ML13009A374
| ML13009A374 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 12/11/2012 |
| From: | Noronha S FirstEnergy Nuclear Operating Co, AREVA |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| L-12-444 32-9195423-000 | |
| Download: ML13009A374 (27) | |
Text
Enclosure A Davis-Besse Nuclear Power Station, Unit No. 1 (Davis-Besse)
Letter L-12-444 Calculation 32-9195423-000, "DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years -
Non-Proprietary" 26 pages follow
For Information Only 0402-01-FOI (Rev. 017, 11/19/12)
A CALCULATION
SUMMARY
SHEET (CSS)
AREVA Document No. 32 9195423 - 000 Safety Related: 0 Yes [-]No Title DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years - Non - Proprietary PURPOSE AND
SUMMARY
OF RESULTS:
AREVA NP Inc. proprietary information in the document are indicated by pairs of braces " [ I".
Purpose:
The reactor vessel inlet and outlet nozzle-to-shell welds are evaluated for low upper-shelf energy levels by linear elastic fracture mechanics analytical techniques to satisfy the requirements of Appendix K to Section XI of the ASME Boiler and Pressure Vessel Code [4].
Summary: The analysis is based on an upper bound surface fluence of 0.23 x 1018 n/cm 2 [15] at 60 calendar years or 52 Effective Full Power Years (EFPY), calculated at the lowest elevation of the outlet nozzle-to-shell weld.
Stresses are derived at the weld location considering the influence of the nozzle-to-shell geometric discontinuity and attached piping reaction for Level A, B, C and D service loadings. The reactor vessel nozzle-to-shell welds satisfy all acceptance criteria of ASME Code,Section XI, Article K-2000. For Level A and B service loading, the applied J-integral at 1.15 times the accumulation pressure plus thermal loadings is less than the J-integral of the material at a ductile flaw extension of 0.10 in. by a margin of 1.27. The applied J-integral for Level C and D Service loadings is less than the required measure of J-integral resistance by a margin of 1.2. Furthermore, the criterion for ductile and stable flaw extensions is satisfied for Level A, B, C, and D service loadings.
THE DOCUMENT CONTAINS ASSUMPTIONS THAT SHALL BE THE FOLLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT: VERIFIED PRIOR TO USE CODE/VERSIONIREV CODE/VERSIONIREV PCRIT/6/3 S'1YES Z]NO Page 1 of 26
0402-01-FOl (Rev. 017, 11/19/12)
AREV Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years Review Method: N Design Review (Detailed Check)
D Alternate Calculation Signature Block P/RIA Name and Title and Pages/Sections (printed .or typed) Signature LP/LR Date Prepared/Reviewed/Approved S. J. Noronha P ALL Engineer IV "IiIt2-Ashok D.Nana R j4 fALL Supervisory Engineer__________
T. M. Wiger ,hul A ALL Technical Manager Wj4fi#7J,74*,.-
Note: P/R/A designates Preparer (P), Reviewer (R), Approver (A);
LP/LR designates Lead Preparer (LP), Lead Reviewer (LR)
Project Manager Approval of Customer References (N/A if not applicable)
Name Title (printed or typed). (printed or typed) Signature Date N/A Mentoring Information (not required per 0402-01)
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AREVA 0402-01-FOl (Rev. 017, 11/19/12)
Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years Record of Revision Revision Pages/Sections/ Paragraphs No. Changed Brief Description / Change Authorization 000 ALL Original Release i- i I. *1 Page 3
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AR EVA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years Table of Contents Page SIGNATURE BLOCK ................................................................................................................................ 2 RECO RD O F REVISION ..................................................... ............................................................ 3 LIS T O F TA B LE S ..................................................................................................................................... 6 LIST O F FIGURES ...................................................................................................... 7 1.0 INTRODUCTIO N ........................................................................................................................... 8 2.0 ANALYTICAL METHO DOLOGY ............................................................................................. 8 2.1 Acceptance Criteria ......................................................................................................................... 8 2.1.1 Level A and B Service Loadings (K-2200) ..................................................................... 9 2.1.2 Level C Service Loadings (K-2300) .............................................................................. 9 2.1.3 Level D Service Loadings (K-2400) .............................................................................. 9 2.2 Temperature Range for Upper-Shelf Fracture Toughness Evaluations ..................................... 9 2.3 Effect of Cladding Material ........................................................................................................ 10 3.0 ASSUM PTIO NS .......................................................................................................................... 10 4.0 DESIGN INPUT .......................................................................................................................... 10 4 .1 G e o m e tric D a ta .............................................................................................................................. 10 4 .2 Ma te ria ls Da ta ................................................................................................................................ 10 4.3 J-integral Resistance Model for Mn-Mo-Ni/Linde 80 W elds ...................................................... 11 4 .4 A p p lie d Lo a d ing s ............................................................................................................................ 12 4.4.1 Pressure and Thermal Discontinuity Stresses ........................................................... 12 4.4.2 Shell Stresses at the W eld Location ............................................................................ 12 4.4.3 Stresses from Attached Piping Loads ......................................................................... 13 4.4.4 Total Stresses ............................................................................................................. 13 4 .5 F lu e n ce Lev e ls ............................................................................................................................... 14 5.0 CALCULATIO NS .......................................................................................................... ........ 14 5.1 Evaluation for Level A & B Service Loadings ............................................................................ 14 5.2 Evaluation for Level C & D Service Loadings ...................................... 18 6.0 RESULTS .................................................................................................................................. 25 Page 4
