United States Nuclear Regulatory Commission - Protecting People and the Environment

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 
                           WASHINGTON, D.C. 20555 

                              March 12 , 1979  

                                                     IE Bulletin No. 79-03 


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

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 

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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 

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., 

Approved by GAO, B180225 (R0072); clearance expires 7-31-80. Approval was 
given under a blanket clearance specifically for identified generic 

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