ML20323A157
| ML20323A157 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 10/22/2020 |
| From: | NextEra Energy Seabrook |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20323A163 | List:
|
| References | |
| SBK-L-20124 | |
| Download: ML20323A157 (29) | |
Text
SEABROOK UPDATED FSAR APPENDIX 3G CONTAINMENT LINER ANCHOR LOAD TESTS The information contained in this appendix was not revised, but has been extracted from the original FSAR and is provided for historical information.
SB 1 & 2 FSAR APPENDIX 3G CONTAINMENT LINER ANCHOR LOAD TESTS 3G-1 Amendment 53 August 1984
SB 1 & 2 FSAR FHlAL REPORT CONTAINMENT LINER ANCHOR LOAD TESTS by Edwin G. Burdette February 5, 1981 Tests Performed for United Engineers and Constructors 30 South 17th.Street Post Office Box 8223 Philadelphia, Pennsylvania 19101 Testing Facilities:
Department of Civil Engineering The University of Tennessee Knoxville, Tennessee 37916 Amendment 52 December 1983 C~6-~~
Edwin G. Burdette Consultant 3G-2
- 1.
INTRODUCTiON SB 1 & 2 FSAR Containment Liner Anchor Load Tests by Edwin G. Burdette Amendment 52 December 1983 The containment structure for the Public Service Company of New Ramp-shire's Seabrook Nuclear Power Station consists of a right vertical cylin-der, a hemispherical dome, and a thick, flat base.
In order to meet leak-tightness requirements for the containment actin.g.* as a pressure vessel, the entire inside surface of the concrete is covered with a steel liner.
This liner is anchored to the concrete by embedded structural tees, angles, or studs \\vhich are \\velded to the steel liner plate.
The containment is designed to resist the high temperature and pressure associated with the most severe break in a reactor coolant pipe.
Under this postulated loading condition, the liner anchors must be adequate to maintain the structural integrity of the liner-;liner ~nchor system *. In order to evaluate, analytically, the adequacy of the liner anchors to perform their required function, experimental load-deflection data for individual anchors are needed for shear loads and displace-ments along the surface of the containment wall.
The results of load tests on liner anchors have been reported in Refer-ences 2, 3 and 4.
Of particular interest relative to the tests reported here-in are the results reported in Reference 2 of tests performed at the University of Tennessee.
These test results provide considerable information on load-deflection behavior of angles and a smaller amount of data on structural tees, both angl~s and tees being attached to 1/4 inch thick liner plates.
The tests reported herein utilized the same test equipment and essentially the same teqt 3G-3
SB 1 & 2 FSAR Amendment 52 December 1983 procedure as those tests in Reference 2 and were designed to provide experi-mental data directly applicable to the containment liner at Seabrook.
1.1 Objective The objective of the tests aeported here is to obtain the shear load-displacement relationships for a) the Japanese Tee lOOxlOOmm with 1/4 inch fillet welds \\vhich was used to anchor the containment liner at Seabrook and b) for 3/4 inch diameter x 12 inch long studs.
The boundary support condi-tions for the liner plate test specimens were designed to represent, as near-ly as practic.::ble,* those existing in the field; if an accurate simulation of field conditions was not practical,_ the support conditions were designed to produce conservative results.
1.2 Scope A total of six shear tests were performed to accomplish the stated ob-jective three tests on the Japanese Tee lOOxlOOmrn and three tests on 3/4 inch diameter x 12 inch long studs.
Information was obtained in each test to plot the load-deflection curve for the anther being tested.
1.3 Acknowledgment The work reported herein was performed as a part of United Engineers and Constr~ttors, Inc., Purchase Order No. H.O. 56971, Change Order No. 1.
The facilities of the Department of Civil Engineering ~t the University of Tennes-see, Knoxville, were used to perform the tests.
A number of Civil Engineering students participated in the performance of the tests, with special commenda-tion due to Steve Stethen, graduate student in charge, and to James Haley.
- 2.
TEST SPECIHENS SB 1 & 2 FSAR Amendment 52 December 1983 All of the test specimens were prepared on the Seabrook plant site using procedures and materials approved for construction of the containment struc-ture.
A complete description of the test specimens with appr~priate drawings is contained in Reference 1, and a sketch showing the dimensions of the test specimens is shown in Figure 1 herein.
