Text

Response to Request for Additional Information - Relief Request RR-12-02 Re Installation of Full Structural Weld Overlay on Lower Cold Leg Letdown Nozzle Dissimilar Metal Welds & Alloy 600 Safe-End
	ML13018A248
Person / Time
Site:	Three Mile Island
Issue date:	01/17/2013
From:	Jesse M; Exelon Generation Co
To:	; Office of Nuclear Reactor Regulation, Document Control Desk
Shared Package
ML130180329	List: TMI-13-009, Response to Request for Additional Information - Relief Request RR-12-02 Re Installation of Full Structural Weld Overlay on Lower Cold Leg Letdown Nozzle Dissimilar Metal Welds & Alloy 600 Safe-End;
References
	TMI-13-009, TAC ME9818
	Download: ML13018A248 (174)
	v • d • e

{{#Wiki_filter:200 Exelon Way Kennett Square, PA 19348 Exelon Generation , www,exeloncorp com PROPRIETARY INFORMATION - WITHHOLD UNDER 10 CFR 2.390 10 CFR 50.55a TMI-13-009 January 17, 2013 u.s. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Three Mile Island Nuclear Station, Unit 1 Renewed Facility Operating License No. DPR-50 NRC Docket No. 50-289

Subject:

Response to Request for Additional Information - Relief Request RR-12-02 Concerning the Installation of a Full Structural Weld Overlay on the Lower Cold Leg Letdown Nozzle Dissimilar Metal Welds and Alloy 600 Safe-End

References:

1) Letter from M. Jesse *(Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission, "Submittal of Relief Request RR-12-02 Concerning the Installation of a Full Structural Weld Overlay on the Lower Cold Leg Letdown Nozzle Dissimilar Metal Welds and Alloy 600 Safe-End," dated October 18, 2012

2) Letter from P. Bamford (U.S. Nuclear Regulatory Commission) to M. Pacilio (Exelon Generation Company, LLC), "Three Mile Island Nuclear Station, Unit 1 - Request for Additional Information Regarding Relief Request RR-12-02, Relief Request Concerning Full Structural Weld Overlay of Dissimilar Metal Welds on the Lower Cold Leg Letdown Nozzle and Safe-End (TAC No. ME9818)," dated December 14, 2012 In the Reference 1 letter, Exelon Generation Company, LLC proposed an alternative to the requirements contained in the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code associated with the fourth Inservice Inspection (lSI) interval for Three Mile Island Nuclear Station (TMI), Unit 1. TMI, Unit 1 is proposing to perform a weld overlay of the lower cold leg letdown nozzle dissimilar metal welds (DMWs) and Alloy 600 safe-end. In the Reference 2 letter, the U.S. Nuclear Regulatory Commission Staff requested additional information. Attachment 1 contains our response to this request. Attachment 2 provides a copy of ASME Code Case N-740-2.

Attachment 3 transmitted herewith contains Proprietary Information. When separated from attachments, this document is decontrolled.

Response to Request for Additional Information Relief Request RR-12-02 January 17, 2013 Page 2 contains AREVA NP Inc. (AREVA) proprietary calculations. AREVA requests that the calculations be withheld from public disclosure in accordance with 10 CFR 2.390. contains a non-proprietary version of the calculations. An affidavit supporting this request is contained in Attachment 5. If you have any questions concerning this letter, please contact Tom Loomis at (610) 765-5510. Respectfully, Michael D. Jesse Director - Licensing an egulatory Affairs Exelon Generation Company, LLC Attachments: 1) Response to Request for Additional Information

2) Code Case N-740-2

3) Proprietary Version of Calculations

4) Non-Proprietary Version of Calculations

5) Affidavit cc: Regional Administrator, Region I, USNRC USNRC Senior Resident Inspector, TMI USNRC Project Manager, [TMI] USNRC

Attachment 1 Response to Request for Additional Information

Response to Request for Additional Information Attachment 1 Page 1 Question 1:

1. Section 3.0 of the relief request lists ASME Code Case N-740-2 as an applicable code requirement. Various sections of the relief request stated that the proposed alternative is based on the code case. The NRC has not approved Code Case N-740-2. The NRC cannot approve a relief request that is based on a code case that the NRC has not approved. However, the NRC has approved weld overlay designs from licensees that have included provisions of Code Case N-740-2 in their relief request. Therefore, as part of the technical basis for the relief request, please include or identify the relevant portions of ASME Code Case N-740-2 that are applicable to the requested relief.

Response: provides a copy of ASME Code Case N-740-2 for NRC review. The code case is being applied in its entirety to the subject weld overlay with two exceptions: a) The Full Structural Weld Overlay (FSWOL) is designed in accordance with Code Case N-740-2. Final ultrasonic (UT) examination of the finished FSWOL will be performed using Electric Power Research Institute (EPRI) Performance Demonstration Initiative (POI) demonstrated UT examination procedures and personnel in lieu of ASME Section XI, Appendix VIII, Supplement 11 as discussed in the Three Mile Island (TMI), Unit 1 Relief Request 14R-05 which was approved in a U.S. Nuclear Regulatory Commission Safety Evaluation Report dated July 20, 2011 (ML111730475). The relief request addressed ASME Section XI, Appendix VIII, Supplement 11 qualification requirements for examination of FSWOLs and is applicable to existing and future structural weld overlays and all fourth lSI interval examinations on this weld overlay. b) The geometry of the stainless steel elbow limits UT coverage at the intrados of the elbow which results in less than 100% coverage. Response to RAI 2 below provides a detailed discussion of the expected examination coverage and a justification for this coverage. The design and installation of the FSWOL are applicable to the current fourth lSI interval and the remaining service life of the plant. The fourth lSI interval began on April 20, 2011 and will conclude on April 19, 2022.

Response to Request for Additional Information Attachment 1 Page 2 Question:

2. Section 5.0 of the relief request states that after the FSWOL is installed, ultrasonic (UT) examination coverage may achieve less than 98 percent (%) of the required volume because of the intrados of the elbow, but it is still expected to be greater than 90%. The NRC staff requests the following:

(a) Provide a figure with dimensions of the examination volume. FIGURE 2(a)(1)

Response

Figures 2(a)(1), 2(a)(2), and 2(a)(3), and the associated tables provide PSI/lSI required and expected examination volumes. Zero degree (0 0 ) profile location (intrados) ITOTAl ficii - !

PIIilII AREA l.

coverage limitation is due to the edge of !IS APPROX. * -, I UIIN' I the transducer wedge contacting the elbow which results in transducer lift-off and loss of contact with the FSWOL. There is no loss of coverage at the 180 0 (extrados) profile location. The following tables list the individual scan coverages for each profile at both minimum and maximum FSWOL thickness. The average coverage for all scan directions is listed in the composite coverage column. Exam Volume Calculations for Minimum Thickness FSWOL Exam Volume Calculations for Maximum Thickness FSWOL Total Coverage Individual Scan CoveraQes Profile Composite Area Obtained CW CCW Beam toward Beam toward Location Inch2 Inch2 Coverage (Cire. scan) (Cire. scan) Nozzle (Axial scan) Elbow (Axial scan) 0 0 Intrados 2.65 2.03 100% 100% 76.60% 100% 94.15% 180 0 Extrados 2.45 2.45 100% 100% 100% 100% 100%

Response to Request for Additional Information Attachment 1 Page 3 FIGURE 2(a)(2) 90 0 and 270 0 profile location coverages are limited due to the edge of the transducer wedge losing contact with the FSWOL surface where the FSWOL tapers down to the elbow. The tables below show coverage at both .17 minimum and maximum FSWOL ITOiALRQD"~ STAINLESS thickness. All susceptible weld ' PSIIISI AREA l

                                           ! IS APPROX. ,",

I, STEEL CLAD material is examined in four (4) IH5J~2_"_! I

                                                          ....,.....-~~r-/              I directions.                                                                              I I

II 1100 90' 270* PROFILE PROFILE Exam Volume Calculations for Minimum Thickness FSWOL Total Coverage Individual Scan CoveraQes Profile Composite Area Obtained CW CCW Beam toward Beam toward Location Inch2 Inch2 Coverage (eire. scan) (eire. scan) Nozzle (Axial scan) Elbow (Axial scan) 90 0 1.65 1.62 100% 100% 98.18% 100% 99.55% 270 0 1.65 1.62 100% 100% 98.18% 100% 99.55% Exam Volume Calculations for Maximum Thickness FSWOL Total Coverage Individual Scan Coveraqes Profile Composite Area Obtained CW CCW Beam toward Beam toward Location Inch2 Inch2 Coverage (eire. scan) (eire. scan) Nozzle (Axial scan) Elbow (Axial scan) 90 0 2.45 2.37 100% 100% 96.73% 100% 99.18% 270 0 2.45 2.37 100% 100% 96.73% 100% 99.18%

Response to Request for Additional Information Attachment 1 Page 4 FIGURE 2(a)(3) 0 0 315 and 45 profile location coverage is limited due to the I edge of the transducer wedge I I contacting the elbow which I results in transducer lift-off and I loss of contact with the I I FSWOL. I I I 225 0 and 135 0 profile location I coverage is limited due to the IroiALRQD-~ !STAINLESS

PSIIISI AREA I ISTEELCLAD edge of the transducer wedge ! IS APPROX. * -,

losing contact with the FSWOL lH5.l~ ___ ! ~\ surface where the FSWOL tapers down to the elbow. The tables below show coverage at both minimum and maximum ;roTA': iiQD-, FSWOL thickness. All -...

