Information Notice No. 84-53: Information Concerning the Use of Loctite 242 and Other Anaerobic Adhesive/Sealants
SSINS No. : 6835 IN 84-53 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, DC 20555 July 5, 1984 Information Notice No. 84-53: INFORMATION CONCERNING THE USE OF LOCTITE 242 AND OTHER ANAEROBIC ADHESIVE/SEALANTS Addressees: All nuclear power reactor facilities and fuel facilities holding an operating license (OL) or construction permit (CP). Purpose: This information notice is being provided as a notification of a potentially significant problem pertaining to the use of certain anaerobic adhesive/sealants. The NRC staff expects recipients to review this notice for applicability to their facilities and consider actions, if appropriate, to preclude similar problems from occurring at their facilities. However, suggestions contained in this information notice do not constitute NRC requirements; therefore, no specific action or written response is required. Description of Circumstances: Philadelphia Electric Company reported that, on November 17, 1983, two control rods had exceeded their allowed scram times at Peach Bottom Unit 3. An investigation determined the cause of the failure to be a foreign substance that bonded the solenoid core plunger to the solenoid base assembly of the scram pilot solenoid valve. The foreign material was determined to be Loctite 242. Apparently, excess Loctite 242 had not been wiped off when it was used on the acorn nut of the solenoid housing. The material on the nut had appeared to be a solid and was thought to be cured. Upon the return of the system to service, the Loctite 242 that was exposed to air liquified and migrated to the position where it eventually caused a failure of pilot solenoid valves. The NRC is aware of other uses of Loctite in the industry: Loctite 242 at an operating pressurized water reactor (PWR) on safety injection pump impeller locknuts, Loctite 277 at PWRs under construction used as pipe sealant on tubing connections to the feed water isolation valve, and Loctite 580 at a boiling water reactor under construction in various emergency core cooling system valve set screws. No other problems have been identified in these other applications. 8407030085 . IN 84-53 July 5, 1984 Page 2 of 2 Discussion: The Loctite Corporation describes Loctite 242 Threadlocking Adhesive/Sealant as well as Loctite 580 Nuclear Grade PST (r) Pipe Sealant as thixotropic (gels at rest and liquid when agitated) and anaerobic (cures in absence of air) compounds. This material does not cure in the presence of air, i.e., outside the joint. Loctite 277 Threadlocking Adhesive/Sealant is also anaerobic but not thixotropic. Loctite 580 is the substitute product for 242 and 277 for applications in nuclear power plants according to the Loctite Corp. Technical and maintenance personnel alike are advised to maintain familiarity with the most current product data sheets for Loctite and similar materials that they use and particularly to utilize nuclear grade materials in appropriate applications. Loctite technical information may be obtained through Loctite Technical Service Centers in Newington, Connecticut, phone (203) 278-1280. No written response to this information notice is required. If there are any questions regarding this matter, please contact the Regional Administrator of the appropriate NRC Regional Office or this office. Edward L. Jordan Director Division of Emergency Preparedness and Engineering Response Office of Inspection and Enforcement Technical Contact: M. S. Wegner, IE (301) 492-4511 Attachment: List of Recently Issued IE Information Notices
Page Last Reviewed/Updated Tuesday, March 09, 2021
Page Last Reviewed/Updated Tuesday, March 09, 2021