ML20033A740
| ML20033A740 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 11/13/1981 |
| From: | Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Sinken L AFFILIATION NOT ASSIGNED |
| References | |
| NUDOCS 8111270197 | |
| Download: ML20033A740 (3) | |
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i NOV 2 5198F 4 g M.7 " M Lanny Sinkin, Esquim
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Dear Mr. Sinkin:
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l-2 This is in msponse to your letter, dated September 2,1981, to Mr. Richarti Herr of this office. Your request for investigative action dealt with appamnt weld j
discrepancies on stmetural steel mceived from American Bridge at the South ;
1 Texas Nuclear site. The following information on this subject was obtained L from the licensee and from our NRC inspectors. The specific questions in your
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letter have been rearranged and am being answered in generic groups to avoid j
mdundancy.
l Houston Lighting and Power (HL&P) originally identified the problem of nonconforming weld conditions and on January 8,1981, reported these to theNRC,RegionIVofficeinaccordancewith10CFR50.55(e). Interim reports wem issued by HL&P on February 6 and June 1,1981, stating 11cenree actions taken and giving status updates.
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Your quitions 1, 2, e:.c 5 make refemnces to arc strikes and weld splatter referring to these as flaws and detects. On certain steels, arc strikes' present a definite problem. High alloy steel and certain stainless steels am very succeptible to cracking in the area of arc strikes. The columes, beams, and trusses, which are the subject of your concern, are manufacttred i
from steel produced in accordance with Specification ASME SA-36 (identical with ASTM A-36-75). This is a general purpose : teel commonly ordered ftr structural applications because of the ease with which it can be worked l and its ability to maintain its properties through fabrication without l i
special treatment. SA-36 material is a very " forgiving" steel, and iso,-
lated arc strikes do not pmsent a significant problem. The arc strikes in question should be referred to as " anomalies" or " discrepancies" as i
i opposed to " flaws" or " defects" which are normally used with the conno j tation that failure is likely 1.o result. For SA-36 material, arc strilles and weld splatter are not considered detrimental unless they are extensive.
i The concern with extensive arc strike and weld splatter is that the me.te-i rial deposited on the metal surface egy not be tightly adhering and ecluld i
adversely affect subsequent coatings applicatior.
In the case of the/
j American Bridge structural steel, all of the structures and shapes have been sandblasted and at least one prime coat of paint has been applic/.
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It is reasonable to assume that any extraneous material remaining on the steel after a sandblasting operation is tightly adhering and does net
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present a future problem to coating integrity.
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Lanny Sinkin, Esquire November' 13,.1981 Your questions 1, 2, 3, and 6'make reference to inspection and surveil-lance activities associated with the American Bridge structural steel.
No mcortis are available on site of the actual inspections performed by American Bridge prior to shipment of the steel fabrications. -The steel was ordered to comply with Specification 3A010SS012-G which allows the use of the latest American Welding Society (AWS) Code.- The purchase order was issued when the latest AWS Code was the 1976 version. The various commdttees, which author the AWS Code, are constantly refining and updating it to keep it in accord with state-of-the-art changes and current industry practices.
't has been detemined by these cousittees that earlier versions of the Code placed very strict limits on the acceptance of certain weld irregularities. Engineering analyses of these conditions revealed that removal and/or rowelding was expensive and tiu' consuming and that the conditions, if not removed, presented no appmiable loss of strength in the welds. AWS Code versions since 1976 have relaxed the requirements for certain weld conditions. The msults of inspections performed in accordante with later versions of the AWS Code can vary 9reatly from those using the 1976 mquirements for acceptance. Since Specification 3A010SS012-G allows the use of the latest AWS Code version, HL&P is currently in tQe process of requesting a change to their Safety Analysis Report to incorporate the use of the latest Code revision for all AWS welding.
A group of three welding consultants, including two current Code committee members, has been retained by HL&P to independently inspect and evaluate the discrepancies noted on the American Bridge steel structures. This inspection was performed on April 22,1981, with the requirements and intent of the 1981 AWS Code as acceptance criteria. The results of this random inspection indictte that on-site examinations were conducted in a manner not in accord with the updated requirements. - The recommendation of the three consultants is to reinspect all areas presently marked for corrective work It is the concensus of this panel that the use of the 1981 AWS Code for acceptance would eliminate at least 90% of the condi-i tions marked for rework without compromising the structural integrity of l
the beams, columns, and trusses.
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If previous Broun & Root (B&R) inspections had been perfomed to the present acceptance criteria, the 995 NCRs issued for these structures through August 1, 1981, would probably have been reduced by about 90%.
From this it can be seen that if the original American Bridge inspections and B&R surveillances had been conducted in accordance with the 1981 Code version very few questions would have existed concerning weld integrity i
or the relevant inspection and surveillance programs. The NRC inspector,
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who is cognizant of this situation, examined approximately 100 welds in the storage yard and 500 welds on beams and columns alrea(y installed in j
the upper portions of Mechanical Electrical Auxiliary Building No.1 i
and Fuel Handling Building No. 1.
Due to the location of the installed roof beams, it was not practical to accurately trbulate the conditions
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Lanny Sinkin, Esquire November 13, 1981 noted, but it appeared to the NRC inspector that welds on the installed beams were similar to those in the storage yard. All of the disempancies on installed and stored beams were identical in nature and severity.
B&R has finished a comprehensive program of minspection for 1000 beams, columns, and tmsses, but the results have not been compiled and analyzed.
The number of welds to be included in the reinspection report will far exceed 1000 as each structural asser includes a varying nueer of welds.
The NRC will myiew the msults of this reinspection and will sonitor the realt e follow-up activities.
.o.. question 4 is in refemace to the number of NCRs written on the steel alrea(y installed. During the reinspection program, approximately 995 NCRs were written to document deficiencies noted on American Bridge steel, 268 of which applied directly to steel alrea(y installed. Of the 1000 beams inspected, 270 had been installed. A comparison of the total number of inspections (1000) with tha total number of NCRs (995) and the installed beams inspected (270) with the number of NCRs against them (268) leads to the conclusion that essentially identical conditions exist. This comparison also indicates that the inspection and acceptance criteria were the same for both phases of the reinspection.
Your question 7 asked if the management responses to this prchlem have been appropriate. This office was notified in a timely manner, of the existence of a potential construction deficiency in accordance with 10CFR50.55(e). As was mentioned, two subsequent interim reports have been issued updating the actions taken. Management also mtained the services of three welding engineers to act as an independent evaluation panel to assess the implementation and c:sults of the re-examination program. The recommendations of this panel, two of whom are active AWS committee members, are contained in a letter, dated April 23,1981, addressed to Mr. J. R. Geurts. The Region IV office feels that the B&R and HL&P management responses to date have been appropriate.
We trust that this answers the questions that you have in regard to the American Bridge structural steel welds at the South Texas Project.
Sincerely, uPJJd?81 ",
gLt coluu John T. Collins Regional Administrator
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