Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
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
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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
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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
..
