ML101400405
| ML101400405 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 05/06/2010 |
| From: | Noronha S, Xu H AREVA NP |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| L-10-143, TAC ME3703 32-9136884-001 | |
| Download: ML101400405 (48) | |
Text
ENCLOSURE A DB-1 CRDM NOZZLE WELD ANOMALY FLAW EVALUATION OF IDTB ALTERNATE REPAIR WITH ALLOY 52M/82 (NONPROPRIETARY VERSION)
AREVA CALCULATION 32-9136884-001 Forty-Seven Pages Follow
Uontrolled Locument 0402-01-F01 (20697) (Rev. 014, 04/13/2009)
A CALCULATION
SUMMARY
SHEET (CSS)
AREVA Document No.
32 9136884 001 Safety Related: M Yes [i No DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Title Alloy 52M/82 PURPOSE AND
SUMMARY
OF RESULTS:
Purpose:
This document is a non-proprietary version of AREVA NP Document 32-9136807-001.
The AREVA NP proprietary information removed from 32-9136807-001 is indicated by a pair of braces "{ }".
The purpose of this analysis is to perform a fracture mechanics evaluation of a postulated anomaly in the Davis-Besse Unit 1 (DB-1) Control Rod Drive Mechanism (CRDM) nozzle ID temper bead (IDTB) alternate repair weld with Alloy 52M/82. For information, the qualification for the original IDTB repair weld with Alloy 52M exclusively is documented in 32-9135800 separately.
This anomaly is assumed to be a 0.1 inch semi-circular flaw extending 360 degrees around the circumference at the "triple point" location where there is a confluence of three materials; the Alloy 600 nozzle, the Alloy 82 weld, and low alloy steel head. Two potential flaw propagation paths are considered in the flaw evaluations. The analysis includes prediction of fatigue crack growth in an air environment since the anomaly is located on the outside surface of the new weld, just below the bottom of the severed nozzle. Flaw acceptance is based on the 1995 through 1996 ASME Code Section XI [51 criteria for applied stress intensity factor (IWB-3612) and limit load (IWB-3642).
The purpose of Revision 001 is to update the references and perform the analysis based on the updated steady state condition operating temperature of{
} F.
Summary of Results:
The results of the analysis demonstrate that the 0.1 inch weld anomaly is acceptable for a 25 year evaluation life of the CRDM nozzle ID temper bead alternate weld repair. However, note that the design life of the RVCH, as per the design specification is 4 years [4]. Significant fracture toughness margins have been demonstrated for each of the two flaw propagation paths considered in the analysis. The minimum fracture toughness margin is 3.72, compared to the required margins of 410 for normal/upset conditions and 42 for emergency/faulted conditions per IWB-3612. Fatigue crack growth is minimal since the maximum final flaw size is {
} inch. The margin on limit load is 10.44 for normal/upset conditions and 7.38 for emergency/faulted conditions, compared to the required margins of 3.0 and 1.5, respectively, per IWB-3642.
THE DOCUMENT CONTAINS ASSUMPTIONS THAT SHALL BE THE FOLLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT:
VERIFIED PRIOR TO USE CODENERSION/REV CODENERSION/REV
[I YES Z
NO AREVA NP Inc., an AREVA and Siemens companyP Page 1 of 47
Uontrolled Document A
0402-01-FOl (20697) (Rev. 014, 04/13/2009)
AREVA Document No. 32-9136884-001 AREVA NP Inc.,
an AREVA and Siemens company DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Review Method: [* Design Review (Detailed Check)
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v 576(42 S. J. Noronha All Pages (Detailed check)
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T. M. Wiger A
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.1.
Page 2
Uontrolled Document A
ARE VA AREVA NP Inc.,
an AREVA and Siemens company 0402-01-FOl (20697) (Rev. 014, 04/13/2009)
Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Record of Revision Revision PageslSectionsl No.
Date Paragraphs Changed Brief Description / Change Authorization 000 04/2010 All Original 001 05/2010 CSS Page Added the purpose of this revision Section 3.0 Added a minor assumption for updated temperature Section 4.0 Updated the steady state operating temperature Section 4.1 Updated code minimum yield strengths based on the steady state operating temperature
'Section 4.3.2 Updated the fracture toughness calculation based on the steady state operating temperature Section 5.0 Revised calculations based on updated steady state operating temperature Section 6.0 Updated the results Section 7.0 Updated References 1 and 16 Appendix B Removed Page 3
Uontrolled Document A
A Document No. 32-9136884-001 AR-EVAý ARLEkA:
NP Inc.;
an"AREVA and Siemens company DB-I1 CRDM Nozzle Weld Anomaly Flaw Evaluation ofIDTB Alternate Repair with Alloy 52M/82 Table of Contents Page SIG NATURE BLOCK................................................................................................................................
2 RECORD O F REVISIO N..........................................................................................................................
3 LIST O F TABLES.....................................................................................................................................
6 LIST O F FIGURES...................................................................................................................................
7 1.0 INTRO DUCTIO N..........................................................................................................................
8 1.1 CRDM Nozzle IDTB Alternate W eld Repair.................................................................................
8 1.2 Potential W eld Anomaly...............................................................................................................
8 1.3 Postulated Flaws............................................................................................................................
10 2.0 ANALYTICAL M ETHO DOLOGY...........................................................................................
11 2.1 SIF Solutions..................................................................................................................................
11 2.2-Fatigue Crack Growth in Air.......................................................................................................
13 2.3 Acceptance Criteria........................................................................................................................
14 3.0 ASSUM PTIO NS..........................................................................................................................
16 4.0 DESIGN INPUTS....................................................
17 4.1 Code Minimum Yield Strength..................................................................................................
17 4.2 Applied Stresses..........................................................................................................................
17 4.2.1 Fatigue Stresses.........................................................................................................
17 4.2.2 Residual Stresses.......................................................................................................
21 4.3 Fracture Toughness.......................................................................................................................
26 4.3.1 Low Alloy Steel RV Head Material...............................................................................
26 4.3.2 Alloy 600 and Alloy 690 Materials..............................................................................
26 5.0 CALCULATIO NS.........................................................................................................................
27 6.0 RESULTS....................................................................................................................................
42 6.1 Propagation of a Continuous External Circumferential Flaw along Path 1...............................
42 6.2 Fatigue Crack Growth of a Semi-Circular External Axial Flaw along Path I............................
42 6.3 Fatigue Crack Growth of a Continuous Cylindrical Flaw along Path 2.....................................
42
7.0 REFERENCES
44 Page 4
Uontrolled Document A
AREvA NP Inc.;
an ARE VA and Siemens'company Document No, 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Fla'4 Evaluation of IDTB Alternate Repair with Alloy 52M/82 Table of Contents (continued)
Page APPENDIX A:
COMPARISION OF DB-1 AND ANO-1 REACTOR VESSEL CLOSURE HEADS............... 46 Page 5
liontrolleci Document A
AREVA Document No. 32-9136884-001 AREVA NP Inc.,
an AREVA'and Sienmens'c6mpany DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 List of Tables Page Table 4-1: Stresses for Flaw Evaluations along Path 1 [18].............................................................
19 Table 4-2: Stresses for Flaw Evaluations along Path 2 [18]............................................................. 20 Table 4-3: Residual Stresses in Repair Weld after Chamfering* J-Weld..........................................
24 Table 4-4: Residual Stresses in Repair weld after Chamfering* J-weld (Cont'd)...............................
25 Table 5-1: Evaluation of Continuous External Circumferential Flaw for Fatigue Crack Growth along P a th 1...............................................................................................................................................
2 7 Table 5-2: Limit Load Analysis for a Continuous External Circumferential Flaw.............................. 31 Table 5-3: Evaluation of External Axial Flaw for Fatigue Crack Growth along Path 1...................... 31 Table 5-4: Evaluation of a Continuous Cylindrical Surface Crack for Fatigue Crack Growth along Path 2.......................................................................................................................................................
3 7 Table A-I: Comparison of Critical Dimensions of DB-1 and ANO-1................................................
46 Table A-2: Comparison of IDTB Materials of DB-1 and ANO-1.........................................................
46 Page 6
uontrolled Document A
AREVA Document No. 32-9136884-001 AREVA NP Inc.,
an AREVA and Siemens company DB-1 CROM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 List of Figures Page Figure 1-1: W eld Anomaly in Temper Bead W eld Repair..................................................................
