ML20083A083
| ML20083A083 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 03/31/1990 |
| From: | Caine T, Ranganath S, Stevens G COMMONWEALTH EDISON CO. |
| To: | |
| Shared Package | |
| ML20082V318 | List: |
| References | |
| SASR-89-02-DRFT, SASR-89-02-DRFT-R02, SASR-89-2-DRFT, SASR-89-2-DRFT-R2, NUDOCS 9109240021 | |
| Download: ML20083A083 (25) | |
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4 S/sSR 89 02 Revision 2 DRT 137 0010 March 1990 VESSEL FATICUE EVALUATION CONSIDERING D.EVISED TitLRMAL CYCLES FOR QUAD CITIES NUCLEAR STATION UNITS 1 AND 2 1
Prepared by: bC v-t s T. A. Caine, Senior Engineer
. Structural Analysis Serviceo Verified by: . O t/ 1g[M G. L. itevens, Senior Engineer Structural Analysis Services Reviewed by: -
,/ ,
hO S. Ranganath, Manager Materials Monitoring &
Structural Analysis Services 7$ 99 3 gg ,
r.f,{9240021 ADOCE 05000 8 4 PDR
IMPORT, ANT NOTICE RECARDINC
. CONTENTS OF THIS REPORT -
PLEASE READ CAREITLLY This report was prepared by the General Electric Company. The information contained in this report is believed by General Electric to be an accurate and true representation of the facts known, obtained or provided to General Electric at the tirne this report was prepared.
The only undertakings of the General Electric Cornpany respecting information in this document are contained in the contract governing Commonwealth Edison Cornpany Purchase Order No. 327135 t,% 1 $ and nothing contained in this document shall be construed as changing said contract. The use of this inforrnation except as defined by said i contract, or for any purpose other than that for which it is intended, !
is not authorized; and with respect to any such unauthorized use, neither- General Electric Company nor any of the contributors to this document makes any representation or warranty (express or itoplied) ac to the completeness, accuracy or usefulness of the infortnation i contained in this document or that such use of such infortnation may not infringe privately owned rights; nor do they a s surne any responsibility for liability or damage of any kind which may result from such use of such information, t
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,' . . i
. I TABLE OF CONTENTS I
f.agt i 1.0 SUKdARY AND REC 0KMENDATIONS 11 i 1
2.0 INTRODUCTION
21 l
2.1 BACKGROUND
21 2.2 REPORT SCOPE 22 3.0 TECH!!ICAL APPROACH AND ANALYSIS 31 3.1 TECHNICAL APPROACH 31 3.2 COMPONENT ANALYSIS F0k SRVB CYCLE DETERMINATION 32 3.2.1 RECIRCULATION INLET 32 3.2.2 SHROUD SUPPORT 3+3 3.2.3 SUPPORT SKIRT 34 ,
3.2.4 FEEDWATER 34 3.3
SUMMARY
OF SRVB ANALYSIS RESULTS 36 3.4 EVALUATION OF REHAINING COMPONENTS 36 3.4.1 RECIRCULATION OUTLET 36 3.4.2 CORE SPRAY 37 3.4.3 CRD HYDRAULIC RETURN 37 ,
3.4.4 CRD PENETRATION 38 3.4.5 2" INSTRUMENT N0ZZLE 38 '
3.4.6 REFUELING CONTAINMENT SKIRT 38 3.4.7 CLOSURE FLANGE REGION 39
-3.4.8 VESSEL SHELLS 3 10 4.0 RESULTS 41 5.0- RFrERENCES- 51 111
1.0 SUMMnRY AND RECOMMENDAT10NS The current revision of this report summarizes the fatigue usage analysis performed for Quad cities Units 1 and 2 using the latest .
revision of the thermal cycles tabulation report (5 8). The fatigue usage analysis is based on the revised duty cycles, including 12 cycles of the safety relief valve blowdown (SRVB) event. Twenty cycles of SRVB vere previously included in Revision 1 of this report; !
however, due to the modifications included in (5 8), that number has
-been modified herein to twelve. This is the largest number of SRVB cycles that can be acconanodated without increasing any component fatigue usages above a value of 1.0. The numbers of cycles analyzed are shown in Table 1 1.