                                                                                                                 .. I PSI/lSI AREA I
                                                                                                                , l iS APPROX. I susceptible weld material is                                                                                         '"HIU~2   ___,

examined in four (4) directions. II

                                                                                          \I
                                                                                           \

AREA OF REDUCED COVERAGE DUE TO PROXIMITY OF ELBOW IS APPROX. 0.03 IN' leo. 45 0 & 315' 225 & 135" 0 PROFILES PROFILES Exam Volume Calculations for Minimum Thickness FSWOL Total Coverage Individual Scan Covera es Profile Composite Area Obtained CW CCW Beam toward Location Coverage Inch2 Inch2 (eirc. scan) (eirc. scan) 315 0 & 45 0 1.70 1.67 100% 100% 99.56% 225 0 & 135 0 1.65 1.63 100% 100% 98.79% 100% 99.70% Exam Volume Calculations for Maximum Thickness FSWOL Total Coverage Individual Scan Coverages Profile Composite Area Obtained CW CCW Beam toward Beam toward Location Coverage Inch2 Inch2 (eirc. scan) (eire. scan) Nozzle (Axial scan) Elbow (Axial scan) 315 0 & 45 0 2.50 2.40 100% 100% 96.00% 100% 99.00% 225 0 & 135 0 2.45 2.40 100% 100% 97.96% 100% 99.49%

Response to Request for Additional Information Attachment 1 Page 5 Question: (b) Provide a diagram showing the required examination volume for the acceptance examinations with dimensions of the examination volume and show the area(s) that will not be examined within the required examination volume.

Response

The acceptance examination volume is highlighted in Figures 2(b)(1), 2(b)(2), and 2(b)(3). There is a small region of acceptance volume at the intrados that will not be examined due to the proximity of the elbow interfering with the UT transducer and causing transducer lift-off and loss of contact with the FSWOL. The angle beam circumferential scans and the downstream axial scans are reduced as shown in Figure 2(b)(1). The EPRI PDI qualified UT procedure does not require axial examination in more than one direction; therefore, the upstream axial scan volume is not shown in Figure 2(b)(1) . As shown on Figures 2(b)(2) and 2(b)(3), full coverage is achieved within +/-45° of the intrados (0° profile location). FIGURE 2(b}(1) I, I, I, I I

                                                ~TAINLESS rTEELCLAD I,

I,

                                               !I        DMW ALLOY8Z DMW ALLOY8Z
                                                 ,MU.,1Q5BM
                                                  \
                                                   \
                                                    \ \

AREA OF REDUCED

Response to Request for Additional Information Attachment 1 Page 6 FIGURE 2(b)(2) I ACCEPTANCE i i EXAMINATION *

VOLUME I I

SUSCEPTIBLE\ MATERIAL I I SAFE-END ALLOY 600 90 0 270 0 PROFILE PROFILE FLOW

Response to Request for Additional Information Attachment 1 Page 7 FIGURE 2(b)(3) i

ACCEPTANCE
EXAMINATION *
VOLUME
I I ALLOY82 DMW I

I MU-394BM I II

45 0 & 315 0 225 0 & 1350 PROFILES PROFILES FLOW

Response to Request for Additional Information Attachment 1 Page 8 Question: Further, it is the NRC staff's expectation that, at a minimum, 100% of the Alloy 82/182 dissimilar metal weld, (Le. the susceptible material within the required examination volume), be covered by UT after the weld overlay installation, if the coverage of the required examination volume cannot achieve 100%. Figure 1 shows that the Alloy 821182 dissimilar metal weld joining the safe-end and the elbow will not receive 100% examination coverage. Therefore: (c) Justify how the structural integrity of the Alloy 82/182 dissimilar metal weld joining the safe-end and the elbow can be verified in the future.

Response

Structural integrity of the FSWOL and Alloy 82/182 DMW joining the elbow to the safe-end is acceptable due to:

1. There is excessive FSWOL thickness at the intrados. The minimum deposited FSWOL thickness is 0.30 in.; however, due to the elbow geometry at the intrados the FSWOL thickness is significantly greater at the intrados to allow for UT examination (see Figures 2(a)(1) through 2(a)(3)) above. A flaw that originates at the elbow DMW toe is expected to be detected as it grows through the Alloy 52M FSWOL material.

2. A supplemental analysis has been performed to address potential flaws in the DMW in the region of limited coverage. Both axial and 360 0 circumferential flaws that extend through the full thickness (100%) of the original DMW material at the region of limited coverage are evaluated. The supplemental analysis results show that the final flaw depths after 22 years of service (through current end of license) is less than the allowable flaw depths per ASME Section XI acceptance criteria. Thus, the analysis demonstrates that the design has sufficient FSWOL thickness.

3. If a flaw initiates from the inside surface at the elbow to DMW interface, it is expected to follow the weld edge bevel towards the outside surface which results in a flaw oriented so that detection is possible with the axial scan that is directed toward the elbow. 100%

coverage of the susceptible material is obtained with the axial scan directed toward the elbow.

4. Degradation in the FSWOL material would be expected to be due to fatigue. Flaws due to fatigue in the FSWOL would be expected to be perpendicular to the outside surface of the FSWOL. This type of flaw would be detectable by the axial scan oriented toward the elbow.

5. Liquid penetrant examinations are performed prior to FSWOL application to verify the absence of surface flaws.

Response to Request for Additional Information Attachment 1 Page 9 Question: Page 4, second paragraph, of the relief request states that n *** [t]his coverage will not interrogate 100% of the susceptible material volume in one of the four directions in the intrados region shown in Figure 1. The combined coverage for all four examination directions is expected to be approximately 98% because of the inherent scan limitation of the elbow ... n (d) Discuss the four examination directions. Discuss the direction that could not achieve 100% examination coverage. Provide the detailed calculation to show the maximum UT examination coverage.

Response

Refer to the figures and tables provided for RAI 2(a) above for figures showing PSI/lSI examination coverage. The FSWOL will be examined in two axial directions and two circumferential directions for a total of four (4) directions. The downstream scan will direct the UT beam toward the elbow and the upstream scan will direct the beam toward the nozzle. There will also be clockwise and counter clockwise circumferential scans. The upstream axial scan cannot achieve 100% coverage of the susceptible DMW material at the intrados. The reduced coverage is due to the edge of the transducer wedge contacting the elbow intrados, causing transducer lift-off and loss of contact with the FSWOL surface. The limitation is maximum at the intrados and 100% coverage of susceptible material is achieved after the transducer travels +/-45° circumferentially from the intrados. The UT coverage listed in the previous tables is summarized in the table below. The minimum calculated UT coverage occurs at the maximum FSWOL thickness. The table below conservatively shows the UT coverage obtained at the maximum FSWOL thickness. The actual FSWOL thickness will be less than the maximum thickness; therefore, UT coverage will be greater than that shown in the table. 100% coverage is obtained in 3 of the 4 scan directions. The composite % coverage is calculated for each Profile Location by summing the 4 coverage percentages and then dividing by 4. The total composite coverage is the average of the eight (8) composite % coverages. Exam Volume Calculations Total Coverage Individual Scan Coverages Profile Composite Area Obtained CW CCW Beam toward Beam toward Location 2 Coverage Inch Inch2 (Cire. scan) (Cire. scan) Nozzle (Axial scan) Elbow (Axial scan 0 0 Intrados 2.65 2.03 100% 100% 76.60% 100% 94.15% 45 0 2.50 2.40 100% 100% 96.00% 100% 99.00% 90 0 2.45 2.37 100% 100% 96.73% 100% 99.18% 1350 2.45 2.40 100% 100% 97.96% 100% 99.49% 1800 Extrados 2.45 2.45 100% 100% 100% 100% 100% 225 0 2.45 2.40 100% 100% 97.96% 100% 99.49% 270 0 2.45 2.37 100% 100% 96.73% 100% 99.18% 315 0 2.50 2.40 100% 100% 96.00% 100% 99.00% Total 98.69%

Response to Request for Additional Information Attachment 1 Page 10 Question:

3. Section 5.0 of the relief request stated that examination of the completed FSWOL will be performed according to ASME Code Cases N-740-2 and N-770-1, which is conditioned by Title 10 of the Code of Federal Regulations (10 CFR) Section 50.55a(g)(6)(ii)(F). Section 5.0 further stated that subsequent ultrasonic examinations will be performed as required by Code Case N-770-1. The NRC staff notes that Code Case N-770-1 contains provisions for various weld configurations and degradation. For regulatory clarity, please identify all the specific provisions in N-770-1 that are applicable to the proposed weld overlay installation, including at a minimum, the relevant inspection items, footnotes, subsections, and figures.