9 Figure 1-2: Illustration of Crack Propagation Paths on the Finite Element Stress Model.................. 11 Figure 4-1: FEA Model for Center CRDM Nozzle with Weld Repair.................................................
22 Figure 4-2: FEA Model for Center CRDM Nozzle after Weld Repair and Chamfer*.........................
23 Page 7
Uontrolled Document A
Document No. 32-9136884-001 ARE VA AREVA NP Inc.,
an AREVA and Siemens company DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82
1.0 INTRODUCTION
The purpose of this analysis is to perform a fracture mechanics evaluation of a postulated anomaly in the Davis-Besse Unit 1 (DB-1) Control Rod Drive Mechanism (CRDM) nozzle ID temper bead (IDTB) alternate repair weld.
This anomaly is assumed to be a 0.1 inch semi-circular flaw extending 360 degrees around the circumference at the "triple point" location where there is a confluence of three materials; the Alloy 600 nozzle, the Alloy 82 weld, and low alloy steel head. Two potential flaw propagation paths are considered in the flaw evaluations.
1.1 CRDM Nozzle IDTB Alternate Weld Repair The CRDM nozzle ID temper bead (IDTB) alternate weld repair is described by the design drawing [11 and AREVA Special Instruction [2]. Per the Procedure Supplement [3], the Alloy 82 filler metal is applied first, then the wire spool is changed to Alloy 52M and the remainder of the weld is completed with Alloy 52M. This weld repair establishes a new pressure boundary above the original J-groove weld. The five steps involved in the repair design are listed below.
- 1)
Roll Expansion
- 2)
Nozzle Removal and Weld Prep Machining
- 3)
Welding
- 4)
Grinding/Machining and NDE
- 5)
Original Weld Grinding During the welding process (step 3), a maximum 0.1 inch weld anomaly may be formed due to lack of fusion at the "triple point", as shown in Figure 1-1. The anomaly is conservatively assumed to be a "crack-like" defect 3600 around the 'circumference at the "triple point" location. The technical requirements document [4] provides additional details of the ID temper bead weld repair procedure. The purpose of the present fracture mechanics analysis is to provide justification, in accordance with Section Xl of the ASME Code [5], for operating with the postulated weld anomaly at the triple point. Predictions of fatigue crack growth are based on an evaluation life of 25 years.
1.2 Potential Weld Anomaly The anomaly could be located in the triple point region as shown in Figure 1-1. The region is called a "triple point" since three materials intersect at this location. The materials are:
a) the Alloy 600 CRDM nozzle material, b) the Alloy 82 weld material, and c) the low alloy steel RV head material.
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Controlled Document A
ARE VA AREVA NP Inc.;
an AREVA and Siemens company Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82
~MAX
/
200 MIN TRIPLE POINT POSSIBLE FUSION
(.10 MA)
LACK OF ANOMALY AS-WELDED SURFACE SHALL BE SUITABLE FOR PT Figure 1-1: Weld Anomaly in Temper Bead Weld Repair Page 9
Controlled Document A
Document No. 32-9136884-001 ARýE A
AREVA NP Inc.;
anAREVA and Siemens company DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 1.3 Postulated Flaws The triple point weld anomaly is assumed to be semi-circular in shape with an initial radius of 0.10", as indicated in Figure 1-1. It is further assumed that the anomaly extends 3600 around the nozzle. Three flaws are postulated to simulate various orientations and propagation directions for the anomaly. A circumferential flaw and an axial flaw on the outside surface of the nozzle would both propagate in a horizontal direction toward the inside surface.
A cylindrically oriented flaw along the interface between the weld and head would propagate downward between the two components. The horizontal and vertical flaw propagation directions are represented in Figure 1-2 by separate paths for the downhill and uphill sides of the nozzle, as discussed below. For both these directions, fatigue crack growth will be calculated considering the most susceptible material for flaw propagation.
Horizontal Direction (Path 1):
Flaw propagation is across the CRDM tube wall thickness from the OD of the tube to the ID of the tube.
This is the shortest path through the component wall, passing through the new Alloy 52M/82 weld material.
For completeness, two types of flaws are postulated at the outside surface of the tube. A 3600 continuous circumferential flaw, lying in a horizontal plane, is considered to be a conservative representation of crack-like defects that may exist in the weld anomaly. This flaw would be subjected to axial stresses in the tube. An axially oriented semi-circular outside surface flaw is also considered since it would lie in a plane that is normal to the higher circumferential stresses. Both of these flaws would propagate toward the inside surface of the tube. For axial flaws, Alloy 82 and Alloy 600 material properties are considered separately to cover the possible flaw propagation in IDTB alternate repair weld and CRDM tube, respectively.
Vertical Direction (Path 2):
Flaw propagation is down the outside surface of the repair weld between the weld and RV head. A continuous surface flaw is postulated to lie along this cylindrical interface between the two materials. This flaw, driven by radial stresses, may propagate along either the new Alloy 52M/82 weld materials or the low alloy steel head material. For the crack growth in the weld, Alloy 82 material properties are used for flaw evaluations.
Page 10
Controlled Document A
AREVA AREVA NP Inc..
an AREVA and Siemens company Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Figure 1-2: Illustration of Crack Propagation Paths on the Finite Element Stress Model 2.0 ANALYTICAL METHODOLOGY This section presents several aspects of linear elastic fracture mechanics (LEFM) and limit load analysis (to address the ductile Alloy 600 and Alloy 52M materials) that form the basis of the present flaw evaluations. As discussed in Section 1.3, flaw evaluations are performed for flaw propagation Paths I and 2 in Figure 1-2.
2.1 SIF Solutions Path I represents a section across the new Alloy 52M/82 weld metal which is equivalent to the thickness of the CRDM tube wall. Since the weld anomaly is located at the base of the OD of the CRDM tube and is assumed to be all the way around the circumference, a stress intensity factor (SIF) solution for a 3600 circumferential crack on the OD of a circular tube is deemed appropriate. Therefore, the SIF solution of Buchalet and Bamford [6] is used in the analysis. However, this solution is applicable to a 3600 part-through ID flaw. To develop an SIF solution for a 3600 part-through OD flaw, an F function is determined based on SIF solutions of Kumar [7, 8]. Appropriate F functions for internal and external circumferential flaws are determined for a cylinder subjected to remote tension.
The ratio of the F functions for the external and internal flaws is considered to be an appropriate multiplying factor for the Buchalet and Bamford SIF solution to extend its application to an external flaw. Similar ratios have been reported by Kumar [9]. The materials to be considered for this path are the Alloy 52M/82 weld metal. Fatigue crack growth is calculated using crack growth rates for Ni-alloy welds per NUREG/CR-6921 [10]. A limit load analysis for an external circumferential flaw in a cylinder subjected to remote tension [8] is also performed for applied loads on the CRDM tube.
Page 11
uontroIled uocument A
AREVA AREVA NP Inc.,
an AREVA and siemens company Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation oflIDTB Alternate Repair with Alloy 52M/82 An axially oriented semi-circular OD surface flaw is also considered in the evaluation, as illustrated by the schematic below.
t
.4
- where, a = initial flaw depth
= 0.100 inch I = 2c = flaw length t = wall thickness
= 0.200 inch
={
} inch An axial flaw is considered since the stresses in the CRDM penetration region are primarily due to pressure and therefore the hoop stresses are more significant. The SIF solution by Raju & Newman [11] for an external surface crack in a cylindrical vessel is used in the evaluation, considering growth in both the radial and axial directions.
The materials to be considered for axial flaws are the Alloy 600 for CRDM tube and Alloy 52M/82 for IDTB alternate repair. The fatigue flaw growth rates in an air environment for Alloy 600 and Ni-alloy welds are obtained from NUREG/CR-6921 [10] and NUREG/CR-6721 [12], respectively.
The Irwin plasticity correction is also considered in the SIF solutions discussed above. This plastic zone correction is discussed in detail in Section 2.8.1 of Anderson's fracture mechanics book [13]. The effective crack length is defined as the sum of the actual crack size and the plastic zone correction:
a, =a+ ir where ry for plane strain conditions (applicable for this analysis) is given by:
ry
.6 (KI** 2 Path 2 represents the interface between the new repair weld and the RV head material. The potential for flaw propagation along this interface is likely if radial stresses are significant between the weld and head. This assessment utilizes an SIF solution for a continuous surface crack in a flat plate from Appendix A of the 1995 Edition of Section Xl [5]. Flat plate solutions are routinely used to evaluate flaws in cylindrical components such as the repair weld since the added constraint provided by the cylindrical structure reduces the crack opening displacements. The solution is therefore inherently conservative for this application. Crack growth analysis is performed considering propagation through the Alloy 52M/82 weld materials or the low alloy steel head material, whichever is limiting.
