United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 81-36: Replacement Diaphragms for Robertshaw Valve (Model No. VC-210)

                                                          SSINS No.: 6835 
                                                          Accession No.: 
                                                          8107230039 
                                                          IN 81-36 

                                UNITED STATES
                        NUCLEAR REGULATORY COMMISSION
                    OFFICE OF INSPECTION AND ENFORCEMENT
                           WASHINGTON, D.C. 20555
                                     
                              December 3, 1981

Information Notice No. 81-36:   REPLACEMENT DIAPHRAGMS FOR ROBERTSHAW 
                                   VALVE (MODEL NO. VC-210) 

Description of Circumstances: 

The Georgia Power Company's Hatch 1 facility experienced problems in early 
July 1981 with the Robertshaw Diaphragm Control Valve (Model No. VC-210) 
installed in the Terry Turbine Mechanical Hydraulic Overspeed Complex which 
contributed toward unreliability of the High Pressure Coolant Injection 
(HPCI) system.  During a routine inspection of the valve, it was discovered 
that the diaphragm supplied by Robertshaw was enlarged and leaking oil.  The
diaphragm was replaced on July 12, 1981 and failed again on July 21 and 
August 11, 1981.  The cause of the failures was determined to be 
incompatibility of a neoprene replacement diaphragm, supplied by Robertshaw,
with oil in the hydraulic overspeed complex.  Following the August 11, 1981 
failure, a fabric-reinforced Buna-N diaphragm was installed.  The diaphragm 
satisfied the following service conditions: 

     o    Compatible with the turbine oil recommended by the turbine vendor 
     o    40 psig maximum service pressure 
     o    250F maximum service temperature 
     o    1000 minimum cycles 

Replacement Buna-N diaphragms are available from Terry Corporation or 
through the General Electric Company.  An order placed directly with 
Robertshaw will result in the supply of a thin, non-reinforced neoprene 
diaphragm with reduced duty cycle life because the valves are supplied for 
other applications.  We understand that the reinforced Buna-N diaphragm 
should be identified as Terry piece No. 890151AO1 on the purchase order.  
Also, if a replacement Robertshaw Valve (Model No. VC-210) is ordered (Terry 
piece No. 107282AO1), it is necessary to separately order the reinforced 
diaphragm (Terry piece No.  890151AO1).  The diaphragm is shown in the Terry 
HPCI Instruction Manual, Section 15-M-14, Instruction for Robertshaw 
Diaphragm Control Valve No. VC-210, Figure 14, Part 4. 

This information notice on replacing diaphragms is being provided as an 
early notification of a potentially significant matter.  This experience 
with diaphragm failures serves as a reminder that a single material change 
may adversely affect safety system reliability.  Such a change may reduce 
service life or negate environmental qualification.  Each component or 
material change in a system important to safety should be carefully reviewed 
in order to assure system operability.  Recipients should review the 
information for possible applicability to their facilities. 
.

                                                           IN 81-36 
                                                           December 3, 1981 
                                                           Page 2 of 2 


No written response to this information notice is required.  For additional 
information regarding this matter, contact the Regional Administrator of the
appropriate NRC Regional Office. 

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