United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 87-48: Information Concerning the use of Anaerobic Adhesive/Sealants

                                                      SSINS No.:  6835
                                                         IN 87-48

                                  UNITED STATES
                          NUCLEAR REGULATORY COMMISSION
                             WASHINGTON, D.C.  20555

                                 October 9, 1987

Information Notice No. 87-48:  INFORMATION CONCERNING THE USE OF 
                                   ANAEROBIC ADHESIVE/SEALANTS


All nuclear power reactor facilities holding an operating license or a con-
struction permit. 


This information notice is provided to alert recipients to a potentially 
significant safety problem pertaining to the use of anaerobic adhesives and 
sealants.  It is expected that recipients will review the information for 
applicability to their facilities and consider actions, if appropriate, to 
preclude a similar problem.  However, suggestions contained in this notice do 
not constitute NRC requirements; therefore, no specific action or written 
response is required.

Description of Circumstances:

On July 1, 1987, Carolina Power and Light Company reported that following a 
reactor trip/turbine trip at the Brunswick Steam Electric Plant, Unit 1 
(Brunswick), one safety relief valve (SRV) failed to open when manually actu-
ated for pressure control.  The SRV is part of the automatic depressurization 
system (ADS) at that plant.  Subsequent testing of other ADS valves on July 3 
resulted in a second valve failing to open on manual actuation.  During post-
failure examination it was determined that Loctite RC 620 was used as a 
secondary lock between the stem and the plunger in the solenoid assembly when 
the valves were rebuilt by Target Rock Corporation at Wyle Laboratory.  This 
material then migrated to the clearance around the plunger before setting.  


This event is similar to the one described in Information Notice 84-53, 
"Information Concerning the Use of Loctite 242 and Other Anaerobic Adhesive/
Sealants."  In that event, Loctite 242 threadlocking adhesive/sealant was used 
in the assembly of scram pilot solenoid valves.  An investigation into the 
failure of several scram solenoid valves revealed that maintenance technicians 
failed to wipe excess Loctite from the assembly, which resulted in the bonding 
of the solenoid core plunger to the core tube.  

.                                                            IN 87-48
                                                            October 9, 1987
                                                            Page 2 of 2

The Brunswick SRVs also failed because the contractor technician did not clean 
the excess Loctite RC 620 from the plunger assembly.  Because this substance 
is anaerobic (cures in the absence of air, e.g., the inerted containment atmo-
sphere), the plunger did not become seized until after the valves with excess 
Loctite were placed in the inerted atmosphere that exists in the reactor 
containment when the reactor is brought to power conditions.

No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the Regional 
Administrator of the appropriate regional office or this office.

                              Charles E. Rossi, Director
                              Division of Operational Events Assessment
                              Office of Nuclear Reactor Regulation

Technical Contact:  Ray Scholl, NRR
                    (301) 492-8213

Attachment:  List of Recently Issued NRC Information Notices

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