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HomeNRC LibraryDocument CollectionsGeneral CommunicationsInformation Notices1993

# 

```



                                 UNITED STATES
                         NUCLEAR REGULATORY COMMISSION
                     OFFICE OF NUCLEAR REACTOR REGULATION
                            WASHINGTON, D.C.  20555

                                 May 19, 1993


NRC INFORMATION NOTICE 93-37:  EYEBOLTS WITH INDETERMINATE PROPERTIES 
                               INSTALLED IN LIMITORQUE VALVE OPERATOR
                               HOUSING COVERS


Addressees

All holders of operating licenses or construction permits for nuclear power
reactors.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information
notice to alert addressees to problems that could result from eyebolts with
indeterminate properties installed in Limitorque valve operator housing
covers.  It is expected that recipients will review the information for
applicability to their facilities and consider actions, as appropriate, to
avoid similar problems.  However, suggestions contained in this information
notice are not NRC requirements; therefore, no specific action or written
response is required.  

Description of Circumstances

During recent inspections at the Crystal River Nuclear Plant and the 
Virgil C. Summer Nuclear Station, the NRC found Limitorque model SMB-000 and
SMB-00 valve operators in which two of the housing cover bolts were replaced
with an eyebolt and nut combination.  The licensees reviewed their design
change programs but did not find any documentation for the installation of the
eyebolts.  The affected valve operators were installed in safety- and 
nonsafety-related applications.  Some of the affected valve operators were
installed on butterfly valves through a worm-drive gearbox such that the
housing cover bolts do not experience stem thrust during valve operation. 
However, some of the affected safety-related valve operators were installed on
gate valves and globe valves such that the housing cover bolts do experience
stem thrust forces during valve operation.  The housing cover bolts transmit
valve stem thrust to the operator housing and ultimately to the valve yoke. 
The bolts are listed as critical to valve operator function in the Limitorque
Critical Component List.  

Discussion

South Carolina Electric and Gas (SCE&G), the licensee for Summer, determined
that the affected valve operators arrived from the Limitorque Corporation, the




9305130037.

                                                            IN 93-37
                                                            May 19, 1993
                                                            Page 2 of 2


valve operator vendor, with the eyebolts installed.  In a letter to SCE&G of
December 11, 1992, Limitorque confirmed that it had shipped valve operators
with eyebolts installed since the early 1970s, that Limitorque did not control
the eyebolt material, and that therefore it could not yet address the
qualification of the eyebolt material for actuator operation.  Limitorque
representatives stated that they had not received any reports of failures
associated with the eyebolts.  Limitorque has issued Maintenance Update 92-2,
in which it discusses this problem in paragraph 9, and recommends that the
eyebolts be replaced by grade 5 housing cover bolts at the next scheduled
maintenance.

The NRC staff believes that ungraded eyebolts are probably installed in
various safety-related applications at other facilities since this condition
was not previously documented by the vendor.  The NRC has attached an excerpt
from the Limitorque Maintenance Update 92-2 because all licensees may not
automatically receive Limitorque maintenance updates. 

This information notice requires no specific action or written response.  If
you have any questions about the information in this notice, please contact
one of the technical contacts listed below or the appropriate Office of
Nuclear Reactor Regulation (NRR) project manager.


                                      ORIGINAL SIGNED BY


                                   Brian K. Grimes, Director
                                   Division of Operating Reactor Support
                                   Office of Nuclear Reactor Regulation


Technical contacts:  Stephen Elrod, RII      Richard Freudenberger, RII 
                     (407) 464-7822          (904) 795-7677

                     Lee Keller, RII         Thomas Scarbrough, NRR
                     (803) 345-5683          (301) 504-2794

Attachments: 
1.   Excerpt from Limitorque Maintenance Update 92-2
2.   List of Recently Issued NRC Information Notices

.ENDEND
```

*Page Last Reviewed/Updated Thursday, March 29, 2012*

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