ML13324A862
| ML13324A862 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 05/19/1986 |
| From: | Medford M Southern California Edison Co |
| To: | Lear G Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML13324A863 | List: |
| References | |
| TASK-03-06, TASK-3-6, TASK-RR NUDOCS 8605210240 | |
| Download: ML13324A862 (11) | |
Text
Southern California Edison Company P. 0. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 M.O.MEDFORD TELEPHONE MANAGER. NUCLEAR LICENSING (818) 302-1749 May 19, 1986 Director, Office of Nuclear Reactor Regulation Attention: G. E. Lear, Director PWR Project Directorate No. 1 U. S. Nuclear Regulatory Commission Washington, D.C.
20555 Gentlemen:
Subject:
Docket No. 50-206 SEP Topic 111-6, Seismic Design Considerations San Onofre Nuclear Generating Station Unit 1 The purpose of this letter is to respond to a number of questions regarding the seismic reevaluation of San Onofre Unit 1. Accordingly, provided as Enclosure 1 are the responses to specific questions raised by the NRC Staff or its consultants.
If you have any questions on the enclosed information, please call me.
Very truly yours, Enclosure cc:
F. R. Huey, USNRC Senior Resident Inspector, SONGS 1, 2 and 3 M. J. Russell, EG&G L. Shieh, LLNL N. C. Tsai, NCT Engineering 6605210240 860519 PDR ADOCK 05000206 P
CONCRETE EXPANSION ANCHORS AND ROCK ANCHORS QUESTION Explain how the group effect of bolts was considered for concrete expansion anchors and rock anchors.
RESPONSE
The group effect of bolts was considered by specifying the allowable design loads based on a minimum center to center spacing between bolts (see attached Table 3 column denoted as "Min. C/C Spacing"). A reduction in the minimum center to center spacing is permitted so long as allowable design loads are reduced according to Note A of Table 3. Similar provisions are considered in the design of concrete expansion anchors which have allowable design loads based on minimum center to center spacings of twelve bolt diameters.
TABLE 3 ALLOWABLE DESIGN LOADS FOR ROCK BOLT EXPANSION ANCHORS Allowable Pretensioning Deaf ~n Torque Torque at Tension Anchor La a n) (2)
(Ft-Lbs) to Installatlon Test Mi.
Min.C/C Mi.
Edge Diameter Tension Shear Expand (Ft-Lbbs) Threads Load Embedment Spacing Distance (Inches)
(Kips)
(Kips)
Shell Not Lubricated (KIPS)
(Inches)
(Inches)
(Inches) 1 25(5) 33(6)
(7) 12(8) 200-250 300 30 14 10 6
1-3/8 S5) 66(6) 16 24 700-750 1100(3) 60 18 14 8
2 100(5) 133(6) 33(7) 48(8) 950-1000(4) 3300(3) 120 24 20 10 (1) For 4000 psi (f'c) or higher concrete (2) Subject to reduction per Notes A and B and combined interaction per Note C (see next page)
(3) Preferred method is to pretension to specified test load using calibrated hollowram hydraulic jack or calibrated stud tensioner.
(4) May be increased to 1500 ft. lbs. if required to prevent slight pullout of bolt which may be experienced upon application of 3300 ft-lb torque for pretensioning prior to grouting.
(5) Manufacturer's recommended design load at 2:1 safety factor.
(6) These increased allowable loads are applicable only for "Abnormal/Extreme Environmental" (Design Basis Earthquake) or faulted loading combinations.
They are based on 0.9 times Manufacturer's maximum working load to elastic limit.
(7) Preferred design load based on AISC limits using manufacturer's ultimate strength values.
TABLE 3 (CONTINUED)
ALLOWABLE DESIGN LOADS FOR ROCK BOLT EXPANSION ANChORS (8)
Design loads increased by 1.5 applicable only for "Abnormal/Extreme Environmental (Design Basis Earthquake) or Faulted Loading combinations.
Additional Notes:
A. A reduction in the minimum center to center spacing and edge distance for anchors is acceptable provided that the allowable design loads (tension and shear) are reduced by the same proportion (i.e.:
25 percent reduction in spacing -
25 percent reduction in allowable design loads).
The reduction in spacing may not exceed 50 percent in any case.
B. A reduction in the minimum embedment for anchors is acceptable provided that the allowable design load (tension only) is reduced In proportion to the square of the reduced embedment (i.e:
embedment reduced to
(.80)2 =.64 times allowable load specified).
The reduced embedment may not be less than 70 percent of the specified minimum embedment.
C. For evaluation of simultaneous tension and shear loading, the loads shall be combined by the following interaction formulas:
2
)2 1.0 for rock bolt expansion anchors Where:
(t, s) = Actual design (tension, shear) loads, respectively (T, S) = Specified allowable (tension, shear) loads, respectively
BATTERY RACKS QUESTION Provide information regarding the design of the new battery racks in Battery Room No. 1 of the Control-Administration Building.
RESPONSE
The new batteries and racks were designed and manufactured by Gould Industrial Battery Division. The battery rack is a two step, 19'-0" long x 3'-8" wide x 3'-2" high steel structure which supports 30 cells of batteries (Figure 1).
