ML19259C773
| ML19259C773 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 07/09/1979 |
| From: | Aswell D LOUISIANA POWER & LIGHT CO. |
| To: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| LPL-11505, NUDOCS 7908150150 | |
| Download: ML19259C773 (2) | |
Text
A
/-
~.
-7]3 9 "3,
s
-1 i:
c:.h' 2 l_OUIS1ANA
- 7' *?
,42 cuAn Nee sweer P O W E A & L I G H T! P O Bcx EcG8 NEW C ALEANs LCUis;ANA 7c174. (5c41 tE6-2345 wccte sco:s LT.uii5 3'r 3?E?.1 July 9, 1979 a t a3a;
- x.,~w % %-o LPL 11505 Q-3-A20.03.13 3-A1.01.04 Mr. Karl V. Seyfrit, Director Region IV U. S. Nuclear Regulatory Cc:=ission Office of Inspection and Enforcecent 611 Ryan Placa Drive, Suite 1000 Arlington, Texas 76012 SU3 JECT: Waterford 3 SES Docket No. 50-382 I.E.Bulletin 79-02
Dear Mr. Seyfrit:
In response to the subject bulletin, the da and installation of base plates using concrete expansion anchor bolts to sup, rt Seisaic Category I piping have been reviewed and items 1 through 4 of the same bulletin are addressed as follows:
1.
The base plate flexibility is accounted for in the calculation of anchor bolt loads. The bolt loads are calculated using plate on elastic foundation theory utilicing ANSYS finite element cceputer program. The base plate design has accounted for the requirements of tinimum anchor spacing and edge distance to assure 100% effective anchor perfor=ance. Total allowable lead of the base plate under axial, shear and bending f orces is deter-sined using the follewing interaction forcula:
Actual V Actual M < l.0 Actual T Allevable T A11cwable V Allewable M axial fercc where T
=
shear f:rce V
=
bending force M
=
The allcwable axial, shear and bending forces are established separately based en the taximun bolt allcwable tension and shear loads.
NYSI$?
l[0
' Mr. Karl V.
Seyfrit July 9, 19 79 d
The base plates, which have already been installed, were designed originally assuming rigid place action in calculating bolt loads.
However, all of these base plates are being re-viewed and their bo't loads recalculated to include the effects of plate flexibility as discussed above.
From a design review of these base plates which have already beec installed, it was found that the majority of the plates (appraximately 857.) have suf ficient design conservativeness, and will not require any design modification.
However, the balance of the plates, approx 1=ately 8'., of them, may require a design codification.
The codification is to add stiffener plates to the base plate so that plate prying action on the bolts will be minimized.
The detailed design for the modi-fication is scheduled to be completed by October 1,1979.
2.
This project has used only wedge type concrete expansion an; hor bolts.
The minimus factor of safety between the bolt design load and the bolt ulti= ate capacity is four (4)- the bol: ultimate capacity is based on static load test on concrete wit h 4000 psi 23 - day compression strength.
3.
The L'lts are designed to withstand seismic loads. All the bolts ut the time of installation are torqued to develop a bolt tension equal to 115% of the =aximum design load.
The torque is applied using a calibrated torque wrench as speci-fied by the bolt =anufacturer. Wrench calibration is based on results of on-site tests which have been reviewed and accepted by the design engineer.
4.
The qC docu=entation for each base plate has included the number of anchor bolts, bolt size, embed:ent length, and verification that the correct torque was applied.
The results of audits performed of records made since October
.977 to April 1979 indicate the installations of the work to be acceptable and in accordance with design requirecents.
If you have any questicas, please advise.
Yours very trul;..
OGY WO D.
L. Aswell DLA:JEH:s d ec:
U. S. Luclear Regulatory Co= mission Office of Inspection and Enforcement Division of Reactor Construction Inspection Washington, D.
C.
20555 O~'F t2-.J.'
us