The analysis results, which are summarized in Table 17, show that the cumulative fatigue usage for the 40 year design life for the revised duty cycles is less than the allowable value of 1.0 for all components except the closure studs. The closure studs are replaceable, so the fact that the usage exceeds 1.0 before reaching 40
. years does not pose a major _ concern. The studs are periodically i subject to visual examination, but a more rigorous- inspection is recommended once the studs are predicted to have reached a usage of 1.0 which is in the year 1998. It is important to note that the studs d2 Dg1 have to be replaced upon react ,g a usage of 1.0.
The vesse1 support skirt, which had a fatigue usage slightly above one (1.07) in the Revision 0 analysis, was reanalyzed with current finite element methods, reducing the 40 year usage to 1.0, even considering 12 cycles of SRVB.
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Table 1 1 SUKKARY OF DESIGN BASIS AND PREDICTED CYCLES ,
UNITS 1 AND 2 UNIT 1 CYCLE UNIT 2 CYCLE NUMBER DE3ICN BASIS PREDICTION PREDICTION OP CYCLES .
I ANALY2EDb CYCLE DESCRIPTION ALLOVABLE YEAR 40a YEAR 40" Plant-Cooldown 119 286 274 286 Plant Heatup 120 292 275 298 Safety Relief- 1 6 1 12 l Valve Blowdown Reduction of Pcwer 119 $0 44 119 for Plant Shutdown * ;
Turbine Roll with 120 $0 44 120 +
Feedwater Injection" l Head Spray Injection 119 3 $ 119 l Loss of Feedwater 80 114 77 114 Heaters . Full Loss of Feedwater 60 6 42 80 Heaters - Partial ,
Loss of Feedwater Flow 80' 15 42 80 SCRAM 200 294 275 294 Butch-Feedwater $95 0 0 202 Addition During Hot '
Standby or Plant Cooldown l
' From Table 1 1 of [5 8], except SRVB cycles are from this report >
I Values'can replaceLdesign basis ~ cycles for all-components but closure studs. Events not shown are unchanged.
- No more of these cycles are expected, since this mode i of. shutdown and startup is no longer used.
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2.0 INTRODUCTION
2.1 BACKCROUND The reactor vessel was originally designed for fatigue to a set of thermal cycles, or design allowables. The original stress report [5 1) showed that the vessel and its components could withstand the designated number of cycles with a fatigue usage factor less than 1.0, as required by the ASME code. Based on a GE thermal cycle counting procedure [5 2), operating transient cycles through March 1988 were ' redefined using actual plant data for Units 1 and 2 [5 3). The method for predicting cycles through 40 years, as recommended b S11, 318 [5 4), resulted in some estimated cycle counts at year 40 that were somewhat higher than the original design basis. As seen h (5 1), cycle predictions for the heatup, cooldown, loss of feedwater heaters and SCRAM transients were predicted to exceed the original design basis within 40 years of operation. Revision 0 of this report recalculated the fatipe usage factors for the vessel and components based on the predicted cycles for 40 years from (5 3], showing usages ; above 1.0 for the support skirt and the closure studs. Revision 1 of this report included the effects of a new analysis
- of -- the support skirt which had been performed [5 5). That analysis showed the fatigue usage for the support skirt for the revised 40 gear rycle predictions to be less than 1.0, In addition, an estimatfor of the time for the closure studs to reach a usage of 1.0 was made, and the allowable number of rapid .cooldown events (asuctated with a stuck open relief valve) was evaluated. This was necessitated by the occurrence of a rapid cooldown event which occurred in April 1989 at Unit 1. This, along with a similar event in 1980, caused the design basis of 1 SRVB cycle to be exceeded. It was determined that a maximum of 20 SRVB cycles could be tolerated.
l 21 _ - -. - _ . . ... _ __. _ _ _ . . . . _ . ~ . _ _ . _ . _ , _ _ - . _ . _ _ . - . _ - . . _ _ . _ . _
4 There has been one development since Revision 1 of this report which has made it prudent to revise this report:
- The (5 3) report has been updated to accommodate some discrepancies found by CEto personnel in the cycle count totals; the revised tabulations are documented in [5-8).
