ML20204H147
| ML20204H147 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 08/01/1986 |
| From: | Miosi A COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 1941K, NUDOCS 8608080018 | |
| Download: ML20204H147 (26) | |
Text
'
/
Commonwealth Edison I
' One First National Plaza. Chicago, Illinois 7 Wess RepV to: Post Mce Box 767
\\ "d Chicago, Illinois 60690 - 0767 N
August 1, 1986 Mr. Harold R. Denton U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, DC.
20555
Subject:
Braidwood Station Unit 2 P.eactor Vessel Nozzle Analysis NRC Docket No. 50-457
Reference:
April 2, 1986 A.D. Miosi letter to H.R. Denton
Dear Mr. Denton:
Enclosed is supplemental information covering three items which you require for review of the Braidwood Unit 2 Reactor Vessel Inlet Nozzle "F"
indication as discussed with members of your staff.
The first item contained in Attachment 1 concerns a substantiation of the fracture toughness requirements found in Appendix G of ASME Section III in light of the proposed grindout.
General Electric compared the hoop stresses in the nozzle section with and without the proposed grindout.
The stress intensity was calculated for both cases (one inch grindout vs.
factor, KI, no grindout).
Both of these comparisons yielded negligible differences from the original Appendix G analysis as performed by Babcock and Wilcox.
Therefore, the original Appendix G analysis is still valid.
The second item, contained in Attachment 2, concerns itself with the validations performed by General Electric for the two compter programs utilized in the analysis addressed in the rcfotenced letter.
Threc example are included for the ctrecs linearization program, STRDIS.
Three sample problems and an information/ program status sheet are included for the finite element program, ANSYS (approved for design use).
The final item, contained in Attachment 3, concerns itself with clarification of the location of the indication, shown in Figure 2, and the classification of the stress in the section analyzed.
The governing section with the highest primary stress is the shell thickness and is classified as a local primary membrane stress (Pg).
It was shown in the General Electric report that euan with the 1 inch grindout, the area of reinforcement requirements are satisfied.
8608080018 860301
[7 f PDR ADOCK 05000 7
g A
e Should you have any questions concerning this matter please contact this office.
One signed original and fifteen copies of this letter and attachments are provided for your review.
Very truly yours.
U A. D. Miosi Nuclear Licensing Administrator
/klj cc:
J. Stevens 1941K
BRAIDWOOD UNIT 2 REACTOR INLET N0ZZLE APPENDIX G ANALYSIS
Background
The fracture toughness requirements for the Braidwood Unit 2 reactor inlet nozzle have been satisfied by demon [trating compliance with Appendix G of the ASME Code.
Specifically, a nozzle corner flaw of 1 inch depth was postulated and pressure temperature curves were established to assure the safety margin requirements of Appendix G (Reference 1).
However, because of a UT indication in the reactor vessel to nozzle weld, a local grindout repair of up to 1 inch depth has been proposed to remove the indications.
The purpose of the analysis described here is to demonstrate that even with the grindout the nozzle still meets the original Appendix G requirements evaluated in [1].
Technical Approach For the beltline region the heatup/cooldown events are limiting from the viewpoint of Appendix G analysis.
- However, the hydrotest is the governing case for the reactor nozzle and is therefore selected for analysis.
The original Appendix G analysis for the nozzle postulated a one inch nozzle corner flaw.
The minimum temperature for the hydrotest was determined corresponding to a safety margin of 1.5.
The approach used here is to compare the hoop stresses in the nozzle section for the one inch grindout case with the corresponding stress distribution without the grindout.
Stress intensity factors are calculated as a function of crack depth for both cases.
Based on a comparison of the calculated stress intensity factor it is shown that the presence of the grindout has a negligible effect so that the original Appendix G analysis is still valid.
I
o Results Figure I shows the axisymmetric finite element model of the nozzle.
The section of the element through the nozzle corner with the highest stress was considered in the evaluation.
The axisymmetric model considered the commonly used assumption of a spherical shell with 1.5 times the radius of the vessel.
J i
Figure 2 shows the variation of hoop stress across the nozzle thickness for a pressure of 3125 psi (corresponding to the design hydrotest)
[ Reference 2].
It is seen that with the grindout, the nozzle section stress is slightly higher but the percent change is very small.
