ML19242B276
| ML19242B276 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 07/06/1979 |
| From: | Leonard J POWER AUTHORITY OF THE STATE OF NEW YORK (NEW YORK |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| JAFP-79-350, NUDOCS 7908070808 | |
| Download: ML19242B276 (4) | |
Text
[k-POWER AUTHORITY OF THE STATE OF NEW YORK J AMES A. FITzPATRICK N UCLE A R POWER PLANT S
JOHN D. LEONARD, JR.
P.O. Box 41 Resident Manager July 6, 1979 Lycoming, New York 13093 JAFP-79-350 ais-a -aa40 Mr. Boyce H. Grier, Di rector Uni ted States Nuclear Regulatory Commission Region 1 631 Park Avenue King of Prussia, Pennsylvania 19406
Subject:
I & E Bielletin 79-02, Revision 1 Pipe Supports Us ing Concrete Expans ion Anchor Bol ts
Dear Sir:
The following information prnvides the report required by I&E Bulletin No. 79-02, Rev.
1.
The numbered paragraphs below correspond to numbered requirements of the bulletin.
1.
During our review of the concrete exc nsion anchors and the pipe support baseplates utilized at the James A. FitzPatrick Nuclear Power Plant it has been determined that baseplate flexibility and cyclic luading was not a design consideration during the original design and construction phase or the plant. Analytical work related to base plate flexibility is currently being performed for the FitzPatrick Plant and the resul ts of the study are expected to become available on or about July 31, 1979 Preliminary findings indicate that flexibili ty considera-tions will not be a major problem in qualifying these baseplates.
The following simple formulation has been used to account for increased bol t load as a result of prying action.
The edge distance and plate thickness are the variable parameters in the simple formulation.
F
+
DL " RP RP(1 + 3b - t)
F g
g where, F
= Bolt design load accounting for prying action.
DL F
= Bolt load calculated on the basis of rigid plate RP a:sumption.
C (d s
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MR. B0YCE H. GRIER, DIRECTOR July 6, 1979 JAFP-79-350 Page Increase in bolt load as a result of prying action.
Q
=
a
= Distance from center line of anchor bolt to edge of plate in the di rection of interes t in inches.
b
= Distance from center line of anchor bol t to the edge of thu
.ructural member in the direction of interest in inches.
t
= Plate thickness in inches.
2.
See tes t program in Item 4 below.
3 See program on item 4 below.
4.
An extensive testing program is being conoucted at tne site to determine the adequacy of the concrete expansion anchore.
The results of this testing program nas allowed us to immediately qualify 30% of thoee expansion anchors used in pipe supports for greater than 2i inch di'. meter piping presently installed in areas inaccessible during power operation.
Of the remainder, none were found to have failed in service.
Approximatuiy 50% of those anchors so tested passed a tension test at five times maximum design load.
Of those not pc: sing this test, only one failed at less than maximum design load, failing at approximately 90% maximum design ioad.
No rapid failures were observed.
Anchors failing the tension test failed our criteria by exceeding the.125 inch maximum permi tted deflection at a load less than 5 times maximum design load as specified in our test procedure.
The program has also provided a basis for correcting any deficiencies found in those installations which require upgrading. A corrective action program has been i r.s t i tu ted to correct deficiencies as they are found.
During this test program which required careful visual inspection of anchor embedment, bol ts, washers, and baseplate hole size; either torque tests or tensile pull tests were applied to the concrete anchor.
Bolt test values of L (wedge type) er 5 (shell type) times bolt maximum design load were used for base.lates in inaccessible areas.
The tensile pull test has shown to date t
.t greater than 90% of the tested anchors support their actual design ad.
A factor of two times design boli load in accessible areas wili be utilized and a 100% inspection program will be conducted in these areas.
The visual inspection program which required removal of the bolt f rom the anchor demc s trated only a very small percentage (%2%) of gross misinstallation.
However, during the inspection program in both accessib'c and inaccessible areas, we are finding the following discrepancies; this data is based on a statistical sampling of 104 expansion anchors.