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AREVA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet &Outlet Nozzle-to-Shell Welds for 60 Years Table of Contents (continued)
Page 7 .0 R E F E R E NC E S .............................................................................................................. ............. 2 5 APPENDIX A: COMPUTER OUTPUT FILES AND VERIFICATION OF PCRIT ......... ............. 26 Page 5
For Information Only
.A AR EVA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years List of Tables Page Table 4-1: Mechanical Properties of Weld Materials ........................................................................ 11 Table 4-2: Applicable Pressure and Thermal Discontinuity Stresses for Flaws ................................ 12 Table 4-3: Shell stresses at the w eld location .................................................................................... 13 Table 4-4: Stresses due to the Attached Pipe Loads ........................................................................ 13 Table 4-5: Level A and B Service Loadings ...................................................................................... 13 Table 4-6: Level C and D Service Loadings (without thermal stresses) ...................... 14 Table 5-1: Flaw Evaluation for Level A & B Service Loadings ......................................................... 15 Table 5-2: Flaw Evaluation for Level A & B Service Loadings .......................................................... 16 Table 5-3: Flaw Evaluation for Level C & D Service Loadings ......................................................... 21 Table 5-4: Flaw Evaluation for Level C & D Service Loadings ......................................................... 22 Page 6
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.A AR EVA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years List of Figures Page Figure 5-1: J-R Curves for level A & B Service Loadings ................................................................ 17 Figure 5-2: Level C and D Transients - Reactor Coolant Temperature versus Time ............. 18 Figure 5-3: Level C and D Transients - Reactor Coolant Pressure versus Time ............................. 19 Figure 5-4: Level C and D Transients - Heat Transfer Coefficient vs Time .................................... 19 Figure 5-5: Kle, Kj, (mean and lower bound), and Applied K, for Level C and D .............................. 20 Figure 5-6: J-R Curves for Level C & D Service Loadings ................................................................ 24 Page 7
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ARE VA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years
1.0 INTRODUCTION
Reactor vessel beltline materials exhibiting Charpy upper-shelf impact energy levels below 50 ft-lbs are required by Appendix G[l1, "Fracture Toughness Requirement," to 10 CFR Part 50, "Domestic Licensing of Production and Utilization Facilities," to be analyzed to show that margins of safety against fracture are equivalent to those required by Appendix G of the ASME Code[4]. Welds in the beltline region of Davis-Besse Unit 1 (DB-1) reactor vessel (RV) have recently been analyzed for 60 years or 52 effective full power years (EFPY) of operation to demonstrate that these low upper-shelf energy materials would continue to satisfy federal requirements for license renewal [2,3]. Although subject to lower fluence levels than the reactor vessel beltline region, weld materials that are used to attach the primary coolant inlet and outlet nozzles to the reactor vessel are also susceptible to fracture toughness degradation from neutron embrittlement. These structural welds are subjected to nozzle-to-shell discontinuity stresses and attached piping loads that are not applicable to the beltline region analyzed in Reference [2]. The purpose of the present analysis is to evaluate the welds that attach the inlet and outlet nozzle to the reactor vessels (Material ID, WF-233[3]), even though the projected upper-shelf energy levels at 52 EFPY is slightly above 50 ft-lbs [3] for the Davis-Besse Unit 1. This equivalent margin fracture mechanics evaluation is performed according to the guidelines and acceptance criteria of Appendix K to Section Xl of the ASME Boiler and Pressure Vessel Code [4]..
The present analysis will consider both the inlet and outlet nozzles. For the purposes of the present fracture mechanics evaluation, the primary coolant [ ] inlet and [ ] outlet nozzle are similar in that the full penetration attachment welds are located in the [ ] thick nozzle belt forging (NBF) section of the reactor vessel shell [9, 10]. Envelop stresses from outlet and inlet nozzles for attached pipe loads [5] will be considered.
Due to the close proximity of the larger diameter outlet nozzle to the reactor core, the outlet nozzle-to-shell weld is subjected to higher levels of fluence than the inlet nozzle. Stresses from available sources will be utilized to characterize Level A and B service loadings. Previously derived pressure stresses will also be used to analyze the nozzle-to-shell interface area for Level C and D Service loadings. Thermal stresses for Level C and D Service loadings will be developed using PCRIT [16] for the most limiting transient for the nozzle belt forging section.
2.0 ANALYTICAL METHODOLOGY Appendix K to Section XI of the ASME Code [4] provides acceptance criteria (described in section 2.1) and evaluation procedures for determining acceptability of low upper-shelf materials in the cylindrical shallow portion of the reactor vessel. Although the nozzle-to-shell weld will be subjected to the acceptance criteria of Appendix K, the linear elastic fracture mechanics procedures of Appendix K will be augmented to account for the membrane and bending discontinuity stresses at the intersection of the nozzle and nozzle belt forgings. Although it may be argued that stress intensity factors could be calculated using solutions for semi-elliptical flaws in cylindrical vessels, it is conservative to utilize a flat plate solution for this purpose. Accordingly, semi-elliptical surface flaws in the nozzle-to-shell weld will be analyzed using a flat plate solution by Newman and Raju [6].
