ML20031C669
| ML20031C669 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 09/28/1981 |
| From: | Stuchfield M BECHTEL GROUP, INC., UNION ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML20031C639 | List: |
| References | |
| ISSUANCES-OL, NUDOCS 8110070456 | |
| Download: ML20031C669 (7) | |
Text
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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of
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UNION ELECTRIC CCMPANY
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Docket No. STN 50-483 OL
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(Callaway Plant, Unit 1
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STUCHFIELD IN SUPPORT OF APPLICAUT'S MOTION FOR
SUMMARY
DISPOSITION OF JOINT INTERVENORS' CONTENTION NO. II.A.1 (SA-358 PIPING)
County of Montgomery
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ss State of Maryland
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b.ICHAEL F.
STUCHFIELD, being duly sworn, deposes and says as fol.ows:
1.
I am Gaithersburg Area Office Manager, Materials and Quality Services, Bechtel Group, Inc.
My business address is P. O. Box 607, Gaithersburg, Maryland 20877.
A summary of my professional qualifications and experience is attached hereto as Exhibit "A".
I have personal knowledge of the matters sta".ed herein and believe them to be true and correct.
I make this Affidavit in support of Applicant's Motion for Summary Disposition of Joint Intervenors' Contention No. II.A.1 (SA-358 Piping) in this proceeding.
2.
Bechtel Power Corporation is the Architect / Engineer for the SNUPPS project, including the Callaway Plant.
The Bechtel organizations have be engaged in construction and engineering activities since 1898.
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l Bechtel has substantial experience in the design and engineering of electrical power generation projects.
For over 25 years, Bechtel has been actively working on nuclear projects, including power plant design, engineering and construction.
3.
Part II.A.1 of Joint Intervenors' Contentiot
. 1 alleges that a piece of substandard SA-358 pipe has been inst-(led 4
in the emergency core cooling system at the callaway Plant.
The pipe is alleged to have been substantially out-of-round, to be machined below minimum wall thickness, and to contain rajectable weld defects on the inside surface of the longitudinal weld.
The purpose of this Affidavit is to demonstrate the structural integrity of that pipe.
4.
SA-358 is an ASME material specificaticn for welded stainless steel pipe.
This type of pipe is widely us 2d for pipe sizes generally greater than 8 inches in diameter.
The pipe is made from plate by forming and rolling the plate into a continuous tubular shape.
The longitudinal seam is then welded, usually by the submerged-arc process, with the weld made from both the inside and outside surfaces.
5.
The material specification for this pipe provides a series of limits and permissible variations of several dimen-sional requirements, including out-of-roundness.
With respect to out-of-roundness, the permissible difference between major and minor outside diameters is 1%.
Contrary to the allegation by Joint Intervenors, there is not excess ovality with the pipe in question.
It was measured by NRC Staff personnel, who conducted several measurements of the ovality and determined
O' that the actual maximmt ovality was 0.86%, which is within the 1% limit.
See NRC Inspection Report No. 50-483/81-04, pp. 15, 16.
6.
SA-358 pipe usually is used with wall thicknesses l
which require machining on the inside surface of the pipe (termed "counterboring") for purposes of weld joinu fit-up, and as a means of improving in-service inspectability.
The piece of SA-358 pipe f
which is the subject of Joint Intervenors' contention was not machined below the minimum design wall thickness.
While the speci-fication was written to require 0.874 inch thickness, the actual minimum design wall thickness was conservatively calculated to be 0.795 inch.
The actual measured minimum. wall thickness was 0.814 inch.
Thus, the wall thickness is more than adequate.
7.
The term " reinforcement," as it applies to welding, is defined in ANSI /AWS A3.0-1978, as " weld metal in excess of the quantity required to fill a joint."
In the case of SA-358 pipe, the reinforcement normally would appear as a uniform ridge of excess metal on both the inside and outside surfaces.
SA-358 permits a maximum of 1/8 inch reinforcement.
8.
Daniel International Corporation, the Callaway Plant constructor, in Non-Conformance Report ("NCR") 2SN-0501-P, dated April 30, 1979. stated that there was an area of weld reinforcement on the _inside of a piece of SA-358 pipe with a reinforcement height of 3/16 inch.
Bechtel, in its review of the NCR, incorrectly concluded, based on an inapplicable paragraph
e 0 of the ASME code, that a nonconformance did not exist.
In fact, there was a nonconformance as to the reinforcement height, which was 3/16 inch, whereas 1/8 inch is the maximum permitted by SA-358.