Stress intensity factors for the nozzle corner flaw were determined using the stress distribution for the two cases. The stresses were magnified such that the surface stress at the nozzle corresponds to the ASME Code stress index of 3.1 (NB-3338.2) on the inside surface.
Figure 3 shows the calculated stress intensity factor as a function of crack depth for a nozzle corner flaw in the longitudinal plane.
The differences in the K value are negligible for the 1 inch postulated flaw.
i
-t Conclusion Comparison of the calculated stress intensity factor for the case with the 1 inch grindout and no grindout confirm that the change in the calculated K value is negligible.
Thus the original Appendix G analysis in [1] remains valid.
4
References 1.
" Appendix G Analysis Report #12" for Westinghouse Nuclear Energy
- Systems, Rev.
2.
Performed by Babcock & Wilcox
- Company, February 1983.
2.
"ASME Code Evaluation of the Braidwood Unit 2 Nozzle F to Include Effects of Proposed Grindouts". General Electric Report MDEf41-0386 Rev. O, DRF A00-02669, February 1986, s
l l
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FIGURE 1 - Braidwood Inlet Nozzle Finite Element Model
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THROUGHWALL HOOP STRESS DISTRIBUTION s
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c.ASE ( - Pm b4 INPUT STRESSES ARE:
}
10.0 7.5 2.5
-2.5
-7.5
-10.0 INPUT COORD ARE :
0.
1.250 3.750 6.250 8.750 10.000 NEMBRANE STRESS =
A BENDING STRESSES :(t OR-)
10.00 PEAKS 1 =
-0.00 PEAKS 2 =
0.00 MEMBRANE PLUS BENDING STRESS =
10.00 cAs E 2. - Pure mem bmn<.
INPUT STRESSES ARE:
~
- 10. 0 -~ ~~ 10. 0 10 0 10.0 10.0 10.0' INPUT COORD ARE 1
~U 0.
1.250 3.750 6.250 8.750 10.000 HEMBRANE STRESS =
AAA BENDING STRESSES ett OR-)
0.
PEAKS 1 =
0.
PEAKS 2 =
0.
HEMBRANE PLUS BENDING STRESS =
10.00 CASE 3 Nemtenne
+ be.wd y INPUT STRESSES ARE:
r 20 0 1~.5 12.5 7.5 2.5 0.
INPUT COORD ARE :
0.
1.250 3.750 6.250 8.750 10.000 NEMBRANE STRESS =
__t0.00 BENDING STRESSES =(t OR-)
10.00 PEAKS 1 =
-0.00 PEAhb2 =
0.00 NEHDRANE PLUS BENDING STRESS =
20.00 4
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. -. :;... 7; g.p.::.c.. ::4.~ y 2NGINEERING CCMPUTER ?ROGRAM NAME y
M h
A y #* 9..
(Ref. E0P 40-3.001
,ilSYSC4V ENGINEERING CCMPUTER PROGRN4 STKnJS RECOVERY CLASSIFICATION RESPONSIBLE ENGINEER DESIGi RECORD FILE NUMBER 312-';1272 ENA NUMBER G. C. Mok 523 EAT 20-75 NAME COMP LEVEL 1 PLANNED LEVEL 2 DESIGN REVIEW DATE 8439 t -
Oh c d.'-f.. : '. _l
~:!Ut_ 2 6 97 -
AF ROVING MANAGER
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TITLE DATE LEVEL 2R COMPUTATIONS SECTION LIBRARY IMPLIMENTATION 4 d 9 '/3 09 V
// N SELECT NAME jam
.? *i
'2-E:U)! RATION 2XE p.
@ d
'T jf f C f-T j '. ' 7 - r y TITLE DATE j,PROVINGMANAGER LEVEL 2 COMPUTATIONS SECTION LIBRARY IMPLEMENTATION SELECT NAME DATE V
X>FROVING.'4ANAGER ilTL2
.A E LEVEL 3 COMPUTATIONS SECTION LIBRARY IMPL2 MENTATION SELECT NAME 0 ATE APPROVING MANAGER TITLE
- ATE LEVEL 4 APPROVING MANAGER TITLE DATE
i s
__ age - - m%-
~
ENGINEERING COMPU111R (Ref.E0P40-3.00)
PROGRAM ARSTRACT RESPONSIBLE ENGINEER RECOVERY CLASSIFICATION ENGINEERING COMPUTER PROGRAM NAME AilSYS04V DESIGN RECORD FILE NO.
