ML19330A703
| ML19330A703 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 07/18/1980 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Reed C COMMONWEALTH EDISON CO. |
| References | |
| NUDOCS 8007290061 | |
| Download: ML19330A703 (2) | |
Text
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GLEN ELLYN, ILLINOIS 60137 JUL 18 '9801 Docket No. 50-454 Docket No. 50-455 Commonwealth Edison Company ATTN:
Mr. Cordell Reed Vice President Post Office Box 767 Chicago, IL 60690 Centlemen:
We have cottpleted our review of your final report concerning the report-able deficiency per 10 CFR 50.55(e) which involved the failure of four Byron post-tensioning field anchorheads. The report, which was prepared by INRYCO, and which is titled, " Report on the Failure Investigation of Post Tensioning Anchorheads Used in the Byron Nuclear Containment Struc-ture (Unit 1)", was transmitted to this office by CECO on June 27, 1980.
We concur with the anchor head evaluation and acceptance plan which you have proposed in Section 5 of the report, subject to the following comments:
1.
Since higher carbon content tends to reduce material toughness and to increase the likelihood of quench cracking, a review of carbon content should be added to the plan for those Category B heat lots which have passed the 120% load test, but not the 140% load test.
If the carbon content for any of these heat treat lots is found to be greater than 0.43, the anchorheads from that lot should be re-classified to Category C.
If the carbon content is 0.43 or less, the evaluation and acceptance plan should proceed as shown on Page 5.1 of your report. In this connection, please note that the revised INRYC0 Material Specifications, dated March 1, 1980, now specify a maximun carbon content of 0.43 for procurement of future anchorhead material.
2.
Note 9 of the revised INRYC0 Material Specifications should be changed to specify a maximum hardness of Rockwell C40. This change is also needed for the assurance of material toughness in future applications.
3.
If you or your contractors plan to retemper any of the existing anchorheads or heat treat lots at a higher temperature than that originally used, the original tempering temperature (as shown on the tempering records provided with the procurement documents) 1 80 17290061 e
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a \\( O Commonwealth Edison Company JUL 1 8 500 should be used for the classification of heat treat lots into The Categories A and B, as shown on Page 5.9 of your report.
reason for this stipulation is that retempering cannot be expected to correct existing quench cracks.
In addition, we understand that Note 10 on Page 5.13 of your report will reference a continuous longitudinal (fixed coil) wet magnetic particle method, similar to the requirements of the ASME Code,Section V, Article 25, SE 138.
The above comments were discussed by telephone with J. Westermeir and W. Segresell of CECO on July 16 and 17,1980. We will examine your implementation of the anchorhead evaluation and acceptance plan, including the above comments, during future inspections.
If you have any questions concerning the above, or if you disagree with any of our comments, please contact this office.
Sincerely, G Kp Director cc: Director, RCI/II Director, AEQD Chief, OEB/MPA IE Files Mr. D. L. Peoples, Director of Nuclear Licensing Gunner Sorensen, Site Project Superintendent Central Files PDR Local PDR NSIC Mr. Dean Hansell, Office of Assistant Attorney General Myron M. Cherry, Chicago l
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