ML20213F911
| ML20213F911 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 10/02/1986 |
| From: | BABCOCK & WILCOX CO. |
| To: | |
| Shared Package | |
| ML20213F823 | List: |
| References | |
| 32-1147602-02, 32-1147602-2, NUDOCS 8611170244 | |
| Download: ML20213F911 (30) | |
Text
b~.
BWNP 20697 (6-85)
DOCUMENT
SUMMARY
SHEET O Babcock &Wilcox a McDermott company DOCUMENT IDENTIFIER 32-1147602-02 TITLr 177 OTSG Tube / Sleeve Loads PREPARED BY: REVIEWED BY:
NAMr 6L (d6AT#ERLY NAMF F. fs a s P A o SIGNATURE - SiGNATURF G Q \
TITLF OO [M* bM bN- CATE /o /2./86 UTLE M(pvssory E g r DATE /#!1[b TM STATEMENT:
COST CENTER 308 REF. PAGE(S) /3O REVIEWER INDEPENDENCE b D b.
PURPOSE AND
SUMMARY
OF RESULTS:
Purpose:
Determine the maximum allowable defect for the sleeve and tube in the straight portion of the free-span roll expansion.
Resul ts: Both the sleeve and tube have been shown to be acceptable with a defect depth of 70% of wall thickness.
Revision 2 of this document revised or added the following pages:
1,130, D1, D2, D4, D9, D10, D15 thru D28.
l
\ ((2 SIDE" s
$\ho@gTAPl ,
x{ON THE FOLLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT:
CODE / VERStoN / REV CODE / VERSloN / REV 8611170244 861031 3 PDR ADOCK 0500 P
PAGF I OF /)/
DOS 21036 3 (9 84) s.acoen a wncox GENERAL CALCULATIONS Nuclear Power Division occ. ' o 3 2 - 114 76 0 2.- QX 2
- 30. Draft Regulatory Guide 1.121 dated August 1976, " Basis For Plugging Degraded PWR Steam Generator Tubes," United States Nuclear Regulatory Commission, Washington, D.D. 20555.
- 31. Letter Report, " Collapse Tests on Intentionally Damaged Alloy 600 OTSG Tubing," Alliance Research Center, LR:76 :2341-74 :1, Babcock & Wilcox Company, April 20, 1976, ARC Corporate Information Services Library.
- 32. Microfilm Roll No. 80-12, " Sizing Calculations for Steam Generator,"
620-0008-55.
- 33. 51-1164748-00, "0TSG Mechanical Sleeve Expansion Dimensions," J. A. Lauer, Septembe r 24, 1986.
l t
l i
l PREPARED sy DATE REvtEwtD SY O b, DAfg / ! P AGE No.
q
, a*
PDS.21036 2 (2.sg Babcock
& Wilcox GENERAL CALCULATIONS Utility Power Generation Division .o c. , . 3 2 - 114 7 6 0 2.- OXP.
Appendix D Sleeve Plugging Criteria The present base ISI Program requires plugging of any steam generator tube with a defect indication of 40% or greater through wall. This was based on the possibility of defect growth occurring on tubes with previous wastage on the tube outside diameter above the tubesheet. For OTSG siaeves, the same requirement is considered appropriate.
This appendix describes the calculations perfomed to detemine the minimum acceptable wall thickness for degraded sleeves. The acceptance criteria of NRC draft Regulatory Guide 1.121, Ref. 30,and the ASE Boiler and Pressure Vessel Code, Ref.10, were used to establish allowable stress and pressure limits. The actual stress or pressure applicable to each of these categories was c:r.puted as a function of wall thickness and compared to the proper limit.
The objective was to detemine which category was limiting and the wall thick-ness comparable to this limit.
The analysis uses the procedures and results reported in Ref. 8 for OTSG tubes, OTSG tube failure tests results reported in references 28 and 31 3 statistically determined nominal tube wall thickness, and the dimensions of defects found in operating OTSGs.
i entraseo er b .are /# b enviewro or V care /*Wb Paar wo ~! j y
.=
PD8 21036 2 (2 go '
Babcc.ck
. .. ..... & Wilcox
......' GENERAL CALCULATIONS !