Response

A response describing applicability to Code Case N-770-1 is provided below as modified by the use of EPRI POI demonstrated UT examination procedures and personnel when referring to Section XI, Appendix VIII and coverage limitations (see Response 1(a) above): -1100: -1100(a) and (b) are applicable because the letdown nozzle is Nominal Pipe Size (NPS) 2% inch and operates at approximately 555°F. 1100(c) through (f) are not applicable to the letdown nozzle dissimilar metal welds. -1200: -1200(a) applies prior to the FSWOL being applied. 1200(b) applies after the FSWOL is applied. - 2200: The letdown nozzle DMWs are currently not mitigated and are categorized as Inspection Item B. The DMWs have not received a baseline examination and a baseline examination cannot be adequately completed due to the current configuration. The current configuration does not allow for completing any axial scanning of the elbow to safe-end weld. The letdown nozzle welds were not required to be UT examined under MRP-139 ("Materials Reliability Program: Primary System Piping Butt Weld Inspection and Evaluation Guideline") guidance due to size and function. The FSWOL is being applied to the letdown nozzle DMW locations to obtain an inspectable configuration. - 2220: -2200 applies to the finished FSWOL. Table 1, Figure 2 of Code Case N-770-1 applies to the examination extent for preservice examination and the acceptance criteria of 3130 are applicable with limitations as noted in -2220. - 2410: -2410 applies to the finished FSWOL. Table 1, Inspection Item F of Code Case N-770-1 applies which identifies Figure 2 as the applicable examination extent and 3130 for acceptance criteria. The FSWOL will be re-examined during one of the next two refueling outages following application as required by Table 1 Extent and Frequency of Examination. Examinations after the initial FSWOL application will be scheduled as required by Table 1. If no indications of crack growth or new indications are identified in the examination performed no later than the second refueling outage after application are identified, then the FSWOL will be included in a 25% sample of overlay repairs requiring examination during the inspection interval. Table 1 Footnotes 1,4, 6(a) (for Inspection Item F), 8, 9 and 10 are applicable to these examinations. Deferral of examinations as described in Footnote 11 will not be applied to this FSWOL application. - 2420: See response for -2410.

Response to Request for Additional Information Attachment 1 Page 11 - 2430: The additional examination requirements of -2430 are applicable to this FSWOL location. - 2500: -2S00 is applicable to this FSWOL application with the exception that 2S00(b} does not apply because cast stainless steel is not installed at this location. The additional requirements of 10 CFR SO.SSa(g)(6)(ii)(F)(4} are applicable to 2S00(c}. - 3130: -3130 is applicable to this FSWOL including applicable 10 CFR SO.SSa(g)(6)(ii)(F)(6} conditions. - 3140: -3140 is applicable to the visual examination which will be performed prior to FSWOL application. Visual examinations after FSWOL application are not required by Code Case N-770-1. - 3200: -3200 is applicable to the letdown nozzle FSWOL. Evidence of leakage prior to FSWOL application would be verified by performing a surface examination prior to welding the FSWOL. A pre-FSWOL UT examination would not produce meaningful examination results. The FSWOL is being applied to increase inspectability of the letdown nozzle DMWs. The post FSWOL UT examination will identify degradation within the outer 2S% of the original pipe wall. - 9000: The terms "cracked" and "full structural weld overlay" and "mitigation" are applicable to the letdown nozzle DMW locations. Mandatory Appendix I: This appendix is not applicable to the letdown nozzle DMW FSWOL. Question:

4. Section S.O of the relief request discusses the installation of one layer of sulfur mitigation to prevent hot cracking on the stainless steel piping. Discuss whether the delta ferrite number of this mitigation layer satisfies the delta ferrite requirements of paragraph (e) in Code Case N-S04-4. Discuss the weld material (specification) used for the mitigation layer.

Response

The weld filler material for the sulfur mitigation layer will be ER309L stainless steel that produced a 9FN during vendor testing; therefore, it is expected that the as-deposited ferrite number will be at least 7.SFN. The ER309L improves Alloy S2M weldability by minimizing the potential of hot cracking from contaminants (Le., sulfur, phosphorous, etc.) in the underlying stainless steel material. However, since no structural credit is taken for the ER309L applied weld material the minimum FN specified in Code Cases N-S04-4 (paragraph (e)) and N-740-2 (paragraph 1.2(e)(1)) is not applicable.

Response to Request for Additional Information Attachment 1 Page 12 Question:

5. Provide the wall thickness of the letdown pipe and the thickness of the weld overlay.

Response

The letdown nozzle pipe is NPS 2Y2 Schedule 160 with a nominal wall thickness of 0.375 in. The FSWOL thickness will be 0.30 in. minimum and 0.54 in. maximum, except at the elbow to safe-end transition where the thickness will be greater due to the FSWOL geometry required to facilitate UT examinations (see Figures 2(a)(1) through 2(a)(3)) above. Question:

6. Submit the design analyses of the weld overlay or discuss in detail how the design analyses are performed, including assumptions, references (Le., industry standards or codes), and the results.

Response

The following analyses are being submitted to the NRC (see Attachments 3, 4 and 5):

1. TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay

2. TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis

3. TMI-1 Letdown Nozzle Weld Overlay Sizing Calculation

4. TMI-1 Letdown Nozzle Weld Overlay Section III Analysis

Attachment 2 Code Case N-74D-2

                      !                                                                                                                                                             CASE CASES OF ASME BOILER AND PRESSURE VESSEL CODE                                                                N-740-2 Approval Date: November 10,2008 Code Cases will remain available for use until annulled by the applicable Standards Committee.

Case N-740-2 flaws found during an examination performed in accor-Full Structural Dissimilar Metal Weld Overlay for dance with 2(a)(3), prior to the weld overlay being applied. Repair or Mitigation of Oass 1, 2, and 3 Items (c) Repair Weld Overlay. Weld overlay that is applied Section XI, Division 1 over material with an inside surface connected flaw or subsurface defect, or where a pre-weld overlay examination is not performed. Inquiry: As an alternative to the provisions of (d) see Susceptible Materials. For this Case, the stress-IWA-4410 and IWA-4611 for reducing a defect to an corrosion-cracking (SCC) susceptible materials are UNS acceptable size in accordance with the provisions of the N06600, N06082, or W86182 in PWR environment; or Construction Code or Section XI, is it permissible to UNS N06600, W86182, or austenitic stainless steels and increase the wall thickness, or to apply a mitigation to a associated welds in BWR environments. specified location, by deposition of weld overlay on the outside surface of the piping, component, or associated 1.2 Generai Overlay Requirements weld? (a) A full-structural weld overlay shall be applied by deposition of weld reinforcement (weld overlay) on the Reply: It is the opinion of the Committee that, in lieu outside surface of circumferential welds. This Case applies of the requirements ofIWA-44lO and IWA-46l1, a defect to austenitic nickel alloy and austenitic stainless steel welds in austenitic stainless steel or austenitic nickel alloy piping, between the following: components, or associated welds may be reduced to a flaw (1) P-No. 8 or P-No. 43 and P-Nos. 1, 3, 12A, 12B, of acceptable size in accordance with IWB-3640 by addi- or 12C 1 tion of a reparr weld overlay. lri addttion, for these materi- (2";-P=Nu:-!hm:l-P=N0;-4~--------------l als, in lieu of IWA-44lO, a mitigative weld overlay may (3) Between P-Nos. 1,3, 12A, 12B, and 12C mate-be applied. All Section XI references are to the 2007 Edi- rials tion with the 2008 Addenda. For the use of this Case with (b) If a weld overlay on any of the material combina-other editions and addenda, refer to Table 1. The weld tions in 1.2(a) obstructs a required examination of an adja-overlay shall be applied by deposition of weld reinforce- cent P-No. 8 to P-No. 8 weld, the overlay may be extended ment (weld overlay) on the outside surface of the piping, to include overlaying the adjacent weld. component, or associated weld, including ferritic materials (c) Weld overlay filler metal shall be austenitic nickel when necessary, provided the following requirements are n alloy (28% Cr min., ERNiCrFe-7 A) meeting the require-met: ments of 1.2(e)(I) or (2), as applicable, applied 360 deg around the circumference of the item and deposited using a Welding Procedure Specification (WPS) for groove weld-1 GENERAL REQUIREMENTS ing, qualified in accordance with the Construction Code --~---------~lr.lr~furll~ti~onn------------------------------~annrld~O~w~n~elr'~s~R~e~qmumi~re~m~elrr[thsriimd~enl1riti~fi~e"d~inn~fu~e~R~e~pna~il~i~--------~ (a) Full Structural Weld Overlay. Deposition of weld Replacement Plan. As an alternative to the post weld heat reinforcement on the outside diameter of the piping, com- treatment (PWHT) requirements of the Construction Code ponent, or associated weld, such that the weld reinforce- and Owner's requirements, the provisions of Appendix I ment is capable of supporting the design loads, without may be used for ambient-temperature temper bead welding. consideration of the piping, component, or associated weld (1) For P-No. 1 base materials, the Construction Code beneath the weld reinforcement. Full structural weld over- PWHT exemptions permitted for circumferential butt lay can be either mitigative or repair weld overlay as defined in 1.1(b) and (c). 1 P-Nos. 12A. 12B. and 12C designations refer to specific material (b) Mitigative Weld Overlay. Weld overlay that is classifications originally identified in Section mand subsequently reclas-applied over material with no inside surface connected sified in a later Edition of Section IX. The COmmltt..** function I. to Hlabllah rule. of .afely. relating only to prassure Intagrlly. govamlng the conllrUetlon of bolla ... pres.ure v.... I** tran.port tlnk. and nuclear componenla. and lnaervlce In.pactlon for preaaure Int.grlty of nuel ... r componenla and transport tanka. and to Intarpralthua rulll when qullltlona arl.e regarding their Inlenl. Thla Code doea not addra.. other ufely Isau ** rel.tlng 10 the conllrUctlon of bolla",. prellura vII .. Is. tran.port tanka and nucla .. componanlll. and the In.arvlce Inapaetlon of nuclear componenle end transport tanka. Tha unr of the Code .hould refer 10 other pertinent cod ** Ilandard ** leW1l. regulltlon. or olher relevant documenl*. 1 (N-74D-2)