2.2 REPORT SCOPE The 40 year cycle predictions from [5-8) are used to recalculate fatigue tsages for the Quad Cities vessel components. The new analysis results for the support skirt are used in place of the original stress analysis. For several ecmponents which have the , highest 40. year fatigue usages, the number of SRVB cycles that could be accommodated, keeping usage below 1.0, is determined. SRVB stresses, which in most cases were not computed in the original stress report, are determined by scaling stresses, for other analyzed transients, For the remaining components, the worst case usage associated with SRVB cycles is conservatively added to the 40 year usag.e. Since the fatigus usage of the closure studs is predicted to exceed 1.0 before 40 years, the time at which stud usage of 1.0 will be reached is determined. - 22
- l. ,
l . 3.0 TECHNICAL APPROACH AND ANALYSIS 3.1 TECHNICAL A>:r ACH The (5-1) stress report included a fatigue analysis for the reactor vessel compenents based on a set of design basis duty cycles. In this analysis, fatigue usage factors are recalculated based, in most esses, on methods found in the original stress report, but using the new 40 year cycle predictions as tabulated in [5 8). This approach resulta in the original design cycle numbers being applied for all but six trarsients. For Heatup, Cooldown, Loss of Feedwater Heaters and SCRAM, predicted cycles were increased, based on (5 8) results. Based on irput from Commonwealth Edison, the Batch Feedwater Addition During Ik t Standby or Plant Cooldown transient is not applicable for operation at Units 1 and 2, so the number of these cycles was reduced. The number of SRVB transients was increased from one cycle to tl.e maximum number possible without exceeding usages of 1.0 in any compc nent (except closure studs, which already exceed 1.0). Information from the original stress report was used for all but two components, the feedwater nozzle and the support skirt. For the ferdwater nozzle, a more recent analysis was available [5 6). Therefore, the feedwater nozzle reanalysis considered the [5-6) report, information concerning rapid cycling, removal of batch feodwater addit!.on cycles where appropriate, and the inclusion of the additional 40 year transient cycles in arriving at new fatigue usage factors. For the support skirt, results from the [5 51 fatigue analysis, which are based on the revised 40-year cycles, sere used. Specific calculations of stress and fatigue for the SRVS transient were performed for the recirculation inlet nozzle, the shroud support, the support skirt and the feedwater nozzle. These components were selected because of their high fatigue usage factors. i The allowable number of SRVB cycles was determined from these specific 4 analyses. For the remaining components, the SRVB fatigue duty was conservatively estimated as being equal to the worst duty of the analyzed components above. 3-1
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3.2 COMPONENT ANALYGIS FOR SRVB CYCLE DETERMINATION Based on the approach outlined in section 3.1, each reactor vessel component considered in [5 1) with a significant ' predicted usage factor, except for closure studs, was individually analyzed for fatigue usage for the revised duty cycles shown in Table 3 1. An evaluation was then done to estimate the number of SRVB cycles which resulted in a-total usage of 1.0, closure- studs were not considered here because the predicted usage exceeds 1.0 without SRVB cycles. The specific details for each component are summarized in individual sections below. 3.2.1 Recirculation Inlet The analysis of thie component included separate consideration of a LAS Nozzle, a Type 316 Safe End, and a Type-304 Thermal Sleeve. For this component, plant heatup/cooldown cycles and improper start were the transients analyzed in [5-1). Fatigue ucages resulting from the SCRAM and (full) loss of feedwater heater transients were nct considered in [5 1]. While the loss of feedwater heater transient cycles are in- fact negligible, the total number of cooldowns and heatups due to SCRAMS associated with the SCRAM and interruption of feedwater flow cycles were included in this reanalysia. The (5 " 4
. >wis showed very low usage for the safe end and nozzle. The , -po nalyzed stress range in [51), used to bound all transients was the combination improper start heatup. New fatigue usage values for both the nozzle and safe end were again conservatively calculated by dividing the total number of applicable revised duty cycles from Table 3-1 by the allowable number of cycles for this transient.