The concrete blocks in which both the tees and the studs were embedded ~re 3 1-4" x 3 1 -0" x *2 1 -3" high ~dth the lin-er attached to the 3 1-4" x 3 1-0" top face.
. The embedded tees were 12 inches long, and the two studs Here spaced 12 inches apart.
The ields for the tees were 1/4 inch continuous fillets on both sides of the ste2.
The embedded an-chars were located 20 inches from the loaded front face of the test block, a distance equal to the horizont?l spacing of the structural tee anchors.
The length of the liner piate beyond the front edge of the concrete test block ivas determined by the dimensions of the test rig.
After the specimens were cast, they were shipped to the University of Tennessee via flat-bed truck for testing.
At the time of casting, concrete cylinders rep:-esc:tc.tive of t[;e conc:*ete in each specimen were cast and ' stored at the Seabrook site.
On the day a particular specimen was tested at the University, three corresponding cyl-inders were tested at Seabrook to obtain the compressive strength of the concrete.
Four specimens were cast with embedded tees and four with embedded studs.
The test plan called for the testing of three specimens of each type.
The fourth specimen of each type was cast as a safety measure; if one specimen 3G-S
SB 1 & 2 FSAR Amendment 52 December 1983 was damaged in shipment or if the results of the first three tests suggested a revised testing procedure, the extra specimen would then be tested. It turned out that there was no reason to test the extra specimens; thus, three tee and three stud specimens were tested.
- 3.
HETHOD OF TESTING.
3.1 Test Apparatus The concrete biock with the liner plate anchored to its top face was re-strained by bearing against an abutment beam.
The liner plate was fastened to a moveable head beam which was driven by t'>vO, 200kip capacity hydraulic rams.
The driving of this head beam produced tension in the liner plate and, in turn, a shear load in the anchor.
A hydro cal cap \\vas placed bet\\veen the leading top edge of the concrete block and the top 3 inches of the abutment beaffi.
Calibration curves for the two load cells are included in Appendix C.
The test instrumentation consisted of the following key elements:
- 1.
An LVDT '>vas attached to the liner plate in the vicinity of the anchor.
In the first test the LVDT was located behind the anchor - that is, on the side a\\vay from the applied load - but the rotation of the anchor and the re-sulting uplift of the plate behind the anchor caused some inaccuracies in LVDT readings at deflertions beyonrl peak Joad (see Plates Bland B2).
Thus, for all later tests the LVDT was attached to the liner plate several inches in front of the anchor where there was no vertical movement of the liner plate (see Plate B8).
2.
A Gilmore console was used to control the closed loop testing system ~
A voltage input at the console causes the pump to drive the hydraulic ram until a voltage output from the LVDT sends a feedback signal that precisely matches 3G-6
SB 1 & 2 FSAR Amendment 52 December 1983 the volt~ge input signal, at which point the system is in equilibrium.
- 3.
Load cells are attached ~to the head beam which pulls the plate in such a way that the rams act directly against the cells.
The signal from the load cells is transmitted to.a digital strain indicator which is calibrated to
~ead the load directly in kips.
- 4.
An XY plotter is keyed into the system in such a way that it receives signals from both the LVDT and the load cells.
These t\\vo signals *cause the Ary plotter to prodpce a continuous plot of load versus deflection while a test is in progress.
3.2 Test Procedure The tests ptoceeded as fbllows :
- 1.
A small input voltage, corresponC.ing to a small deflection, Has "dialed in" at the console.
The pumps then drove the rams until sufficient movement of the anchor resulted in an output voltage from the L\\~T which matched the input vol-tage.
The *load required to produce that deflection was read and recorded, and the XY plotter made a continuous record of load and deflection t.:p to that point.
2.
The procedure just described was repeated for increments of deflection small enough to obtain an accurate plot of the measured data.
Heasurement of load and deflection continued until the full 0.5 inch travel of the LVDT was reached or failure of the anchor occurred.
For those tests where failure had not occur-red at the limit of travel of the LVDT, the LVDT was disconnected from the specimen, and the test was continued to failure to observe the mode of fail-ure of the embedded anchors.
A dial gage was attached to the specimen to pro-vide a check on the deflections measured by the LVDT.
3.3 General Comments SB 1 & 2 FSAR Two aspects of the testing procedure merit special comment:
Amendment 52 December 1983
- 1.
The load was applied to the anchors in the tests through a pull on the plate rather than a push on the plate as used in' the tests in Reference 4.