Utility Power Generation Division .oc. , e 3 2 - 114 7 6 0 2'- OX2 Results Minim m Defect Depth, Critical Criterion Thickness % of wall in Accident Inches 0.047" sleeve Condition Monnel Operation Pm i Sy -
3 ap i Pb -
[a(Pm+Pb+Q)13Sm.
(Usage Factor 11.0 j Faulted Conditions Pm 12.45m, 0.7 Sm AP iPb aP 1 09 Pc Pm + Pb 1 36 Sm i Prim ry Plus Thermal
'a p 2 + Pax92
!.E Ei l The minimum wall thickness for the sleeve for the type . defects analyzed in l
section 6 of Ref. 8 is approximatle) 'of the original vall
- thickness. The limit results from
,,,,.... .. 4M e. /"h*
l 1
u ws ..,, azac -
..o. o D-E l .
P 0 5 2103 6.2 (2 84l Babcock & Wilcox GENERAL CALCULATIONS Utility Power Generation Division o o c. i.o.
Minimum Wall Thickness for Normal Operation '
Minimum acceptable wall thicknesses for degraded 0TSG sleeves that' satisfy the criteria of draft Reg. Guide 1.121 (Ref. 30) will be determined.
Primary Membrane Stress Paragraph C.3a (1) of Ref. 30 states that the primary membrane stress intensity may not exceed the yield strength of the tube material at operating temperature (Pm <cy).
The worst-case normal operating conditions are:
Primary temp. , OF =i Primary press. , psi =
Secondary press., psi =
l Letting AP = primary to sec. press. differential =
~
P = primary plus secondary press. =
R = inside radius =
l cy = minimum yield strength from Ref. 10 at 600UF
= 27900 psi apR
- t. = ,
min ey .5p
~.
This represents of a sleeve with a wall thickness of /
Therefore, a through -wall defect would be acceptable.
l l 1 5/,7y a DOC. NO. 32- \ \h'ILO2-00 atoewto av /T Muunin o,1, 6/l[8f PAGE NO. 5 I t
1
P D $ . 21034. 2 12., 41
^
Babcock & Wilcox -
. m o..... ......, .
GENERAL CALCULATIONS Utility, Power Generation Division ooc. ,.o. 1 76 02 -M Burst Pressure Paragraph C.2.a(4) of Ref. 30 states that tne margin of safety against tube rupture under normal operating conditions should not be less than three
~'
(pb >_3ap = B&W has obtained burst pressures for 0.628 OD X 0.038-inch-wall test specimetis which are reported in Ref. 28. The types of defects analyzed in section 6. of Ref. 8 corresponds more closely to the B&W tests. Therefore, this type of defect will be used to establish the burst pressure limit for the sleeve.
From Ref. 28, the B&W test specimens burst pressures were t The resulting stress in the tube is:
'~
o = pR,t ,
t' Assuming the sleeve has comparable material, the minimum wall thickness for the s13 eve is:
t= b=.G w,, -
- This thickness corresponds to a tube wall thinning of t _
which indicates that ____ 1 1
l
! 173 cnclusion, the burst pressure capability of the sleeve l .
t s
,,,...:o ,, AdG ,,,,a M ss
,,,,.... ,,_ S/? -
o.u Ahm ....... o-4
PD5.21036.2 [2.ao Babcock & Wilcox
...o..........., GENERAL CALCULATIONS Utility Power Generation Division ooc. i o.
Minimum Wall Thickness for Faulted Conditions The acceptance criteria of paragraph C.3.a(3) of Ref. 30 will be used to establish minimum wall thicknesses for postulated accident conditions.
