ML20008E027
| ML20008E027 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 09/15/1980 |
| From: | Cavanaugh W ARKANSAS POWER & LIGHT CO. |
| To: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| 1-090-12, 2-090-18, IEB-80-11, NUDOCS 8010240085 | |
| Download: ML20008E027 (7) | |
Text
._
TO DAC:ADM:
CENTRAL FILES PDR:HQ LPDR l--+fC~
NSIC ARKANSAS POWER & LIGHT COMPANY POST OFRCE BOX 551 UTTLE ROCK. ARKANSAS 72203 (501) 3714422 STATE WILLIAM CAVANAUGH lli Vice President September 15, 1980 Genersoon & Construction 1-090-12 2-090-18 Mr. K. V. Seyfrit, Director Office of Inspection & Enforcement U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011
Subject:
Arkansas Nuclear One - Units 1 and 2 Docket Nos. 50-313 and 50-368 License nos. DPR-51 and NPF-6 IE Bulletin 80-11 (File:
1510.1 and 2-1510.1)
Reference:
1: Letters 1-070-07 & 2-070-07 from W. Cavanaugh, III to j
K. Seyfrit dated July 3, 1980.
Gentlemen:
In our 60 day response (reference 1) to IE Dulletin 80 11, item 3, AP&L committed to submit a description of the testing program to be per-formed at ANO to determine shear strength of mortar in the collar joints. Attachment A describes this testing program.
The schedule for completion of this testing program and for the submittal of the test results, has been delayed from February 16, 1981, to March 16, 1981.
This slippage is due to problems encountered during the initial stages of coring samples at ANO.
Several methods of coring were expe...mented with in an effort to extract a core with both faces intact. This trial and error process has developed an acceptable method of coring bu*. in the process it has also resulted in a schedule slippage.
In our 60 day. response to item 2a, we provided a schedule for the de-tailed structural analysis of concrete block walls.
These schedules have been revised to the following.
a).
For block walls supporting Seismic Category I piping, the analysis will be complete by October 17, 1980.
8 010240 ggp ([g" WA M. COLE: SOUTH UT*UT'ES $YSTEM
b)
For block walls supporting Seismic Categ2ry I attachments other than piping, the analysis will be complete by Novem-ber 14, 1980.
c)
For block walls in proximity to Seismic Category I piping or equipment such that wall failure could affect a safety related system, the analysis will be complete by January 23, 1981.
The results of the structural analysis will be described in our 180 day response now scheduled for submittal on February 6,1981.
The above schedule slippage is a result of changes in the evaluation criteria used for the block walls at ANO.
Initial core samples have indicated that the collar joint between wythes may not be of the strength initially presumed.
Using lesser values for this strength have in essence voided some work which was previously thought to be complete and has made it necessary for additional analysis to be done. This in turn extends our schedule.
The field survey, a part of our 60 day response to item 2a, which was made to gather required design data and to document the as-built con-figuration of the walls, was completed on August 21, 1980. No abnormal conditiens affecting the safety of the plant were noted in this survey.
This data is presently being factored into the analytical efforts for the block walls.
Very truly yours 7
/
x W,
William Ca augh, III
?C:RWH:DEJ:nak Attachments cc:
Mc. Victor Stello, Jr., Director Oft'ce of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, D.C.
20555
STATE OF ARKANSAS
)
)
SS COUNTY OF PULASKI
)
Willam Cavanaugh, III, being duly sworn, states that he is Vice President, Generation & Construction, for Arkansas Power & Light Cotapany; that he is authorized on the part of said Company to sigt. and file with the Nuclear Regulatory Commission this Supplementary Information; that he has reviewed or caused to have reviewed all of the statements contained in such information, and that all such statements made and matters set forth therein are true and correct to the best of his knowledge, information and belief.
/.
/
William Cavanaugh', III SUBSCRIBED AND SWORN TO before me, a Notary Public in and for the CountyandStateabovenamed,this/hdayof
, 1980.
AI2u,<.