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Controlled Document A
A RDocument No. 32-9136884-001 ARE VA AREVA NP Inc.,
an AREVA and Siemens company DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 2.2 Fatigue Crack Growth in Air SA-533 Grade B Class 1 Low Alloy Steel Plate Material (RV Head)
From Article A-4300 of the 1995 Edition with 1996 Addendum of Section Xl [5], flaw growth due to fatigue is characterized by da
--*=C 0 (AK, )n where C, and n are constants that depend on the material and environmental conditions, AK1 is the range of applied stress intensity factor in terms of ksi4in, and da/dN is the incremental flaw growth in terms of inches/cycle.
For the embedded weld anomaly considered in the present analysis, it is appropriate to use crack growth rates for an air environment. Fatigue crack growth is also dependent on the ratio of the minimum to the maximum stress intensity factor; i.e.,
R = (KI )min /(KI )m The fatigue crack growth constants for flaws in an air environment are:
n = 3.07 C. = 1.99 x 10"10 S where S = 25.72 ( 2.88 - R )y3.
0 7 for 0:< R < 1 Alloy 600 for CRDM Tube Fatigue crack growth rates for Alloy 600 are used to predict flaw growth in the CRDM tube. From NUREG/CR-6721, Section 3.1 [12], flaw growth due to fatigue is characterized by da
-- = Co (AK, )n dN where C, and n are constants that depend on the material and environmental conditions, AKI is the range of applied stress intensity factor in terms of MPa'/m, and da/dN is the incremental flaw growth in terms of m/cycle.
For the embedded weld anomaly considered in the present analysis, it is appropriate to use crack growth rates for an air environment. Fatigue crack growth is also dependent on the ratio of the minimum to the maximum stress intensity factor, i.e.,
R =(KI rain I(KI)max The fatigue crack growth constants for flaws in an air environment are:
n=
4.1 Co =
CA600 X SR where Page 13
Controlled Document A
AiREVA Document No. 32-9136884-001 AREVA NP Inc.,
an AREVA and Siemens company DB-i CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 CA600 =
4.835xl 0-14+1.622xl 0 1'6T-1.490xl 0"1 "T
2+4.355 X1 0-2 1T3 T= Temperature,°C SR =
(1-0.82R)-2.2 Alloy 52M/82 Weld Metal for I DTB Alternate Repair Fatigue crack growth rates for Alloy 82 are used to conservatively predict flaw growth in the new Alloy 52M/82 repair weld. From NUREG/CR-6921, Section 5.2 [10], flaw growth due to fatigue is characterized by da
.N = C. (AK, )
where C, and n are constants that depend on the material and environmental conditions, AKI is the range of applied stress intensity factor in terms of MPa4m, and da/dN is the incremental flaw growth in terms of m/cycle.
For the embedded weld anomaly considered in the present analysis, it is appropriate to use crack growth rates for an air environment. Fatigue crack growth is also dependent on the ratio of the minimum to the maximum stress intensity factor; i.e.,
R = (KI) mrin I(KI ).x The fatigue crack growth constants for flaws in an air environment are:
n= 4.1 Co =
CNiweld X SR where CNi-weld =
8.659xl 0"14-5.272x1 0-"7T+2.129xl 0-"T 2-1.965x1 02'T 3+6.038x1 0 23T4 T = Temperature, 0C SR =
(1-0.82R)"
2.2 2.3 Acceptance Criteria The low alloy steel reactor vessel head material will be evaluated against the IWB-3612 acceptance criteria of Section Xl [5]. For the highly ductile materials Alloy 600 and Alloy 690 materials, the initial flaw depth to thickness ratio for the postulated weld anomaly is only about 20% and fatigue crack growth is minimal for these materials in an air environment. A convenient acceptance criterion on flaw size is the industry developed 75% through-wall limit on depth [141:
- < 0.75 For the shallow cracks considered in the present analysis, this criterion is easily met. In addition, stress intensity factors will be calculated and evaluated against conservative fracture toughness requirements using a factor of safety of 410 for normal and upset conditions.
Page 14
Controlled Document A
Document No. 32-91136884ý-001 AREVA NP Inc.,
an AREVA and Siemens company DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Another acceptance criterion for ductile materials is demonstration of sufficient limit load margin. From IWB-3642 [5],
the required safety margin, based on load, is a factor of 3 for normal and upset conditions and a factor of 1.5 for emergency and faulted conditions.
Since stresses for emergency/faulted conditions are bounded by the controlling normal/upset condition stresses (see Section 4.2) and the required fracture toughness margins are less stringent for emergency/faulted conditions, satisfying normal/upset conditions requirements implicitly satisfies those for emergency/faulted conditions as well.
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Controlled Document A
A k Document No. 32-9'136884-001 AREVA NP Inc.,
an-AREVA and Siemnens' com6any DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Aiternate Repair with Alloy 52M/82 3.0 ASSUMPTIONS This analysis contains no major assumptions that must be verified prior to use on safety-related work. Listed below are minor assumptions that are pertinent to the present fracture mechanics evaluation.
- 1. The anomaly is assumed to include a "crack-like" defect, located at the triple-point location and extending all the way around the circumference. For analytical purposes, a continuous circumferential flaw is located in the horizontal plane at the top of the weld. Another continuous flaw is located in the cylindrical plane between the weld and reactor vessel (RV) head.
- 2.
In the radial plane, the anomaly is assumed to include a quarter-circular "crack-like" defect (see Figure 1-1).
For analytical purposes, a semi-circular flaw is used to represent the radial cross-section of the anomaly.
- 3.
An RTNDT value of 60°F is conservatively assumed for the SA-533 Grade B Class 1 low alloy reactor vessel head material. This is based on a highest measured value of 40OF for 13 heats of SA-533 Grade B plate material 1[15].
- 4. The transient stress and weld residual stress are not affected by the deposition of a small portion of Alloy 82 prior to application of Alloy 52M, as illustrated in the Procedure Supplement [3].
This is a reasonable assumption since only a small fraction of weld layers deposited is Alloy 82 and the thermal and mechanical properties for Alloy 82 and Alloy 52M are very similar.
- 5. The current operating head temperature is {
} OF. The reactor trip starting temperature (or steady state condition temperature) at transient time 10.000 hours0 days <br />0 hours <br />0 weeks <br />0 months <br /> used in transient stress analysis [18] is {
} OF. The difference between the higher head temperature and the analyzed temperature is only { } OF. The effect of this difference in steady state head temperatures will be negligible on the transient stresses considered in this analysis.
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Controlled Document A
AREVA Document No. 32-9136884-001 AREVA NP Inc.,
an AREVA and Siemens company DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 4.0 DESIGN INPUTS The region of interest for the present flaw evaluations is at the triple point, where three different materials intersect. These materials are the CRDM nozzle material, the new weld material and the reactor vessel head material.
The DB-1 CRDM nozzles are made from Alloy 600 material to ASME specification SB-167 for tubular products
[4]. The new weld, as noted in Section 1.2, is made from Alloy 52M/82 type materials. The portion of the reactor vessel head that contains the CRDM nozzles is fabricated from SA-533 Grade B Class 1 [4]. The normal operating steady state condition temperature is {
} OF [161.
4.1 Code Minimum Yield Strength The code minimum yield strength, Sy, values for SB-167 Material N06600 (Alloy 600 Material) as per the 1989 edition of the ASME Code [22] is 35.0 ksi at room temperature and 27.7 ksi at operating temperature of{
} OF.
For the SA-533 Grade B Class 1 Low Alloy Steel Material (RV Head), the room temperature yield strength is 50.0 ksi and at operating temperature ({
} OF) the yield strength is 43.7 ksi [22].
For the Alloy 52M new weld material, the material properties are obtained from Code Case N-474-2 [17]. The yield strength for Alloy 52M material at operating temperature of {
O
°F is 27.6 ksi.
The code minimum yield strength is used for limit load analysis. The yield strength values used for plastic zone correction of the stress intensity factor as discussed in Section 5.0 are the same as the ones used for residual stress calculation.
4.2 Applied Stresses The applied stresses are the cyclic stresses that contribute to fatigue crack growth. Incremental crack growth is based on six design heatup/cooldown cycles per year of operation. Residual stresses are also developed in the repair weld from the ID temper bead welding process that forms the new pressure boundary.