2.1 Acceptance Criteria Acceptance criteria for the assessment of reactor vessels with low upper shelf Charpy impact levels are prescribed in Article K-2000 of Appendix K to Section XI of the ASME Code [4]. These criteria are summarized below as they pertain to the evaluation of reactor vessel weld metals.
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AR EVA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years 2.1.1 Level A and B Service Loadings (K-2200)
(a) When evaluating adequacy of the upper shelf toughness for the weld material for Level A and B Service Loadings, an interior semi-elliptical surface flaw with a depth 1/4 of the wall thickness and a length six times the depth shall be postulated, with the flaw's major axis oriented along the weld of concern and the flaw plane oriented in the radial direction. Two criteria shall be satisfied:
(1) The applied J-integral evaluated at a pressure 1.15 times the accumulation pressure (Pa) as defined in the plant specific Overpressure Protection Report, with a factor of safety of 1.0 on thermal loading for the plant specific heatup .and cooldown conditions, shall be less than the J-integral of the material at a ductile flaw extension of 0.10 in.
(2) Flaw extensions at pressures up to 1.25 times the accumulation pressure (P,) shall be ductile and stable, Using a factor of safety of 1.0 on thermal loading for the plant specific heatup and cooldown conditions.
(b) The J-integral resistance versus flaw extension curve shall be a conservative representation for the vessel material under evaluation.
2.1.2 Level C Service Loadings (K-2300)
(a) When evaluating the adequacy of the upper shelf toughness for the weld material for Level C Service Loadings, interior semi-elliptical surface flaws with depths up to 1/10 of the base metal wall thickness, plus the cladding thickness, with total depths not exceeding 1.0 in., and a surface length six times the depth, shall be postulated, with the flaw's major axis oriented along the weld of concern, and the flaw plane oriented in the radial direction. Flaws of various depths, ranging up to the maximum postulated depth, shall be analyzed to determine the most limiting flaw depth.
Two criteria shall be satisfied:
(1) The applied J-integral shall be less than the J-integral of the material at a ductile flaw extension of 0.10 in., using a factor of safety of 1.0 on loading.
(2) Flaw extensions shall be ductile and stable, using a factor of safety of 1.0 on loading.
(b) The J-integral resistance versus flaw extension curve shall be a conservative representation for the vessel material under evaluation.
2.1.3 Level D Service Loadings (K-2400)
(a) When evaluating adequacy of the upper shelf toughness for Level D Service Loadings, flaws as specified for Level C Service Loadings shall be postulated, and toughness properties for the corresponding orientation shall be used. Flaws of various depths, ranging up to the maximum postulated depth, shall be analyzed to determine the most limiting flaw depth. Flaw extensions shall be ductile and stable, Using a factor of safety of 1.0 on loading.
(b) The J-integral resistance versus flaw extension curve shall be a best estimate representation for the vessel material under evaluation.
(c) The extent of stable flaw extension shall be less than or equal to 75% of the vessel wall thickness, and the remaining ligament shall not be subject to tensile instability.
2.2 Temperature Range for Upper-S helf Fracture Toughness Evaluations Upper-shelf fracture toughness is determined through use of Charpy V-notch impact energy versus temperature plots by noting the temperature above which the Charpy energy remains on a plateau, maintaining a relatively Page 9
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AREVA. Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years high constant energy level. Similarly, fracture toughness can be addressed in three different regions on the temperature scale, i.e. a lower-shelf toughness region, a transition region, and an upper-shelf toughness region.
Fracture toughness of reactor vessel steel and associated weld metals are conservatively predicted by the ASME initiation toughness curve, K1c, in the lower-shelf and transition regions. In the upper-shelf region, the upper-shelf toughness curve, Kjo is derived from the upper-shelf J-integral resistance model 'described in Section 4.3. The upper-shelf toughness then becomes a function of fluence, copper content, temperature, and fracture specimen size. When upper-shelf toughness is plotted versus temperature, a plateau-like curve develops that decreases slightly with increasing temperature. Since the present analysis addresses the low upper-shelf fracture toughness issue, only the upper-shelf temperature range, which begins at the intersection of K1c and the upper-shelf toughness curves, Kj, is considered.
2.3 Effect of Cladding Material The PCRIT [16] code utilized in the flaw evaluations for Level C and D Service Loadings does not consider stresses due to thermal expansion in the cladding when calculating stress intensity factors. To account for this cladding effect, an additional stress intensity factor, K/clad, is calculated separately and added to the total stress intensity factor computed by PCRIT.
The contribution of cladding stresses to stress intensity factor was examined previously [7]. In the low upper-shelf fracture toughness analysis performed for B&W Owners Group Reactor Vessel Working Group plants [13], the maximum value of K1clad, at any time during the analyzed transients and for any flaw depth, was determined to be
[ ] ksi*iin [7]. This bounding value .is therefore used as the stress intensity factor for KicIld in this Davis-Besse low upper-shelf fracture toughness analysis.
3.0 ASSUMPTIONS This document contains no assumptions that require verification before use for safety related applications. A pertinent minor assumption is that, conservatively semi-elliptical flaws in flat plates were used instead of semi-elliptical flaws in cylindrical vessels.
4.0 DESIGN INPUT The normal operating temperature at the outlet nozzle is 608°F [8] and at the inlet nozzle is 550°F [8].