3-2
The thermal sleeve would have a usage above 1,0 if all cycles were " lumped" under the improper start-heatup allowable. Inst- d, only 10 cycles were counted under this transient. The stresses tor cooldown heatup in [5 1] were combined to get a stress range and allowable cycle value for startup shutdown, SCRAM and interruption of feedwater flow cycles. This approach resulted in the 40-year usage, without SRVB cycles, shown in Table 3 2. The SRVB stresses were evaluated by comparison with the improper start cooldown stresses. Analysis showed that the improper start stresses due to a step change cooldown are more severe than the SRVB ramped cooldown case, so the allowable for improper start heatup was used for the SRVB heatup allowable. The usage per cycle for this stress range and the number of SRVB cycles resulting in a total usage of 1.0 are shown in Table 3 2. 3.2.2 Shroud Suvoort The IAS vessel attachment of the shroud support legs was the only consideration in the analysis of this component. For this component, the plant heatup/cooldown cycle was the transient evaluated for stress range in {5-1]. In addition, one SRVB cycle was analyzed separately. Fatigue usages resulting from the SCRAM and (full) loss of feedwater heater transients were not considered in [5 1]. While the loss of feedwater heater transient cycles are negligible, the total number of cooldown heatup cycles associated with the SCRAM and interruption of feedwater flow cycles were included in this reanalysis. The stress range associated with SCRAM and interruption of feedvater flow was determined by scaling the raage for startup-shutdown by the ratio of cooldown temperature differences. The usage, without SRVB cycles, is shown in Table 3-2. The additional usage per cycle for the SRVB and the number of cycles at which :otal usage reaches 3.0 are also shown in Table 3 2. 3-3 ip
. .. - .- - _ - ~ - _- - __. _-. - . - . -
3.2.3 Succort Skirt After Revision 0 of-this report showed a usage just over 1.0 for the support skirt, an updated analysis was done using current finite element technology (5-5]. The heatup cooldown transient was analyzed,
. just as in the original stress report. Scaling the alternating stress of the heatup cooldown transient by the ratio of temperature i differences for the SCRAM and heatup cooldown transients, an alternating stress and associated number of allowable cycles for the SCRAM and interruption of feedvater flow transients was calculated.
- The usage for the revised 40 year cycles, reported in [5-5), was l determined to be 0,935 as giver, in Revision 1 of this report. That l
l usage total included the effects of 278 heatup/cooldowns, 281 SCRAMS and 80 interruption of feedwater flow events. For the current i analysis, the effects of the additional events given in [5 8] were I also included. The usage for the revised 40 year cycles (0.962) is shown '.n Table 3 2. The SR7B was not analyzed in (5 5), but the critical location determined from the finite element analysis is about two inches from l the vessel outside surface, or at least 8 inches from the vessel coolant. Therefore, the rapid cooldown portion of the SRVB transient to 375'F, followed by cooldown at 100'F/hr to 100*F causes no worse stress at the critical location than the normal cooldown transient. Thus, the SRVB heatup transient is assigned the same usage per cycle as the cooldown heatup. This value, and the number of SRVB cycles required for a total usage of 1.0, are shown in Table 3-2. l t 3.2.4 Feedwater The analysis of this component included separate consideration of a LAS Nozzle and a Carbon Steel Safe End, In this case, a more recent analysis was available (5-6) and was therefore utilized. For this component, 200 plant heatup, 198 plant cooldown, 200 SCRAMS, and 80 (full) loss of feedwater heater cycles were among the transients 3-4
4 considered in (5 6). The fatigue usage ef fects due to rapid cycling, not included in either (5 1) or (5 6), but available in a report concerning usage resulting from the implementation of the Economic Generation Control system (5-7), were also included in this analysis. From [5 7), the limiting usages due to rapid cycling, assumed here to be constant, were ,199 for the Nortle and .322 for the Safe End. Further, (5 6) considered 2600 Batch Feedwater Additions During Hot Standby transients for both the Feedwater Nozzle and the Safe End. Based on input from Commonwealth Edison, the batch feedwater addition does not occur during hot standby, so the transient is not applicable for operation at Units 1 and 2. The number of batch feedwater addition cycles was reduced (not eliminated) to reflect this. The