ABSTRACT G. C. Mok 523 I
I I
B13-01277 NAME COMP DATE REV. NO.
APPLICATION STATEMENT ANSYSO4 is a large scale, general purpose finite element computer program with inter-active capabilities. The program is an expanded version of the ANSYS03 computer program.
The additional capabilities in ANSYSO4 are the interactive capabilities, several new finite elements, and analysis options. ANSYSO4 operates on the VAX computer while ANSYS03 runs on the Honeywell computer.
The ANSYSO4 options shown in Table 1 are acceptable for design use and have been verified.
Use of all other options for design is also acceptable provided the results are independently verified in accordance with E0P 42-6.00.
The analysis method is based on standard displacement formulation of the finite element method.
Users of this program should have some educational background and work experience with the finite element method.
Previous experience is recommended for correct use of the nonlinear analysis option. The user is responsible for determining whether the models are appropriate for the application and that correct results are produced.
PROGRAM DESCRIPTION INPUTS OtfrPUTS Finite element model geometry, Finite element geometry plots. Analysis material properties (mechanical or rc: ult plet:, mechanical Sfe-:thn:,
thermal), structural loadings or forces and stresses, temperature thermal conditions, distribution (for heat transfer analysis only).
I DOCUMENTATION See attachment.
l COMPUTER REQUIREMENTS The ANSYSO4 program is available on the VAX computer and has interactive capabilities.
G.C. Mok
(,h L 12/19/84 PREPARED BY:
(PRINT NAME AND SIGN)
DATE j
I 4
Table 1 Analysis Gecmetry Elements Heat Transfer 1-30 Frames STIF 31,32,33,34,35,56,66 (Key = -1) 2D or Axisym. Solids STIF 31,32,34,55,67,71,75,77 3D Solids STIF 31,33,34,57,68,69,70,71 Static Analysis (Key = 0)
Elastic l-3D Frames STIF 1,3,4,8,9,10,12,23,27,29,58 Shells STIF 11,41,43,63 2D or Axisym. Solids STIF 25,42,54,61,82 3D Solids STIF 44,45,52 Static Analysis (Key = 0)
Elastic-1-3D Frames STIF 1,20,23 Plastic
- Shells STIF 48 2D or Axisym. Solids STIF 42 3D Solids STIF 45 Mode-Frequency Response Spectrum l
(Key = 2) i Elastic 1-3D Frame SFIF 1,3,4,9,10,14,21,40 Shells STIF 11,43,63 2D or Axisym. Solids STIF 25
)
(
- Iterations required with the same or new stiffness matrix.
i i
o 6
Table 1 (Continued) 1 Analysis Gecmatr/
Elstents Non-Linear Transient-Dynamic (Key = 4) 1-3D Frame STIF 8 Elastic 2-3D Frames or STIF 21,40 2D Axisymetric STIF 40 Elastic-1-3D Frame STIF 1,21 Plastic
- Linear Transient-Dynamic l
(Key =5)
Elastic l-3D Fram STIF 1,3,14,21,40 Feduced Harmonic i
(Key = 6) f Elastic 2-3D Fram STIF 1,14,21,40
- Iterations required with the same or nea stiffness matrix.
1 i
t
,--~,-,,,.n-.,_-_,.,,.,--,n,
,_,--n
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m n.
,--~.n-,,
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e S c.
f APPLICABLE DOCUMENIS i
1.
User's Manual:
"ANSYS-Engineering Analysis System User's Manual for ANSYS Revision 4.0,"
G. J. DeSalvo and J. A. Swanson, Swanson Analysis 1
Systems, Inc., 1982.
i 2.
Exanple Manual:
"ANSYS-Engineering Analysis Syste Exanple Manual," by G. J. DeSalvo and J. A. Swanson, Swanson Analysis Systems, Inc., April i
1975.
i i
I 3.
Verification Manual:
"ANSYS-Engineering Analysis System Verification f
Manual," by G. J. DeSalvo, Swanson Analysis System, Inc., June 1976.
l 4.
B. J. Branlund, "ANSYSO4 Software Managment Plan, Revision 0," February 2
1 1984.
(DRF #B13 01272) i I
5.
B. J. Branlund, "ANSYSO4 Hardware / Software System Specification,"
I.D. No. 5230022, Revision 0, February 1984.