CASE (continued) N-740-2 CASES OF ASME BOILER AND PRESSURE VFSSEL CODE welds may be applied to exempt the weld ovelay from thickness, provided the portion of the layer over the austen-PWHT, with the following clarifications: itic base material, austenitic filler material weld, and the (a) The nominal weld thickness is defined as the associated dilution zone from an adjacent ferritic base maximum overlay thickness applied over the ferritic base material contain at least 24% Cr, and the Cr content of the material. deposited weld metal is determined by chemical analysis (b) The base material thickness is defined as the of the production weld or of a representative coupon taken maximum thickness of the ferritic material where the over- from a mockup prepared in accordance with the WPS for lay is applied. the production weld. Alternatively, for BWR applications, (2) If ambient-temperature temper bead welding is a diluted layer may be credited toward the required thick-used, Appendix I shall be used. ness, provided the portion of the layer over the austenitic (d) Prior to deposition of the weld overlay, the surface base material, austenitic filler material weld, and the associ-to be weld overlaid shall be examined using the liquid ated dilution zone from an adjacent ferritic base material penetrant method. Indications with major dimensions contain at least 20% Cr, and the Cr content of the deposited greater than ~6 in. (1.5 nun) shall be removed, reduced in weld metal is determined by chemical analysis of the pro-size, or weld repaired in accordance with the following duction weld or of a representative coupon taken from a requirements: mockup prepared in accordance with the WPS for the (1) One or more layers of weld metal shall be applied production weld. to seal unacceptable indications in the area to be repaired (f) This Case is only for welding in applications pre-with or without excavation. The thickness of these layers dicted not to have exceeded thermal neutron (E < 0.5 eV) shall not be used in meeting weld reinforcement design fluence of 1 X 1017 neutrons per cm2 prior to welding. thickness requirements. Peening the unacceptable indica- (g) A new weld overlay shall not be installed over the tion prior to welding is permitted. top of an existing weld overlay that has been in service. (2) If weld repair of indications identified in 1.2(d) is required, the area where the weld overlay is to be deposited, including any local weld repairs or initial weld overlay 2 CRACK GROWTH AND DESIGN _ _ _ layer. shall be examined bY-JbeJiquid penetrant method. (aJ-Cr.acWr.owth-Calculation-of-F-Iaws-in-tlle.onginal-.- The area shall contain no indications with major dimen- Weld or Base Metal. The size of all flaws detected or ; sions greater than Yt6 in. (1.5 nun) prior to application of postulated in the original weld or base metal shall be used the structural layers of the weld overlay. to define the life of the overlay. The inspection interval (3) To reduce the potential of hot cracking when shall be longer than the shorter of the life of the overlay applying an austenitic nickel alloy over P-No. 8 base metal, or the period specified in 3(c). Crack growth due to both it is permissible to apply a layer or multiple layers of stress corrosion and fatigue shall be evaluated. Flaw char-austenitic stainless steel filler material over the austenitic acterization and evaluation shall be based on the examina-stainless steel base metal. The thickness of these layers tion results or postulated flaw, as described below. If the shall not be used in meeting weld reinforcement design flaw is at or near the boundary of two different materials, thickness requirements. The filler material used shall meet evaluation of flaw growth in both materials is required.

'the-minimUlB--feqWremeots-.fef-delta--fel'fite:e.,.----------,(H1'+)-JiForrepairoverlays;1he-initiaHlaw-size"iorcrac1r-------j (e) Weld overlay deposits shall meet the following growth in the original weld or base metal shall be based requirements: on the as-found flaw or ostulated flaw, if no re-overla (1) The austenitic stainless .steel weld overlay shall examination is performed.

consist of at least two weld layers having as-deposited (2) For postulated flaws, the axial flaw length shall delta ferrite content of at least 7.5 FN. The first layer of be 1.5 in. (38 nun) or the combined width of the weld weld metal with delta ferrite content of at least 7.5 FN plus buttering plus any adjacent SCC susceptible material, shall constitute the first layer of the weld reinforcement whichever is greater. The circumferential flaw length shall that may be credited toward the required thickness. Alterna- be assumed to be 360 deg. The depths associated with tively, layers of at least 5 FN are acceptable, provided the these lengths are specified in 2(a)(3) and 2(a)(4). carbon content of the deposited weld metal is determined (3) If in Appendix VIII, Supplement 10, or Supple-by chemical analysis to be less than 0.02%. ment 2, as applicable, ultrasonic examination is performed (2) The austenitic nickel alloy weld overlay shall con- prior to application of the overlay, and no inside-surface-sist of at least two weld layers deposited using a filler connected planar flaws are discovered, initial flaws origi-material with a Cr content of at least 28%. The first layer nated from the inside surface of the weldment equal to of weld metal deposited may not be credited toward the 10% of the original wall thickness shall be assumed in required thickness. Alternatively, for PWR applications, a both the axial and circumferential directions, and the over-first diluted layer may be credited toward the required lay shall be considered mitigative. 2 (N-740-2)

CASE .(continued) CASES OF ASME BOILER AND PRESSURE VFSSEL CODE N-740-2 (4) If in Appendix VIII, Supplement 10, or (3) The assumed flaw in the underlying base material Supplement 2, as applicable, ultrasonic examination is not or weld shall be based on the limiting case of 2(b)(3)(a) performed prior to application of the overlay, initial inside- and (b) that results in the larger required overlay thickness. surface-connected planar flaws equal to at least 75% (a) 100% through-wall circumferential flaw for the through the original wall thickness shall be assumed, in entire circumference both the axial and circumferential directions, and the over- (b) 100% through-wall flaw with length of 1.5 in. lay shall be considered a repair. For cast austenitic stainless (38 rom) or the combined width of the weld plus buttering steel (CASS) items, a 100% through-wall flaw shall be plus any SCC-susceptible material, whichever is greater, assumed unless the subsequent inservice inspection sched- in the axial direction ule is modified as discussed in 3(c)(8). (4) The overlay design thickness shall be verified, (5) There may be circumstances in which an overlay using only the weld overlay thickness conforming to the examination is performed using an ultrasonic examination deposit analysis requirements of 1.2(e). The combined wall procedure qualified in accordance with Appendix VIII, thickness at the weld overlay, any postulated worst-case Supplement 11 for depths greater than the outer 25% of planar flaws under the laminar flaws in the weld overlay, the original wall thickness (Fig. 2). For such cases, the and the effects of any discontinuity (e.g., another weld initial flaw depths shall be assumed shall be the detected overlay or reinforcement for a branch connection) within depth found by the Appendix VIII, Supplement 11 qualified a distance of 2.5jiii from the toes of the weld overlay, examination, plus the postulated worst-case flaw in the including the flaw size assumptions defined in 2(b)(3), region not covered by the Appendix VIII ultrasonic exami-above, shall be evaluated and shall meet the requirements nation. of IWB-3640, IWC-3640, or IWD-3640, as applicable. (6) In determining the life of the overlay, any inside-(5) The effects of any changes in applied loads, as a surface-connected planar flaw found by the overlay preser-vice inspection of 3(b) that exceeds the depth of (3), (4) result of weld shrinkage from the entire overlay, on other or (5) above shall be used as part of the initial flaw depth. items in the piping system (e.g., support loads and clear-The initial flaw depth assumed is the detected flaw depth ances, nozzle loads, and changes in system flexibility and plus the postulated worst-case flaw depth in the re . weight due to the weld overlay) shall be evaluated. Existing the pipe wall thickness that was not examined using an aws preVIOUS y accepte y an ytic ev uation s e ultrasonic examination procedure meeting Appendix VIII evaluated in accordance with IWB-3640, IWC-3640, or for that region. An overlay meeting this condition shall be IWD-3640, as applicable. considered a repair, rather than mitigation. (b) Structural Design and Sizing of the Overlay. The design of the weld overlay shall satisfy the following, using 3 EXAMINATION the assumptions and flaw characterization requirements in 2(a). The following design analysis shall be completed in In lieu of all other examination requirements, the exami-accordance with IWA-4311: nation requirements of this Case shall be met for the life (1) The axial length and end slope of the weld overlay of the overlay. Nondestructive examination methods shall I

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of the weld, as well as any SCC-susceptible base material herein. Nondestructive examination personnel shall be ad'acent to the weld, and provide for load redistribution qualified in accordance with IWA-2300. Ultrasonic exami-from the item into the weld overlay and back into the item nation procedures and personnel shall be qualified in accor-without violating applicable stress limits ofNB-32oo. Any dance with Appendix VIII, Supplement 11. The laminar flaws in the weld overlay shall be evaluated in the examination shall be performed to the maximum extent analysis to ensure that load redistribution complies with practicable, for axial and circumferential flaws. If 100% the above. These requirements will usually be satisfied if coverage of the required volume for axial flaws cannot be the weld overlay full thickness length extends axially achieved, but essentially 100% coverage for circumferen-beyond the SCC-susceptible material or projected flaw by tial flaws (100% of the susceptible volume) can be at least 0.75jiii, where R is the outer radius 'of the item achieved, the examination for axial flaws shall 'be per-and t is the nominal wall thickness of the item at the formed to achieve the maximum coverage practicable, with applicable side of the overlay (i.e., R and t of the nozzle limitations noted in the examination report. The examina-on the nozzle side and R and t of the safe-end on the safe- tion coverage requirements shall be considered to be met. end side). For cast stainless steel components for which no supple-(2) Unless specifically analyzed in accordance with ment is available in Appendix VIII. the weld volume shall 2(b)( 1), the end transition slope of the overlay shall be examined using Appendix VIII procedures to the maxi-not exceed 30 deg. mum extent practicable. 3 (N-740-2)