This type of load application obviated the need for any bending stiffeners on the liner plate, permitting a realistic representation of the rotation of the liner plate at the anchor.
However, the fact that the unloaded end of the liner plate was unrestrained permitted it to lift off the test block as a result of the.anchor rotation.
In an actual liner-liner anchor system, this lift-off would be restrained by another embedded tee or rov7 of studs, restraint that would add to the stability of the system.
This effect is par-ticular~y important in ~he tee tests.
Therefore, the method of testing these specimens was such that the load-deflection curve obtained for an anchor would be a conservative representation of the actual load-deflection relationship for an anchor in an actual field installation.
- 2.
The tests were controlled by deflection rather than by load.
The input voltage corresponded to a deflection and the rams acted to produce this de-flection; the load required to produce this deflection was then read from the multimeter.
This method of controlling the. tests permitted the definition of the descending portion of the load-deflection curve for an anchor.
- 4.
TEST RESULTS The test results are summarized in Tables 1 and 2, and load-deflection curves are shown in Figures 2 and 3.
Original data, including XY plots, are included in Appendix C.
Selected photographs are presented in Appendix B to 3G-B
SB 1 & 2 FSAR Amendment 52 December 1983 illustrate the testing operations and the mode of failure of the anchors.
4.1 Discussion of Results The irregularities present in the load-deflection curves shown in the h~
plots in Appendix C are due, for the most part, to relaxation of the concrete causing a reduction in load under a constant deflection.
\\fuen the test was stopped to take readings or, for that matter, when the person dialing in the voltage hesitated a bit, the system responded by maintinaing constant de-flection; ~nd the load required to maintain this deflection immediately d~-
creased.
T-he lc?..d-deflection curves for the tees, shm*m in Figure 2, drop off sharply ia~ediately after peak load is reached.
At peak load the rotation of the tee in the concrete produces a crack on the back side of the flange of the tee.
The local instability of the anchor results in a sharply reduced load-carrying capacity; in fact, the only load-carrying capacity remaining is *that required to fail the concrete 'tvedge directly in front of the embedded tee.
The drop-off in load beyond the peak was so sudden that, for T-1 and T-3, the testing equipment was incapable of tracking it accurately. The sud-den load instability of the concrete around the tee would permit the anchor to move too far forward, "overshooting" the dialed in voltage.
The rams would then try to rectify the situation by retracting; however, the rams were not connected to the head beam, so their retraction allowed the load to go to zero.
This situation is illustreted by the load-deflection curves obtained from the XY plotter and included in AppendixC.
.This loss of load presented no partie-ular problem; a new, higher voltage 't.;ras d'ialed in, the test was continued, and 3G-9
SB 1 & 2 FSAR a continuation of the load-deflection curve was obtained.
Amendment 52 December 1983 In an actual con-tainment liner-liner anchor system, the restraint provided by an adjacent anchor would almost certainly reduce the sharpness of the drop-off of the load-deflection curve and enhance the ductility of the tee anchors.
The distinctly different* shapes of the load-deflection curves for the tees and for the studs reflect the different modes of failure for the t~o anchor syste~s. The fillet welds joining the tee's to the liner plate were of sufficient strength to prevent a failure of the steel"embedment; thus, the shear stren~tli of the anchor was limited by concrete tension acting to resist the rotation of the tee produced by the applied shear.
Ductility of the em-bedded tees resulted from.the development of a secondary mode of failure, namely, the diagonal tension failure of the wedge of concrete directly in front of the tee.
Conversely, the limiting strength element in a stud test was the shear strength of the studs.
In each case the studs sheared just below the weld which attached them to the liner plate.
The resulting load-deflection relationship resembles the stress-strain curve for steel, with a corresponding high degree of ductility.
Interestingly, the maximum shear stress in the studs fat an average of the *three* tests was 60 ksi.
- 5.
CONCLUSIONS The load-deflection curves shown in Figures 2 and 3 represent, in the op-inion of this wr.iter, a reasonable description of the shear load-deflection behavior of the anchors tested.
Because of the absence of any hold-down re-straint on the free ends of the liner plates in the tests, the descending por-tions of the curves for the tees should be somewhat higher. *Thus, the curves *in 3G-10
SB 1 & 2 FSAR Amendment 52 December 1983 Figure 2 may be thought of as reasonaole but somewhat conservative represen-tations of the behavior of actual embedded tee anchors.
