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Information Notice No. 89-28: Weight and Center of Gravity Discrepancies for Copes-Vulcan Air-Operated Valves
UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF NUCLEAR REACTOR REGULATION WASHINGTON, D.C. 20555 March 14, 1989 Information Notice No. 89-28: WEIGHT AND center OF GRAVITY DISCREPANCIES FOR COPES-VULCAN AIR-OPERATED VALVES Addressees: All holders of operating licenses or construction permits for nuclear power reactors. Purpose: This information notice is being provided to alert addressees to potential problems resulting from incorrect weight and center of gravity information provided by Copes-Vulcan, Incorporated (CV) with air-operated valves which they supplied before 1980. It is expected that recipients will review the information for applicability to their facilities and consider actions, as appropriate, to evaluate the significance of any discovered discrepancies. However, the suggestions contained in this information notice do not consti- tute NRC requirements; therefore, no specific action or written response is required. Description of Circumstances: During recent reverification of piping stress analyses at the Prairie Island Nuclear Station, significant discrepancies were discovered in valve weight and center of gravity information for air-operated valves supplied by CV. Copes-Vulcan, (formerly the Blaw Knox Company), is a division of White Consolidated Industries. Before 1980, the information listed on the valve drawings in many cases did not account for the air operator and, consequently, significant-ly understated the valve assembly weight and center of gravity. Some of these valves are located in various lines connected to the accumulator tanks of the safety injection system, and in the charging and letdown systems. The new piping stress analyses performed for Prairie Island with the corrected values have shown that, as a result of this discrepancy, the allowable code stresses have been exceeded in many cases. In several instances, the piping stress analyses brought into question the ability of the associated system to withstand a seismic event. The NRC has also confirmed the existence of this discrepancy at the D. C. Cook and Zion stations at which a number of the same valves were identified in safety systems. Reanalyses at the D. C. Cook station using the appropriate values for valve weight and center of gravity resulted in piping stresses that exceeded the allowable code limits. In at least one instance, the stresses exceeded the allowable limits to the extent that the operability of the associated piping 8903080372 .. IN 89-28 March 14, 1989 Page 2 of 3 system was brought into question. At Zion, the extended valve operators were supported independently minimizing the impact of the discrepancies in the weight or center of gravity location on the stress analyses. Discussion: As far as the NRC is aware, the incorrect information supplied by CV has only affected small-bore piping systems having valves ranging in size from 3/4 inch to 3 inches with pressure ratings ranging from 150 psi to 1500 psi. Table 1 is a partial listing of the valves supplied with the incorrect information. NRC does not know if any larger valves are affected. The actual valve weights are as much as 40 percent greater than the values originally provided, although in a few cases the actual weights are less. All of the center of gravity values are significantly different from the original values provided. The original center of gravity locations were given as approximately 5 inches from the datum points, while the actual locations range from 15 to 20 inches from the datum points. The corrections of the center of gravity values typically have resulted in the most significant problems in meeting allowable code stress levels. IE Bulletin 79-14, "Seismic Analyses for As-Built Safety-Related Piping Systems," which was issued July 2, 1979, required all power reactor owners to verify that their seismic analyses applied to the actual configuration of safety-related piping. That bulletin applied only to safety-related piping 2 1/2 inches in diameter and greater and to seismic Category I piping, regardless of size, that was dynamically analyzed by computer. The incorrect information supplied with the CV valves mainly affected small-bore piping systems and is generally outside of the scope of Bulletin 79-14. However, since the small-bore piping had been analyzed by computer, the licensee for Prairie Island included this piping in its verification program required by Bulletin 79-14. It was during a reverifi-cation of the Bulletin 79-14 program that the recent CV valve data was found to differ from the original data. The discovery of the incorrect CV valve data at D. C. Cook and Zion was made as a result of NRC inquiries following the Prairie Island discovery. The original design criteria for small-bore piping at these plants was based on generic span and standardized support criteria and was not part of the Bulletin 79-14 scope. At Zion, the extended valve operators are independently supported, therefore, the incorrect valve information did not cause any significant problems. However, CV typically recommended that attachments be made no higher than the body-to-bonnet flange connection. If the valves are supported in a manner not recommended by the manufacturer, it is important that the utility ensure that the valves are requalified with appropriately induced loads from the piping system. Analyses of the valve assemblies at Zion showed that the valves are qualified with the installed support systems, even though they do not comply with the vendor recommendations for supports. Additional information on this problem was obtained during an NRC inspection at CV. The incorrect valve weight and center of gravity information typically was supplied to the licensees' Nuclear Steam System Suppliers or Architect-Engineers before 1980, who supplied it along with the system designs to the licensees. In 1988, CV notified its purchasers of the incorrect valve weights and center of .. IN 89-28 March 14, 1989 Page 3 of 3 gravity values. A copy of the CV letter to the purchasers is attached. However, as these pur-chasers were usually Nuclear Steam System Suppliers and Architect-Engineers, some licensees who were the final users may not have been notified of the problem in a timely fashion. Additional technical information and a partial list of licensees who may have received the incorrect information can be found in the NRC inspection report (99900080/88-01). No specific action or written response is required by this information notice. If you have any questions about this matter, please contact one of the techni- cal contacts listed below or the Regional Administrator of the appropriate regional office. Charles E. Rossi, Director Division of Operational Events Assessment Office of Nuclear Reactor Regulation Technical Contacts: J. A. Gavula, RIII (312) 790-5761 J. J. Petrosino, NRR (301) 492-0979 Attachments: 1. Table 1 2. Copes-Vulcan Letter 3. List of Recently Issued NRC Information Notices .. Attachment 3 IN 89-28 March 14, 1989 Page 1 of 1 LIST OF RECENTLY ISSUED NRC INFORMATION NOTICES _____________________________________________________________________________ Information Date of Notice No._____Subject_______________________Issuance_______Issued to________ 89-27 Limitations on the Use 3/8/89 All holders of OLs of Waste Forms and High or CPs for nuclear Integrity Containers for power reactors, fuel the Disposal of Low-Level cycle licenses and Radioactive Waste certain by-product materials licenses. 89-26 Instrument Air Supply to 3/7/89 All holders of OLs Safety-Related Equipment or CPs for nuclear power reactors. 89-25 Unauthorized Transfer of 3/7/89 All U.S. NRC source, Ownership or Control of byproduct, and Licensed Activities special nuclear material licensees. 89-24 Nuclear Criticality Safety 3/6/89 All fuel cycle licensees and other licensees possessing more than critical mass quantities of special nuclear material. 89-23 Environmental Qualification 3/3/89 All holders of OLs of Litton-Veam CIR Series or CPs for nuclear Electrical Connectors power reactors. 89-22 Questionable Certification 3/3/89 All holders of OLs of Fasteners or CPs for nuclear power reactors. 89-21 Changes in Performance 2/27/89 All holders of OLs Characteristics of Molded- or CPs for nuclear Case Circuit Breakers power reactors. 88-73, Direction-Dependent Leak 2/27/89 All holders of OLs Supplement 1 Characteristics of Contain- or CPs for nuclear ment Purge Valves power reactors. __________________________________________________________________________________ OL = Operating License CP = Construction Permit ..
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