NRC Bulletin 79-03, Longitudinal Weld Defects in ASME SA-312 Type 304 Stainless Steel Pipe Spools Manufactured by Youngstown Welding And Engineering Company
Longitudinal Weld Defects in ASME SA-312 Type 304 Stainless Steel Pipe Spools Manufactured by Youngstown Welding And Engineering Company
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text
Bulletin 79-03: Longitudinal Weld Defects in ASME SA-312 Type 304 Stainless Steel Pipe Spools Manufactured by Youngstown Welding And Engineering Company
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
March 12 , 1979
LONGITUDINAL WELD DEFECTS IN ASME SA-312 TYPE 304 STAINLESS STEEL PIPE
SPOOLS MANUFACTURED BY YOUNGSTOWN WELDING AND ENGINEERING COMPANY
Description of Circumstances:
On September 27, 1978, the Arizona Public Service Company reported that
defects had been discovered in longitudinal welds in ASME Section III j
class 2 pipe supplied for the Palo Verde Nuclear Generating Station (PVNGS).
On November 17, 1978, the Southern California Edison Company reported
similar defects in pipe supplied for the San Onofre Nuclear Generating
Station, Units 2 and 3.
Pullman Power Products of Los Angeles, California supplies safety-related
fabricated piping spools of various diameters for the PVNGS. The defects
were discovered by Pullman in ASME SA-312 type 304 stainless steel pipe
supplied to Pullman by Youngstown Welding and Engineering Company of
Youngstown, Ohio. The pipe is manufactured by rolling plate into cylinders
and then fusion welding the longitudinal seam without filler metal.
Pullman discovered defects in the longitudinal welds while radiographing
their circumferential shop welds. Further radiographic examination of the
longitudinal welds revealed rejectable porosity and lack of fusion. Pullman
then performed ultrasonic examination of the full length of the longitudinal
welds and discovered indications exceeding the acceptance criteria of ASME
Section III. Further ultrasonic examination revealed indications in other
piping subassemblies where pipe was supplied by Youngstown. Two indications
verified by radiography were identified as porosity and measured 0.350 inch
by 0.125 inch in one case and 0.300 inch by 0.125 inch in another case in
pipe with a nominal wall thickness of 0.375 inch.
The additional examinations revealed that of 103 spools and four pipe
supports shipped to PVNGS, 44 spools and one pipe support were found to
contain ultrasonic indications exceeding those permitted by the ASME Code.
Of 65 partially fabricated piping spools, 30 were found to be similarly
defective. The acceptance criteria for the pipe supplied by Youngstown
includes 100 percent ultrasonic examination of the longitudinal
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IE Bulletin No. 79-03 March 12, 1979
welds in accordance with ASME Section III. The documentation provided with
the pipe indicated that the required ultrasonic examination had been
performed by Youngstown but the rejectable indications were not identified.
A special inspection was performed at Youngstown by NRC inspectors during
the week of January 22, 1979. It was determined that the apparent cause of
the identified defects was inadequate control of welding parameters although
no specific ASME Code violations could be identified. Youngstown has
recently hired a consultant to reevaluate the fusion welding parameters and
revised their welding procedures to provide better control of welding
current, voltage and travel speed for all material thickness ranges.
Ultrasonic examinations of the pipe welds were performed by a subcontractor
to Youngstown. The reason why this subcontractor's ultrasonic testing did
not detect indications exceeding ASME Code acceptance criteria was not
determined. The piping was known to have been tested in the heat treated
condition, prior to the removal of surface oxides. However, a comparison of
attenuation of the pipe in as heat treated vs. heat treated and pickled
condition did not reveal a discernible difference.
The NRC inspectors could not determine a definite time period during which
the welding and ultrasonic testing problems are thought to have existed. All
type 304 or 316 SA 312 pipe manufactured before mid-November, 1978 may have
been shipped in similar condition. As a large supplier, Youngstown is known
to have supplied piping for nuclear applications to the Dravo Corporation,
Chicago Bridge and Iron, Flowline Corporation and ITT Grinnell Industrial
Piping Inc. In addition, piping was also supplied to material warehousing
operations including Albert Pipe Supply, Guyon Alloys Inc., and Allegheny
Ludlum Steel Corporation which may have eventually been used in
safety-related nuclear applications.
Action to be Taken by the Licensees and Permit Holders:
For all power reactor facilities with an operating license or a construction
permit:
1. Determine whether ASME SA-312, type 304 or other welded (without filler
metal) pipe manufactured by Youngstown Welding and Engineering Company
is in use or planned for use in safety-related systems at your
facility.
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IE Bulletin No. 79-03 March 12, 1979
2. For those safety related systems where the subject piping is in use or
planned for use, identify the application of the piping including
system, pipe location, pipe size and design pressure/temperature
requirements.
3. Develop a program for volumetric examination of the longitudinal welds
including acceptance criteria for the piping identified in Item 2
above. Describe planned corrective actions if acceptance criteria are
not met. If a sampling program is utilized explain the basis for the
sample size.
4. For facilities with an operating license, a report of the above
actions, including the date(s) when they will be completed shall be
submitted within 30 days of receipt of this Bulletin.
5. For facilities with a construction permit, a report of the above
actions, including the date(s) when they will be completed shall be
submitted within 60 days of receipt of this Bulletin.
Reports should be submitted to the Director of the appropriate NRC Regional
Office and a copy should be forwarded to the NRC Office of Inspection and
Enforcement, Division of Reactor Construction Inspection, Washington, D.C.,
20555.
Approved by GAO, B180225 (R0072); clearance expires 7-31-80. Approval was
given under a blanket clearance specifically for identified generic
problems.