SB 1 & 2 FSAR REFERENCES Amendment 52 December 1983
- 1.
Galunic, Branko, "Procedure for Containment Liner Anchor Load Test",
United Engineers and Constructors, Inc., Philadelphia, PA 19101, Revised August 25, 1980 (attached to Purchase Order No.
H.O~ 56971, Change Order No. 1).
- 2.
Burdette, Edwin G. and Rogers,.Larry W., "Liner Anchorage Tests", Jour-nal of the Structural Division, ASCE, Vol. 101, No. ST7, Proc. Paper 11432, July 197.5, pp 1455-1468.
- 3.
Lee, T. ~md Gurbuz, 0., "Assessment of Behavior and Designing Steel Liners for Concrete Reactor Vessels", Final Report, Engineering Research Institute, Iowa State University, Ames, Iowa, Nov. 197.3 (prepared for the U.S. Atomic Energy Conunission Under Contract No. AT(ll-1)-2267).
- 4.
"Liner Plate Anchorage Tests", Bechtel Corporation, San Francisco, Cal-ifornia, for *:\\rkansas Nuclear One, Arkansas Po\\oJer and Light Co., April 18, 1969, 3G-12
SB 1 & 2 FSAR APPENDIX A TABLES AND FIGURES 3G-13 Amendment 52 December 1983
I Specimen T-1 T-2 T-3 Avg.
I Specimen S-1 S-2 S-3 Avg.
Concrete Age
£' c (Davs)
(psi) 20 5,710 24 5,770 28 5,950 5,810 SB 1 & 2 FSAR Table 1 Test Data for Tee Specimens Peak Peak Defl. Peak Load Load Load (kin~)
(k/in) fins )
152 12.67 0.070 156 13.0
.0.070 144 12.0 0.060 150.7 12.6
- 0. 067 Table 2 Test Data for Stud Specimens Concrete Peak Peak Defl. at Age f I Load Load Peak Load c
(Ins.)
(Davs)
(psi)
(kips) *
(k/stud) 42 6,100 51.5 25.8 0.390 56 6,060 54.8
- 27.4 0.620 67 6,500 52.5 26.3 0.395 6,220 52.9 26.5 0.468 3G-14 Amendment 52 December 1983 Load at
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(kins) 36 34 32 34 Load at
!::. = 0. 25 (kips.)
in.
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SB 1 & 2 FSAR APPENDIX B PHOTOGRAPHS 3G-18 Amendment 52 December 1983
SB 1 & 2 FSAR Plate Bl: Specimen T-1.
Test Assembly at Start of Test
.II Plate B2:
Specimen T -1.
Plate Deformation During Final Stages of Testing 3G-19 Amendment 52 December 1983
Specimen T -1.
Concrete Surface After Removal of Liner Plate Plate B4:
Specimen T-1.
Liner Anchor (Tee) After Test 3G-20 Amendment 52 December 1983
Specimen T -2.
Liner Deformation at End of Test Plate B6:
Specimen T-2.
Top of Concrete at End of Test 3G-21 Amendment 52 December 1983
Specimen T -2.
Liner and Tee at End of Test Plate B8:
Specimen T -3.
Instrumentation at Start of Test 3G-22 Amendment 52 December 1983
Specimen T -3.
Concrete Surface After Removal of Liner Plate Plate BlO: Specimen T-3.
Liner and Tee After Removal of Liner Plate 3G-23 Amendment 52 December 1983
SB 1 & 2 FSAR Plate Btl: Specimen S-1.
Start-up of Test Plate B12:
Specimen S-1.
Studs in Concrete After Shear Failure 3G-24 Amendment 52 December 1983
Specimen S-1. Detail of Sheared Stud in Plate Plate B14:
Specimen S-1.
Detail of Sheared Stud in Concrete 3G-25 Amendment 52 December 1983
Specimen S-2.
Concrete Surface After Failure of Studs Plate B16:
Specimen S-2.
Liner After Stud Failure 3G-26 Amendment 52 December 1983
Specimen S-2.
Detail of Sheared Stud in Concrete Plate B18:
Specimen S-2. Detail of Sheared Stud in Plate 3G-27 Amendment 52 December 1983
Specimen S-3.
Sheared Studs in Concrete After Test Plate B20:
Specimen S-3.
Sheared Stud in Plate After Test 3G-28 Amendment 52 December 1983