Primary Membrane Stress The primary membrane stress intensity is limited to the lesser of 2.4 Sm or
.7 au. Using minimum properties of inconel 600 sleeve material at 650 F from Ref. 10, these limits are:
2.4 Sm = 2.4 (23300) = 55920 psi e- use
.7 au = .7 (80000) = 56000 psi The worst-case accident conditions for primary membrane stress occur For a pressure differential of 2672 psi (Ref. 8, para. 6.3.1), the operating conditions are Then, p = primary plus secondary pressure R= inside radius =
l and the minimum thickness is :
=
apR _
t min 2.4 Sm .5 p i
This thickness represents I
through-wall defect would be acceptable.
h///gg DOC,No. 32-J147402-oo PitPAREo $Y /$/
si m wie i, 0 M h n v>1 o,,, S///84- . . . . . . D-5 l
l' -
, o mi a . . . . . . .,
Babcock & Wilcox GENERAL CALCULATIONS l Utility Power Generation Division o,c. to.
Burst Pressure Ref. 30 states that the ultimate burst pressure should not be exceeded by any accident condition pressure loading ( pblap from Ref. 8). Since the sleeve was shown to have a burst strength capability f(page D-t ), this criteria is satisfied.
Collapse Pressure Reference 10 states that during a LOCA where there is external pressure-loading on the tube, the pressure differential must not exceed 90% of the collapse pressure (0.9 pc 3ap Collapse pressures have been obtained by B&W for 0.628 OD X 0.038-inch wall test specimens. From Table 4 of Ref. 31, Curve A (OTSG tube) and Curve B (sleev?) on page D-13 are plots of the external pressure which will cause a yield stress in a circular geometry having various amounts of ellipticity. These curves are based on equations from Ref. 27 and show that the sleeve can sustain i
Curve C on the same page is based on collapse data form Ref. 31 for an OTSG tube having a machined flat which reduces the wall thickness. This reduced A comparison of Curves C and A indicates that at re,PAE,0 ,Y K gggg 5!/ / DOC. NO. 32-114-74,02-00
,,,,,,, ,, M Ann . , , ems + , , , , , , 0-t
Pos.21036 2 (2. 8 4)
Babcock & Wilcox GENERAL CALCULATIONS Utility Power Generation Division ooc. to.
The maximum % ellipticity for the sleeve is specified as*
If this is combined with This value is about i The total margin of safety for the sleeve should be appreciably greater than this amount.
Primary Membrane Plus Bending Stresses From comparison of the OTSG tube loads for faulted conditions (see Table 5-7 of Ref. 8), it is concluded that the maximum loads The maximum primary pressure.
This assumption results in conservative stresses. It will be shown that a sleeve will satisfy the primary membrane plus bending acceptance criterion (Pm + Pb < 3.6Sm). The loadings to be considered from Ref. 8 are as follows:
Primary pressure Secondary pressure ener.a.o av o,,,
//8 y. DOC.No. 32-114-7602-00 a...... ,, Mhm o.,, Shh+ . . . , . . . D-7
P0 5.21036 2 (2.841 Babcock & Wilcox GENERAL CALCULATIONS
. ..D.....,......,
Utility Power Generation Division ooc i.o.
Primary-to-secondary pressure differential op
" Initial condition" axial tube load from pressure and preload f axial tube load =
bending moment =
Axial =k+(M-yp){
Ref. 8 page 6-7 shows this term for the tube to be positive and its value about 1/4 of the hoop stress. Assuming similar ratios for the sleeve, the axial stress will not effect the magnitude of the SI and its value is not required.
Hoop = APg Radial = .5 (primary + secondary pressure) (
S I < 3. 6 Sm =
SI = ch - or l
This thickness represents la sleeve with a wall thickness '.
Therefore, av 6through-wall defect would be acceptable.
PRtPARED SY ik Daft S///6y Doc. No. 32-ll+7402-00 f
RivitWED gy Daft P AGE NO.
PD S 31030.2 12.84:
Babcock & Wilcox GENERAL CALCULATIONS Utility Power Generation Division ooc. , o 32-1147602-02 Primary Pl.s Thermal Stresses Ref 30 states that pressure and thermal loads must be considered in determining tube plugging limits for postulated accident conditions. It further states that these loads be accomodated within the faulted condition stress-limits of Appendix F to the ASME Code, Ref. 10. Appendix F prescribes stress limits only for primary stresses; are defined by Ref.10 [ Paragraph NB-3213.13 (a)] as secondary stresses and thus do not lend themselves to scrutiny under the rules for faulted conditions. Indeed, Ref. 10 states (paragraph NB-3213.9) that one application of a secondary stress is not expected to cause failure.
