Information Notice No. 87-48: Information Concerning the use of Anaerobic Adhesive/Sealants
SSINS No.: 6835
IN 87-48
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555
October 9, 1987
Information Notice No. 87-48: INFORMATION CONCERNING THE USE OF
ANAEROBIC ADHESIVE/SEALANTS
Addressees:
All nuclear power reactor facilities holding an operating license or a con-
struction permit.
Purpose:
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.
Discussion:
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.
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October 9, 1987
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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
Page Last Reviewed/Updated Tuesday, March 09, 2021