ML20245B875
| ML20245B875 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 04/30/1989 |
| From: | Chang K, Coslow B, Mel Gray WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| To: | |
| Shared Package | |
| ML19297H576 | List: |
| References | |
| WCAP-12152-S01, WCAP-12152-S1, NUDOCS 8904260336 | |
| Download: ML20245B875 (21) | |
Text
. #
WESTINGHOUSE PROPRIETARY CLASS 3 WCAP-12152 Supplement 1 J'
ADDITIONAL INFORMATION IN SUPPORT OF THE ASSESSMENT OF THERMAL STRATIFICATION FOR THE SEABROOK UNIT 1 PRESSURIZER SURGE LINE M.k. >"
APRIL 1989 Verified by: //#
K. C. Chin'g'
/ Verifiedby:/ W
/ 5. A. Swamp Approved by: N M N J4 V N f,f G~. R. Ellis,' Manager Approved by:/5 '. S'. Pal >
apy,< Manager df>,
Structural Engineering & Structural aterials Piping Technology Engineering Work Performed Under Shop Order NGXP-961 4
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WESTINGHOUSE ELECTRIC CORPORATION l Nuclear and Advanced Technology Division P.O. Box 2728 -
- 2'**
Pittsburgh, Pennsylvania 15230-2728 - - - - - . =
/ C/ 3
TABLE OF CONTENTS Section Title ,
1.0 INTRODUCTION
2.0 THERMAL TRANSIENT ASSESSMENT 2.1 Heatup and Cooldown Procedures 2.2 Preliminary Monitoring Program and Results 3.0 ASSESSMENT OF PIPING LAYOUT 3.1 Comparison with Analyzed Plants 4.0 FEASIBILITY OF DEMONSTRATING ASME CODE ACCEPTABILITY 4.1 Pipe Stress 4.2 Support Loads 4.3 Fatigue Life -
3683s/D2304910 q
SECTION
1.0 INTRODUCTION
WCAP 12151 provided an assessment of thermal stratification for the Seabrook Unit 1 Pressurizer Surge Line for the purpose of evaluating ASME Code compliance prior to performing a detailed plant specific analysis for thermal stratification. The assessment was based on a comparison of the Seabrook Unit 1 surge line with that of several other plants for which detailed plant specific analyses have been performed and is supported by a limited Seabrook-Specific Finite Element Structural Analysis and Thermal Monitoring Test. This comparison included the following: f.
o An assessment of thermal transients based on Seabrook operating procedures and surge line monitoring data.
o A general assessment of the Seabrook surge line piping layout and geometry.
o An assessment of pipe stress, support loads, and fatigue life based on an enveloping case structural analysis of the Seabrook surge line.
Based on this study, it was judged that a detailed plant specific thermal -
stratification analysis of the Seabrook Unit 1 surge line will demonstrate .
compliance with all applicable ASME Code requirements.
On March 27, 1989, New Hampshire Yankee and Westinghouse discussed WCAP 12151 with the NRC staff. During this discussion, the Staff requested additional information regarding the comparison of the Seabrook surge line with those for ,
which plant specific analysis has been performed.
The purpose of this supplement is to provide the additional information ,
requested by the Staff. Detailed information is provided comparing the ,
Seabrook surge line to four plants (designated as Plants A, B, C, and D) for which detailed plant specific surge line thermal stratification analyses have been performed and results presented to the Staff.
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SECTION 2.0 THERMAL TRANSIENT ASSESSMENT 2.1 Heatup and Cooldown Procedures' Table 1 presents a comparison of various Seabrook Unit 1 operating parameters with those for Plants A, B, C, and D. This table demonstrates the operational similarity of Seabrook and plants for which plant specific analysis has been performed. [
3a,c.e 2.2 Preliminary Monitoring Program and Results Table 2 presents a comparison of the Seabrook thermal monitoring results with those for Plants A, B, and C. Plant D has not yet performed monitoring of the surge line. This table compares the maximum temperature differences measured during heatup of the plants. This table demonstrates that, based on monitoring results from one heatup, the Seabrook Unit 1 temperature differences are consistent with those observed at other plants and are less than those of the envelope transients which have been used for plant specific analyses.
