ML19253B018
| ML19253B018 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 08/21/1979 |
| From: | CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | |
| Shared Package | |
| ML19253B016 | List: |
| References | |
| MCAR-1, NUDOCS 7909140379 | |
| Download: ML19253B018 (6) | |
Text
OUALITY ASSURANCE PROGRAM
.~
MANAGEMENT CORRECTIVE ACTION REPORT Howe-247-79 MCAR1 REPORT NO.
34
- QOBNO.
7220 O NO. __ Various DATE August 21, 1979 i
- DESCRIPTION (including reierences):
Specification 7220-C-305, Section 6.2.2 requires tension testing of Drop-In Anchors to nect the values indicated in table 3.2.
Additional testing was required by Project Engineering in Ictter BEEC-2404, dated 8-21-78 and EEBC-2965, dated 5-18-79, to verify past installation practices.
A sample and test of 60 rando=ly selected anchors were to be tested with no failures.
Contrary.to this, 9 out of 32 drop-in anchors tested utilizing 4 sizes have failed. NCR-2461 has been generated to identify these failures.
' RECOMMENDED ACTION (Optional) 1.
Construction a) Provide Engineering with data as to utilization, quantity, location and size of all "Q" Supports, utilizing drop-in anchors installed to date.
b) Determine the cause (how and why) of the anchors failures.
(continued on page 2)
REFERRED TO GENGINEERING GCONSTRUCTION DOA MANAGEMENT E Ouality Control O PROCUREMENT Pro;ect OA Eng1ncer Da:e k/O /7[/
il REPORTABLE DEFICIENCY i Potentially Reportable, to t
.: ED CLIENT be deter =ined by Project 0 NO O YES Engineerin
/
1
/p o ect u.ana;;er Die til CAUSE CORREC;WE ACTION TAKEN D) @ @ I5))
t[
il j [Q T i
l c ', 'R F r
n_
i 1
Jl
. d. b UL LIn a AUTHORIZE 0 BY Date
'.;T ANDARD D:STR'8UTION ADDITIONAL DISTRIDUDCN. AS APPROPRIATE FORM AL REPORT TO CLIENT sv;5ONCA UANASER ENCWII Afs3 MANAGLR v4NActacv OA veO rnO;teri v.etR
(!! Settion 11 Apphes)
Date LD C A M AN AGE f4 AAO F AOCU44 v( NT ttPrL;[R OU AUTV MGR
.A5'DOAMANAGER CONSTRUC1 ION M Ar. AG[ ft A AO CA M AN '.GC H PROJ $U8'T FDOJ CON %TR V AN ACER
- 403f CT M ANAGER CNEF CONSTR OC LN37.lE R ute e r Oct CORRECTIVE ACTION lMPLEMENTED m Ac rnxter occn4 TONS VANAG(R CMMCN Fl40CUGEVENT UGR AAO PROCustiMf t.1 vaNant R pncy PnOC(4q M_NT MGH AAQ WGF4 Of (NCisNQ f RN
%s $GPPU[M QU,gTV M( R am or e(s.ssnue,Ge 79o93 4 gpq 943,qyy, VERIFIED BY tw,c. e uw.,o.ece..e rin
.,.ac. coc-t Pro ect OA Enyneer Date s
3 955
MCAR-34 August 21, 1979 Page 2 RECOMMENDED ACTION (Cont!.nued) c) Take necessary actions to preclude recurlonce.
2.
Quality control a) Determine why this high rate of failure for the Drop-In Anchors was not indicated by the normal in-process testing of anchors, referenced in section 6.0 of Spec. 722 0-C-305.
3.
Proiect Engineering n) Evaluate this condition for reportability under 10 CFR 50.55(e) and issue interim report to the PQAE by Septc=ber 4,1979, based on input from engineering and construction and quality control.
b) Determine adequpey of all "Q" Drop-In Anchors, c) Deter =ine cause of failure and take action to prevent recurrance.
34321.?,
Encle::uie 2
~
Howe-21+7-79 Bechtel Power Corporation 777 East Eisenhower Parkway Ann Arbor, Michigan uenaaress P.O. Box 1000. Ann Arbor, Michigan 48106 September 5, 1979 BLC-8115 Mr. G. S. Keeley Project Manager Consumers Power Company 1945 West Parnall Road Jackson, Michigan 49201 Midland Units 1 & 2 Consu=ers Power Company Bechtel Job 7220 MCAR 34 INTERIM REPORT 1 Files:
2417/2801 Dear Mr. Keelcy; Attached for your information and use is Interim Report 1 for MCAR 34, which addresses Drop-In Anchors.
The report indicated a failure rate of 28%.
However, since writing the Interim Report, additional results have indicated that of 66 Drep-In lachors tested, there were 13 failures, resulting in a failure rate of 20%.
The next report is scheduled to be issued on October 2, 1979.