To account for these thermal loads, tube defect limits were based on B&W ten-sile tests, Ref. 28 fn which tube specimens with machined defects are pulled 3
to failure by tensile fracture. The following has been extracted from Table 4 of Ref. 28 and is limiting for the defects analyzed in section 6.
Percent Thinning U1timate Tensile Defect Geometry 0.038-in. wall force, Ib The calculations on page D-Ik show that l
l
,R, PAR,o SY o AT,
,,,,.... 8, A,W o.,, /oh/a ..., ,o P - 7
P D S. 210 3 6. 2 12. 8 4 p Babcock & Wilcox GENERAL CALCULATIONS Utility P. wer Generation Division o o c. , .. 32-1147602-02 Before comparing the limit to the calculated axial load, it should be adjusted to account for the effects of internal pressure. From Table 3 of reference 28,-
of the types analyzed' in Ref. 8, section 6. This pressure is also applicable to the sleeve since it has previously been shown (page D ) that ttre The effects of external pressure ultimate tube load at fracture.
In order to analytically combine the results of the separate burst and tensile tests, an elliptical failure curve is assumed:
where: ap = primary to secondary pressure differential (from Table 5-7 of Ref. 8),
pb= burst pressure, pax= calculated tube axial load (from Table 5-7),
pu = ultimate tensile load.
Applying this acceptance criterion to tubes the wall:
l l
PREPAttD SY gAfg / !2"!8G
.eviewio iv A ,I I eare /o/2/rs ,,,, y o D -/O l
PD$.21036.2 (2.8 4 Babcock & Wilcox
.D.,.... GENERAL CALCULATIONS
)
Utility Power Generation Division ooc. , ,
+
Acceptable wall thinning for primary plus thermal stresses is therefon PREPARED SV [k Daft
$/f/gy Doc.% 32-114 'l402-00 RivitWED sv Daft PAGE NO
Babccck&Wilcsx ros>'a7> o ai
. m ... .......
Nuclear Power Generation Division GENERAL CALCULATIONS M ac.Abd F la.1
_ E, uan t % .,q o x 4 j' ___ o . where I is */o+=
f -
a a y fobe wa> J reAcunug D , = .6%
- p,
. .l
[ T Assue we_.
a.n tilip Mcc I tube-mcudsin ed (tal re_s ults IE L
, \
P. I 'l Pi y \__ .h a
Po
- 6 k(Oo-D) I w ere De =
Do - ( t - I d = Po - (i - K 6) 1 "k "
Do - Do - b(I -X["
To be. 5 ceve.
- l~ Y No Po
-.2 P-s Test (l-E).
~
o 3gg,yg l encino .v h o,n 8/'9/S# ooc. no. 32- 1 I4'7/,02-00 nmwuo s, A Mnmon o,n $lIl84- race no. D-R
Babeock&Wilcox a s- > > = 7 > ii ' >>
Nuclear Power Generation Division GENERAL CALCULATIONS N
t l
l t
l l
...... o ., i<'ne. o.1, i /,e / a$ occ. ~o. 32-1147402-00
......... BAhan o.1, I/t/d4 .... . D-a
Babcock &Wilcox ras >an > o in Nuclear Power Generation Division GENERAL CALCULATIONS N
\
N
\
s N
\
\
\
\
N n u uro ., Atae o,n , /i, /sg ooc 32-1147002-00 nmmo ., A lI h n>A o,n N//Bh ..oi no. D-it
POS 21036-3 (9 80) s.scocu a wucox GENERAL CALCULATIONS
. - - .~.,
Nuclear Power Division o o c. i o.
32-1147602-02 Sleeve Thinning The maximum allowable defect in the sleeve wall at the straight portion of the free-span roll expansion is determined on the following pages. If the joint is completely tight the sleeve would benefit from the tube's structural rigidity and the allowable cefect would be larger than for the sleeve away from the joint.
Howeve r, it will be assumed the upper free span joint leaks allowing the secondary side pressure to penetrate the joint and the sleeve looses all contact with the tube.