4.1 Geometric Data From a review of sub-assembly drawings for both the outlet [9] and inlet nozzles [10], the thickness of the reactor vessel nozzle-to-shell weld is taken to be [ ] . The radius of the reactor vessel nozzle-to-belt forging at the cladding is [ ] and at the base metal is [ ] [11]. Thus the cladding thickness is I ] and the outer radius of the reactor vessel at this forging is [ ]
4.2 Materials Data The reactor vessel inlet and outlet nozzle-to-shell welds are formed from Mn-Mo-Ni/Linde 80 weld materials. The mechanical properties of the Linde 80 metals are given in Table 4-1, along with the ASME code values [12] for the base metal. The weld materials properties are based on tests conducted on samples from surveillance capsule and are reported in reference [2].
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AR EVA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years Table 4-1: Mechanical Properties of Weld Materials Temp(°F) E(ksi) Yield strength, ay(ksi) a (/OF)
Material: Base Metal Base Metal Weld metal Base Metal Source: Code j12] Code[12] Test Data [2] Code[12]
100.0 27800 50.00 87.30 6.50E-06 200.0 27100 47.50 84.81 6.67E-06 300.0 26700 46.10 82.89 6.87E-06 400.0 26100 45.10 80.98 7.07E-06 500.0 25700 44.50 79.06 7.25E-06 550.0 25450 44.11 78.10 7.34E-06 600.0 25200 43.80 77.14 7.42E-06 4.3 J-integral Resistance Model for Mn-Mo-Ni/Linde 80 Welds A model for the J-integral resistance versus crack extension curve (J-R curve) required to analyze low upper-shelf energy materials have been derived specifically for Mn-Mo-Ni/Linde 80 weld materials. A previous analysis of the reactor vessels of B&W Owners 'Reactor Vessel Working Group' [13] described the development of this toughness model from a large data base of fracture specimens. Using a modified power law to represent the J-R curve, the mean value of the J-integral is given by:
where and
- also, Page 11
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AREVA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years As dictated by paragraph K-2000(b) of Reference [4], the J-integral resistance versus flaw extension curve is a conservative representation for the vessel material under evaluation. The conservatism is introduced by multiplying the mean value of the J-integral calculated from the model by a factor of [ ] , which is twice the standard error (-2Se) of the test data used to create the model [13].
4.4 Applied Loadings In the area of the nozzle-to-shell weld, applied loadings consist of pressure, thermal and attached piping reactions. Stresses from pressure and piping loads are obtained from previously documented analyses [5, 14], as are thermal stresses for level A and B service loadings [5, 14]. Thermal stresses are derived as part of the analysis performed using PCRIT herein for Level C and D service loadings.
4.4.1 Pressure and Thermal Discontinuity Stresses Stresses due to pressure and thermal loads at the nozzle-to-shell discontinuity are obtained from a previous analysis of the TMI-1 outlet nozzle [14]. These stresses are then scaled by the applicable pressure loading to derive the stresses required for the subsequent low upper-shelf energy analysis. In the calculations that follow, the design pressure, Pd is taken to be [ ] psi. Level A and B service loadings are based on the cooldown transient since it produces tensile stresses at the inside surface of the nozzle-to-shell intersection. Stresses are derived for hot leg LOCA pressure conditions since it was determined that this event was the limiting transient for Level C and D service loadings in the low upper shelf analysis performed for the belt line region [2].
Table 4-2: Applicable Pressure and Thermal Discontinuity Stresses for Flaws Internal Surface Stresses Membrane Bending Condition Pressure Inside Outside Stress Stress (ksi) (ksi) (ksi) (ksi) (ksi)
RV Outlet Nozzle Stress Analysis[14]:
Initial pressure, Po [ ] [ ] [ i [ I ]
Cooldown (pressure + thermal) _[_ _] ]._I _L _ _
Intermediate Loadings:
Accumulation pressure, Pa=l.1 *Pd [ ] ] [ ] [ ] [ I Cooldown (pressure only)
Cooldown (thermal only) I,_ L I I I I Appendix K, Level A & B Service Loadings:
1.15*Pa + Thermal IC ]I[ ] T ( [C ]
1.25*Pa + Thermal II_ 1.L._ _ __ . I Appendix K, Level C & D Service Pressure Loadings:
Hot Leg LOCA at max. pressure [ JI [ ] ] IC [
Hot Leg LOCA at min. pressure 1 1i.LJ][ L1 [ ] L 4.4.2 Shell Stresses at the Weld Location The normal/upset condition load combination is dead weight (DW) + thermal (TH) + Operating Basis Earthquake (OBE) loads [5]. The load combination for emergency/faulted condition includes DW+ TH + Square root of sum of squares (SRSS) of Safe Shutdown Earthquake (SSE) and Loss of Coolant (LOCA) transients. Circumferential Page 12
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AREVA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years and longitudinal bounding stresses for both outlet nozzle and inlet nozzles are conservatively used (location 3 in Reference [5].) The stresses are listed below:
Table 4-3: Shell stresses at th e weld location Circumferential Longitudinal Surface Stresses Condition [51 Stresses Surface Stresses [51 Stresses Inside Outside Membrane Bending Inside Outside Membrane Bending (ksi (ksi) (ksi) (ksi) (ksi) (ksi) (ksi) (ksi)
Normal/Upset (( lI_ (( l]I I I I I I II Emergency/Faulted I ) I [ I I.] 1 I I 4.4.3 Stresses from Attached Piping Loads Stresses at the nozzle-to-shell intersection due to nozzle loads from the attached hot leg piping have recently been determined for the DB-1 plant [5]. Circumferential and longitudinal bounding stresses for both outlet nozzle and inlet nozzles are conservatively used (location 3 in reference [5]).