9.
It would not have been significant, however, if the excess reinforcement had not later been removed.
Maximum reinforcement heights for welds are established somewhat arbitrarily, but usually represent practical, achievable limits and generally are intended to be a guide to good fabrication practice.
Section III of the ASME Code permits a reinforcement height of 3/16 inch for circumferential welds in this size piping.
Having the same reinforcement height on a longitudinal l
weld would have no effect on the useability of the pipe.
10.
The Daniel NCR also identified a condition described as overlap in the same area as the excess welded reinforcement.
The overlap apparently was excess weld material which had rolled over onto the surface of the pipe material.
Bechtel responded to this NCR by citing an anapplicable section of the ASME Code for the proposition that overlap was not listed as a rejectable condition of radiography.
While the code reference was incorrect, the applicable code section has l
identical requirements.
This type of weld imperfection is not i
considered rejectable because it does not affect the volumetric l
l quality of the weld.
It is a condition that occurs at the l
intersection of the weld with the pipe material surface, but could not propagate through the thickness of the weld because it is in the wrong location for propagation.
It is parallel to the hoop stresses.
O 11.
The overlap condition was identified by ARMCO, the manufacturer of the pipe, during radiography of the weld i
seam, where it was described as washout on the radiograph report sheet.
This condition was considered acceptable by ARMCO.
12.
The welding process used to make the longitudinal weld in this pipe is called the submerged arc process.
This is a machine welding process, where general weld quality depends on a series of parameter settings, such as are voltage, current, travel speed and wire feed speed.
A slight or momentary varia-tion in any of these parameters would cause the condition described.
Burn-through during the process of welding from the outside could not have caused this overlap condition.
Burn-through is a condition where a total passage of molten material occurs through the root of the weld, causing slag and weld metal to a
adhere to the inside surface in a totally unacceptable condition, from both a visual and radiographic point of view.
13.
Even if Daniel had not reworked weld imperfection by gridding, the presence of the overlap and the slightly higher reinforcement would not have affected the strength or structural 1
integrity of the weld joint.
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14.
During hydrotesting of the ECCS prior to plant operation, this pipe will be hydrostatically tested to a pressure of 1.25 times its design pressure.,. This test will confirm the structural integrity of the weld.
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Jb oA0k Michael F. Stuchfield Q
Subscribed and sworn to before me this w T day of September, 1981.
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t Notary Publi My commission expires w/
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EXHIBIT "A"
l NAME MICHAEL F. STUCHFIELD POSITION Gaithersburg Area Office Manager, Materials and Quality Services EDUCATION BS, Metallurgy, Leeds University, England
SUMMARY
7 Years Metallurgical research and development 13 Years Metallurgical consultancy in nuclear power plant components 5 Years Development of welding technology EXPERIENCE Mr. Stuchfield joined the Bechtels San Francisco office in 1971, assigned as a senior engineer in the Materials and Quality Services.
He was shortly there-after transferred to the Bechtel Gaithersburg Office, where as a metallurgical engineering specialist he provided technical consultancy services in the fields of metallurgy and welding to'all projects within the Gaithersburg Power Division.
In 1976 he was transferred back to the San Francisco Office of Materials and Quality Services where he served as a group supervisor and then as technical assistant to the Department Manager.
In 1977 l
he was transferred back to the Gaithersburg Area Office of Materials and Quality Services as the Office Manager.
He has been associated with the Callaway Project since its inception.
Prior to joining Bechtel, Mr. Stuchfield was staff metallurgist at the General Atomic Co., associated with the metallurgical aspects of prestressed concrete reactor vessels for the high-temperature gas reactor system.
Earlier, Mr. Stuchfield was a senior metallurgist with the Whessoe, Ltd., concerned with metallurgical problems and developments associated with pressure vessels, nuclear reactor vessels, heat exchangers, storage tanks, etc.
PROFESSIONAL MEMBERSHIPS ASME Section III, Division 1, Nuclear Power Plant Components; Member of Subgroup on Materials (1976-1979).
ASME,Section III, Division 2, Concrete Reactors and Containments; Chairman of Subgroup on Materials, Fabrication, and Examina'41on (1973-1977).
PUBLICATIONS
- Bystram, M.C.T.,
and Stuchfield, M.F.
" Nickel-base Electrodes for Plant Operatina at High and Low Tempera-tures," British Welding Journal, September 1964.
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