CASE (continued) N-740-2 CASES OF ASME BOILER AND PRESSURE VESSEL CODE (a) Acceptance Examination that could exist within that volume. This assumed flaw (1) The weld overlay shall have a surface finish of shall meet the preservice examination acceptance standards 250 j.Lin. (6.3 j.Lffi) RMS or better and contour that permits ofIWB-3514, with nominal wall thickness as defined above ultrasonic examination in accordance with procedures qual- the planar flaws. Alternatively, the assumed flaw shall be ified in accordance with Appendix VIII. The weld overlay evaluated and meet the requirements of IWB-3640, shall be inspected to verify acceptable configuration. IWC-3640, and IWD-3640, as applicable. Both axial and (2) The weld overlay and the adjacent base material circumferential planar flaws shall be assumed. for at least ~ in. (13 mm) from each side of the overlay (4) After completion of all welding activities, VT-3 shall be examined using the liquid penetrant method. The visual examination shall be performed on all affected weld overlay shall satisfy the surface examination accept- restraints, supports, and snubbers, to verify that design ance criteria for welds of the Construction Code or tolerances are met. NB-5300. The adjacent base material shall satisfy the sur- (b) Preservice Inspection face examination acceptance criteria for base material of the Construction Code or NB-2500. If ambient temperature (1) The examination volume in Fig. 2 shall be ultra-temper bead welding is performed, the liquid penetrant sonically examined. The angle beam shall be directed per-examination of the completed weld overlay shall be con- pendicular and parallel to the piping axis, with scanning ducted no sooner than 48 hr following completion of the performed in four directions, to locate and size any planar three tempering layers over the ferritic steel. flaw that have propagated into the outer 25% of the base (3) The examination volume A-B-C-D in Fig. l(a) metal thickness or into the weld overlay. Forwe1doverlays shall be ultrasonically examined to assure adequate fusion on cast austenitic stainless steel base materials, if a 100% (Le., adequate bond) with the base material and to detect through-wall flaw is used for crack growth, only planar welding flaws, such as interbead lack of fusion, inclusions, flaws that have propagated into the weld overlay, or are or cracks. The interface C-D shown between the overlay in the overlay, are required to be located and sized. and weld includes the bond and heat-affected zone from (2) The preservice examination acceptance standards the overlay. If ambient temperature temper bead welding ofIWB-3514 shall be met for the weld overlay. In applying is performed. the ultrasonic examination shall be conducted the acceptance standards to planar indications. the thick-no sooner than 48 hr following completion of the three ness, tl or t2, defined in Fig. 1(b), shall be used as the tempering layers over the ferritic steel. Planar flaws nominal wall thickness in IWB-3514, provided the base detected in the weld overlay acceptance examination shall material beneath the flaw (i.e., safe end, nozzle, or piping meet the preservice examination standards of IWB-3S14. material) is not susceptible to SCC. For susceptible mate-In applying the acceptance standards to planar indications, rial, tl shall be used. Planar flaws in the outer 25% of the thicJ<ness, t1, or t2 defined in Fig. 1(b), shall be used the base metal thickness shall meet the design analysis as the nominal wall thickness in IWB-3514, provided the requirements of 2(b). base material beneath the flaw (Le., safe end, nozzle, or (3) The flaw evaluation requirements of IWB-3640, piping material) is not susceptible to SCC. For susceptible IWC-3640, or IWD-3640 shall not be applied to planar material, tl shall be used. If a flaw in the overlay crosses flaws, identified during preservice examination. that exceed ________~thabouD~e~e~~~oDs~~~onse.~~-.~~~~~~=-*-~=-~==~~~~~~~----------~ tive of the two dimensions (11 or t~ shall be used. Laminar flaws in the weld overlay shall meet the following require-

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(a) The acceptance standards of IWB-3514 shall (1) The weld overlay examination shall be added to be met, with the additional limitation that the total laminar the inspection plan. The weld overlay inspection interval flaw area shall not exceed 10% of the weld surface area shall not be greater than the life of the overlay as deter-and that no linear dimension of the laminar flaw area shall mined in 2(a) above. All weld overlays shall be examined exceed the greater of 3 in. (76 mm) or 10% of the pipe prior to the end of their design life. circumference. (2) The weld overlay examination volume in Fig. 2 (b) For examination volume A-B-C-D in Fig. l(a), shall be ultrasonically examined during the first or second the reduction in coverage due to laminar flaws shall be refueling outage following application. Alternatively, for less than 10%. The uninspectable volume is the volume mitigative weld overlays, in which pre-overlay examina-in the weld overlay underneath the laminar flaws for which tions are performed in accordance with 2(a)(3), post-over-coverage cannot be achieved with the angle beam examina- lay examinations are performed in accordance with 3(a) tion method. and 3(b), and no inside-surface-connected planar flaws are (c) Any uninspectable volume in the weld overlay discovered, the overlay may be placed immediately into shall be assumed to contain the largest radial planar flaw the popUlation to be examined in accordance with 3(c)(5). 4 (N-74D-2)

CASE (continued) CASES OF ASME BOlLER AND PRESSURE VESSEL CODE N-740-2 FIG.l ACCEPTANCE EXAMINATION VOLUME AND THICKNESS DEFINITIONS A B D (al Examination Volume A~ A r D H (bl Thlckne.. (t, and fzl for Table IWB-3514-2 GENERAL NOTES: (al DImensIon b Is equIvalent to the nomInal thIckness of the nozzle or pIpe beIng overlaId, as approprIate. (b The nomInal wall thIckness Is tl for flaws In E-F-G-H, and tz for flaws In A-E-H-D or F-B-C-G. (c) For flaws that scan two examInation volumes (such as Illustrated In F-G) the t, thIckness shall be used, (d) The weld Includes the nozzle or safe end butter, where applied, plus any SeC-susceptible base materIal In the nozzle. (3) The weld overlay examtnation volUme in Fig. 2 the base matenal thickness shall meet the desIgn anlllysis I 1-shall be ultrasonically examined to determine if any new requirements of 2. Any indication characterized as stress or existing planar flaws have propagated into the outer corrosion cracking in the weld overlay material is unac-25% of the base material thickness or into the overlay. ceptable. The angle beam shall be directed perpendicular and parallel (5) Weld overlay examination volumes in Fig. 2 that to the piping axis, with scanning performed in four show no indication of planar flaw growth or new planar directions. flaws shall be placed into a population to be examined on (4) The weld overlay shall meet the inservice exami- a sample basis, except as required by 3(c)(1). Twenty-five nation acceptance standards ofIWB-3514. In applying the percent of this population shall be examined once during acceptance standards to planar indications, the thickness, each inspection interval. tl- or f2, defined in Fig. 1(b), shall be used as the nominal (6) If inservice examinations reveal planar flaw wall thickness in IWB-3514, provided the base material growth, or new planar flaws, meeting the acceptance stan-beneath the flaw (i.e., safe end, nozzle, or piping material) dards ofIWB-3514, IWB-3600, IWC-3600, or IWB-3600, is not susceptible to SCC. For susceptible material, tl shall the weld overlay examination volume shall be reexamined be used. If the acceptance standards of IWB-3514 cannot during the first or second refueling outage following dis-be met, the weld overlay shall meet the acceptance stan- covery of the growth or new flaws. dards of IWB-3600, IWC-3600, or IWD-3600, as applica- (7) For weld overlay examination volumes with unac-ble. If a planar flaws is detected in the outer 25% of ceptable indications in accordance with 3(c)(4), the weld 5 (N-74D-2)

CASE (continued) N-740-2 CASES OF ASME Bon.ER AND PRESSURE VESSEL CODE FIG.2 PRESERVICE AND INSERVICE EXAMINATION VOLUME Minimum "2 In. (13 mml Minimum 1/2 in. (13 mml [Note (1)] A t/4 t D C T t As-found Flaw 1 Examination Volume A-B-C-D GENERAL NOTE: The weld Includes the nozzle or safe end butter, where applied. NOTE: (1) For axial or circumferential flaws, the axial extent of the examination volume shall extend at least ~ In. (13 mm) beyond the as-found flaw and at least ~ In. (1.3 mm) beyond the toes of the original weld, Including weld end butter, where applied. overlay and original defective weld shall be removed. A materials. After the required examination volume is exam-repair/replacement activity shall be performed in accor- ined by qualified ultrasonic examination for the cast austen-dance with IWA-4000. itic stainless steel material and no planar flaws are detected, (8) If preservice and inservice examinations in accor- the weld may be placed in the 25% inspection sample

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11 cannot be performed for the entire weld overlay exami- (d) Additional Examinations. If inservice examinations nation volume in Fig. 2 because of cast austenitic stainless reveal a defect, in accordance with 3(c)(4), planar flaw steel items, and a 100% initial flaw assumption is not used growth into the weld overlay design thickness, or axial in the crack growth evalu~tion of 2(a), a 75% thro~gh- flaw growth beyond the specified examination volume, , wall ?epth may be ass~med m ~e a:ac k growth .calcula~on, additional weld overlay examination volumes, equal to the proVl~ed that the reqwred exarmnati~n volume .1S exarmned number scheduled for the current inspection period, shall at ~ higher frequency than th~ requl1'eme~ts m 3(~). The be examined prior to return to service. If additional defects subject weld shall be ultrasODlcally exammed dunng the are found in the second sample 50% of the total population first or second refueling outage following the weld overlay of weld overlay examination ~olumes shall be examined installation. If ~trasoni~ examination. is perf~rmed. prior rior to return to service. If additional defects are found, the to weld overl~alla.tion and after 1DstalJaWllJ...lllawow~_P~=-====-;====-=..-;.=-;;;;-=;;:-;-====:--_ _ _ _---r_ detecting any planar flaws in the original weld or the weld en remhammbeg popu ~ °dn o. we over ay ex~ation