Table 4-4: Stresses due to the Attached Pipe Loads Circumferential Longitudinal Surface Stresses Stresses Condition Inside.[51 Outside Membrane StressesBending Inside Stresses[5]
Surface Outside Membrane Bending (ksi) (ksi) (ksi) (ksi) (ksi) (ksi) (ksi) (ksi)
Normal/Upset I ] I ] [ ] I I] I ] I ] [ ] [ ]
Emergency/Faulted I[ _IIJ L -I I__ _]__ I II I I [ ]I [ I 4.4.4 Total Stresses The combined stresses listed below are formulated to provide necessary input to the low upper-shelf analysis that follows.
Table 4-5: Level A and B Service Loadings Circumferential Longitudinal Condition Stresses Stresses Membrane Bending Membrane Bending (ksi) (ksi) . (ksi) (ksi) 1.15*Pa + Thermal + Piping Loads [ ]II I I I I 1.25*Pa + Thermal + Piping Loads ] [ C1 ] I Page 13
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AR EVA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years Table 4-6: Level C and D Service Loadings (without thermal stresses)
Circumferential Longitudinal Condition Stresses Stresses Membrane Bending Membrane Bending (ksi) (ksi) I(ksi) (ksi)
HL-LOCA at max. pressure + Piping Loads [ ] [
HL-LOCA at min. pressure + Piping Loads [ ] J] j[ ]
4.5 Fluence Levels At 52 EFPY, an upper bound surface fluence is estimated [15] to be 0.23 x 1018 n/cm 2 at the lowest elevation of the outlet nozzle-to-shell weld. This fluence is nearly two orders of magnitude lower than the maximum value of 16.9 x 1018 nicm 2 used in the low upper-shelf analysis of the belt line region [2].
5.0 CALCULATIONS Level A and B service loadings were described in Section 4.4 as were pressure and attached piping stresses for Level C and D service loadings. The PCRIT [161 computer code was utilized to obtain stress intensity factors due to hot leg LOCA thermal conditions since it was determined that this event was the limiting transient for Level C and D service loadings. in the low upper-shelf analysis performed for the belt line region [2]. PCRIT also calculates a stress intensity factor from residual stresses in the weld. A stress intensity factor associated with the cladding/base metal thermal discontinuity gradient is also included by adding a value of [ ] ksilin to the sum of stress intensity factors due to pressure, attached piping, PCRIT thermal, and PCRIT residual stresses.
The hot leg LOCA transient is described in documentation for the low upper-shelf analysis of the beltline region
[2]. The PCRIT run for the hot leg LOCA event is attached in the form of COLDSTOR files listed in Appendix A.
The output file also includes a listing of the input records. PCRIT is also verified for use in the present analysis and is reported in Appendix A.
5.1 Evaluation for Level A & B Service Loadings Initial flaw depths equal to 1/4 of the vessel wall thickness are analyzed for Level A and B Service Loadings following the procedure outlined in Section 2.0 and evaluated for acceptance based on values for the J-integral resistance of the material from Section 4.3. The results of the evaluation are presented in Table 5-1 and Table 5-2, where it is seen that the minimum ratio of material J-integral resistance (J0.1) to applied J-integral (J1) is 1.27 and 1.7 for flaws oriented in the axial and circumferential direction with respect to the RV, which are higher than the minimum acceptable value of 1.0.
The flaw evaluation for the weld (material ID WF-233) is repeated by calculating applied J-integrals for various amounts of flaw extension with safety factors (on pressure) of 1.15 and 1.25 in Table 5-2. The results, along with mean and lower bound J-R curves developed in Table 5-2, are plotted in Figure 5-1. An evaluation line at a flaw extension 0.10 in. is also included to confirm the results of Table 5-1 by showing that the applied J-integral for a safety factor of 1.15 is less than the lower bound J-integral resistance of the material. The requirement for ductile and stable crack growth is also demonstrated by Figure 5-1 since the slope of the applied J-integral curve for a safety factor of 1.25 is considerably less than the slope of the lower bound J-R curve at the point where the two curves intersect.
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AREVA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years Table 5-1: Flaw Evaluation for Level A & B Service Loadings Flaw characterization aot =
ao = in. (initial flaw depth) da = in. (flaw extension) a= in. (flaw depth at extension) a/t=
I/a =
I= in. (flaw length)
C= in. (flaw half length) a/c=
Geometry factors for use in stress intensity factor equation 4(at deepest point) = iT/2 M, = 1.13 - 0.09 (a/c)
M2 = -0.54 + 0.89/[0.2+(a/c)]
24 M3 = 0.5 - 1.0/[0.65+(a/c)] + 14 [1.0-(a/c)]
= [(a/c)2(cos((0))2 + (sin(0))2]0.25 fw= [sec(7c/(2W)(a/t)0 5)]0 5 (assume = 1.0) 2 2 g = 1 + [0.1 + 0.35 (a/t) ] [1-sin(4)]
p = 0.2 + (a/c) + 0.6 (a/t)
G1 = -1.22 - 0.12 (a/c) 07 5 + 0.47 (a/c)'5 G2 = 0.55 - 1.05 (a/c)
H1 = 1.0 - 0.34 (a/t) - 0.11 (a/c) (a/t) 2 H2 = 1.0 + G1 (a/t) + G2 (a/t) 1 65 Q = 1.0 + 1.464 (a/c)
F = [M1 + M2 (a/t)2 + M3 (a/t) 4] fo fw g H = H1 + (H 2 - H 1) (sin(4))p Page 15
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AREVA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years Table 5-2: Flaw Evaluation for Level A & B Service Loadings Stresses for Levels A and B Service Loadings Safety Factor = 1.15 Safety Factor = 1.25 Stress Direction Stress Direction Circ. Long. Circ. Long.