4.2.1 Fatigue Stresses Fatigue stresses are obtained from the generic stress analysis for the B&W 177 FA plants contained in Reference
- 18. The maximum stresses, which occur during cooldown (at 10.004 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> into the composite heatup/cooldown transient), are combined with a zero stress at shutdown to produce a maximum cyclic load since stresses remain positive during this transient due to the dominating effect of pressure. The reactor coolant pressure at the 10.004 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> time point is {
} psig [18]. A slightly higher pressure ({
} psia) occurs during a rod withdrawal accident, which is classified as an upset condition in the reactor coolant system functional specification [19].
Stresses for the rod withdrawal transient will be obtained by multiplying the stresses at 10.004 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> into the composite heatup/cooldown transient by the ratio of the pressures for the two transients.
Component stresses are obtained for the two crack propagation paths outlined on the finite element model [18].
Stresses for Paths 1 and 2 are obtained from Reference 18. Stresses are reported in a cylindrical coordinate system relative to the CRDM nozzle and include the three component stresses (axial, hoop and radial) needed to calculate mode I stress intensity factors for the various postulated flaws. These stresses, provided at four uniform increments along each path, were derived for ligament thicknesses of 0.488" for Path 1 and 1.143 inches for Path 2.
The stresses in Reference 18 apply directly to a weld thickness of 0.488". After grinding the inside surface of the weld, the thickness of the weld relative to the outside surface of the nozzle (triple point location to grounded ID of the IDTB weld) is {
} [1]. The length of the actual weld is 1.35 inches [1]. Since the Page 17
Uontrolled Document A
Document No. 32-9136884-001 ARkEVA NP inc..
an AREVA and Slemens$c6mpany DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 actual weld thickness and length are greater than the analyzed thickness, no adjustment will be made to the Reference 18 stresses in the present flaw evaluations.
To ensure that the bounding stresses are captured for use in the present flaw evaluations, stresses are obtained at every 45 degrees from the downhill (0°) to the uphill (1800) locations, as shown by the figure in Appendix D of Reference 18. It is concluded in that reference that the most limiting path is at the 1800 uphill location. The uphill stresses are presented in Tables 4-1 and 4-2 for Paths 1 and 2, respectively.
As noted in the conclusions of Appendix F of Reference 18, stresses due to emergency/faulted conditions are bounded by the controlling normal/upset condition stresses. Therefore, the emergency/faulted condition stresses are bounded by the normal/upset condition stresses, considered above, for the fatigue crack growth analysis.
Page 18
A AREVA AREVA NP Inc.,
an AREVA and Siemens company Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Table 4-1: Stresses for Flaw Evaluations along Path 1 [18]
Composite HeatuplCooldown Transient (Normal Operating Conditions)
Path:
WA180 Length = 0.488 Triple Point Location:
0.000 0.000 0.000 0.122 0.122 0.122 0.244 0.244 0.244 0.366 0.366 0.366 0.488 0.488 0.488 Pressure Time
-SX-
-SY-
--SZ-
-SX--
-SY--
-SZ-
-SX--
-SY--
-SZ-
--SX-
-SY--
-SZ-
-SX-
-SY-
--SZ-(psiq)
(hr.)
Radial Hoop Axial Radial Hoop Axial Radial Hoop Axial Radial Hoop Axial Radial Hoop Axial 0.001 4.770 4.871 7.000 7.313 7.412 1(0 000 10000
.4 I
I IA fl04 r" 10 004 r41 10.013 10.117 10.217 10.250 10.718 12.939 Ratioed Stresses for Rod Withdrawl Accident (Upset Condition)
Note: Rod Withdrawal Accident Stress = {
}
- Heatup/Cooldown Stress Triple Point Location:
0.000 0.000 0.000 0.122 0.122 0.122 0.244 0.244 0.244 0.366 0.366 0.366 0.488 0.488 0.488 I Pressure
-SX-
-SY-
--SZ-
-SX--
-SY--
-SZ-
-SX-
--SY--
-SZ--.
.SX-
-SY--
-SZ-
-SX-
-SY-
--SZ-(psig)
Radial Hoop Axial Radial Hoop Axial Radial Hoop Axial Radial Hoop Axial Radial Hoop Axial Legend:
SX = radial stress SY = hoop stress SZ = axial stress Page 19
A AREVA AREVA NP Inc.,
an AREVA and Siemens company Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Table 4-2: Stresses for Flaw :Evaluations along Path 2 [18]
Composite HeatuplCooldown Transient (Normal Operating Conditions)
Path:
WV180 Length = 1.143 Triple Point Location:
0.0000 0.0000 0.0000 0.2858 0.2858 0.2858 0.5715 0.5715 0.5715 0.8573 0.8573 0.8573 1.1430 1.1430 1.1430 Pressure Time
--SX-
-SY--
-SZ--
-SX-
--SY-
-SZ--
-SX-
-SY-
--SZ-
-SX--
-SY--
-SZ-
-SX-
-SY-
-SZ-(psig)
(hr.)
Radial Hoop Axial Radial Hoop Axial Radial Hoop Axial Radial Hoop Axial Radial Hoop Axial 0.001 4.770 4.871 7.000 7.313 7.412 10.000
{
10.004 10.013 10.117 10.217 10.250 10.718 12.939 Ratioed Stresses for Rod Withdrawl Accident (Upset Condition)
Note: Rod Withdrawal Accident Stress = {
} Heatup/Cooldown Stress Triple Point Location:
0.000 0.000 0.000 0.122 0.122 0.12210.244 0.244 0.244 0.366 0.366 0.366 0.488 0.488 0.4881 Pressure
--SX-
-SY-
-SZ--
-SX-
--SY-
-SZ-
-SX-
-SY-
--SZ-
-SX--
-SY--
-SZ-
-SX-
-SY-
-SZ-I
_psi_)
Radial Hoop Axial Radial Hoop Axial Radial Hoop Axial Radial Hoop Axial Radial Hoop Axial Legend:
SX = radial stress SY = hoop stress SZ = axial stress Page 20
Controlled Document A
AREVADocument No. 32 9i36884-001 AR EVA AREVA NP Inc.,
an AREVA and Siermens company DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 4.2.2 Residual Stresses A three-dimensional elastic-plastic finite element analysis [201 was performed to simulate the sequence of steps involved in arriving at the configuration of the CRDM nozzle and reactor vessel head after completion of the ID temper bead repair. A comparison of the geometry and materials of reactor vessel closure heads of ANO-1 and DB-1 is presented in Appendix A of this document to justify the use of the weld residual stresses from the analysis of Reference 20. To simplify the analysis of the complete repair process, only the center nozzle was modeled as shown in Figure 4-1. Although this axisymmetric analysis was based on the geometry of the center nozzle penetration, adjustments were made to represent significant aspects of the controlling nozzle at the outermost hillside location ({
}O from the top of the vessel). In particular, the repair weld was positioned at the minimum distance above the J-groove and the J-groove weld was chamfered to simulate the largest chamfer (7/8"). The model also used the highest yield strength of any nozzle in the head ({
}). The {
}o nozzle location was limiting for all three of these conditions.
The FE analysis simulated the laying of the original weld butter and the subsequent post-weld stress relief, the heatup of the original J-groove weld and adjacent material during the welding process and the subsequent cooldown to ambient temperature, a pre-service hydro test, and operation at steady state conditions. After the steady state loads were removed and the structure was again at ambient conditions, the portion of the nozzle below the cut line [1] was deleted. Deposition of the repair weld was simulated using four weld passes, and the J-groove weld was chamfered as shown in Figure 4-2. The analysis of this final configuration provided residual stresses in the repair weld for use in the present flaw evaluations. These stresses are listed in Table 4-3 and Table 4-4.
The welding simulation in Reference 20 used a multi-linear isotropic hardening model to characterize the nozzle material and elastic-perfectly plastic material models for the welds, butter, cladding and head. The yield strengths for the non-strain hardening models were selected to represent the flow stress of the various materials. The following yield strength values were used in the welding simulation:
Component Material Yield Strength at 600 OF (1)
Nozzle Alloy 600
{
} ksi Repair weld Alloy 52M
{
} ksi J-groove weld Alloy 182
{
} ksi (2)
Butter Alloy 182
{
} ksi (2)
Head Low alloy steel
{
} ksi Cladding Stainless steel
{
} ksi Note:
- 1) The operating temperature of the plant is {
} OF. However the effect of this small difference in the temperature should be minimal.