The same analysis presented on the previous pages of this Appendix will be repeated using dimensions for the sleeve at the straight portion of the free-span roll expansion.
33 Referenceggives typical, maximum, and minimum dimensions for the free-span expansion joint. The minimum expanded sleeve thickness and the maximum expanded sleeve inner diameter will conservatively be used in the following calculations.
pa can,o av b oar, Mbb5 a..... , A,& o.1, "A /n ....~o o-/r
, n , , . m . ,, . . ,
Babcock
. ..o.....
& Wilcox GENERAL CALCULATIONS
[ Utility Power Generation Division see i.e.
3 2 - 114 7 6 0 2.- OX a Results Miniman Defect Depth, Critical Criterion Thickness 5 of wall in Accident Inches 0.0431" sleeve Condition Normal Operation Pm i Sy -
3 ap i Pb e
b a(Pm + Pb + Q) 1 3 Sm),
( Usage Factor 1 1.0 j Faulted Conditions Pm 12 45m, 0.7 Sm AP 1Pb AP < 0.9 Pc Pm + Pb s3.6 Sm Prirt.ary Plus Thermal aP 2 + @ax92 by
[1 1
The minimum wall thickness for the sleeve at the free-span expansion joint for the type defects analyzed in section 6 of Ref. 8, is l
4
\
Petraero av DAtt enviewto av 5 satt k b0 Pact wo
~
,ol.2to36.2 12 Gal Babcock & Wilcox GENERAL CALCULATIONS I Utility Power Generation Division ooc. ..o 32-1147602.-027.
Minimum Wall Thickness for Nonnal Operation Minimum acceptable wall thicknesses for degraded 0TSG sleeves that satisfy the criteria of draft Reg. Guide 1.121 (Ref. 30) will be determined.
Primary Membrane Stress Paragraph C.3a (1) of Ref. 30 states that the primary membrane stress intensity may not exceed the yield strength of the tube material at operating temperature (Pm < cy).
The worst-case normal operating conditions are:
Primary temp. , F=
Primary press. , psi =
Secondary press., psi Letting AP = primary to sec. press. differential P = primary plus secondarv nress. =
R = inside radius = f' oy = minimum yield strength from Ref. 10 at 600 0F
= 27900 psi
=
apR ,
t
. min e .5p This represents of a sleeve with a wall thickness of Therefore, a through -wall defect would be acceptable.
.. ... o ., J#4) o ,, /,/de6
...,.... .. AR e .1, /oh/F6 __,. o. ~ e___ D-O
FD$.21036 2 (2.3g6 Babcock & Wilcox
. -.o...... ......'
GENERAL CALCULATIONS
( Utility Power Generat. ion Division ooc , o 3 2 - 114 76 0 2.- OYE Burst Pressure Paragraph C.2.a(4) of Ref. 30 states that the margin of safety against tube rupture under normal oper'ating conditions should not be less than three (pb > 3ap = , B&W has obtained burst pressures for 0.628 OD X 0.038-inch-wall test specimens which are reported in Ref. 28. The types of defects analyzed in section 6 of Ref. 8 corresponds more closely to
'the B&W tests. Therefore, this type of defect will be used to establish the burst pressure limit for the sleeve.
From Ref. 28, the B&W test specimens burst pressures were above The resulting stress in the tube is:
o = pR 3 ,
t l Assuming the sleeve has comparable material, the minimum wall thickness for the sleeve is:
t=9'= 0 This thickr.ess corresponds to a tube wall thinning of-which indicates that th-In conclusion, the burst pressure capability of the sleeve with 5 l
,,,,,,,, , - Af4) o,,,10 M 86
.mmut E em mh/& ...~e B -/ 8
D0 5- 210 30 2 12. 4)
Babcock & Wilcox mio.........,..,
GENERAL CALCULATIONS
(
Utility Power Generation Division ooc. , ,
32-1147602.-022, Minimum Wall Thickness for Faulted Conditions The acceptance criteria of paragraph C.3.a(3) of Ref. 30 will be used to establish minimum wall thicknesses for postulated accident conditions.