(DRF #B13 01272) 1 6.
B. J. Branlund, "ANSYSO4 Software Test Report," Revision 0, June 1984 (DRF #B13 01272) 7.
G.C. Mok and B. J. Branlund, "Sunmary of Results of ANSYSO4V l
i Verification," Istter report, SASR, (Structural Analysis Service Report) 84-57, December 1984.
i 8.
B.J. Branlund, "ANSYSO4V Engineering Cmputer Program," Revision 0, Decenber 1984.
(DRF #B13 01272)
I 9.
B.J. Branlund and G.C. bbk, "ANSYSO4V User's Manual," Istter to ANSYS Users, Decenber 20,1984, (Iatter Number BJB-84-05).
I
-16.i-VERIFICATION PROBLEM NO. 16 TITLE:
Bending of a Solid Beam.
TYPE:
Static analysis (K20=0), plane stress elements (STIF42).
REFERENCE:
Roark (Ref. 6), Pages 104,106.
. PROBLEM:
A beam of length L and height h is built-in at one end and loaded at the free end with 1) a moment M, an.d 2) a shear force F.
Determine the deflection 5 at the free end and the.bencing stress c I in. fr m the wall.
8end h
M l
4 F
/
g
/
i
/
f
/
/
/
I L
Case 1 Case 2 AY L
q 1) 12 I3 Ib 15 16 4:
G G
G h
f
- p
- 1 x
2 3
4 5
6 Finite Element Model GIVEN:
L = 10 in, h = 2 in, M = 2,000 in-lb, F = 300 lb,
?. = 30 x 100 psi.
MODELING HINTS: The stiffness matrix formed in the first load step is also used in the second load step.
The end moment is represented by equal and opposite forces separated by a distance h.
9 9
-16.3-VERIFICATION PROBLEM 10. 16 (Continued)
SOLUTION COMPARISON:
I Case 1 l
Case 2 Bend' Psi 6, in a
6, in 0
8end, psi Theory,
0.005 3000.
0.005 4050.
ANSYS 0.005 3000.
0.00505 6050.
Difference None None 1.(5 None RUN TIME:
5 Central Processing Seconds C,E ran o\\vyhe$u hblSTh awSw hs ca h y
$6A l
ee
.)
I.
httachment 2
-33 1-VERIFICATION PROBLEli NO. 33 TITLE:
Thermal Stresses in a Long Cylinder.
TYPE:
Static, thermal stress analysis (K20=0), axisymetric plane elements (STIF42).
REFERENCE:
Timoshenko (Ref. 4), Page 234, Problem 1.
PROBLEli:
Determine the axial stress :,and the tangential (hoop) stress e at the inner and outer surfaces of the long thick-walled t
cylinder described in Verification Problem No. 32.
To b
X Y
k b
7 Y
+ a -~l 1: 13 14 15 16 17 18 11:
w_ _
X
/
y 1
2 3
4 5
6 7
8 q, T,
/
//
l
,., N o
/,-
@,/
_ - __ 4 Problem Sketch Finite Element Model 6
-5 GIVEN:
a = 0.1875 in, b = 0.625 in, E = 30 x 10 psi,G = 1.435 x 10 in/in oF, V = 0 3 MODELING HINTS:
Use the same model as developed for the thermal analysis.
Surface stresses are requested on elements 1 and 7.
The extra displacement shapes are suppressed.
Nodal coupling is used to insure synynetry.
a
-33 3-
'/CRIFICATION PROBLEM :10. 33 (Continued)
SOLUTION COMPARISON:
X = 0.1875 in X = 0.625 in a' Psi o ' P*i U
Psi a, psi G
t t
a Theory 420.
420.
-194.
-194.
ANSYS 417.
410.
-196.
-197 l,0.8%
Difference 2.5%
l.0%
1 5%
RUN TIME:
3 Central Processing Seconds Q 4mMt/S b lceae.
f resd+s g,w.
kere..
I i
Attachement 2
-38.1-
'/ERIFICATION PROBLEM NO. 18 TITLE:
Plastic Loading of a Thick-Walled Cylinder Under Pressure.
TYPE:
Static, piastic analysis (K20=0), axisynmetric plane elements (STIF42).
REFERENCE:
Timoshenko (Ref. 4), Page 388, Article 70.