- 2) Also applicable to the alternate IDTB weld material, Alloy 82.
In this evaluation for Davis-Besse, chamfering is not applicable. However, the effect of chamfering of J-groove weld on IDTB weld will be minimal since J-Groove weld chamfering range is far enough from the triple point. In addition, comparing with transient stresses that determine the AK,, the sustained residual stresses are usually not a major contributor to fatigue crack growth since they do not contribute to AK,, but only to the ratio of the minimum to the maximum stress intensity factor.. Therefore, the residual stresses used in Reference 20 are considered a reasonable approximation for this flaw evaluation.
Page 21
Controlled Document A
AREVA AREVA NP Inc.,
an AREVA and Slemens comany Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52MW82 Nozzle Cut Line 2601/
Nozzle Repair Weld Region Pass 4/
Pass I/
Nozzle Elements Removed During Repair Weld Prep
/
9 Node Nunibers Increase by 100 up the length of the tube and shell Node Nutmbers Increase by I aloncg the tube and shell radius Nodes 609 through 1409 are coincident wilh 610 throuigl 1410 Figure 4-1: FEA Model for Center CRDM Nozzle with Weld Repair Page 22
Controlled Document A
AREVA AREVA NP Inc.,
an ARffVA an& Semn company Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Nozzle Repair Weld Region Region Removed for Wel d C ham fer Figure 4-2: FEA Model for Center CRDM Nozzle after Weld Repair and Chamfer*
- Chamfering not applicable for this analysis Page 23
Uontrolled Document A
Document No, 32-9136884-001 ARýEVA.
AREVA NP Inh.,
an AREVA and Siemens company DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Table 4-3: Residual Stresses in Repair Weld after Chamfering* J-Weld Residual Stresses in Repair Weld after Chamfering J-Weld Penetration angle = 0 degrees Nozzle yield strength = {
}
Time: 16001 Path Along Interface Between Repair Weld and Remaining Nozzle (Corresponds to Path 1)
Radial Hoop Axial Coordinates Location Node Stress Stress Stress X
Z (psi)
(psi)
(psi)
(in.)
(in.)
Triple Point 2609 2608 2607 2606 2605 2604 2603 2602 Inside Surface 2601
- Chamfering not applicable for this analysis Page 24
Controlled Document A
ARE VA, AREVA NP Inc.,
an AREVA and siemens company Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Table 4-4: Residual Stresses in Repair weld after Chamfering* J-weld (Cont'd)
Residual Stresses in Repair Weld after Chamfering J-Weld Penetration angle = 0 degrees Nozzle yield strength = {
}
Time: 16001 Path Along Interface Between Repair Weld and Reactor Vessel Head (Corresponds to Path 2)
Stresses in Weld Location Radial Node Stress (psi)
Hoop Stress (psi)
Axial Stress (psi)
Coordinates X
Z (in.)
(in.)
Relative Position (in.)
Triple Point Lower End 2609 2509 2409 2309 2209 2109 2009 Stresses in Head Location Radial Node Stress (psi)
Hoop Stress (psi)
Axial Stress (psi)
Coordinates "X
Z (in.)
(in.)
Relative Position (in.)
Triple Point Lower End 2610 2510 2410 2310 2210 2110 2010
- Chamfering not applicable for this analysis Page 25
Controlled Document A
A RE VA AREVA NP Inc.;
an AREVA and Siemens company Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 4.3 Fracture Toughness 4.3.1 Low Alloy Steel RV Head Material Fracture toughness curves for SA-533 Grade B Class 1 material are illustrated in Figure A-4200-1 of Reference 5.
At an operating temperature of about { -
)F, the Kia and KI, fracture toughness values for this material (using an assumed RTNDT of 600F) are above 200 ksi4in. An upper bound value of 200 ksi'in will be conservatively used for the present flaw evaluations.
4.3.2 Alloy 600 and Alloy 690 Materials In Table 7 of Reference 21, Mills provides fracture toughness data for unirradiated Alloy 600 material at 24 0C (75 OF) and 427 0C (800 OF) in the form of crack initiation values for the J-integral, Jc. Using linear interpolation and the LEFM plane strain relationship between Jc and fracture toughness, Kjc, f JcE the fracture toughness at an operating temperature of{
)OF is derived as follows:
Note:
v = 0.3 I kN/m = 1 kN/m + 4.448 N/lb x 0.0254 m/in = 0.00571 kip/in Mills [211 Code [22]
Temp.
Jc Jc E
Ijc (9F)
(kN/m)
(kip/in)
(ksi)
(ksi4in) 75 382 2.18 31000 273
{ 8
{ 5
{
2
{
}
{31 800 575 3.28 27600 316 Since brittle fracture is not a credible failure mechanism for ductile materials like Alloy 600 or Alloy 690, these fracture toughness measures, provided for information only, are not considered in the present flaw evaluations.
However, it should be noted that the fracture toughness measures of these ductile materials is significantly greater than the fracture toughness measure of the low alloy RV head material reported in Section 4.3.1. The failure mechanism for the ductile Alloy 600 and 690 materials is limit load.
Page 26
Controlled Document A
Document No. 32-9136884-001 AR EVA NP Inc.,
an AREVA and Siemens cormpany DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 5.0 CALCULATIONS The evaluation of the postulated external circumferential flaw for propagation along Path 1 is contained in Tables 5-1 and 5-2. The fatigue crack growth analysis is provided in Table 5-1 and a limit load analysis is presented in Table 5-2.
The evaluation of an external axial flaw for fatigue crack growth along Path 1 is contained in Table 5-3.
A continuous surface flaw along the cylindrical interface between the repair weld and the reactor vessel head is analyzed for fatigue crack growth along Path 2 in Table 5-4.
The flaw evaluations utilize the upset set condition stresses shown in Tables 4-1 and 4-2, which are obtained from heatup/cooldown transient stresses by multiplying the stresses by 1.05 {
), the ratio of maximum upset condition stresses to heatup/cooldown transient stresses. The stresses used for fatigue crack growth are resulting from the sum of the residual stresses and the transient stresses. This is a conservative approximation of the actual state of stress since the elastic transient stresses are added directly to the elastic-plastic residual stresses, with no attenuation for additional plastic strain. It is therefore appropriate to use the yield strengths from the repair weld residual stress analysis when applying the Irwin plastic zone correction for crack length.
As required by Article IWB-3612 [5], a safety factor of 410 is used to evaluate applied stress intensity factors for normal and upset conditions, considering the lower KIa fracture toughness for crack arrest. Article IWB-3612 [5]
also specifies that a safety factor of 42 must be used for emergency and faulted conditions, along with the higher K1c fracture toughness for crack initiation. Since the required safety margin for the emergency condition rod withdrawal accident is less than that for normal and upset conditions by a factor of 410 / 42 = 2.24 and emergency condition stresses are less than the maximum normal and upset condition stresses (Appendix F, Reference 18),
the flaw evaluations performed for normal and upset conditions serve as a bounding analysis for the emergency condition rod withdrawal accident.
Table 5-1: Evaluation of Continuous External Circumferential Flaw for Fatigue Crack Growth along Path 1 INPUT DATA Geometry:
Outside diameter, Do =
in.
Inside diameter, Di =
in.
Thickness, t =
in.
Ri/t=
Flaw Size:
Flaw depth, a =
in.
a/t =
Environment:
Temperature, T =
OF oC Page 27
Controlled Document A
AREVA Document No. 32-9136884-001 AREVA NP Inc.,
an AREVA and Siemnens company DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Table 5-1: Evaluation of Continuous External Circumferential Flaw for Fatigue Crack Growth along Path I (Cont'd)
Variation of F Function between Continuous External and Continuous Internal Circumferential Flaws Using Solutions by V. Kumar et al.
Source:
EPRI NP-1931 Topical Report, Section 4.3 for an internal circumferential crack under remote tension [7].
The applied KI equation is given by the expression:
KI = v*4Q(*a)*F(a/b, Ri/Ro) where
P/(n*(RoA2 - RiA2) and F is a function of a/b and b/Ri, where a/b
0.177 b/Ri =
0.383 By extrapolation from Table 4-5 of EPRI-1931, the internal F-factor is estimated to be:
Finternal =
1.12 Source:
GE Report SRD-82-048, Prepared for EPRI Contract RP-1237-1, Fifth & Sixth Semi-Annual Report, Section 3.5 for an external circumferential under remote tension [8].
