: ML19211C124 (1)


Text

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C-UNITED STATES tma ascoq'o, NUCLEAR REGULATORY COMMISSION p

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611 RYAN PLAZA DRIVE. SUITE 1000 3.4

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December 20, 1979 In Reply Refer To:

RIV Docket Nos. 50-498/IE Circular No. 79-25 50-499/IE Circular No. 79-25 Houston Lighting & Power Company ATTN:

Mr. E. A. Turner, Vice President Power Plant Construction and Technical Services Post Office Box 1700 Houston, Texas 77001 Gentlemen:

The enclosed IE Circular 79-25, is forwarded to you for information.

No written response to this Circular is required.

If you require additional information regarding this subject, please contact this office.

Sincerely, j

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.y Karl V. Seyfrit

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Director

Enclosures:

1.

IE Circular No. 79-25 2.

List of IE Circulars Recently Issued 1738 297 0001100

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SSINS:

6830 Accession No: 7910250514 UNITED STATES

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NUCLEAR REGULATORY COMMISSION

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0FFICE OF INSPECTION AND ENFORCEMENT

,J WASHINGTON, D.C.

20555 IE Circular No. 79-25 Date: December 20, 1979 Page 1 of 1 SHOCK ARRESTOR STRUT ASSEMBLY INTERFERENCE The Bergen Paterson Pipesupport Corporation reported to the NRC a potential problem with their mechanical shock arrestor

" Strut Assembly." The Bergen Paterson, Part 2540 Strut Assembly, is being used as a rear bracket for different sizes of Pacific Scientific Company (PSCO) mechanical shock arrestors. Some of these shock arrestor sizes may not function as intended due to insufficient clearances. The following problems were identified:

For PSCO shock arrestors sizes 15 and 50, the Bergen Paterson Part 2540 Strut Assembly does not provide sufficient clearance for the shock arrestor to function freely, when installed at an off axis angle greater than 83*.

For PSCO shock arrestor size 120 there is insufficient clearance throughout the 180* installation angle.

For PSCO shock arrestor sizes 50 and 120 with Bergen Paterson Adaptor Part 2108 the shock arrestor unit may sustain functional damage when the adaptor unit comes in contact with the rear of the snubber, causing distortion of the end dust cover.

PSCO shock arrestors sizes

.35,

.65, 1.5 and 6 do not have this interference condition and therefore are not part of the potential problem of this circular.

Bergen Paterson stopped shipment as of October 1979 of all Part 2540-15, 2540-50, and 2540-120 strut assemblies and is reviewing all applicable design detail drawings, to identify all affected items and the facilities to which those items have been delivered.

Licensees and holders of construction permits are advised to proceed with the inspection of Pacific Scientific Mechanical Shock Arrestor installations with Bergen Paterson Part 2540-15, 2540-50 and 2540-120 Strut Assemblies and deter-mine whether any of the following conditions are applicable:

1.

The shock arrestor installation orientation presents a possible interference problem.

2.

Inspection of shock arrestors 50 and 120 with adaptor show damaged or deformed snubber.

Corrective action should be coordinated with the Strut Assembly cupplier (Bergen Paterson) and appropriate resolutions promptly implemented.

1738 298

IE Circular No. 79-25 December 20, 1979 RECENTLY ISSUED IE CIRCULARS Circular Subject Date Issued To No.

Issued 79-18 Proper Installation of 9/10/79 All Holders of a Target Rock Safety-Relief Power Reactor Operating Valves License (OL) or Construction Permit (CP) 79-19 Loose Locking Devices on 9/13/79 All Power Reactor Ingersoll-Rand Pumps Licensees with a Construction Permit (CP) and/or Operating Licensee (OL) 79-20 Failure Of GTE Sylvania 9/24/79 All Power Reactor Relay, Type PM Bulletin Licensees with a 7305, Catalog SU12-11-AC Construction Permit (CP)

With A 120V AC Coil and/or Operating Licensee (OL) 79-21 Prevention of Unplanned 10/16/79 All holders of Power Releases of Radioactivity Reactor Operating Licenses (OLs) or Construction Permits (cps) 79-22 Stroke Times.for Power 11/16/79 All Power Reactor Oper-Operated Relief Valves ating Facilities and all Utilities having a Construction Permit (CP) 79-23 Motor Starters and 11/26/79 All Power Reactor Oper-Contactors Failed to ating Facilities and Holders Operate of Reactor Construction Permits (cps) 79-24 Proper Installation and 11/26/79 All Holders of a Calibration of Core Spray Power Reactor Operating Pipe Break Detection License (OL) or Equipment on BWRs.

Construction Permit (CP)

Enclosure i738 299