Membrane stress, Sm s]
Bending stress, Sb EF i Ik js:
Stress intensity factor Kj(a/t,a/c,cIW,0) = [Sm + H Sb F [ 7 a/Q IL ksi~~in Plastic zone correction ry= 1/(6 7r) (KI(a)/SY)2 in.
ae = a + ry in.
Corrected stress intensity factor KI(ae) =[Sm + H Sb ] F [i ae/Q 0.5
ýýksN]n Equivalent J-integral Applied J-integral = J1 = 1000 [KI(ae)] 2 / [E/(1-v 2 )]:
[LL Evaluation of the applied J-integral at a ductile flaw extension of 0.10 in.
J-integral resistance at a ductile flaw extension of 0.10" = J 0 .1 = . ilb/in Safetry Factor = 1.15 Stress Direction Circ. Long.
Ratio J 0 .1 /J1 1.27 I1.70I Page 16
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AREVA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years Figure 5-1: J-R Curves for level A & B Service Loadings 1400 1200 1000
. 800
.0
"¢ 600 400 200 0 1 1 0.00 0.05 0.10 .0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 Flaw Extension, da (in.)
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AR EVA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years 5.2 Evaluation for Level C & D Service Loadings A flaw depth of 1.0 inch is used to evaluate the Level C and D Service Loadings. The stress intensity factor K, calculated by the PCRIT code is the sum of thermal, residual stress, deadweight, and pressure terms. PCRIT is run for Hot Leg LOCA transient, the input used in the current analysis are described below.
Fluence at 52 EFPY = 0.23e18 n/cm2 [15]
Percentage of Copper content = .21%[17]
Percentage of Ni Content = .65% [17]
RTNDT = -5.0 °F[18]
Margin = 68.5 °F[18]
Geometry data used is the same as that mentioned in Section 4.1. The materials properties used are the same as that listed in Section 4.2. Weld type used is Double-J circ weld, the closest to existing weld as per the drawings [9, 10]. Initial vessel wall temperature is taken as the normal operating inlet temperature, [ ] OF
[9]. The transient temperature, pressure and heat transfer coefficients used are plotted in Figure 5-2, Figure 5-3 and Figure 5-4 respectively. They are the same as that used for the EMA analysis of beltline welds [2] and are obtained from the COLDSTOR of Reference [2].
Figure 5-2: Level C and D Transients - Reactor Coolant Temperature versus Time Page 18
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AR EVA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years Figure 5-3: Level C and D Transients - Reactor Coolant Pressure versus Time Figure 5-4: Level C and D Transients - Heat Transfer Coefficient vs Time Page 19
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AR EVA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years Figure 5-5: Kic, Kjc (mean and lower bound), and Applied K1 for Level C and D Fracture Toughness Margins for HL LOCA atda= 0.10 in.
500 I I
- - - Kjc Mean 450
-Kjc Lower Bi 400 . . . . Klappl (uppe Kic 350 350 ...- -Evaluation p U 300 ____ ___ _______
" 250* minut~esl 100 - - .,, ____
50 I 0
150 200 250 300 350 400 450 500 550 T( 0 F)
Figure 5-5 shows the variation of applied stress intensity factor, Kh, transition toughness, Kjc, and upper shelf-toughness, K with temperature In the upper shelf-toughness range, the K, curve is closest to the lower bound K& curve at 10.01 minutes into the transient. This time is selected as the critical time in the transient at which to perform the flaw evaluation for Level C and D service loadings.
Applied J-integrals are calculated for the weld for flaw depth of 1.0 inch in Table 5-3 using stress intensity factors from PCRIT for the Hot Leg Large Break LOCA (at 10.01 min.) and adding I I ksiqin [7] to account for cladding effects. Stress intensity factors are converted to J-integrals by the plain strain relationship, J-apid (a) = 1000 (l -_ 2)
E Table 5-3 lists flaw extensions evaluation parameters. As the Davis-Besse vessel is [ ] in. thick, 1/10 of the wall thickness is [ ] in., so an initial flaw depth of 1.0 in used as per Appendix K- guidelines. Flaw extension from this depth is calculated by subtracting 1.0 in. from the built-in PCRIT flaw depths. The results, along with mean and lower bound J-R curves developed in Table 5-3 and Table 5-4, and are plotted in Figure 5-6.
An evaluation line is used at a flaw extension of 0.10 in. to show that the applied J-integral is less than the lower bound J-integral of the material, as required by Appendix K [2]. The requirements for ductile and stable crack growth are also demonstrated by Figure 5-6 since the slope of the applied J-integral curve is considerably less than the slopes of both the lower bound and mean J-R curves at the points of intersection.
