IE Circular No. 79-25 - Shock Arrestor Strut Assembly Interference
CR79025 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 December 14, 1979 (Corrected) MEMORANDUM FOR: B. H. Grier, Director, Region I J. P. O'Reilly, Director, Region II J. G. Keppler, Director, Region III K. V. Seyfrit, Director, Region IV R. H. Engelken, Director, Region V FROM: Harold D. Thornburg, Director, Division of Reactor Construction Inspection, IE SUBJECT: IE CIRCULAR NO. 79-25 - SHOCK ARRESTOR STRUT ASSEMBLY INTERFERENCE The subject circular should be dispatched for action to all licensees and holders of power reactor construction permits no later than December 20, 1979. The text of the circular and draft letter to licensees are enclosed for this purpose. Harold D. Thornburg, Director Division of Reactor Construction Inspection Office of Inspection and Enforcement Enclosures 1. Draft transmittal letter 2. IE Circular No. 79-25 CONTACT: W. Laudan, IE 49-27551 . SSINS: 6830 Accession No: 7910250514 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C. 20555 December 20, 1979 IE Circular No. 79-25 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 2103 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 determine 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 supplier (Bergen Paterson) and appropriate resolutions promptly implemented. . (Corrected) (Draft letter to all licensees and holders of construction permits) IE Circular No. 79-25 Gentlemen: The enclosed 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, Signature (Regional Director) Enclosures: 1. IE Circular No. 79-25 2. List of IE Circulars Recently Issued
Page Last Reviewed/Updated Tuesday, March 09, 2021
Page Last Reviewed/Updated Tuesday, March 09, 2021