Feedwater Nozzle fatigue usage analysis within (5 6] consisted of a number of transient combinations. This analysis isolated the combinations containing the plant heatup, plant cooldown, SCRAM, and (full) loss of feedwater heater transients and calculated their usage contributions per cycle. Since these transients, in either a warm-up or cooldown form, were each found in a number of combinations, the combination for each that produced the greatest usage per cycle for each transient was determined, in this way, the extrapolations to the number of cycles in Table 3-1 resulted in conservative usages for the nozzle and safe end. In the analysis presented in (5 6), the calculatiuns for both the Nozzle and the Safe End included isolated combinations of batch feedwater addition cycles. Removing the usages due to these combinations - 2072 cycles with a usage of .3131 for the Nozzle and 2398 cycles with a usage of .4996 for the Safe End - the usage for each could be lowered. While the number of batch feedwater addition cycles was substantially reduced, it is important to note that 202 such cycles remain in the set of allowables. Taking into account the information concerning rapid cycling, removal of hot standby cycles, and the incremental usage contributed by the inclusion of the additional transient cycles, new fatigue usage factors were determined, as shown in Table 3-2. ! 3-5
{ The SRVB transient is less severe than the cooldown associated with the batch feedwater addition. The usage per cycle for the batch feedwater addition transient was used as a bounding value for the SRVB heatup transient. The usage per cycle and number of SRVB cycles at which total usage equals 1.0 are shown in Table 3 2. 3.3
SUMMARY
OF SRVB ANALYSIS RESULTS The results of fatigue analysis including SRVB-heatup cy - how that as many as 12 such cycles can be tolerated before r , 4t , other than the closure studs, reaches a 40 year usg ot 1.0. Therefore, 12 SRVB cycles and aa additional 12 heatup cycles will be considered in each component's fatigue reanalysis. For the four components already ciscussed, determination of the usage associated with 12 SRVB heatup cycles is done with the numbers in Table 3 2. For the other components, discussed in Section 3.4, the fatigue is low, so the most limiting SRVB usage per cycle from Table 3 2 is added to the total usage for these components. 3.4 EVALUATION OF REMAINING. COMPONENTS The specific details of the fatigue reanalysis for each of the remaining components are provided in individual sections below. 3.4.1 Recirculation Outlet The analysis of this component included separate consideration c; a Low Alloy Steel (LAS) Nozzle and a Stainless Steel (SS) Safe End. For this component, 120 plant heatup/cooldown cycles and 80 SCRAMS were among the transients considered in [5-1]. Fatigue usage resulting from the (full) loss of feedwater heater transient was not considered in (5-1] and was assumed to be negligible. New facigue usage values for both the Nozzle and Safe End were conservatively calculated by dividing the total number of applicable rettsed duty cycles from Table 3-1 by the allowable number of cycles representative of the limiting transient event. Fatigue usage for 12 cycles of SRVB heatup was added as well. 3-6
, w
- 3.4.2 Core Sorav The analysis of this component included separate consideration of a 1AS Nozzle and a SS Safe End. For this component, 120 plant heatup/cooldown cycles were among the transients considered in [5 1).
Fatigue usages resulting from the SCRAM and (full) loss of feedwater heater transients were not considered in [5 1]. While the loss of feedwater heater transient cycles are negligible, the total number of SCRAM cycles were also included in this reanalysis. New fatigue usage values for both the Nozzle and Safe End were conservatively calculated I by dividing the total number of applicable revised duty cycles from Table 31 by the_ allowable number of cycles representative of the limiting transient event. Usage for 12 SRVB heatup cycles was also cdded. 3.4.3 CRD Hydraulie Return The analysis of this component included separate consideration of a IAS Nozzle and a SS Safe End. For this component, 120 plant heatup/cooldown cycles and 250 SCRAMS were among the transients considered in_(5-1]. Fatigue usage resulting from the (full) loss of feedwater heater transient was not considered in (5-1] and was assumed to be negligible. New fatigue usage values for both the Nozzle and
- Safe End were conservatively calculated by dividing the total number of applicable revised duty cycles from Table 31 by the allowable number of cycles representative of the limiting transient event.