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over1ay, then the ultrasornc examma on unng e or

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inservice examination, the required examination volume shall be ultrasonically examined every 10 years from the 4 PRESSURE TESTING date of the installation until such time when ultrasonic examination is qualified to examine the cast austenitic A system leakage test shall be performed in accordance stainless steel portion of the required inspection volume with IWA-5000. in accordance with the performance demonstration require-ments of ASME Code, Section XI, Appendix VIII. The inspection of the overlaid weld shall not be credited to 5 DOCUMENTATION satisfy the requirement of the 25% inspection sample every ten years of overlaid welds without cast stainless steel Use of this Case shall be documented on Form NlS-2. 6 (N-740-2)

CASE (continued) CASES OF ASME BOn.ER AND PRESSURE VESSEL CODE N-740-2 MANDATORY APPENDIX I AMBIENT-TEMPERATURE TEMPER BEAD WELDING 1*1 GENERAL REQUIREMENTS as the materials to be welded. The materials shall be post-(a) This Appendix applies to dissimilar austenitic filler weld heat treated to at least the time and temperature that metal welds between P-Nos. 1, 3, 12A, 12B, and 12C1 was applied to the materials being welded. materials and their associated welds and welds joining (b) The maximum interpass temperature for the first P-No. 8 or 43 materials to P-Nos. 1, 3, I2A, 12B, and three layers of the test assembly shall be 150°F (66°C). 1 I2C materials with the following limitation. This Appen- (c) The weld overlay shall be qualified using groove dix shall not be used to repair SA-302 Grade B material weld coupon. The test assembly groove depth shall be at unless the material has been modified to include from 0.4% least 1 in. (25 mm). The test assembly thickness shall be to 1.0% nickel, quenching, tempering, and application of at least twice the test assembly groove depth. The test a fine grain practice. assembly shall be large enough to permit removal of the (b) The maximum area of an individual weld overlay required test specimens. The test assembly dimensions on based on the finished surface over the ferritic base material either side of the groove shall be at least 6 in. (150 mm). 2 2 shall be 500 in. (325 000 mm ). The qualification test plate shall be prepared in accordance (c) Repair/replacement activities on a dissimilar-metal with Fig. 1-1. weld in accordance with this Appendix are limited to those along the fusion line of a nonferritic weld to ferritic base (d) Ferritic base material for the procedure qualification - T I

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e-ss-o'f:-n-o-n£-:;-e-m"'ti"'c-w el'-; d- te-shhalr-meenlre-imp1i-cLtesne-quirenrentroh1re:-------j deposit exists above the original fusion line. Construction Code and Owner's Requirements. If such (d) If a defect penetrates into the ferritic base material, requirements are not in the Construction Code and Owner's repair of the base material, using a nonferritic weld filler Requirements, the impact properties shall be determined by material, may be performed in accordance with this Charpy V-notch impact tests of the procedure qualification Appendix, provided the depth of repair in the base material base material at or below the lowest service temperature does not exceed ~ in. (10 mm). of the item to be repaired. The location and orientation of (e) Prior to welding, the area to be welded and a band the test specimens shall be similar to those required in I around the area of at least 1~ times the component thick- 1-2.1(e) but shall be in the base metal. ~ ness or 5 in. (130 mm), whichever is less, shall be at least (e) Charpy V-notch tests of the ferritic heat-affected ______SAOLOF~(~10~O~C~)__---------------~ze.R~hallhepeaeBB~~~~~pem (f) Welding materials shall meet the Owner's Require- as the base metal test of 1-2. 1(d). Number, location, and ments and the Construction Code and Cases specified in orientation of test specimens shall be as follows: (1) The specimens shall be removed from a location as near as practical to a depth of one-half the thickness of the deposited weld metal. The coupons for HAZ impact specimens shall be taken transverse to the axis of the weld and etched to define the HAZ. The notch of the Charpy V-notch specimen shall be cut approximately normal to the material surface in such a manner as to include as 1*2 WELDING QUALIFICATIONS much HAZ as possible in the resulting fracture. When the The welding procedures and operators shall be qualified material thickness permits, the axis of a specimen shall be in accordance with Section IX and the requirements of inclined to allow the root of the notch to be aligned parallel 1-2.1 and 1-2.2. to the fusion line. 1*2.1 Procedure Qualification (2) If the material thickness pennits, the axis of a (a) The base materials for the welding procedure quali- specimen shall be inclined to allow the root of the notch fication shall be of the same P-Number and Group Number to be aligned parallel to the fusion line. 7 (N-74D-2)

CASE (continued) N-740-2 CASES OF ASME BOILER AND PRESSURE VESSEL CODE FIG.I-1 QUALIFICATION TEST PLATE Discard Transverse Side Bend Reduced Section Tensile Transverse Side Bend A HAZCharpv A V-Notch A Transverse Side Bend Reduced Section Tensile Transverse Side Bend Discard Fusion i1ne Weidmetal GENERAL NOTE: Base metal Charpy Impact specimens are not shown. This figure Illustrates a. similar-metal weld. (3) If the test material is in the form of a plate or (2) An Adjustment Temperature for the procedure forging, the axis of the weld shall be oriented parallel to qualification shall be determined in accordance with the - - - -the..principal direction...of.rolling-ot..forgin.",g~------<atlJ.lpplicable.-pr<MsioDs-of...NB.4335.2..f-SectiOD-1II,-2, uu,I-------I-(4) The Charpy V-notch test shall be performed in Edition with the 2002 Addenda. The RTNOT or lowest accordance with SA-370. Specimens shall be in accordance service temperature of the materials for which the welding Wlth SA-3 JO, Fig. II, Type A. 'lbe test shan consist of a procedure Wl e use s e mcrease y a empera set of three full-size 10 mm X 10 mm specimens. The equivalent to that of the Adjustment Temperature. lateral expansion, percent shear, absorbed energy, test tem- 1-2.2 Performance Qualiftcation. Welding operators perature, orientation, and location of all test specimens shall be qualified in accordance with Section IX. shall be reported in the Procedure Qualification Record. (f) The average lateral expansion value of the three HAZ Charpy V-notch specimens shall be equal to or greater 1-3 WELDING PROCEDURE REQUIREMENTS than the average lateral expansion value of the three unaf-fected base metal specimens. However, if the average lat- The welding procedure shall include the following eral expansion value of the HAZ Charpy V -notch requirements: specimens is less than the average value for the unaffected (a) The weld metal shall be deposited by the automatic base metal specimens and the procedure qualification meets or machine GTAW process. all other requirements of this Appendix, either of the fol- (b) Dissimilar metal welds shall be made using A-No.8 lowing shall be performed: weld metal (QW-442) for P-No. 8 to P-No. I, 3, or 12 (A, (1) The welding procedure shall be requalified. B, or C) weld joints or F-No. 43 weld metal (QW-432) 8 (N-740-2)

CASE (continued) CASES OF ASME BOn.ER AND PRESSURE VESSEL CODE N-740-2 TABLE 1 REFERENCES FOR ALTERNATIVE EDITIONS AND ADDENDA OF SECTION XI 1995 Edition with 1989 Edition 1986 Edition with 2001 Edition with 1996 Addenda with 1991 1988 Addenda 2003 Addenda through through 2001 1995 Edition Addenda through 1989 2007 Edition with Edition with 2002 with 1995 through Edition with 1990 2008 Addenda Addenda Addenda 1995 Edition Addenda IWA-4000 IWA-4000 IWA-4000 IWA-4000 IWA-4000 & Repair/Replacement IWA-7000 Activities IWA-4410 IWA-4410 IWA-4410 IWA-4170 IWA-4120 Welding, Brazing, Metal Removal, and Installation - General Requirements IWA-3300 IWA-3300 IWA-3300 IWA-3300 IWA-3300 Flaw Characterization IWA-4611 IWA-4611 IWA-4421 & IWA-4170Ib) IWA-4120 Defect Removal IWA-4424 IWB-3S14 lWB-3S14 IWB-3S14 IWB-3S14 IW8-3S14 Standards for Category 8-F IW B/C/D-3600 IWB/C-3600 IWB/C-3600 IW8/C-3600 IWB/C-3600 Analytical Evaluation IWB/C/D-3640 IWB/C-3640 IWB/C-3640 IWB/C-3640 IWB/C-3640 Evaluation Procedures or or or or IWB/C-36S0 lWB/C-36S0 IW8/C-36S0 IWB/C-36S0 for P-No. 8 or 43 to P-No. 1,3, or 12 (A, B, or C) weld welding. If direct measurement is impmcticaI. interpass joints. temperature shall be determined in accordance with (c) The area to be welded shall be buttered with a deposit I-3(e)(2) or (3). of at least three layers to achieve at least ~ in. (3 mm) (2) heat-flow calculations using at least the variables overlay thickness with the heat input for each layer con- listed below. trolled to within +/-1O% of that used in the procedure quali- (a) welding heat input fication test. The heat input of the first three layers shall (b) initial base material temperature not exceed 45 kJ/in. (1.8 kJ/mm) under any conditions. (c) configuration, thickness, and mass of the item Particular care shall be taken in the placement of the weld being welded ________~I=ayLe=rs~o~f=th=e~a=u=st=em=*=ti=c~o~v=er=la~y~fi=ll~e=r~m=a~te=n~'al~a~t=th=e~t=oe~of~____--+(~e~~m~'~~~~______~ the overlay to ensure that the HAZ and ferritic base metal materials being welded are tempered. Subsequent layers shall be deposited with a e) arc time r weld ass and dela time between --'------flheat-ieput--not eKeeerung lbat--aseEl--for layers beyenEl-the------::--....L..::,,' -....:::..::....:=:c..L..=-..:..:.=::c..<:.=-=;::.::;=<-:::::=-===-..:O'=----------! third layer in the procedure qualification. each pass (d) The maximum interpass temperature for field appli- (f) arc time to complete the weld cations shall be 3500 P (I80°C) for all weld layers regard- (3) measurement of the maximum interpass tempera-less of the interpass temperature used during qualification. ture on a test coupon that is no thicker than the item to be The interpass temperature limitation of QW-406.3 need welded. The maximum heat input of the welding procedure not be applied. shall be used in welding the test coupon. (e) The interpass tempemture shall be determined as (f) Particular care shall be given to ensure that the weld follows: region is free of all potential sources of hydrogen. The (1) temperature measurement (e.g., pyrometers, tem- surfaces to be welded, filler metals, and shielding gas shall perature-indicating crayons, and thermocouples) during be suitably controlled. 9 (N-740-2)