For the external circumferential crack, (he expressions for KI and a are as defined above for the internal circumferential crack, where a/b =
0.177 Ri/Ro =
0.723 From Figure 3-11 of SRD-82-048, the external F-factor is estimated to be:
Fextemal 1.25 Multiplying Factor:
To estimate the stress intensity factor for an external circumferential crack from the solution for an internal circumferential crack under remote tension, the appropriate multiplying factor is:
Fextemai / Finternal = 1.25 / 1.12;z 1.12 This value seems reasonable since from Figure 3-9 of EPRI NP-3607 [9], the multiplying factor for circumferential flaws with an a/t ratio of 0.2 is estimated to be:
Fexternal / Finternal 1.10 Page 28
Controlled Document A
AR EVA AREVA NP Inc.,
anAREVA and Siemens company Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Table 5-1: Evaluation of Continuous External Circumferential Flaw for Fatigue Crack Growth along Path I (Cont'd)
STRESS INTENSITY FACTOR FOR CIRCUMFERENTIAL FLAW Basis:
Buchalet and Bamford solution for continuous circumferential flaws on the inside surface of cylinders [6]
KI = 4(=*a) * [0A F1 + (2a/it) A1 F2 + (a2/2) A2 F3 + (4a3)/(3-n) A3 F4 1
- where, F1 = 1.1259 + 0.2344(a/t) + 2.2018(a/t) 2 0.2083(a/t) 3 F2 = 1.0732 + 0.2617(a/t) + 0.6661(a/t) 2 + 0.6354(a/t)3 F3 = 1.0528 + 0.1065(a/t) + 0.4429(a/t)2 + 0.6042(a/t)3 F4 = 1.0387 - 0.0939(a/t) + 0.6018(a/t) 2 + 0.3750(a/t) 3 and the through-wall stress distribution is described by the third order polynomial, S(x) = Ao + Ajx + A2x2 + A3x3.
Applicablility:
Ri/t = 10 a/t*< 0.8 Axial Stresses:
Stress Coefficients:
Wall Residual Normal/Upset Cond.
Total Stresses Position Stress Stresses at Operation x
in Weld Cooldown Shutdown Cooldown Shutdown
(*in.)
(*ksi)
(ksi)
(ksi)
(ksi)
(ksi)
Normal/Upset Stress Loading Conditions Coeff.
NUI NU2 (ksi)
(ksi)
Ao A1 A2 A 3 Page 29
A
ýARIE VA AREVA NP Inc.,
an AREVA and Siemens company Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Table 5-1: Evaluation of Continuous External Circumferential Flaw for Fatigue Crack Growth along Path I (Cont'd)
CRACK GROWTH FOR CIRCUMFERENTIAL FLAW (IN-AIR) - Alloy 821182 Basis:
Operating Time (yr.)
0 1
2 3
4 5
6 7
8 9
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Aa = AN *C0(AKI )n
- AT AN =
6 AT=
1 fatigue cycles / year year NU1 NU2.
KI(a)max KI(a)min Sy={
ksi NU1 Aa Aa ry ae KI(ae)max (m)
(in.)
(ksklin)
Cycle a
(in.)
AKI AKI R
SR C0=CNt-WeId*SR (ksklin)
(ksiNfin)
(ksi4in)
(MPaVm) 0 6
12 18 24 30 36 42 48 54 60 66 72 78 84 90 96 102 108 114 120 126 132 138 144 150 j
Page 30
Uontrolled Document A
AREVA Document No. 32-9136884-001 AREVA NP Inc.,
an AREVA and Siem~ens company DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Table 5-2: Limit Load Analysis for a Continuous External Circumferential Flaw Basis:
GE Report SRD-82-048, Combined Fifth and Sixth Semi-Annual Report by V. Kumar et al, Section 3.5 [81 For remote tension loading, Po = 2/43*aot*(Rc2-Ri2) where Rc = Ro - a and C7o =f psi (using the minimum yield strength of Alloy 52M)
Ro =
in.
a=
in.
Rc =
in.
Ri =
in.
Then Po=
}Ibs From Reference 23, the applied loads on a typical B&W design CRDM tube are:
a) Normal/Upset conditions, P = f 1 lbs b) Emergency/Faulted conditions, P =
lbs The limit load margins are greater than those required by Article IWB-3642 of Section Xl [5], as shown below.
a) Normal/Upset conditions, Po/P =
10.44
> 3.0 b) Emergency/Faulted conditions, Po/P =
7.38
> 1.5 Table 5-3: Evaluation of External Axial Flaw for Fatigue Crack Growth along Path 1 INPUT DATA Geometry:
Outside diameter, Do =
in.
Inside diameter, Di =
in.
Thickness, t =
in.
Ri/t =
Flaw Size:
Flaw depth, a =
in.
Flaw length, 2c =
in.
a/t =
Environment:
Temperature, T =
OF
°C Page 31
Controlled Document A
AR EyA, AREVA NP Inc.;
an AREVA and Siemnens company Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Table 5-3: Evaluation of External Axial Flaw for Fatigue Crack Growth along Path 1 (Cont'd)
STRESS INTENSITY FACTOR FOR AXIAL FLAW Basis:
Raju & Newman, "Stress Intensity Factors for Internal & External Surface Cracks in Cylindrical Vessels [111]
KI = 4(n/Q) * [Go A0 a° 5 +G1 A1 a1'5 +G2 A 2 a2 5 + G 3 A 3 a 3.5
- where, from Table 4 of Reference 11, for an external surface crack with t/R = 0.25, alt = 0.2, a/c = 1.0, the influence coefficients are as follows:
Location:
Deepest Point (2ýh/ = 1)
Go G,
G2=
G3=
1.030 0.720 0.591 0.513 Surface (24/n = 0) 1.163 0.204 0.077 0.040 and Q =
2.464
= 1 + 1.464*(a/c)A,1.65 and the through-wall stress distribution is described by the third order polynomial, S(x) = Ao + Ajx + A2x2 + A3x3.
Hoop Stresses:
Stress Coefficients:
Wall Residual Normal/Upset Cond.
TotalStresses Position Stress Stresses at Operation x
in Weld Cooldown Shutdown Cooldown Shutdown (in.)
(ks__
(ksi)
(ksi)
(ksi)
(ksi)
Normal/Upset Stress Loading Conditions Coeff.
NU1 NU2 (ksi)
(ksi)
A0 A1 A2 A 3 Page 32
A AREVA AREVA NP Inc.,
an AREVA and Siemens company Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Table 5-3: Evaluation of External Axial Flaw for Fatigue Crack Growth along Path 1 (Cont'd)
RADIAL CRACK GROWTH FOR AXIAL FLAW (IN-AIR) - Ailoy 600 Basis:
Aa = AN
- Co(AKI)n
- AT AN =
6 fatigue cycles / year Sy={
} ksi AT =
1 year Operating NU1 NU2 NU1 Time Cycle a
KI(a)max KI(a)min AKI AKI R
SR Co=CA600*SR Aa Aa
- r.
a, KI(ae)max (yr.)
(in.)
(ksiklin)
(ksiqin)
(ksiqin)
(MPa*/m)
(M)
(in.)
(ksiklin) 0.00 0
1.00 6
2.00 12 3.00 18 4.00 24 5.00 30 6.00 36 7.00 42 8.00 48 9.00 54 10.00 60 11.00 66 12.00 72 13.00 78 14.00 84 15.00 90 16.00 96 17.00 102 18.00 108 19.00 114 20.00 120 21.00 126 22.00 132 23.00 138 24.00 144 25.00 150 Page 33
A AREVA AREVA NP Inc.,
an AREVA and Siemens company Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Table 5-3: Evaluation of External Axial Flaw for Fatigue Crack Growth along Path 1 (Cont'd)
AXIAL CRACK GROWTH FOR AXIAL FLAW (IN-AIR) - Alloy 600 Basis:
Aa = AN
- Co(AKI)n
- AT AN =
6 fatigue cycles / year Sy= {
} ksi AT =
1 year Operating NU1 NU2 NU1 Time Cycle a
KI(a)max KI(a)min AKI AKI R
SR CO=CA600*SR Aa Aa ry ae Kl(ae)max (yr.)
(in.)
(ksiklin)
(ksiklin)
(ksihlin)
(MPa,\\m)
(M)
(in.)