The rack was designed for the.67g modified Housner seismic event and a 4%
damping value was used.
Dynamic analysis was performed with the computer code, STRUDL, and design was in accordance with Specifications IEEE 323-1983, IEEE 344-1975, AISC 8th Edition and AWS D1.1-1983. Allowable stresses were limited to 90% of minimum material yield strength.
8 -9.4
-k I CELLS PER ROW)
AC0 DE I
SOTERE NOTCED S 2R.PRRC 22 HC EA BATAT A
IL:
ANCHOREDR8 6 ~~ ~ ~~~~
229.2 929-
-222 6
12 5 2 21 4
- ..r;~,PLAES O BY UING SbDOALANCOR BOTSAA 1+
0 12 2
qE~INGiA~UNU~y~i NCOROLT OCEOCAT0 I/BS UHONLAE (2)RE-PER RACK
~r~.rAILnIL~n..
,METHOD OFANCHORING AND ANCHOR BOLT ANC THO STEP RACK1.
AORUINGTONBE DETERMIGNED BY.
Ay5TOBOER PA.-
r'A.
B~TQ SRDTE58L,..
ORIGINAL CONSTRUCTION WELDING PRACTICES QUESTION Provide additional information regarding the welding practices for original pipe support A-36 steel.
RESPONSE
Overall information regarding the original welding practices at San Onofre Unit 1 was provided in our April 16, 1986 submittal to the NRC. The additional procedure qualification record (PQR) for welding A-36 steel is attached. The PQR shows that the minimum tested tensile strength was 59.4 ksi which was greater than the minimum base metal strength of 58.0 ksi.
£~cnsu~E~
(a)Form Nbo. WR.ZA
-~~
?A~E le;ELCRORTO
-Log BPG/SCE 0 4 BCTLCROAIr San FranCisco. California PROCEDUJRE QUALIFICATION RECORD)
]Procedure Specification No. P1-A-c (NC)
- Dat, wovember 4, 1966 Weldineg ProcessShielded bretal Arc Lo~cation San Francisco, Californ~ia Nam W. B. Keyser 01bo Test Conducted by IJ Mantle Parent Material Ouslified On:
CheTn14&l C.S.
-Spec.
ASTM A-36 P-No
- 1Shape, PLATE Thickness
- 9. 25"1 Electrode or Filler Material Used:
AWS class E 6010 ASTM Spec.
A-233 F-No.
3 A-No.
Manufacturer aznd frie Name I..4ncoln Sp' 1, 3C%
& 40 Joint Desi,n C;OL ooat Gap: 3/16 Backing Strips Used YES Fleat Treatment Pr~~h.&t
~Stress Relieve Temp.
Stress relieve Tirme_____
Radiographic Results Physical Testin&g Tensile and bends by Anamet,Labs.
Be rkeley bends interpreted by Bechtel Corp.
HORIZONTAL VERTICAL OVERH{EAD
- SPCZMN PSITON(20)
(30)
(4G.)
Reduced Yield Stren~th Dsi Section Tensile Strengzth k.-i 60. 0 S9.4
- 67. 1
- 65. 0 _67.
57 Tensile Elon',ation,
% in 2" Bend Free %
I__
Bend oI70t 180 OK 180K 180IS OK 180 OK 190~j 0L IQQ Band Face 11800OK 18O90OK 1PQL§0KQ.Q.1Q.I We certify that the statements in thi's record are correct ad that the test welds were pre pared, W* lded, and tested in accordance with the rquiremnents of Section XX of the ASME Code.
BECHTEL CORPORATION DM0* 11/4/66 Wedi Esno
SEISMIC QUALIFICATION OF ELECTRICAL EQUIPMENT QUESTION Provide information regarding the seismic qualification of electrical equipment.
RESPONSE
The anchorage of safety related electrical equipment was evaluated and modifications were implemented, where required, as documented in SCE's letters to the NRC dated March 25, 1981, May 29, 1981 and June 28, 1982. These evaluations included the anchorage of electrical cabinets.
The seismic adequacy of the electrical cabinets themselves will be demonstrated during the implementation phase of the resolution of Unresolved Safety Issue A-46, Seismic Qualification of Electrical Equipment. It is our understanding that the NRC resolution of A-46 is scheduled for issuance later this year.
SI SUPPORT STIFFNESS QUESTION Is the influence of beam flexibility considered in the piping analyses?
RESPONSE
Beam flexibilty was considered when support structures could affect the response of piping systems. Beams were determined to be non-rigid if the beam deflection under the pipe support seismic load was greater than 1/8 inch or the beam's first modal frequency was below the zero period acceleration region of the applicable instructure response spectra (Reference SER Section 3.13).
Non-rigid support beams were evaluated for their effect on piping analyses by calculating the beam stiffnesses at the pipe support locations. These beam stiffnesses were either considered in the piping analyses or compared with generic pipe support stiffnesses to confirm that the analysis results would not be significantly affected.
1854X:jk
CONDENSATE STORAGE TANK QUESTION Evaluate the effect of a seismic event on the condensate storage tank.
RESPONSE
The results of the evaluation of the condensate storage tank are included in the enclosed report "Seismic Evaluation of the SONGS 1 Condensate Storage Tank" dated May 1986.
JLR:6750F