Fatigue usage for 12 SRVB cycles was included as well. The CRD hydraulic return nozzle has not been used for CRD coolant return for some time, and the nozzle is being capped this - year. Therefore, the fatigue results for the nozzle are conservative. In fact, the nozzle will probably be exempt from fatigue analysis in the future. ! 3-7 l
3.4.4 CRD Penetration The analysis of this component included separate consideration of S S , IAS , and INCONEL at the penetration. For this component, a total , of 401 cycles representing heatup-cooldown and SCRAM were among the traasients considered in [5-1). Effects of loss of feedwater heater were not analyzed, but are negligible. New fatigue usage values for the three materials were conservatively calculated by dividing total number of applicable revised duty cycles from Table 3-1 by the allowable number of cyc4es representative of the limiting transient event. SRVB usage was also considered. 3.4.5 2" Instrument No:rle A lAS Nozzle was the only consideration in the analysis of this component. For this component, 120 plant heatup/cooldown cycles were among the transients considered in [5-1]. Fatigue usages resulting from the SCRAM and (full) loss of feedwater heater transients were not considered in [5-1). While the loss of feedwater heater transient cycles were assumed to be negligible, the total number of SCR W cycles were also included in this reanalysis. A new fatigue usage value for the Nozzle was conservatively calculated by dividing the total number of applicable revised duty cycles from Table 31 by the allowable number of cycles representative of the limiting transient event. Usage for 12 SRVB cycles was also included. 3.4.6 Refueline Containment Skirt The 1AS Refueling Containment Skirt was the only consideration in the analysis of this component. For this component, 120 plant heatup/cooldown cycles were the only cycles considered in [5-1), Fatigue usages resulting from the SCRAM and (full) loss of feedwater heater transients were not considered in [5 1]. While the loss of feedwater heater transient cycles were assumed to be negligible, the total number of SCRAM cycles were also included in this reanalysis. A new fatigue usage value for the Refueling Containment Skirt was conservatively calculated by dividing the total number of applic able 3-8
l= . . 4 revised duty cycles from Table 3 1 by the allowable number of cycles representative of the limiting transient event. SRVB cycles wera.also included in the fatigue analysis. 3.4.7 Closure Flance Recion The analysis of this component included separate consideration of a IAS - Flange and a LAS Stud. For this component, 120 plant heatup/cooldown cycles were among the transients considered in [5 1). Fatigue usages resulting frorn the SCPM and (full) loss of feedwater heater transients were not considered in [5 1). Since different-methods are used here for the Flango and Stud, they are discussed separately. The Closure Flange analysis in [5-1) considered only the 120 plant heatup/cooldown cycles. While the loss of feedwater heater transient cycles were assumed to be negligible, the total number of SCRAM cycles were also included in this reanalysis. A new fatigue usage value for the Closure Flange was conservatively calculated by i dividing the total number of applicable revised duty cycles from Table 3 1 by the allowable , number of- cycles representative of the
. limiting transient event. Twelve SRVB cycles were also included in the total usage.
L -The analysis of the stud included 120 plant he.itup/cooldown cycles in (5-1) within 12 total transients considered. Howeve;, i neither SCRAM nor loss of feedwater heaters were incluo.:d i.. the j analyzed cycles. While the loss of feedwater heater transient cycles l were assumed to be negligible, the total number of SCRAM cycles were included in this reanalysis. Scaling the alternating stress of the limiting plant heatup/cooldown transient by the ratio of temperature differences for the SCRAM and heatup/cooldown transients, an alternating stress and associated number of allowable cycles for the SCRAM was calculated, l 39
l i In deterrnining the stresses for the SRVB trans i e nt , which also was not analyzed in [5-1), the impact on the stud stresses was assumed to be the same as a normal cooldown. This is justified by the facts that the stud is separated from the coolant by a substantial amount of flange metal, and the coolant is steam, rather than water, so heat transfer is less effective. Thus, the rapid cooldown portion of the SRVB would not affect the stud stresses. Total usage is the sum of the original usage from [5 1) plus that due to the additional heatup, cooldown, SCRAM, interruption of feedwater flow and SRVB cycles. Usage due to SCPAM was determined by dividing the SCRAM and interruption of feedwater flow cycles from Table 3 1 by the allowable for SCRAMS. i.ga ins t the heatup/cooldown transient allowable, the additional cycles of heatup cooldown from Table 3 1 and 12 cycles of SRVB heatup were applied. 