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.A AREVA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years Referring to Figure 5-6, the Level D Service Loading requirement that the extent of stable flaw extension be no greater than 75% of the vessel wall thickness is satisfied since the applied J-integral curve intersects the mean J-R curve at a flaw extension that is only a small fraction of the wall thickness (less than 1%).
The PCRIT computer output files for the Level C and D Service Loadings analysis of the transients discussed here are stored on COLDSTOR as listed in Appendix A. The output file also includes a listing of the input records. PCRIT is verified for use in the present analysis and output of the test files are listed in Appendix A.
Table 5-3: Flaw Evaluation for Level C & D Service Loadings Base metal flaw characterization Initial total flaw depth min t/10 + cladding thickness, 1.0 3
- - n.
Initial flaw depth, a, = n. (total flaw depth - cladding thickness) ao/t =
da = n. (flaw extension) a = n. (flaw depth at extension) alt =
I/a =
I= n. (flaw length) c = n. (flaw half length) a/c =
Geometry factors for use in stress intensity factor equation 4(at deepest point) = 7r/2 M, = 1.13 - 0.09 (a/c)
M2 = -0.54 + 0.89/[0.2+(a/c)]
M3 = 0.5 - 1.0/[0.65+(a/c)] + 14 [1.0-(a/c)]24 f= [(a/c) (cos(4))2 + (sin(0))2]0.25 fw= [sec(iTc/(2W)(a/t) 0 5)]0.5 (assume = 1.0) 2 2 g = 1 + [0.1 + 0.35 (a/t) ] [1-sin(4)]
p= 0.2 + (a/c) + 0.6 (a/t)
G1 = -1.22 - 0.12 (a/c) 75 15 G2 = 0.55 - 1.05 (a/c)° + 0.47 (a/c)
H1 = 1.0 - 0.34 (a/t) - 0.11 (a/c) (a/t)
H2 = 1.0 + G1 (a/t) + G2 (a/t)2 16 5 Q = 1.0 + 1.464 (a/c)
F = [M1 + M2 (a/t)2 + M3 (a/t) 4] fý fw g H= H1 + (H2 - H1) (sin(4))p Page 21
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ARkEVA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years Table 5-4: Flaw Evaluation for Level C & D Service Loadings At time = 0 (Pressure loads dominate):
Stress Direction Circ. Long.
Membrane stress, Sm [ ksi Maximum pressure Bending stress, Sb L. ksi plus piping loads Stress intensity factor Kj(a/t,a/c,c/W,4) = [Sm + H Sb ] F [7r a/Q ]05 Pressure + piping loads ksi'in PCRIT thermal loads ksi*in Residual loads ksilin Cladding thermal gradient ksi'/in Total ksi'4in Plastic zone correction 2
ry 1/(6 it) (KI(a)/SY) ae a +ry Corrected stress intensity fac tor KI(ae)= [ Sm + HSb ] F [iTae/Q ]05 Pressure + piping loads ksi'in PCRIT thermal loads Residual loads Cladding thermal gradient ksi'Iin Total -ksi~Iin Equivalent J-integral Applied J-integral = J, = 1000 [Kj(ae)] 2 / [E/(I-v 2 )]:
LL I_.* lb/in Evaluation of the applied J-integral at a ductile flaw extension of 0.10 in.
J-integral resistance at a ductile flaw extension of 0.10" = J 0.1 =[z----lb/in Stress Direction Circ" Lon Ratio J 0.1 /J 1 Page 22
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ARE VA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years Table 5-4: Flaw Evaluation for Level C & D Service Loadings (Cont'd)
At time = 10.01 min. (Thermal loads dominate):
Stress Direction Circ. I Long.
Membrane stress, Sm F- ksi Minimum pressure Bending stress, Sb ksi plus piping loads Stress intensity factor Kj(a/t,a/c,cVW,4) = [Sm + H Sb ] F [7r aIQ ]0.5 Pressure + piping loads PCRIT thermal loads ksi'lin ksi'in Residual loads ksr~in Cladding thermal gradient ksi'in Total ksi'in Plastic zone correction ry 1/(6 Ti)(K,(a)/Sy)2 ae= a +ry Corrected stress intensity factor KI(ae) =[Sm + H Sb ] F [1 ae/Q ] 0.5 Pressure + piping loads ksi'lin PCRIT thermal loads ksi'lin Residual loads ksi'in Cladding thermal gradient ksi'in Total ksilin Equivalent J-integral Applied J-integral = J, = 1000 [KI(ae)]2 / [E/(1-v 2)]:
L7.- Illb/in Evaluation of the applied J-integral at a ductile flaw extension of 0.10 in.
J-integral resistance at a ductile flaw extension of 0.10" = J 0 1 =C**]lb/in StrssDirection Ratio J0.1/J 1 Circ I ong Page 23
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AREVA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet &Outlet Nozzle-to-Shell Welds for 60 Years Figure 5-6: J-R Curves for Level C & D Service Loadings 2500 2000 1500 C
1000 500 0-0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 Flaw Extension, da (in.)