Primary Membrane Stress The primary membrane stress intensity is limited to the lesser of 2.4 Sm or 0
.7 ou. Using minimum properties of inconel 600 sleeve material at 650 F from Ref. 10, these limits are:
2.4 Sm = 2.4 (23300) = 55920 psi e- use
.7 au = .7 (80000) = 56000 psi The worst-case accident conditions for primary membrane stress occur For a pressure differential of 2672 psi (Ref. 8, para. 6.3.1), the operating conditions are Then, p = primary plus secondary pressure R= inside radius =
and the minimum thickness is :
ApR "
tmin " 2.4 Sm .5 p This thickness represents through-wall defect would be acceptable.
.. ... ., MMd ,,,, /o/v/S6
...o.,
f3 o 1, <ofz/F4 ,,c, o c D -/ 9
PoS 21030 2 (2 80)
Babcock & Wilcox GENERAL CALCULATIONS 602.-RE
< Utility Power Generation Division ooc. to.
Burst Pressure Ref. 30 states that the ultimate burst pressure should not be exceeded by any accident condition pressure loading ( pb > from Ref. 8). Since the sleeve was shown to have a burst strength capability (page D- l8), this criteria is satisfied.
Collapse Pressure Reference 10 states that during a LOCA where there is external pressure loading on the tube, the pressure differential must not exceed 90% of the collapse pressure (0.9 pc-'ap Collapse pressures have been obtained by B&W for 0.628 OD X 0.038-inch wall test specimens. From Table 4 of Ref. 31, a Curve A (OTSG tube) and Curve B (sleeve) on page D-13 are plots of the external pressure which will cause a yield stress in a circular geometry having various amounts of ellipticity. These curves are based on equations
, from Ref. 27 and show that the sleeve can sustain l
l Curve C on the same page is based on collapse data form Ref. 31 for an OTSG tube having a machined flat which reduces the wall thickness. This reduced
( A comparison of Curves C and A indicates that at PR, PAR,o SY gggg 8,....., ,, GF5 V
o.,, dz / h. ...,,,, b -2 o
,05.2 036.2 12. e d Babcock & Wilcox GENERAL CALCULATIONS Utility Power Generat.ion D.ivis . ion o o c. , o 3 2 - 114 7 6 0 2.- 0XE The maximum % ellipticity for the sleeve is specified as If this is combined with l
- psi. This value is about The total nargin of safety for the sleeve should be appreciably greater than this amount.
Primary Membrane Plus Bending Stresses From comparison of the OTSG tube loads for faulted conditions (see Table 5-7 of Ref. 8), it is concluded that the maximum loads The maximum primary pressure /
This assumption results in conservative stresses. It will be shown that a sleeve will satisfy the primary membrane plus bending acceptance criterion (Pm + Pb < 3.6Sm). The loadings
( to be considered from Ref. 8 are as follows:
l l
l Primary pressure ='
Secondary pressure =
( -.
.. ... ., MMU ,,,,/oh/S6
....o., M e.,, m/z/h ..o,~e D - 2. /
PD5 21033 3 (9 84)
Babcock & Wilcox
- """~~"'
GENERAL CALCULATIONE Nuclotr Power Division o o c. i.o.
3 2 - 114 7 6 0 2.- Ok&
Primary-to-secondary pressure dif ferential p=_
" Initial condition" axial tube load from pressure and preload _
l axial tube load bending moment =
l A sleeve with a defect at its outer surface (worse location) will be subjected to n /C- hs
/\ / .
