United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 92-68, Supplement 1: Potentially Substandard Slip-On, Welding Neck, and Blind Flanges

                                 UNITED STATES
                         NUCLEAR REGULATORY COMMISSION
                            WASHINGTON, D.C.  20555

                              September 16, 1996

                                             WELDING NECK, AND BLIND FLANGES


All holders of operating licenses or construction permits for nuclear power


The U.S. Nuclear Regulatory Commission (NRC) is issuing this information
notice supplement to alert addressees to problems with potentially substandard
stainless steel butt weld fittings and flanges from Taiwan and to advise
licensees of plant events that involved carbon steel flanges from the People's
Republic of China.  It is expected that recipients will review this
information for applicability to their facilities and consider actions, as
appropriate, to avoid similar problems.  However, suggestions contained in
this information notice supplement are not NRC requirements; therefore, no
specific action or written response is required.


The NRC issued Information Notice (IN) 92-68, "Potentially Substandard Slip-
On, Welding Neck, and Blind Flanges," on September 10, 1992, to alert
addressees to problems with potentially substandard carbon steel slip-on,
welding neck, and blind flanges.  The National Board of Boiler and Pressure
Vessel Inspectors had discussed with the NRC the board investigation of
problems associated with flanges that originated from the People's Republic of
China.  Specifically, the suspect flanges marked "China" were sold to U.S.
suppliers through several trading companies and contained cracks, inclusions,
and slugged weld repairs and were constructed from two pieces of material.

The suspect flanges were marked as forgings that complied with the
requirements of American Society for Testing and Materials (ASTM) Standard 
A-105, "Specification for Forgings, Carbon Steel, for Piping Components," and
American National Standards Institute (ANSI) Standard B16.5, "Dimensional
Standards for Steel Pipe Flanges and Flanged Fittings."  However, the suspect
flanges were manufactured with ring inserts welded to the inside diameter of
the flange and the outer surfaces were machined.  Consequently, neither the
welding nor the two-piece construction would be detected during a visual
inspection.  Other flanges were found with slugged weld repairs to the flange
hub, and still others failed to meet the material specification requirements
for thermal treatment, mechanical properties, or chemistry.

9609100227.                                                            IN 92-68, Supp. 1
                                                            September 16, 1996
                                                            Page 2 of 4

Description of Circumstances

Stainless Steel Butt Weld Fittings and Flanges

As a result of issuing IN 92-68, the NRC received information that the 
U.S. Federal Trade Commission was investigating potentially substandard
stainless steel butt weld fittings and flanges imported from Taiwan.  The
information suggested that two Taiwan manufacturers (Tru-Flow and Tung Teng)
had sold U.S. suppliers potentially substandard stainless steel butt weld
fittings and flanges and that potentially substandard stainless steel fittings
and flanges can be sold to U.S. suppliers by other foreign manufacturers.

Specifically, stainless steel stub-end butt weld fittings, marked in
conformance with ASTM Standard A-403, "Standard Specification for Wrought
Austenitic Stainless Steel Piping Fittings," and ANSI Standard B16.9,
"Factory-Made Wrought Steel Butt-Welding Fittings," with the manufacturer
name, pipe size and schedule, A403 WP 316L-W, heat number, Type A, and Taiwan,
failed to conform to applicable standards.  The fitting manufacturer had
fabricated the suspect stub-end fittings by welding the flange or lap to
starting pipe material.

A cross-sectioned stub end examined by the NRC was marked, "Tru-Flow, 1 1/2-
inch schedule 40s, A403 WP 316L-W, HT:15425 Type A, Taiwan."  ASTM A-403
specification Class WP-W fittings shall meet the requirements of ANSI B16.9
and shall have all welds made by the fitting manufacturer and all pipe welds
made with the addition of filler metal radiographically examined throughout
the entire length.  However, a visual inspection of the cross-sectioned stub
end showed that the welds attaching the flange or lap to the pipe did not
fully penetrate the weld joint.

Additionally, the NRC was given documentation of an independent inspection of
six stub ends also manufactured by Tru-Flow and marked "2-inch schedule 10s,
A403 WP 316L-W, HT:20327 Type A, Taiwan."  Independent radiographic
examination of the fitting manufacturer weld of the flange or lap to the
starting pipe showed that the welds on all six stub ends examined lacked full
penetration welds.  A visual inspection would not be able to detect the
welding deficiencies.  Additionally, although all six fittings had the same
material heat number, a reported chemical analysis showed that two heats of
material were supplied and that the flange or lap was yet another heat of

Carbon Steel Flanges

IN 92-68 stated that the National Board of Boiler and Pressure Vessel
Inspectors had received numerous reports of flanges marked "China" that
contained cracks, inclusions, and slugged weld repairs and were constructed
from two pieces of material.  When IN 92-68 was issued, the NRC did not have
evidence that any suspect flanges from China had been installed in U.S.
nuclear power plants.  However, after the IN was issued, two instances of
these suspect flanges at licensee facilities have been reported.