Very tr-
- yours, 2
%s, kff'j/~
h/
ohn A. Rutgers '
Project Manager JAR /SKC/kb Attachment (3 pages) cc:
Mr. W. R. Bird Mr. B. W. Marguglio Mr. D. B. Miller Y;:le.,
f,h J'<-M y %_ '
J SEP7 1979 00Allsl' ASS %.5 343214
Bechtel Associates ProfessionalCorporation Attachnent to ELC-8115
SUBJECT:
MCAR 34 (issued 8/21/79) Drop-In Anchors INTERIM REPORT 1 DATE:
September 4, 1979 PROJECT:
Consumers Power Company Midland Plant Units 1 & 2 Bechtel Job 7220 Introduction As requested in MCAR 34, this report su=marizes project engineering's evaluation and action regarding the failure of the drop-in anchors to the tension testing criteria furnished by project engineering.
meet Description of Deficiency Specificat$on 7220-C-305, Section 6.2.2 requires tension testing of drop-in anchors to meet the values indicated in Table 3.2 of that specification. Inprocess inspection of drop-in anchors is required in Specification 7220-C-305. Hcwever, when it was learned that this inspection at the time of installation was not being done at all times, testing was requested by project engineering on August 21, 1978, and again on Pay 18, 1979, to verify the adequacy of past installation.
For the testing results to be acceptable, it was necessary that a sample of 60 randomly selected anchors be tested with no failures. According to Specification 7220-C-305, the anchor is censi'dered acceptable if a test load equal to twice the design allowable tensile load is applied and the concrete does not break out; the anchor does not break, distort, or deform; and the an: hor does not slip cxcessively or become loose.
Excessive slippage is evident when the washer between the bolt and the concrete can be rotated by hand. However, upon completing ter ; ion tests on 32 drop-in anchors involving four different bolt diameters, nine failures had occurred.
A nonconformance Report (NCR) has been generated to identify these failures. Approximately 900 drop-in anchors had been installed as of August 17, 1979, when project engineering requested that drop-in anchor installation be suspended until further notice.
_(
Bechtel Associates Professional Corporation Attachment to BLC-Bil5 MCAR 34 Interim Report 1, September 4,1979 Page 2 Investigation The loads listed for drop-in anchors in Specification 7220-C-305, Table 3.2 were established by Hilti, the nanufacturer, through their own testing program.
Project engineering met recently with a representative of Hilti at the Midland site to witness testing and installation practices used for the drop-in anchors. Only the electrical group used the drop-in anchor bolts for substantial loads; the other groups have limited their usage to loads of less than approximately 200 pounds.
The Hilti representatice verified that the testing procedure used is consistent with Hilti's own test procedure. He emphasized that, if the plug which expands the anchor is not driven in completely with the Hilti tool, the full capacity will not be attained.
The design of the Hilti drop-in anchors and the method of setting are illustrated in Figure 1.
Based on a preliminary investigation on August 23, 1979, some of the installed plugs were found to be not fully driven into the anchor; however, the extent to which this contributed to the cause of the anchor failurcs was not established.
It was determined that further testir.2 would be needed to establish the specific cause(s) and extent of the anchors' failure to pass the test.
Safety Implication.
Project engineering's investigation of the deficiency shows an implication of an adverse effect on plant safety, and therefu-c is reportable under 10 CFR 50.55(c). Prelininary indication of a 28*4 failure rate demonstrates an inability to ensure the adequacy of anchor bolt capacities.
Corrective Action Project engineering has requested that additional testing be performed on a random sampling of 100 drop-in anchors to establish what portion were not correctly set and the effect of this deficiency on the bolt capacity. Results are expected by September 7, 1979; the evaluation will be presented in the next report scheduled for October 2, 1979.
Submitted by:
/ab
/7 f /,
Approved by:
s Concurrence by:
-'4'5,'
I
/-
', "' / '
//
/,
But/js 8/28/2 S4321G 9
1)nc.'-;:,..::Clion Attachment to III.C-8115 MCAR 34 11.IERI!1 REPORT 1 Septetber 4,1979 Page 3 I'
J. - - -
.s r.m. -.3
. b.?,:*,"' .:.:1:a1?f TYPICAL IIILTI DROP-IN ANCHOR e~ a.. m. =
u.2..m
-~.y,,
x_..m.- -J HILTI. SETTING TOOL PLUG L
r-
, I O_e.. _,, g. ;,,
t-
. A<.out.' i, '
- ._.l!.,N5 M ;f.,,'j4,f3,.f,. '.}jlj i[,,__
BEFORE EXPANSION AFTER EXPANSION I
J tv liul[Q i riO l f'ij /3d[L A6[U du90[La (PER HILTI ANCI!OR AND FASTENER DESIGN MANUAL)
FIGURE 1.
S4.32.17
!