(ksi-\\in) 0.00 0
1.00 6
2.00 12 3.00 18 4.00 24 5.00 30 6.00 36 7.00 42 8.00 48 9.00 54 10.00 60 11.00 66 12.00 72 13.00 78 14.00 84 15.00 90 16.00 96 17.00 102 18.00 108 19.00 114 20.00 120 21.00 126 22.00 132 23.00 138 24.00 144 25.00 150 Page 34
A ARkEVA AREVA NP Inc..
an AREVA and Siemens company Document No. 32-9136884-001 DB,1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Table 5-3: Evaluation of External Axial Flaw for Fatigue Crack Growth along Path I (Cont'd)
RADIAL CRACK GROWTH FOR AXIAL FLAW (IN-AIR) - Alloy 82/182 Basis:
Aa = AN
- Co(AKI)
- AT AN =
6 fatigue cycles year Sy={
} ksi AT =
1 year Operating NU1 NU2 NU1 Time Cycle a
KI(a)max KI(a)min AKI AKI R
SR Co=CNi.wed*SR Aa Aa ry ae KI(ae)max (yr.)
(in.)
(ksiin)
(kshlin (ksihin)
(MPa*im)
(m)
(in.)
(ksi'in 0.00 0
1.00 6
2.00 12 3.00 18 4.00 24 5.00 30 6.00 36 7.00 42 8.00 48 9.00 54 10.00 60 11.00 66 12.00 72 13.00 78 14.00 84 15.00 90 16.00 96 17.00 102 18.00 108 19.00 114 20.00 120 21.00 126 22.00 132 23.00 138 24.00 144 25.00 150 Page 35 C) 0
- 3 0
0 0
CD
A AR EVA AREVA NP Inc.,
an AREVA and Siemens company Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Table 5-3: Evaluation of External Axial Flaw for Fatigue Crack Growth along Path I (Cont'd)
AXIAL CRACK GROWTH FOR AXIAL FLAW (IN-AIR) - Alloy 821182 Basis:
Aa = AN
- Co(AKI)n
- AT AN =
6 fatigue cycles I year Sy=
}
ksi AT =
1 year Operating NU1 NU2 NU1 Time Cycle a
KI(a)max KI(a)min AKI AKI R
SR C0=CN.weJdSR Aa Aa ry as Ki(ae)max (yr.)
(in.)
(ksiqin)
(ksifin)
(ksi~fin)
(MPaJm)
(m)
(in.)
(ksifin) 0.00 0
1.00 6
2.00 12 3.00 18 4.00 24 5.00 30 6.00 36 7.00 42 8.00 48 9.00 54 10.00 60 11.00 66 12.00 72 13.00 78 14.00 84 15.00 90 16.00 96 17.00 102 18.00 108 19.00 114 20.00 120 21.00 126 22.00 132 23.00 138 24.00 144 25.00 150 Page 36
Controlled Document A
AREVA Document No. 32-9136884-001 AREVA NP Inc.;
an AREVA and Siemens company DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Table 5-4: Evaluation of a Continuous Cylindrical Surface Crack for Fatigue Crack Growth along Path 2 INPUT DATA Geometry:
Plate thickness, t =
in.
Flaw Size:
Flaw depth, a =
in.
a/t =
Environment:
Temperature, T =
OF
°C Page 37
Controlled Document A
ARE; V Document No. 32-9136884a-001 AREVA NP Inc.,
an AREVA.and Siemens company DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Table 5-4: Evaluation of a Continuous Cylindrical Surface Crack for Fatigue Crack Growth along Path 2 (Cont'd)
STRESS INTENSITY FACTOR FOR CYLINDRICAL FLAW IN WELD Basis:
Analysis of Flaws, 1995 ASME Code, Section Xl, Appendix A [5]
KI = [A0 Go + A1 G1 + A2 G2 + A3 G3 ] q(,naIQ) where Q = 1 + 4.593*(aI)A1.65 - qy and qy = [(A 0 Go + A, G, + A2 G2 + A3 G3) 1s]2 /6 For a/I =
0.0 (continuous flaw) aft <=
0.1 Go =
1.195 G, =
0.773 G2 =
0.600 G3 =
0.501 Stresses are described by a third order polynomial fit over the flaw depth, S(x) = A0 + A, (x/a) + A2(xla)2 + A3(x/a)3 Radial Stresses in Weld:
Wall Residual Normal/Upset Cond.
Total Stresses Position Stress Stresses at Operation x
in Weld Cooldown Shutdown Cooldown Shutdown
{
(in.)
(ksi)
(ksi)
(ksi)
(ksi)
(ksi)
Stress Coefficients:
a 0.100 in.)
Normal/Upset Stress Loading Conditions Coeff.
NU1 NU2 (ksi)
(ksi)
A0 A,
A 2 A 3 Page 38
A AREVA AREVA NP Inc.,
an AREVA and Siemens company Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Table 5-4: Evaluation of a Continuous Cylindrical Surface Crack for Fatigue Crack Growth along Path 2 (Cont'd)
CRACK GROWTH FOR CYLINDRICAL FLAW (IN-AIR) - Alloy 82/182 Basis:
Operating Time (yr.)
0 1
2 3
4 5
6 7
8 9
10 11 12 13 14 15 16 17
- 18 19 20 21 22 23 24 25 Aa = AN
- Co(A)KI)
- AT AN =
6 AT=
1 NU1 NU2 Cycle a
Q KI(a)max KI(a)min AKI cycles/year year Sy= {
I ksi AKI R
SR COýCNý-Id*SR Aa (m)
Aa (in.)
qy Q(ae)
KI(ae)max (kshfinl (in.)
(ksiVin)
(ksiVin)
(ksi-,Iin)
(MPa-%Im) 0 6
12 18 24 30 36 42 48 54 60 66 72 78 84 90 96 102 108 114 120 126 132 138 144 150 f
J Page 39
Controlled Document A
A Document No. 32-9136884-001 ARRVA AREVA NP Inc.,
an AREVA and Siemens company DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Table 5-4: Evaluation of a Continuous Cylindrical Surface Crack for Fatigue Crack Growth along Path 2 (Cont'd)
STRESS INTENSITY FACTOR FOR CYLINDRICAL FLAW IN HEAD Basis:
Analysis of Flaws, 1995 ASME Code, Section Xl, Appendix A [5]
KI= [A0 Go + A1 G1 + A2 G2 + A 3 G 3 I 4(7a/Q) where Q = 1 + 4.593*(a/I)A1.65 - qy and qy = [(Ao Go + A G1 + A2 G2+ A3 G3) ay. 12 /6 For all =
0.0 (continuous flaw) a/t <=
0.1 Go =
1.1945 G, =
0.7732 G2 =
0.5996 G3 =
0.5012 Stresses are described by a third order polynomial fit over the flaw depth, S(x) = A0 + A, (x/a) + A2(x/a) 2 + A3(x/a)3 Radial Stresses in Weld:
Wall Residual Normal/Upset Cond.
Total Stresses Position Stress Stresses at Operation x
in Weld Cooldown Shutdown Cooldown Shutdown
{in._)
ksi)
(ksi)
(ksi)
_ksi)
_ksi)
Stress Coefficients:
(a=
0.100 in.)
Normal/Upset Stress Loading Conditions Coeff.
NU1 NU2 (ksi)
(ksi)
A0 A,
A2 A3 Page 40
A AREVA AREVA NP Inc.,
an AREVA and Siemens company Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Table 5-4: Evaluation of a Continuous Cylindrical Surface Crack for Fatigue Crack Growth along Path 2 (Cont'd)
CRACK GROWTH FOR CYLINDRICAL FLAW (IN-AIR) - FERRITIC MATERIAL Basis:
Aa = AN
- Co(AKI)n" AT AN =
6 cycles/year Sy = {
}
ksi AT =
1 year Operating NU1 NU2 Time Cycle a
Q KI(a)max KI(a)min AKI R
S C0 Aa qy Q(ae)
Kl(a,)max (yr.)
(in.)
(ksi/inn (ksiin ksqin)
(in.)
(ksiqin) 0 0
1 6
2 12 3
18 4
24 5
30 6
36 7
42 8
48 9
54 10 60 11 66 12 72 13 78 14 84 15 90 16 96 17 102 18 108 19 114 20 120 21 126 22 132 23 138 24 144 25 150 Page 41
Controlled Document A
ARýEVA AREVA NP Inc.;
an AREVA and Siemens company Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 6.0 RESULTS The flaw evaluation results for 25 years of fatigue crack growth are as follows.