DISCREPANCY
% of DISCREPANCIES Embedment length of anchor not as prescriced by manufacturer 4.8%
L -
.AO a U ;s
- 9o
MR. BOYCE H. G?.lER, DIRECTOR July 6, 1979 JAFP-79-350 Page DISCREPANCY
% of DISCREPANCIES Wedge in shell type anchor not fully seated 67.8%
Hole in baseplate larger than prescribed for bol t diameter 62.1%
Shoulder of shell type anchor touching baseplate 36.8%
Support baseplate improperly grouted Less than 1%
Anchor loose in concrete 7.7%
The above discrepancies are being corrected on a support by support basis as the support is inspected.
In many cases it has been determined that the quickest corrective action is to replace the r 'sently installed shell type anchor wi th a larger size wedge type anchor.
This program is being implemented to the mnximum extent practicable in the inaccessible area supports and af ter these new anchors are installed, preloading is being applied to eliminate cyclic loads.
Other corrective action consists of replacing present washers wi th heavy gauge plate type washers on which an engineering analysis has been conducted to show that they can supporc proper loading, redriving anchors where this can yield sat'sfactory results, utilizing Belleville washers to insure preload equal to or greater than the design value, and utili7ing a beveled washer to insure proper bol t contact wi th the baseplate if the ancaor has been drilled into the concrete at a slight angle.
Where Belleville wasbars cannot be installed, proper bolt preload is established by tightening bol ts to speci fic torque, it is our intention to fully qualify prior to startup the concrete expansion anchors in areas inaccessible during power operation for piping of more than 21 inches in diameter.
In the case of small piping supports in inaccessible areas, our test da ta f rom the actual testing of the other base plates illus trates that operation wi thout inspection is not a safety consideration.
More than 90% of the large bore pipe supports inspected have dtmonstrated that the supports are capable of supporting the required design load.
In the case of small bore piping (less than 2h inches in diameter) because of significantly smaller loads, we would expect a greater percentage.
Furthermore, on the basis of the herein described results of inspections to date we believe that the accessible large bore piping supports can be completed during operation at minimal risk to safety.
Results of visual inspection during pipe verification has indicated that 99% of the pretantly installed suppor s on large bore pipes on safety related systems have successfully perfor.ed their function of carrying pipe dead weight loads, absorbing thermal expansion loads, withstanding cyclic loading, and in some cases withstanding large hydraulic pressure transients for a period of at least five years since the preoperational testing and commercial operation of the plant.
505
- .19
MR. B0YCE H. GRIER, ulRECTOR July 6, 1979 JAFP-79-350 Page The condition of the hangers and piping upon inspection constitutes prima facie evidence that these supports are fully capable of performing their design functions under normal operating conditions, e.g.,
they are stil. supporting the piping af ter five years of service.
The nature of failures observed during testing and the loads at which these failures occurred, give a high degr ee of confidence that the supports would hava functioneo durine a seist..c event.
The failures observed by testing indicated primarily that the safety factor above maximum design load was less than desired, not that the anchors are incapable of carrying design load.
The only supports which have not fully performcd the support function satisfactorily have been identified and are approximately one percent (11) of the 1156 supports we have examined during the pipe verification program.
If during the continual inspec tion repai r process, a signi ficant operability problem is determined with respect to a system because of a support; the same consideration for repair of that support will be given is lis ted in the Technical Speci fic ations for that sys tem's operabili ty.
as We believe that we have a conservative and technically correct program for any remedial action requi red on the concrete expansion anchors in the plant.
We will continue to process this program vigorously to completion.
Should you have any further ques tions regarding this, please contact Mr. Verne Childs, Ass is tai.t to the..es iden t Manager, for additional plant specific
..fo rma t i on.
Very truly yours,
/ f
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John'D. Leonar'd, Jr.
JDL:sw CC:
G. T. Berry, PASNY, NY0
'. A. Wilverding, PASNY, NY0 P. W.
Lyon, PASNY, NY0 M. C. Cosgrove, JAF R. J.
Pasternak, JAF Document Control Center bd
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