INTENrraNAILY- [EFrB[)\NI(~------------,

Attachment 4 Non-Proprietary Version of Calculations TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis TMI-1 Letdown Nozzle Weld Overlay Sizing Calculation TMI-1 Letdown Nozzle Weld Overlay Section III Analysis

0402-01-F01 (Rev. 017. 11/19/2012) A CALCULATION

SUMMARY

SHEET (CSS) AREVA Document No. 32 - 9196236 - 000 Safety Related: C8l Yes D No TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Title ,. .;N;. ,;.o.; ;,;n:. :. .;. P.;. ,;ro;;.o;p;.;.n,;.; *e;.; ,;ta=ry""--_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ PURPOSE AND

SUMMARY

OF RESULTS: AREVA NP Inc. proprietary information in the document are removed and their locations are indicated by pairs of braces "[ ]". This document is the non-proprietary version of AREVA Document 32*9186192-001. The purpose of this report is to document the results of weld residual stress finite element analysis of the Cold leg (eL) Letdown Nozzle Dissimilar Metal Welds (DMW) and Structural Weld Overlay (SWOL) at the Three Mile Island Unit 1 (TMI-1) Nuclear Power Plant. The analysis includes simulation of the existing DM Weld attaching the Letdown Nozzle to Safe end, DMW attaching Safe end to Elbow and the proposed Weld Overlay mitigation of the DM welds. The analysis also includes simulation of worst case repair welds of DMW that would have been performed. The state of stress after welding and operating (heat up/cool down) cycles as predicted by the ANSYS Version 13.0 finite element analysis, are summarized to support flaw evaluations of the DM welds. THE DOCUMENT CONTNNS ASSUMPTIONS THAT SHALL BE THE FOlLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT: VERIFIED PRIOR TO USE COOENERSIONIREV CODENERSIONIREV DYES ANSYS 13.0 SP2

                                                                                                                                 ~ NO Page 1 of41

0402-01-F01 (Rev. 017, 11/19/2012) Document No, 32-9196236-000 PROPRIETARY TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Review Method: [gJ Design Review (Detailed Check) D Alternate Calculation Signature Block P/R/A Name and Title and Pages/Sections (printed or typed) Signature LP/LR Date Prepared/Reviewed/Approved Silvester Noronha Engineer IV 7rvv~ P tl4/n All Doug Killian "'" Technical Consultant Tim Wiger

                      !lItu.-                -  I-R    1(4(( 3                      All Unit Manger            ~~                            A     (/~                         All

-- ?/ Note: P/RIA designates Preparel' (P), Reviewer (R), Approvel' (A); LP/LR designates Lead PrepareI' (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) Name Title Mentor to: (printed or typed) (printed or typed) (P/R) Signature Date N/A Page 2

A 0402-01-F01 (Rev. 017,11/19/2012) AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Record of Revision Revision Pages/Sections/Paragraphs No. Changed Brief Description / Change Authorization 000 All Original release Page 3

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Table of Contents Page SIGNATURE BLOCK ................................................................................................................................2 RECORD OF REVISION ..........................................................................................................................3 LIST OF TABLES .....................................................................................................................................6 LIST OF FIGURES ...................................................................................................................................7

1.0 INTRODUCTION

...........................................................................................................................8 2.0   PURPOSE AND SCOPE ...............................................................................................................8 3.0   ANALYTICAL METHODOLOGY ...................................................................................................8 3.1     Welding Analysis Methodology ........................................................................................................ 9 3.2     Design inputs .................................................................................................................................. 15 3.2.1    Geometry ......................................................................................................................... 15 3.2.2    Finite Element Model ....................................................................................................... 15 3.2.3    Material ............................................................................................................................ 16 3.2.4    Welding Parameters ........................................................................................................ 21 3.3     Boundary Conditions for Welding Simulation ................................................................................. 21 3.3.1    Thermal Analysis - Welding Simulation ........................................................................... 21 3.3.2    Structural Analysis - Welding Simulation ......................................................................... 22 4.0   ASSUMPTIONS ..........................................................................................................................23 4.1    Assumptions Requiring Verifications .............................................................................................. 23 4.2    Modeling Simplifications ................................................................................................................. 23 4.3    Engineering Approximations .......................................................................................................... 24 5.0   COMPUTER USAGE ..................................................................................................................24 5.1    Software and Hardware.................................................................................................................. 24 5.2    Computer Files ............................................................................................................................... 24 6.0   CALCULATIONS/RESULTS .......................................................................................................26

7.0 REFERENCES

............................................................................................................................34 APPENDIX A :    HOOP AND AXIAL STRESS TABLES ....................................................................................... 35 Page 4

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Table of Contents (continued) Page APPENDIX B : VERIFICATION OF ANSYS COMPUTER CODE ...................................................................... 39 Page 5

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary List of Tables Page Table 3-1: Letdown Nozzle I Cold leg Dimensions ................................................................................ 15 Table 3-2: Component Material Designation ......................................................................................... 16 Table 3-3: Welding Parameters .............................................................................................................21 Table 5-1: Listing of Computer Files ......................................................................................................25 Table A-1: Hoop and Axial Stress Distributions at Shutdown Condition (70°F) ..................................... 35 Table A-2: Hoop and Axial Stress Distributions at Steady State Operating Condition ([ ] OF) ........ 37 Page 6

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary List of Figures Page Figure 3-1: CL Letdown Nozzle FSWOL Model ....................................................................................... 9 Figure 3-2: Welding of the DM Welds Attaching Nozzle to Safe end and Safe end to Elbow ............... 11 Figure 3-3: ID Repair welds extending 50% of the original DM Weld .................................................... 12 Figure 3-4: Full Structural Weld Overlay covering the DM Welds and the Safe end ............................. 13 Figure 3-5: Symmetry Planes ................................................................................................................ 17 Figure 3-6: Finite Element Mesh ............................................................................................................ 18 Figure 3-7: Detailed mesh showing DM Welds ...................................................................................... 19 Figure 3-8: Detailed mesh showing Repair Welds ................................................................................. 19 Figure 3-9: Detailed mesh showing Weld Overlay ................................................................................. 20 Figure 3-10: Detailed mesh showing Weld Overlay ...............................................................................20 Figure 3-11: Insulated Surfaces at Cut Planes ......................................................................................22 Figure 3-12: Structural Model Constraints .............................................................................................23 Figure 6-1: Hoop stress contours at shutdown (70°F). Obtained by applying three steady state loading cycles following the completion of the SWOL ..................................................................................27 Figure 6-2: Axial stress contours at shutdown (70°F). Obtained by applying three steady state loading cycles following the completion of the SWOL ..................................................................................28 Figure 6-3: Hoop stress contours at steady state ([ ] OF). Obtained by applying two and a half steady state loading cycles following the completion of the SWOL ................................................. 29 Figure 6-4: Axial stress contours at steady state ([ ] OF). Obtained by applying two and a half steady state loading cycles following the completion of the SWOL ................................................. 30 Figure 6-5: Path lines for hoop and axial stress distribution in the DM welds and safe end region ....... 31 Figure 6-6: Hoop stress distributions at shutdown (70°F). Obtained by applying three steady state loading cycles following the completion of the SWOL. ..................................................................... 32 Figure 6-7: Axial stress distributions at shutdown (70°F). Obtained by applying three steady state loading cycles following the completion of the SWOL. ..................................................................... 32 Figure 6-8: Hoop stress distributions at steady state ( [ ] OF). Obtained by applying two-and-a-half steady state loading cycles following the completion of the SWOL ................................................. 33 Figure 6-9: Axial stress distributions at steady state ( [ ] OF). Obtained by applying two-and-a-half steady state loading cycles following the completion of the SWOL ................................................. 33 Page 7