'r s
.N/
t,
/. , v.t
~
( i\ R ,.7
\
Eo ,
\
e, -
) x x
\
\ l 1 Y
i I v \
\
4 /
i
\,\ \
/
~ j i
ea,e.... ey o,,, /8 N M55 ..,, e /v F e . ...,~o D - 2 2-
. . . . . . . . s.
o
PDS 21036 3 (9 84)
Babcock & Wilcox 4 MCDermott CotMpany GENERAL CALCULATIONS Nuclear Power Division o o c. i.o. 3 2 - 114 7 6 0 2.- Ok7 (1)
(2) 4 h
t (3)
(4) l l
,,,,.... .. JAJ o.,,/oA/S6
, , , , . . . . ,, des o ,, ub/?A ,. , ,o. o-z2
PDS-21033-3 (0-Q4) s.w.ca a wisco,
~~-~"'
GENERAL CALCULATIONS Nuclear Power Division oc c. i o- 3 2 - 114 76 0 2.- 03r1 (5) ,
(6)
T (7) rear.nto sv o.it
,,,,, ,,, ,, acs ..,, dz / & ...~o. D'E+
fl
PDS 21036 3 (9 Ed)
Babcock & WHcox
"'" ~ '** '
GENERAL CALCULAT10NS Nuclear Power Division o,c. to 3 2 - 114 76 0 2.- Ok&
F Hoop = apR Radial = .5 (primary + secondary pressure) i S I < 3. 6 Sm =
SI = ch - or =
This thickness represen+.s ) a sleeve with a wall thickness of Therefore, a through-wall defect would be acceptable.
PE PAR,0 SY DAT, E,...... ,, ws U
..,, ~NPc . . . , ~ , o-1r
P D S - 210 3 4. 2 12. 0 4l Babcock & Wilcox GENERAL CALCULATIONS Utility o er Generation Division ooc . D 6 0 2.- WE Primary Plus Thermal Stresses Ref 30 states that pressure and thermal loads must be considered in detemining tube plugging limits for postulated accident conditions. It further states that these loads be acconmodated within the faulted condition stress limits of Appendix F to the ASE Code, Ref.10. Appendix F prescribes stress limits only for primary stresses; I
Ref. 10 (Paragraph NB-3213.13 (a)] as secondary stresses and thus do not lend themselves to scrutiny under the rules for faulted conditions. Indeed, Ref. 10 states (paragraph NB-3213.9) that one application of a secondary stress is not expected to cause failure.
To account for these themal loads, tube defect limits were based on B&W ten-sile tests,Ref. 28,in which tube specimens with machined defects are pulled to failure by tensile fracture. The following has been extracted from Table 4 of Ref. 28 and is limiting for the defects analyzed in section 6.
Percent Thinning Ultimate Tensile Defect Geometry 0.038-in. wall force, Ib The calculations on page D-It show that PhtPAtt0 SY Daft etvitwt0 SY Daft PAGE NO
//
PD 5. 21036 2 12 e d i Babcock & Wilcox
. .D.............
GENERAL CALCULATIONS
<, Utility Power Generation Division ooc. to 3 2 - 114 76 0 2 - OX3.
Before comparing the limit to the calculated axial load, it should be adjusted to account for the effects of internal pressure. From Table 3 of reference 28, of the types analyzed in Ref. 8, section 6. This pressure is also applicable to the sleeve since it has previously been shown (page D- 16 ) that the The effects of external pressure ultimate tube load at fracture.
In order to analytically combine the results of the separate burst and tensile tests, an elliptical failure curve is assumed:
i where: Ap = primary to secondary pressure differential (from Table 5-7 of Ref. 8),
(
pb= burst pressure, p,x= calculated tube axial load (from Table 5-7),
pu= ultimate tensile load.
Applying this acceptance criterion to tubes with thinning extending 70% through the wall:
(
1 Pat,AlfD BY Daft l 8 m...D ., pFs ,,,, ferz/a, ...,~o D-27 1
r PD$.21036 3 (9 84)
Babcock & Wilcox GENERAL CALCULATIONS
- * ~ ~ '
Nuclear Power Division occ. i o- S 2 - 114 7 6 0 2.- 0X2 Acceptable wall _ thinning f_or primary plus thermal stresses 1s therefore A
Tube Thinnino Jhe_f_teeyspan__,rp l 1.__ expansion of_the sleeve will.cause some plastic deformation of the _ tube._ . Re.fe rence M .1.ndicates_ the. tube. 00
_t r
8 I
e 7 h
..e . -e _ ,
i
,,,,n ,o ,, J Wk) oc, loh/86
,,,,...o ,, W5 ou, /o/a/% ,o,~o 6 -L S