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AR.EVA Document No. 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years 6.0 RESULTS The reactor vessel inlet and outlet nozzle-to-shell welds were evaluated for low upper-shelf energy levels by linear elastic fracture mechanics analytical techniques to satisfy the requirements of Appendix K of ASME Code [4].
The analysis is based on an upper bound surface fluence of 0.23 x 1018 n/cm 2 at 52 EFPY, calculated at the lowest elevation of the outlet nozzle-to-shell weld. This fluence is nearly two orders of magnitude lower than the maximum value of 16.9 x 1018 n/cm 2 utilized for low-upper shelf analysis of the beltline region [2]. Stresses were derived at the weld location considering the influence of the nozzle-to-shell geometric discontinuity and attached piping reactions for Level A, B, C, and D service loadings.
The reactor vessel nozzle-to-shell welds satisfy all acceptance criteria of ASME Code,Section XI, Article K-2000
[4]. For Level A and B service loadings, the applied J-integral of the material at 1.15 times the accumulation pressure, plus thermal loadings is less than the J-integral of the material at a ductile flaw extension of 0.10", by a margin of 1.27. The applied J-integral for Level C Service loadings is less than the required measure of J-integral resistance by a margin of 1.20. Furthermore, the criterion for ductile and stable flaw extensions is satisfied for all Level A, B, C and D service loadings.
7.0 REFERENCES
- 1. Code of Federal Regulations, Title 10, Part 50 - Domestic Licensing of Production and Utilization Facilities, Appendix G - Fracture Toughness Requirements, March 10, 2010
- 2. AREVA NP Document No. 32-5017465-003, "Low Upper-Shelf Toughness Fracture Analysis, Davis Besse"
- 3. AREVA NP Document No. 32-9120793-000, "Davis-Besse Unit 1 Upper Shelf Energy Values for 52 EFPY"
- 4. ASME Boiler & Pressure Vessel Code, Section Xl, Division 1, 1995 Edition including 1996 addendum
- 5. AREVA NP Document No. 32-9120525-000, "Davis Besse Unit 1, Reactor Vessel Stress Input for Fracture Mechanics Analysis"
- 6. Newman, J C, Jr and Raju, I S, "An Empirical Stress Intensity Factor Equation for Surface Cracks",
Engineering Fracture Mechanics, Vol. 5, pp. 185-192, 1981
- 7. AREVA NP Document No. 32-1218513-01, "LUS Analysis for Level C & D Loads"
- 8. AREVA NP Document No. 33-1201205-10, "Stress Report Summary for Reactor Vessel"
- 9. AREVA NP Document No. 02-154619E-02, "Detail and Sub-assembly Outlet Nozzle"
- 10. AREVA NP Document No. 02-154620E-02, "Detail and Sub-assembly Inlet Nozzle"
- 11. AREVA NP Document No. 02-154616E-04, "Upper Shell Assembly"
- 12. ASME Boiler and Pressure Vessel Code,Section II, Part D, 1995 Edition with Addenda through 1996.
- 13. AREVA NP Document No. 43-2192PA-000, "Low Upper-Shelf Toughness Fracture Mechanics Analysis of Reactor Vessels of B&W Owners Reactor Vessel Working Group for Level A&B Service Loads", April 1994
- 14. AREVA NP Document No. 32-1206020-00, "RV outlet Nozzle Stress Analysis for LEFM"
- 15. AREVA NP Document No. 86-9025792-001, "Davis Besse Fluence Analysis - Cycles 13-14 Summary Report"
- 16. AREVA NP Document No. 32-1174278-007, "Verification of PCRIT 6.3 User's Manual"
- 17. AREVA NP Document No. 32-9123247-000, "RTPTS values of Davis-Besse Unit 1 for 52 EFPY, Including Extended Beltline"
- 18. AREVA NP Document No. 32-9124893-001, "DB-1 Pressurized Thermal Shock (PTS) Analysis for 32 and 52 EFPY" Page 25
For Information Only
.A A, EVA, Document No., 32-9195423-000 NON-PROPRIETARY DB-1 EMA of RPV Inlet & Outlet Nozzle-to-Shell Welds for 60 Years APPENDIX A: COMPUTER OUTPUT FILES AND INSTALLATIONNERIFICATION OF PCRIT PCRIT was installed and verified for use in the present analysis by executing TestCase 1 and Test Case 2 and comparing results with those reported in the PCRIT verification package. The output for these two test cases is included in the COLDSTOR directory \cold\General-Access\32\32-9000000\32-9110426-000\official. The files are listed below. The test results are found to be identical to those of Reference [16].
File Name Description Install Date Checksum DB-LOCA.OUT Hot-leg Loss-of-Coolant Accident 05/26/2010 09622 Test-1 .out Verification. Test Case 1 05/26/2010 10982 Test-2.out Verification Test Case 2 05/26/2010 32526
- Computer program tested: PCRIT 6.3
" Hardware used: Dell Precision 390, Service Tag# / SN: 44HK5D1
" Name of Person running test: S. J. Noronha
" Date of test: 05-26-2010
- Results and applicability: The results in table below are found to be identical to that in PCRIT verification report [16].
Stress Intensity Factors, ksirin Test Case 1 Test Case 2 (longitudinal flaw) (circumferential flaw)
Source Test-1 .out Test-2.out Deadweight 0 1.09 Residual Stress 9.42 4.98 Pressure 25.65 13.11 Thermal 2.28 21.59 Page 26