PROBLEM:
A long thick-aalled cylinder is subjected to an internal pressure p.
For p = p l, the maximum pressure at which the e
wall remains elastic, determine the radial stress a and the r
tangential (hoop) stress a at locations near the inner and t
outer surfaces. For p = pW t, the pressure required to just bring the entire wall into a state of plastic flow, determine the effective stress a at the same locations.
fp PROBLEM SKETCH:
See Verification Problem No. 25
}
a i_
h U
y.p.
- a
)
I l i, 12 13 lh 15 16 E l l
,x y
8 y.p.
1 2
3 4
5 6
Stress-Strain Curve Finite Element Model 6
i GIVEN:
E = 30 x 10 psi, c
= 30,000 psi, v = 0 3, a = 4 in, b = 8 in.
YP CALCULATED INPUT:
pg = 12,990 381 psi, p lt = 24,011 32 psi.
Note, the u
theory available for this problem is based on the Tresca (maximum shear) yield criterion. ANSYS uses the Von Mises yield criterion. The pressures are calculated from the theory by using y.p./[T.
This procedure is sufficient to calculate T
=c y.p.
approximate loads but the resulting stress components should not be compared.
i MODELING HINTS:
Three intermediate loadings are input between p,j and pd t' The extra displacement shapes are suppressed, although it is not l
necessary to do so.
Nodal coupling is used to insure synmetry.
-38 3-
'/ERIFICATION PROBLEM NO. 38 (Continued)
DATA INPUT LISTING (Continued):
i i
L.
-2 0-10 10 M
0 N
E*lD 0
END P
1 1 16664 028 0
L
-2 0-10 10 M
0 N
EMD 0
END P
1 1 20337 675 0
L
-2
~0-20 1
M 0
u END n
END P
1 1 24012.
0 FINISH l
r 1
12 24 36 48 60 72 80 SOLUTION COMPARISON:
l Fully elastic:
X = 4.4 in.
X = 7.6 in.
c, psi c, psi a, psi o
psi
^
y e
y i
Theory
-9,984.
18,644.
667.
9,128.
ANSYS
-9,960.
18,682.
h64.
9,100.
Difference 0.24%
0.20%
0.827 0 31%
4 1
M gi;p rb @j
i
-38.h-VERIFICATION PROBLEM NO. 38 (Continued)
SOLUTION COMPARISON (Continued) l Fully plastic:
X = 4.4 in.
X = 7.6 in.
eff, psi Status a pf, psi Status c
Theory 30,000 Plastic 30,000 Plastic ANSYS 29,860.
Plastic 29,953 Plastic Difference 0.47%
None 0.15%
None RUN TIME: 60 Central Processing Seconds j
J
- -.-...,. - -,. - -,- - - - - - -,.. -. -.. ~ ~, -, - -.. -. -.. -..
BRAIDWOOD N0ZZLE ANALYSIS Figure 1 shows the location of the proposed grindout. The grindout is located at the nozzle to shell weld.
Figure 1 illustrates the section through which the ASME Code Section III analysis was performed (Reference 1).
This section considers a cut through the shell wall.
This section was considered since it was the limiting section as shown.
in Reference 2.
In Reference 2, the membrane stress for a section through the nozzle wall was 9.4 ksi.
Calculations in Reference I show that even with the 1" deep grindout, the area of reinforcement requirements are satisfied.
Therefore, the grindout is outside the area of reinforcement.
Furthermore, since the governing section with the highest primary stress is in the shell thickness, the appropriate classification for the stress through the section is P (Table NB-3217-1) under "Any Shell or Head".
It should also be noted that according to Section NB-3331-b of Section III, ASME Code (1973),
satisfaction of the area of reinforcement requirement assures compliance with NB-3221.1 (P ),
NB-3221.2 (P ) and NB-3221.3 (P +P ) in the vicinity of the openings g
g b and no specific analysis showing satisfaction of these stress limits is required.
REFERENCES 1.
"ASME Code Evaluation of the Braidwood Unit 2 Nozzle F to Include Effects of Proposed Grindouts".
General Electric Report MDEf41-0386 Rev. O, DRF A00-02669, February 1986.
2.
" Thermal / Mechanical Analysis of the Inlet Nozzle Report #5" for Westinghouse Nuclear Energy Systems, Rev.
1.
Performed by Babcock & Wilcox Company, March 1983.
i
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