I 3003s/C33389 to g
SECTION 3.0 ASSESSMENT OF PIPING LAYOUT . -
3.1 Comparison with Analyzed Plants Table 3 presents a comparison of the Seabrook Unit I surge line layout with that for Plants A, B, C and D.
As indicated in this table, the Seabrook Unit 1 surge line is basically similar to that of the other plants. [
3a,c,e
[
ja,c.e Table 3 also indicates that Seabrook compares favorably with respect to piping components which will cause intensification of thermal stresses.
Figures 1 through 4 present the layout of Plants A, B, C and D. The Seabrook layout is shown in figure 5.
3683s/031089 to 3
SECTION 4.0 FEASIBILITY OF DEMONSTRATING ASME CODE ACCEPTABILITY 4.1 Pipe Stress Specific comparisons made between Seabrook and other plants are shown in tables 4 through 7. Maximum resultant moments for [
]a,c,e and corresponding Equation 12 stresses at various locations are shown. At all locations, the Seabrook Equation 12 stress is below the allowable 3S, value. Equation 12 stresses were calculated using ASME Code stress indices in all cases [
3a c.e It should also be noted that different ratios of moment versus stress exist due to differences in pipe size, schedule, and nozzle geometry.
Equation 13 stress at the hot leg nozzle is affected by stratification loading [
[
ia,c e it was concluded that Eq.13 stress limits will be satisfied with a detailed evaluation.
4.2 Support load Support loads [ ]a,c e are compared in table 8 to original design thermal loads and support 3683s/033069 10 4 ..
- n. . . . .. ... -. .
4 capacities, where required. As can be seen, the Seabrook support capacities are adequate for.the' stratification' loadings.
~
1' L 4.3 Fatigue Life LThe maximum usage factor on Plants A, C and D occurred at [
'Ja,c.e For Plant B, the maximum usage factor occurred at [ ]a,c.e which does not exist in the Seabrook surge line. The usage factor is highly dependent on the' range of stress between' thermal cases, of which the maximum Eq. 12 stress is representative. Thus, since the Seabrook [ Ja,c.e Eq.
12: stress is less than that.for plants A and C and only slightly higher than plant D, it is judged that a detailed fatigue evaluation would show a total L usage factor less than the.l.0 allowable. For the maximum girth butt weld location, Seabrook Eq.12 is less than Plant B and slightly higher than the others,.and all have usage factors [ la,c,e For the 50 bend, SeabrookEq.12 is less than that of Plants A, B, and D. It is therefore concluded that the usage factor for Seabrook can be shown to be less than 1.0 with a detailed analysis.
Note also that, while usage factors are strongly affected by Eq. 12 stress, the fincl usage factor.is also dependent on material properties, pipe schedule, and component geometries. These factors have been considered in the comparison process.
Finally, for the pressurizer nozzle, fatigue is typically addressed [
Ja,c,e However, for Plant B, the pressurizer nozzle was re-evaluated for stratification thermal loads and was found to be acceptable. Therefore, since Seabrook Eq. 12 is less than Plant B, it was concluded that a detailed evaluation will show the Seabrook Preuurizer Nozzle to be acceptable for fatigue. '
3083s/040389 10 5
a,c.e
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FIGURE 1 - Pressurizer Surge Line (Plant A) 3683s'C3308910 g _ _
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l FIGURE 2 - Pressurizer Surge Line (Plant B) 1 s
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e a,c e FIGURE 3 - Pressurizer Surge Line (Plant C)
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1 FIGURE 4 - Pressurizer Surge Line (Plant D) 3M3s/C3308810 g
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TABLE 2 COMPARISON OF SEABROOK THERMAL MONITORING RESULTS WITH PLANTS A, B, C, D
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o TABLE 3 COMPARISON OF SEABROOK LAYOUT WITH PLANTS A, B, C, D
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TABLE 4 MOMENTS AND STRESS COMPARIS0N AT REACTOR COOLANT N0ZZLE -
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s TABLE 5 M0MENTS AND STRESS COMPARISON AT GIRTH BUTT WELD
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3683s/C33089 to 15 -
TABLE 6 MDMENTS AND STRESS COMPARISON AT SD BEND
- a,c.e t
i 3083s/033089 10 g
TABLE 7 HOMENTS AND STRESS COMPARIS0N AT PRESSURIZER N0ZZLE
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TABLE 8 ,
SEABROOK SUPPORT LOADS
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