.                                                            IN 92-68, Supp. 1
                                                            September 16, 1996
                                                            Page 3 of 4

In November 1992, the licensee for Seabrook Station reported finding flanges
in a safety system (six 4-inch nominal welding neck flanges installed in the
control room ventilation system) that could be part of the potentially
substandard group identified in the IN.  These flanges were stamped with the
word "China."  The flanges had been procured as nonsafety-related items.

The licensee performed in situ evaluations of the flanges installed at the
Seabrook Station to assess their quality, integrity, and capability to perform
their safety function in a ventilation system.  The licensee determined that
the "China" flanges were acceptable for this particular installation.  The
licensee identified and inspected about 20 "China" flanges installed in non-
safety systems, but found no additional suspect flanges in safety systems.

In February 1993, the licensee for Browns Ferry rejected piping assemblies at
receipt inspection because they contained flanges stamped with the word
"China."  Specifically, the piping assemblies contained 30-, 24-, 20-, 16-,
and 12-inch nominal diameter, 150-lb. pressure-class, schedule 40, slip-on
"China" flanges.  The assemblies were procured by the licensee as safety-
related items from Press Mechanical (Cicero, Illinois) for a filter assembly
for the control room emergency ventilation system.  Press Mechanical procured
the flanges as safety-related items from Albany Steel & Brass (Chicago,
Illinois), who procured them from Weld Bend (Argo, Illinois).  The flanges
were supplied to Press Mechanical with Weld Bend material certificates that
did not indicate the original source of manufacture as China.  However, the
flanges were all marked "China."

The National Board of Boiler and Pressure Vessel Inspectors reported that an
18-inch nominal diameter, 150-lb. pressure-class "China" flange also supplied
by Weld Bend (for use not related to the nuclear industry) had cracked (inside
diameter to outside diameter) beneath the raised face flange area (gasket
surface).  The 18-inch nominal diameter flange was reported as originating
from heat 6FO3FO; which is the same heat number reported for the 24-inch
nominal diameter flanges supplied to Press Mechanical by Weld Bend for the
Browns Ferry piping.  Press Mechanical testing of selected China flanges,
including the 24-inch nominal diameter ones, did not identify any deviations
from the specifications.


The Federal Trade Commission advised the NRC that it had not made a final
disposition of its investigation of the potentially substandard stainless
steel butt weld fittings and flanges that had originated in Taiwan, and that
they referred the matter to the Occupational Safety and Health Administration
to alert users to the risks associated with these potentially substandard
fittings and flanges. 

The NRC does not have evidence that any of these suspect stainless steel butt
weld fittings and flanges from Taiwan had been installed in U.S. nuclear power
plants.  However, identified problems are described above for information.

.                                                            IN 92-68, Supp. 1
                                                            September 16, 1996
                                                            Page 4 of 4

With regard to China flanges, the U.S. Customs Service reported that it had
not received any additional complaints or further information and, therefore,
closed its case.

A potentially substandard fitting or flange could pass among multiple
distributors before reaching the end-user facility.  A nuclear power plant
licensee could buy a commercial grade fitting or flange from a distributor to
dedicate the component for safety-related use, or safety-related components or
subassemblies that contain fittings and flanges could be supplied by licensee-
approved manufactures or fabricators.  Procedures to trace procured equipment
and material to the original manufacturer or mill is an important prerequisite
to inspecting and testing during the dedication process.  It is possible for a
licensee to install potentially substandard or defective equipment or material
if it does not adequately verify that the product can be traced to the
original manufacturer.  Properly implemented, NRC-required quality assurance
programs should prevent licensees from installing substandard fittings and
flanges in safety systems.

This information notice requires no specific action or written response.  If
you have any questions about the information in this notice, please contact
the technical contact listed below or the appropriate Office of Nuclear
Reactor Regulation (NRR) project manager.

                                          signed by

                                    Thomas T. Martin, Director
                                    Division of Reactor Program Management
                                    Office of Nuclear Reactor Regulation

Technical contact:  Steven M. Matthews, NRR
                    (301) 415-3191
                    E-mail:  smm@nrc.gov
Page Last Reviewed/Updated Friday, May 22, 2015