3.4.8 Vessel Shells The 1AS Vessel Shells represented the only consideration in the analysis of this component. For this component, 120 plant heatup/cooldown cycles were the only cycles considered in [5-1). Fatigue usages resulting from the SCRAM and (full) loss of feedwater heater transients were not considered in [5 1). While the loss of feedwater heater transient cycles were assumed to be negligible, the total number of SCRAM cycles were also included in this reanalynis. A new fatigue usage value for the Vessel Shells was conservatively calculated by dividing the total number of applicable resised duty cycles fron. Table 3 1 by the allowable number of cycles representative of the limiting transient event. Usage for 12 SRVB cycles was included as well. 3-10 l
Table 3-1 CYCLES USED TO PREDICT USAGE VITHOUT SRVB CYCLES - UNITS 1 AND 2 UNIT 1 CYCLE UNIT 2 CYCLE NUMBER DESIGN BASIS PREDICTION PREDICTION OF CYCLES ALLOVABLE YEAR 40a YEAR 40a b G1CLE DESCRIPTION ANALYZED Plant Cooldown 119 286 274 287 Plant Heatup 120 287 275 287 Reduction of Power 119 50 44 119 C for Plant Shutdown Turbine Roll with 120 50 44 120 c Feedwater Injection Head Spray Injection 119 3 5 119 Loss of Feedwater 80 114 77 114 Heaters - Full Loss of Feedwater 80 6 42 80 Heaters - Partial Loss of Feedwater Flow 80 15 42 80 SCRAM 200 294 275 294 Batch Feedwater 595 0 0 202 Addition During Hot Standby or Plant Cooldown 8 From Table 1 1 of Reference [5-8) b Revised Duty Cycles for this Reanalysis C No more of these cycles are expected, since this mode of shutdown and startup is no longer used. 3-11
l t i Table 3 2 SUE %RY OF RESULTS FOR SRVB HEATUP CICLE FATIGUE Total Usage Usage per SRVB Cycles without SRVB Cycle for U-1.0 Component Analyzed SRVB Cveles (Cvele'll (Cveles) Recirculation Inlet 0.272 600'l 436 Shroud Support 0.565 950'I 413 Feedwater Nozzle 0.530 4000'l 1878 Support Skirt 0.962 310*I 12 Note: Smallest allowable SRVB cycle value in fourth column becomes design basis number for all components. Usage for components not listed above: USRVB - 12/310 - 0.039 3-12
s a l 4.0 RESULTS Utilizing the methods outlined in section 3,0, vessel fatigue usages were evaluated based on_the 40 year cycle predictions provided in [5 8), including 12 cycles of SRVB and 12 additional cycles of heatup, as shown in Table 41 as " Number of Cycles Analyzed", The usage results based on this set of revised duty cycles is provided as Table 4 2. A review of Table 4 2 shows that the latigue usage values for all components except the closure studs are at or below the limit of 1.0, The results for the CRD hydraulic return nozzle, which do not account for the nozzle being capped this year, are conse rva tive , The fact that the head spray nozzle is also being capped has no effect on the results in_ Table 4-2, as head spray is not a limiting transient for any of the vessel- components except the head spray nozzle, and that
~
nozzle is exempt from fatigue analysis. Therefore, the analyzed cycles in Table 4-1 can be adopted as the revised fatigue design basis cycles for those components, Additional analysis has been performed to determine the time at which the - closure studs are predicted to reach a usage of 1,0. The cycle counting procedure [5 2) included methods for predicting numbers of cycles for. a given~ year of operation, These were used in conjunction with the usage per cycle values for boltup, pressure test and unbolt (one value), for heatup cooldown and for SCRAM to determine fati6 ue usage as a function of years of operation. The results, shown in Table 4 3, show that both units should operate about 26 years, or to_the year 1998, before the stud usage reaches 1.0, The analytical nature of the approach used in Table 4-3 gives fractions of cycles, which of course is unrealistic as cycles do not L accumulate in fractional amounts. There are many combinations of boltup-unbolt, heatup-cooldown and SCRAM possible, One such possible l _ combination is shown at the bottom of Table 4-3. 4-1
l~. 9 l Table 4 1
SUMMARY
OF DESIGN BASIS AND PREDICTED CYCLES l UNITS 1 AND 2 UNIT 1 CYCLE UNIT 2 CYCLE + NUMBER j DESIGN BASIS PREDICTION PREDICTION OF CYCLES b CYCLE DESCRIPTION ALLOVABLE YEAR 40a YEAR 40a ANALY2ED Plant Cooldovn 119 286 274 286 ,
-l Plant Heatup 120 292 275 298 !
Safety Relief 1 6 1 12 Valve Blowdown Reduction of Power 119 50 44 119 for Plant Shutdown
- Turbine Roll with 120 50 44 120 Feedwater Inj ection#
Head Spray Injection 119 3 5 119 Loss of Feedwater 80 114 77 114 . Heaters - Full Loss of Feedwater 80 6 42 80 Heaters - Partial Loss of Feedwater Flow 80 15 42 80 SCRAM 200 294 275 294 Batch Feedwater 595 0 0 202 Addition During Hot Standby or Plant Cooldown
- From Table 1 1 of [5 8), except SRVB cycles are from this report b
Values can replace design basis cycles for all components.but closure studs, Events not shown are unchanged.
- No more of these cycles are expected, since this mode of shutdown and startup is no longer used.
