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. Attachment: Recently issued IE Information Notices
Page Last Reviewed/Updated Tuesday, March 09, 2021
Page Last Reviewed/Updated Tuesday, March 09, 2021