6.1 Propagation of a Continuous External Circumferential Flaw along Path I a) Fatigue crack growth analysis:
Initial flaw size, Final flaw size, Stress intensity factor at final flaw size, Fracture toughness Fracture toughness margin, b) Limit load analysis:
Limit load, Applied loads:
Limit load margins:
ai =
af <
K, (aef) <
K1. =
KIa / KI >
P0 =
P0 /P =
Po/ P=
0.100 in.
{
in.
0 ksi4in 200 ksi-/in 410 normal/upset, emergency/faulted, normal/upset, emergency/faulted,
((.
{
} lbs
} lbs
} lbs 10.44 > 3.0 7.38 > 1.5 6.2 Fatigue Crack Growth of a Semi-Circular External Axial Flaw along Path 1 Initial flaw size, ai = 0.100 in.
Radial Growth Final flaw size, Stress intensity factor at final flaw size, Fracture toughness Fracture toughness margin, Axial Growth Final flaw size, Stress intensity factor at final flaw size, Fracture toughness Fracture toughness margin, af <{
}in.
KI (ad) = 29.45 ksi-4in KIa =
200 ksi-/in KIa / KI = 6.79 > 410 af <{
}in.
KI (ad) = 34.46 ksi/in Ki, =
200 ksi4in Kia / K, = 5.80 > 410 6.3 Fatigue Crack Growth of a Continuous Cylindrical Flaw along Path 2 Initial flaw size, Final flaw size, Stress intensity factor at final flaw size, Fracture toughness Fracture toughness margin, a1 0. 100 in.
af < (
n.
K, (ad) = 53.74 ksi-Oin Kia = 200 ksi-in Kia 1KI =
3.72 > 410 Page 42
Controlled Document A
AiR'E VA Document No. 32-9136884-001 AREVA NP Inc..
an AREVA end Siemens company DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 The results of the analysis demonstrate that the 0.10 inch weld anomaly is acceptable for a 25 year evaluation life of the CRDM ID temper bead alternate weld repair. However, note that the design life the RVCH as per the design specification [41 is 4 years. Significant fracture toughness margins have been demonstrated for both the flaw propagation paths considered in the analysis. The minimum fracture toughness margins for flaw propagation Paths 1 and 2 have been shown to be 5.80 and 3.72, respectively, as compared to the required margins of 410 for normal/upset conditions and 42 for emergency/faulted conditions per Section X1, IWB-3612 [5). Fatigue crack growth is minimal. The maximum final flaw size is {
} inch (considering both flaw propagation paths). A limit load analysis was also performed considering the ductile Alloy 600 and Alloy 690 materials along flaw propagation Path 1. The analysis showed limit load margins of 10.44 for normal/upset conditions and 7.38 for emergency/faulted conditions, as compared to the required margins of 3.0 and 1.5, respectively, per Section XI, IWB-3642 [5].
Page 43
Controlled Document A
AREVA Document No. 32-9136884-001 AREVA NP Inc.;
an AREVA and Siemens company DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair With Alloy 52M/82
7.0 REFERENCES
- 1.
AREVA NP Drawing 02-9134305E-004, "Davis Besse CRDM Nozzle ID Temper Bead Weld Repair."
- 2.
AREVA NP Document 39-9136718-000, Special Instruction for [1].
- 3.
AREVA NP Document 55-PS0139-000, "Procedure Supplement."
- 4.
AREVA NP Document 08-9134304-000, "Davis Besse RVCH CRDM Penetration Modification."
- 5.
ASME Boiler and Pressure Vessel Code, Section Xl, Rules for Inservice Inspection of Nuclear Power Plant Components, 1995 Edition with 1996 Addendum.
- 6.
C.B. Buchalet and W.H. Bamford, "Stress Intensity Factor Solutions for Continuous Surface Flaws in Reactor Pressure Vessels," Mechanics of Crack Growth, ASTM STP 590, American Society for Testing and Materials, 1976, pp. 385-402.
- 7.
EPRI Topical Report, EPRI NP-1931, "An Engineering Approach for Elastic-Plastic Fracture Analysis,"
Research Project 1237-1, prepared by V. Kumar et al of General Electric Company, July 1981.
- 8.
General Electric Report, SRD-82-048, "Estimation Technique for the Prediction of Elastic-Plastic Fracture of Structural Components of Nuclear Systems," by V. Kumar et al, Contract RP1237-1, Combined Fifth and Sixth Semi-Annual Report, March 1982.
- 9.
EPRI Topical Report, EPRI NP-3607, "Advances in Elastic-Plastic Fracture Analysis," Research Project 1237-1, prepared by V. Kumar et al of General Electric Company, August 1984.
- 10.
NUREG/CR-6921, "Crack Growth Rates in a PWR Environment of Nickel Alloys from the Davis-Besse and V.C. Summer Power Plants," U.S. Nuclear Regulatory Commission (Argonne National Laboratory),
April 2006.
- 11.
I.S. Raju and J.C. Newman Jr., "Stress Intensity Factors for Internal and External Surface Cracks in Cylindrical Vessels," Transactions of the ASME, Journal of Pressure Vessel Technology, pp. 293-298, Vol. 104, November 1982.
- 12.
NUREG/CR-6721, "Effects of Alloy Chemistry, Cold Work, and Water Chemistry on Corrosion Fatigue and Stress Corrosion Cracking of Nickel Alloys and Welds," U.S. Nuclear Regulatory Commission (Argonne National Laboratory), April 2001.
- 13.
T.L. Anderson, Fracture Mechanics: Fundamentals and Applications, CRC Press, 1991.
- 14.
AREVA NP Document 38-1288355-00, "Flaw Acceptance Criteria."
- 15.
BAW-110046A, Rev. 2, "Methods of Compliance with Fracture Toughness and Operational Requirements of 10 CFR 50, Appendix G," B&W Owners Group Materials Committee Topical Report, June 1986.
- 16.
AREVA NP Document 51-9137401-000, "Evaluation of Fluid Temperature in DB RV Closure Head."
- 17.
Code Case 474-2, Design Stress Intensities and Yield Strength Values for UNS N06690 with a Minimum Specified Yield Strength of 35 ksi, Class 1 Components,Section III, Division 1.
- 18.
AREVA NP Document 32-5012424-12, "CRDM Temper Bead Bore Weld Analysis," April 2004.
- 19.
AREVA NP Document 18-1149327-003, "Reactor Coolant System for Davis-Besse."
- 20.
AREVA NP Document 32-5021539-02, "ANO-1 CRDM Nozzle IDTB Weld Anomaly Flaw Evaluations."
- 21.
W.J. Mills, "Fracture Toughness of Two Ni-Fe-Cr Alloys," Hanford Engineering Development Laboratory Document HEDL-SA-3309, April 1985.
- 22.
ASME Boiler and Pressure Vessel Code,Section III, Rules for Construction of Nuclear Power Plant Components, Division 1 -Appendices, 1989 Edition No Addenda.
Page 44
Controlled Document A
ARENVA AREVA NP Inc..
an AREVA and Siemens company Document No..32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82
- 23.
AREVA NP Document 32-5012403-00, "OC-3 CRDM Nozzle Circumferential Flaw Evaluations," April 2001.
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Controlled Document A
AREVA AREVA NP Inc.,
an AREVA and Siemens company Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 APPENDIX A:
COMPARISION OF DB-1 AND ANO-1 REACTOR VESSEL CLOSURE HEADS The table below provides comparison of the critical dimensions that are applicable to the DB-1 and ANO-1 reactor vessel replacement closure heads.
Table A-I: Comparison of Critical Dimensions of DB-1 and ANO-1 f
+
4 J
Table A-2: Comparison of IDTB Materials of DB-1 and ANO-1 I
As the tables above indicate, the DB1/Midland Head and ANO-1 are identical in geometry and material composition.
It is therefore concluded that the Stress calculations for IDTB weld repair for ANO-1 performed in Doc. # {
} is applicable for the DB-1/Midland replacement RVCH and that resulting residual stresses for the ANO-1 ID temper bead welds are applicable to DB-1 as well.
Page 46
Controlled Document A
AREVA AREVA NP I*c.,
an AREVA and Siefiens company Document No. 32-9136884-001 DB-1 CRDM Nozzle Weld Anomaly Flaw Evaluation of IDTB Alternate Repair with Alloy 52M/82 Appendix
References:
f V
J Page 47