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f... . Table 4 3 . USAGE PREDICTION FDR DUAD CIflES CLOSURE studs UNIT is
$fARTUP/ STARTUP/
BOLTUP $HU100VN SCRAM SRvt BOLTUP $NUTDOWN SCRAM $RV5 TOTAL YEAR CYCLES CYCLES CYCLES CYCLES USAGE U$ AGE U$ AGE U$ AGE U$ ACE 16.50 11.00 129.00 141.00 2.00 0.03 0.54 0.07 0.01 0.64 20.00 13.24 152.92 165.92 3.49 0.04 0.64 0.08 0.01 0.77 21.00 13.86 159.24 1 73.04 3.91 0.04 0.66 0.08 0.02 0.80 22.00 14.52 165.96 180.16 4.34 0.04 0.69 0.08 0.02 0. 84 23.00 15.16 172.68 187.28 4.77 0.05 0.72 0.09 0.02 0.87 24.00 15.80 179.40 194.40 5.19 0.05 0. 75 0.09 0.02 0.91 25.00 16.44 183.12 201.52 5.62 0.05 0.78 0.09 0.02 0.94 I 26.00 17.08 192.84 208.64 6.04 0.05 0.80 0.10 0.03 0.98 27.00 17.72 199.56 215.7o 6.47 0.05 0.83 0.10 0.03 1.01 28.00 18.36 206.28 222.88 6.89 0.05 0.86 0.10 0.03 1.05 UNIT 21 STAttVP/ $1ARTUP/ BOLTUP $HUTDOWN $ CRAM $tVB BOLTUP $HUTDOWN SCRAM $RVB TOTAL YEAR CYCLES CYCLES CYCLE S CYCLES USAGE USAGE U$ AGE USAGE USAGE 16,00 13.00 133.00 143.00 2.00 0.04 0.55 0.07 0.01 0.67 20.00 15.67 156.67 172.00 3.67 0.05 0.65 0.08 5.02 0.79 21.00 16.33 162.58 179.25 4.08 0.05 0.68 0.08 0.02 0.83 22.00 17.00 168.50 186.50 4.50 0.05 0.70 0.09 0.02 0.86 23.00 17.67 174.42 193.75 4.92 0.05 0.73 0.09 0.02 0.89 24.00 18.33- 180.33 201.00 5.33 0.05 0.75 0.09 0.02 0.92 25.00 19.00 186.25 208.25 5.75 0. 06 0.78 0.10 0.02 0.95 26.00 19.67 192.17- 215.50 6.17 0.06 0.80 0.10 0.03 0.90 27.00 20.33 198.08 222.75 6.58 0.06 0.83 0.10 0.03 1.02 28.00 - 21.00 204.00 230.00 7.00 0.06 0.85 0.11 0.03 1.05 l EXAMPLE 20.00 195.00 216.00 6.00 0.06 0.81 0.10 0.03 1.00 l 1 l i l l l
5.0 REFERENCES
51 Quad Cities 1 and 2 Stress Report: " Certified Design Document for Quad cities - I & II", B&W Contract No. 610 0122-51/52, CE Order No. 205 55599. Nuclear Power Generation Division, Bab;ock & Wilcox Co., Mt. Vernon, Indiana, November, 1970. 5-2 Caine, T. A., " Thermal Cycle Counting Procedure for Dresden Units 2 and 3 and Quad Cities Units 1 and 2," GE Report EAS 128 1086, July 1987. 53 Caine, T. A., " Tabulation of Thermal Cycles for Quad Cities Nuclear Station Units 1 and 2 " CE Report SASR 88 64, October 1988. 54 "BWR Reactor Vessel Cyclic Duty Monitoring," Nuclear Services Information Letter 318 December 1979. 55 Papandrea, C. J., " Evaluation of Support Skirt Fatigue Usage for Quad Cities Nuclear Station Units 1 and 2 " GE Report SASR 89 24, March 1989.
- 5-6 "Feedwater Nozzle Stress Report," CE Report 22A6650 for Dresden Units 2 and 3 and Quad Cities Units I and 2. Saptember 1979.
5-7 Stevens, G. L.-and B. J. Cheek, " Economic Generation and Control Fatigue Usage for Dresden Units 2 and 3 and Quad Cities Units 1 and 2," CE Report AE 78 0884, August 1904, 1 5-8. Caine, T. A., " Tabulation of Thermal Cycles for Quad Ci tir s Nuclear Station Units 1 and 2." GE Report SASR 88-64, Revision 1., l- March 1990. 5-1 m}}