ML20091H034
| ML20091H034 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 05/25/1984 |
| From: | Jackie Cook CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 30296, 83-03-#2, 83-3-#2, OL, OM, NUDOCS 8406050034 | |
| Download: ML20091H034 (8) | |
Text
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3r C00sumels Power James W Cook O
00f Vice President - Projects, Engineering and Construction General o'Hes: 1945 West Parnell Road, Jackson, MI 49201 2(517) 788-0453 May 25, 1984 84-03 #2 Mr J G Keppler, Regional Administrator US Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL 60137 MIDLAND ENERGY CENTER PROJECT DOCKET NOS 50-329 AND 50-330 CONCRETE EXPANSION ANCHORS INSTALLED IN METAL DECKING FILE:
0.4.9.90 SERIAL:
30296
Reference:
J W Cook letter to J G Keppler, same subject:
- 1) Serial 28058, dated March 29, 1984 On February 28, 1984, Consumers Power Company notified your staff of a potential 10CFR50.55(e) condition involving the installation of concrete expansion anchors in metal decking.
This letter is an interim 10CFR50.55(e) report. The attachment to this letter describes the concern and summarizes the investigation and corrective action taking place.
Another report, either interim or final, will be sent on or before July 27, 1984.
e JWC/AHB/lr : MCAR-82, Interim Report 1, dated May 8, 1984 CC: Document Control Desk, NRC Washington, DC BBurgess, NRC Resident Inspector Midland Nuclear Plant DSHood, NRC Office of NRR Bethesda, MD INPO Records Center 0C0584-0038A-MP01 0406050034 840525 I[
PDR ADOCK 05000329 B
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2 Serial 30296 84-03 #2 OM/0L SERVICE LIST Mr Frank J Kelley Atomic Safety & Licensing Attorney General of the Appeal Board State of Michigan U S Nuclear Regulatory Commission Ms Carole Steinberg Washington, DC 20555 Assistant Attorney General Environmental Protection Division Mr C R Stephens (3) 720 Law Building Chief, Docketing & Services Lansing, MI 48913 U S Nuclear Regulatory Commission Office of the Secretary Washington, DC 20555 Mr Myron M Cherry, Esq Suite 3700 Ms Mary Sinclair Three First National Plaza 5711 Summerset Street Chicago, IL 60602 Midland, MI 48640 Mr Wendell H Marshall Mr William D Paton, Esq RFD 10 Counsel for the NRC Staff Midland, MI 48640 U S Nuclear Regulatory Commission Washington, DC 20555 Mr Charles Bechhoefer, Esq Atomic Safety & Licensing Atomic Safety & Licensing Board Panel Board Panel U S Nuclear Regulatory Commission U S Nuclear Regulatory Commission East-West Towers, Room E-413 Washington, DC 20555 Bethesda, MD 20014 Ms Barbara Stamaris Dr Frederick P Cowan 5795 North River Road 6152 N Verde Trail Rt 3 Apt B-125 Freeland, MI 48623 Boca Raton, FL 33433 Dr Jerry Harbour Mr Fred C Williams Atomic Safety & Licensing Isham, Lincoln & Beale Board Panel 1120 Connecticut Ave, NW, Suite 840 U S Nuclear Regulatory Commission Washington, DC 20036 East-West Towers, Room E-454 Bethesda, MD 20014 Mr James E Brunner, Esq Consumers Power Company Mr M I Miller, Esq 212 West Michigan Avenue Isham, Lincoln & Beale Jackson, MI 49201 Three First National Plaza 52nd Floor Chicago, IL 60602 OC0584-0038A-MP01
(f(
3 Serial 30296 84-03 #2
-Mr'D F Judd' Babcock & Wilcox PO' Box'1260
.Mr John Demeester, Esq Lynchburg, VA 24505 Dow Chemical Building Michigan Division Mr Steve Gadler, Esq Midland MI 48640 2120 Carter Avenue St Paul, MN 55108 Ms Lynne Bernabei Government Accountability Project Mr P Robert Brown 1901 Q Street, NW
' Clark Klein & Beaumont Washington, DC 20009 1600 First Federal Bldg Woodward Ave Detroit, MI 48226 3/14/84 OC0584-0038A-NP01
Serial 30296 Bechtel Associates Professional Corporation i50190 1503I8
SUBJECT:
NCAR 82 Expansion Anchors Installed in Netal Decking INTERIN REPORT 1 DATE:
May 8, 1984 PROJECT:
Consumers Power Company Midland Plant Units 1 and 2 Bechtel Job 7220 Introduction This report addresses a potential safety concern regarding use of expansion anchors installed in metal decking (reference Quality Action Report N-010 and Safety Concern Reportability Evaluation 95).
Backaround In some cases where grouting under a base plate was required (i.e., in the valley portion of metal decking), torquing of expansion anchor bolts may have been performed after the grout had reached its design strength. This raised the concern that where bolt torque is applied after the grout has hardened, the bond between the grout and anchor l
may prevent proper setting of the anchor's wedges.
f During the investigative phase of the condition described above, an additional potential area of concern was identified regarding the shear capacity of expansion anchors installed through metal decking.