</4'
-Notary Public /
/
My Commission Expires:
W Qumsson Expires 9/1/a1
ATTACHMENT A 4
PROGRAM FOR THE DETERMINATION OF COLLAR JOINT SHEAR STRENGTH IN CONCRETE MASONRY WALLS 1.
GENERAL This specification prevides a coring procedure and test method for determining the shear strength of the motared collar joint of multi-wythe masonry walls.
This specification shall be used only if the collar joint is required to provide shear transfer between two wythes.
the sampling activity shall be under the overall direction of a representative from University of Missouri. The representative shall have the knowledge and the authority, with the concurrence from the Project Engineer, to redirect the program if it appears that the objectives are not being met.
2.
SAMPLING PROGRAM 2.1 POPULATION The populatica from which samples are to be taken shall be es-tablished with regard only to walls requireing a collar joint to provide shear transfer between two wythes.
2.2
( RE SPACING If more than one core is required in any wall, the minimum distance t
bewtween the centers of two adjacent cores along the length of the wall shall be approximately one-half the length of the wall.
Cores should preferably not-be spaced closer than five (5) feet on center.
3.
TESTING PROGRAM The tAst prngram involves core drilling existing multiple wythe j
motared blocA walls and testing the cores to determine the in-situ shear capacity of *he mortar in the collar joint.
3.1 CORE-DRILLING
-Test specimens shall be obtained by core drilling perpendicular to the designated block walls with a portable electric machine.
Approximately 6 inch diameter cores shall be taken in such a way as to minimize cutting any rebar.
Care should be taken while drilling.
the cores and while' extracting the_ core sample so as not to damage the' sample. Tapping the drum to remove the core shall not be
allowed. Water used for core drilling shall be limited to a mini-mum.
Prior to core drilling, two 13/16 inch diameter through holes for 3/4 inch diameter bolts for each sample shall be drilled.
These two bolts shall be at 2-3/4 inch spacing symetrically about the center of the sample. A 1/2 inch thick, common washer (5 inch diameter) for both bolts shall be placed on each side of the wall.
The bolts shall be torqued to a minimum of 75 ft/lbs so that com-pression is maintained in the core until the sample is placed in the testing apparatus.
Test samples thus obtained will be inspected to ensure the sample demonstrates boundary between the concrete blocks and the multi-wythe mortar.
Samples will then be forwarded to the laboratory for investigation of the shear strength of the mortar.
3.2 DIRECT SHEAR TEST A suggested schematic setup of the shear test of the mortar joint is shown in Figure 1.
The test specimen should be loaded to failure and the failure load, mode of failure and net mortared area of the joint recorded.
If the failure mode is other than shear across the mortared joint, the test can either be considered void or the resulting failure load can be considered a lower bound capacity of the core specimen.
The specimen should subsequently be split at the mortared joint and the net mortared area determined.
The test setup will be arranged to minimize stress concentrations and bending stresses at the collar joint.
It is recommended that some dummy cores be used for the purpose of testing the test apparatus before actual testing begins.
4.
ULTIMATE SHEAR STRENGTH The ultimate shear strength shall be determined as follows:
Mean Value iu (Mean)
Lower Bound Value (90% confidence) 2 a
"v + (al,v2,[")2 u (90%) = i a 1.28 o
v a
Where:
Y is the average shear strength of all undamaged core specimens based on the net area of the core, expressed in psi.
II is the average of the net effective mortared areas divided by the gross area of the cores.
0 is the standard deviation of the shear strengths based on net area, y
expressed in psi.
is the standard deviation of the net effective mortared areas a
divided by the gross area of the cores.
In determiningII and ca, data from all undamaged samples shall be included.
5.
REPORT The report shall include a description of each sample lot, location and test results (failure load and net mortared area) including mode of failure of each core and the ultimate shear strength (mean and lowerbottnd 90% confidence in psi),3I, ca, v, and o for each y
lot.
l
[
1 l
Cored Sample f
Mortar Joint Rigid y Loading Frame Loading l'
Attached to the Frame Loading Appcratus s
G W
U Fig. 1:
Schematic Test Set up for Shear Test of Mortar Joint s
l