ML20071E424
| ML20071E424 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 03/01/1983 |
| From: | Jackie Cook CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, 20721, 82-12-2, MCAR-63, NUDOCS 8303100219 | |
| Download: ML20071E424 (5) | |
Text
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COnSilmBIS power James W Cook C0mpany vi e, is
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Generet offices: 1946 West Parnell Road, Jackson, MI 49201 e (517) 788 0453 March 1, 1983 82-12 #2 Mr J G Keppler, Regional Administrator US Nuclear Regulatory Commission Region III 799 Roosevelt Road
. Glen Ellyn, IL 60137 MIDLAND NUCLEAR C0 GENERATION PLANT DOCKET NOS 50-329 AND 50-330 SHEAR LUG DESIGN FOR EMBEDS FILE:
0.4.9.68 SERIAL:
20721
Reference:
J W Cook letter to J G Keppler, Same Subject, Serial 19105 3
dated December 3, 1982 This letter, as was the referenced letter, is an interim 50.55(c) report regarding the design of embedments in concrete that use shear lugs located in tension zones. The attachment to this letter provides a description of the investigation and the corrective actions being taken with regard to this subject.
Another report, either interim or final, will be sent on or before May 20, 1983.
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Attachment:
(1) MCAR-63, Interim Report 2, dated February 1, 1983 CC: Document Control Desk, NRC
ashington, DC RJCook, NRC Resident Inspector Midland Nuclear Plant 8303100219 830301 PDR ADOCK 05000329 I@[
S PDR 7 f9g OC0283-0025A-MP01
2 82-12 #2 Serial 20721 CC: CBechhoefer, ASLB Panel FPCowan, ASLB Panel JHarbour, ASLB Panel AS&L Appeal Panel MMCherry, Esq MSinclair BStamiris CRStephens, USNRC WDPaton, Esq, USNRC FJKelley, Esq, Attorney General SHFreeman, Esq Asst Attornel General WHMarshall GJMerritt, Esq TNK&J OC0283-0025A-MP01
Attachment to Serial 20721 82-12 H2 ngyy Bechtel Associates Professional Corporation IO2883
SUBJECT:
NCAR 63 (ISSUED 11/10/82)
Design or Steel Embedments That Use Shear Lugs Located in Tension Zones INTEMIM REPORT 2 DATE:
February 1, 1983 PROJECT:
Consumers Power Company Midland Plant Units 1 and 2 Bechtel Job 7220 Introduction This report addresses a concern with the design of steel embedments in concrete that use shear lugs located in tension zones.
BackKround The ACI 349 Code, Appendix B. issued August 1919. specifies that shear lugs in embedment designs shall be considered effective only in compression zones. Midland embedment designs were completed and installed before this date and considered that shear lugs accommodate all shear loads and tension bars accommodate all tension loads. Other than ACI 349, Appendix B. no known design code or industry standard issued before ACI 349. Appendix B. restricts the design of embedments using shear lugs.
For embedments within the scope of this MCAR. the Midland Final Safety Analysis Report Section 3.8 is committed to design reinforced concrete according to ACI 318-63 and 318-71, and structural steel according to the AISC 1969 edition; however, these codes do not specifically address embedment design.
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l 0 2 8 8 Bechtel Associates Professional Corporation IO2883 NCAR 63 Interim Report 2 February 1, 1983 Page 2 investiaative Action Presently, engineering has identified approximately 2,500 embedmonts having shear lugs. An evaluation is in progress to determine which of the embedmonts identified hcVe shear lugs located in tension zones.
Investigative action to determine if the embedmonts used in the Midland plant are satisfactory as designed is under way by means of additional analyses and testing. The additional analyses are to be based on a review criterion being developed to address the concerns regarding shear lugs located in the tension zones.
Concurrently, a steel embedment testing program is being developed to determine the effectivity of shear lugs located in tension zones. The results of the test program will be used to refie:.e the criteria established in the evaluation of the adequacy of existing embedments.
If existing embedments are found to be unsatisfactory during this review. necessary corrective measures will be taken.
Erobable cause The apparent root cause is that before the issuance of ACI 349 Appendix B. this possible behavior of shear lugs in tension zones was not recognized by codes or industry standards.
Corrective Action No corrective action has been established at this time. The results of the investigation will determine any required corrective actions.
Analysis of Safety Implications The concern is that shear lugs located in tension zones may not be effective and that this may result in a nonconservative design. The design may be nonconservative to the extent that it may not be capable of performing its required safety function.
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a-102884 Bechtel Associates Professional Corporation 102883 MCAR 63 Interim Report 2 February 1, 1983 Page 3 Reportability This concern is considered potentially reportable in accordance with Title 10 of the Code of Federal Regulations Part 50.55(e).
7b Submitted by:
S.L. Sobkowski Civil / Structural Group Supervisor Approved by:
E.M. Hughes (
Ann Arbor Project Engineer Concurrence by:
T.Ej/ohnson Civil Discipline Chief concurrence by:
ILL E.H. Smith Engineering Manager Concurrence by:
p.( M.A. Dietrich J
Project Quality Assurance Engineer 0909a
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