Design allowables used for these installations were based on manufacturer's recommended design allowables that did not address l
installations into metal decking. As a result, certain installation j
configurations may possibly experience a reduction in shear capacity l
because of the way the load is transferred through the grout or rib of l
the metal decking.
This report addresses both bonding effects and the possible reduction in shear capacity of expansion anchors installed in metal decking.
Investiaative Action 1.
Bond Testing done in accordance with specification 7220-C-308(Q),
required for response to Quality Action Request H-010, did not conclusively indicate that the wedges of the expansion anchors had been properly set during installation if the bond between the anchor and grout develops. The number of anchors installed in the valleys of metal docking, which would exhibit this bonding effect, is estimated to be around 500 anchors.
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Bechtel Associates Professional Corporation I S 0 W s2 IS03l8 Interim Report 1 page 2 2.
Shear Testing has been performed to evaluate the shear capacity of expansion anchor bolts installed in metal decking in accordance with Specification 7220-C-309(Q). These tests indicated that for some installation configurations, the anchor exceeded 100% of its ultimate capacity. For other types of installation, the capacity ranged as low as 50% of the anchors' ultimate capacity.
Additional shear tests are being planned. The number of anchors installed in metal decking being investigated for a reduction of design shear capacity is around 15,000 anchors.
Ana1Ysis of Safety Imolication 1.
Bond If, during the installation process, the bond between the grout and the anchor precluded the anchor's wedges from setting properly, a maximum base plate displacement of up to 1/2 inch (depending on anchor size) may occur before the wedges set. This additional displacement has an indeterminate effect on the support component without additional evaluation of each specific installation type where this situation exists. Considering the small number of anchors installed in the valleys of metal decking, corrective action will be taken to verify that the wedges are set l
properly.
l 2.
Shear t
Results from initial C-309(Q) testing showed that, for some cases, i
I the shear capacity of expansion anchors installed in metal decking l
was less than the allowable design load times the current factor of safety of 4.
However, no cases have indicated that the allowable design load exceeds the capacity of the anchor. The need for using the factor of safety of 4 for use on expansion anchors installed on commodities other than piping is being evaluated.
In addition, the effects of displacement at the allowable load using a revised factor of safety is being evaluated.
Based on information to date, the reduction in shear capacity does not indicate a safety concern.
Probable Causs, 1.
Bond l
Regarding the bond between the grout and anchor, the probable cause is that the installation torque may not have been applied 0547u
150190 Bechtel Associates Professional Corporation 1503I8 meAR 82 Interim Report 1 Page 3 before the grout had cured, thus allowing a bond to develop between the anchor and the grout. This bonding effect may have prevented the wedges of the anchor from setting properly.
2.
Shear Regarding the reduced shear capacity of expansion anchors, the probable cause is the shear capacity reduction associated with the shear load transfer mechanism.
Corrective Action 1.
Bond For base plates with expansion anchors installed in the valleys of metal decking, the anchors will be properly set. Nonconformance Report A-00154 has been issued to track this activity. A plan and schedule to develop procedures for setting the anchors are to be completed by July 11, 1984.
For future installations, the sequence for installing expansion anchors elli be to apply 100% of the installation torque before grouting.
In addition, based on test data obtained from Specification 7220-C-308(Q), base plates installed on slabs and walls using expansion anchors and grout are being evaluated for the effects of the grout bonding to the anchors.
I t
2.
Shear The extent of corrective action required for installations with potentially reduced anchor shear capacity will be based on the results from additional testing being planned and further review of the existing test data from specification 7220-C-309(Q).
3.
Bond and Shear Based on determination of the root cause, further investigations will be performed, as applicable, to determine if similar or related conditions of these types exist on the Midland project.
Results of the investigation will be stated in the next report.
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I 150,190 Bechtal Associates Professional Corporation 1503i8 mCA 82 Interim Report 1 Page 4 Reportability This concern was reported to the Nuclear Reguletory Conunission by Consumers Power Company as a potentially reportable condition on February 28, 1984.
5 Submitted by:
E.B. Poser y Project Engineering Manager Approved by:
T.E. % nson Civil Chie Eng6eer I
tM N
Approved by:
E.H. Smith Engineering Nanager Concurrence by:
-6r 'N'. A. DietriM Project Quality Assurance Engineer l
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l t50190 Bechtel Associates Professional Corporation 1503I8
,,cA,er Interim Report 1 Page 4 Reportability This concern was reported to the Nuclear Regulatory Conunission by Consumers Power Company as a potentially reportable condition on February 28, 1984.
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Submitted by:
,}y E.B. Poser Project Engineering Manager Approved by:
T.E. p nson Civil Chie Engfr4eer Approved by:
~
E.H. Smith Engineering Manager Concurrence by:
d r 'N'.A. Dietrl46 Project Quality Assurance i
Engineer f
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l I
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