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary

1.0 INTRODUCTION

Primary water stress corrosion cracking (PWSCC) of Alloy 600/821182 materials is a well-documented phenomenon in the nuclear power industry. Components have risk for PWSCC at the dissimilar metal welds (DMWs). The risk due to PWSCC increases with service time. AREVA plans to mitigate the Three Mile Island (TMI -1) cold leg (CL) letdown nozzle Alloy 600/82/182 safe end and DMWs with a full structural weld overlay (FSWOL) during the TlR20 refueling outage in the fall of 2013. The planned modification using a FSWOL is a preemptive measure to reduce susceptibility of the DMW to PWSCC and to enhance the configuration such that improved coverage using ultrasonic examination of the nozzle to safe end DMW and the adjacent elbow to safe end weld DMW is accomplished. 2.0 PURPOSE AND SCOPE The purpose of this document is to report results of the weld residual stress finite element analysis of the Cold leg (CL) Letdown Nozzle Dissimilar Metal Welds (DMW) and Weld OverLay (WOL) at the Three Mile Island Unit 1 (TMI-l) Nuclear Power Plant. This analysis includes simulation of the existing DMWs attaching the safe end to the Letdown nozzle and the pipe-elbow as well as repairs to these DMWs. The proposed FSWOL is also simulated. The state of stress after welding and operating (heat up/cool down) cycles as predicted by the ANSYS Version 13.0 finite element analysis, are provided in this report to support fracture mechanics evaluation of postulated flaws in degraded DMWs and safe end. 3.0 ANALYTICAL METHODOLOGY The analytical methodology used to predict the weld induced residual stresses in the DMWs and WOL involves three-dimensional finite element analysis. Due to the symmetric nature of the cold leg, pipe/elbow and WOL, a half symmetric model is used to represent the geometry of interest. The half symmetric model used to represent the letdown nozzle with FSWOL is shown in Figure 3-1. The following subsections discusses the modeling and methodology used in the welding simulations performed in this document. Page 8

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Figure 3-1: CL Letdown Nozzle FSWOL Model 3.1 Welding Analysis Methodology The WRS (Weld Residual Stress) finite element analysis is carried out per the WRS analysis procedure [1]. Due the symmetric nature of the model, a half-symmetric model was used in the analysis. The various stages of the welding processes for the structural components, including the Alloy 82/182 butt-welds and repair welds; and Alloy 52M Structural Weld Overlay (SWOL) are simulated using a 3-dimensional finite element model with the following sequential steps:

1. Simulate the Dissimilar Metal butt-weld joining the safe end to the letdown nozzle using Alloy 82/182 weld metal by activating the elbow and sequentially adding the weld passes.

2. Simulate the ill repair of the above weld by removing material and adding passes sequentially.

3. Simulate the Dissimilar Metal butt-weld joining the Alloy 600 safe end to the stainless steel elbow.

4. Simulate the repair weld by deactivating the repair weld volume and adding repair weld passes sequentially.

Page 9

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary

5. Simulate hydro-static testing by applying a static load step of [ ] psig and [ ] OF at the wetted surface with corresponding endcap pressures at the pipe ends.

6. Simulate three operating condition cycles by applying the steady state temperature and pressure

([ ]oF and [ ] psig [2]) as a static load step. Each operating cycle starts from ambient conditions (zero pressure and room temperature), applies steady state pressure and temperature conditions, and then returns to ambient conditions.

7. Simulate the Alloy 52M weld overlay by sequentially adding weld passes layer by layer.

8. Simulate three operating condition cycles by applying the steady state temperature and pressure

([ ]oF and [ ] psig [2]) as a static load step. Each operating cycle starts from ambient conditions (zero pressure and room temperature), applies steady state pressure and temperature conditions, and then returns to ambient conditions. As explained above this simulation follow the sequential steps that consist of building the original geometry of the Letdown down nozzle DMWs including the original repairs and the SWOL buildUp. The key steps of the welding simulations, illustrated with the finite element model, are shown in Figure 3-2 through Figure 3-4. Page 10

A ARI!VA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Figure 3-2: Welding of the OM Welds Attaching Nozzle to Safe end and Safe end to Elbow SS Cladding CS Letdown Alloy 600 Safe en!Il---' Alloy 821182 OM Welds Page 11

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Figure 3-3: ID Repair welds extending 50% of the original DM Weld Alloy 821182 Repair Welds Page 12

A AFU!VA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Figure 3-4: Full Structural Weld Overlay covering the DM Welds and the Safe end Page 13

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary The general purpose finite element code ANSYS [3] is used to perfonn the WRS finite element analysis. The finite element analysis is based on a 3-dimensional half-symmetric model. The basic steps comprising the multi-pass welding simulation of the DM welds, Repair welds and the Structural Weld overlay are as follows:

1. Develop the finite element model with the features necessary to accommodate weld pass deposition of the DM welds, repair welds and SWOL.

2. Define the temperature range for melting (solidus and liquidus temperatures).

3. Define thennal and mechanical temperature dependent material properties from ambient conditions (700P) up to and including the melting region.

4. Define thennal and structural boundary conditions.

5. Define volumetric heat sources from welding procedure specifications, if available.

6. Simulate the thennal phase of the welding process using the ANSYS "birth and death" feature

Deactivate finite elements in all weld passes.
Activate finite elements in one weld pass at a time and perfonn transient thennal analysis to develop the history of the temperature field for subsequent structural analysis.

7. Simulate the structural phase of the welding process using the ANSYS "birth and death" feature

Deactivate finite elements in all weld passes.
Activate finite elements in one weld pass at a time and perfonn static structural elastic-plastic analysis using the temperature history from the thennal phase.

Static load steps are applied to simulate hydrostatic testing after the simulation of the DM welds and repair welding. Also, load steps are applied to simulate steady state operating conditions. On completing the structural weld overlay simulation, static load steps to simulate the steady state operating conditions are applied again. Page 14

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary 3.2 Design inputs 3.2.1 Geometry The detailed dimensions of the CL Letdown nozzle and SWOL modeled in the WRS finite element analysis are obtained from References [4] and [5]. The key dimensions are shown in Table 3-1. Table 3-1: Letdown Nozzle I Cold leg Dimensions Dimension Value Letdown Nozzle 10 - - Letdown Nozzle 00 at OMW Cladding Thickness (Nominal) at Nozzle Cold leg 10 Cold leg 00 Cladding Thickness (Minimum) at Cold leg 3.2.2 Finite Element Model The finite element model is a three-dimensional half-symmetric model, as shown in Figure 3-5. The finite element mesh consists of ANSYS 8-noded thermal (SOLID70) and structural (SOLIDI85) elements. The weld pass depositions for the DM welds, repair welds and the SWOL are simulated using ANSYS's element "birth and death" feature. The thermal finite element model is documented in File "Thermal Model.db" and the stress finite element model is documented in File "Stress Model.db". Both files are archived as listed in Table 5-1. The finite element mesh for the letdown nozzle and weld overlay are shown in Figure 3-6 through Figure 3-10. The dimensions of the letdown nozzle weld overlay finite element model are developed per References [4] and [5]. The weld passes employed in the dissimilar metal weld and repair weld simulations are based on the information in Reference [6]. The SWOL weld passes are based on information in References [7] and [8]. Page 15

fA. AFU£VA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary 3.2.3 Material Reference [9] provides the material designation of the components modeled in the WRS analysis. Table 3-2: Component Material Designation Component Material Designation Cold leg - Letdown Nozzle Cladding OM Welds and Repairs Safe end Elbow First layer of WOL over SS Elbow until within 3116 in. of outboard edge of OMWt Layer at the interface of SS Elbow and OMW attaching Elbow to Safe endt SWOL t Structural credit is not taken for this layer The analysis herein uses the physical properties (thermal conductivity, specific heat. mean coefficient of thermal expansion, density, Young's modulus, and Poisson's ratio) and the stress-strain curves from Reference [10] that are representative of the materials listed in Table 3-2. For the letdown nozzle material A-lOS Grade 2 that is not directly available in Reference [10], the material properties of A-I06 Grade C are use~ since the material properties for both materials were comparable [11]. All of the physical and mechanical properties, except the Poissou's ratio, are temperature dependent. The multi-linear kinematic hardening model in ANSYS [3] is employed in this elastic-plastic structural analysis. Temperature dependent, tme stress-strain material properties are used with the multi-linear kinematic hardening model for simulating the structural phase of the welding procedure and the operating transients. Page 16

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Figure 3-5: Symmetry Planes _ _ _-====10 .000 (in) 5 5.000 Page 17

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Figure 3*6: Finite Element Mesh (a) Overall Mesh for Half-Symmetric 3D Model Page 18

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Figure 3*7: Detailed mesh showing OM Welds Figure 3*8: Detailed mesh showing Repair Welds Page 19

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Figure 3*9: Detailed mesh showing Weld Overlay Figure 3*10: Detailed mesh showing Weld Overlay Page 20

A AFU!VA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary 3.2.4 Welding Parameters References [6, 7 and 8] provide a set of welding procedure or parameters that are used in the present welding simulations to establish required parameters for the DM welds, repair welds and the SWOL. The welding parameters used in the modeling of the welding processes are shown in Table 3-3. Table 3-3: Welding Parameters Welding Parameter Value DMW / RW Passes: Groove weld heat input calculated from typical welding parameters for a manual metal arc or manual gas shielded tungsten arc weld Rod Diameter - - Current Voltage Travel Speed Arc Efficiency Maximum Interpass Temperature Overlay Weld Passes Heat Input for the first layer [8] Heat Input for 2nd layer onwards [81: Maximum Interpass Temperature [ J 3.3 Boundary Conditions for Welding Simulation 3.3.1 Thermal Analysis - Welding Simulation The thenna! model is loaded by a volumetric heat source applied to each weld pass. To enforce thermal continuity with adjacent components, adiabatic boundary conditions are applied at the symmetry planes (Figure 3-5) and the CL cutting planes (Figure 3-11). Thus no heat transfer occurs through the symmetry plane of the model as shown Figure 3-5 and the three cutting planes shown in Figure 3-11. Heat loss at the inner and outer surfaces is simulated using a heat transfer coefficient of [ ] btulhr-ftl_oF per the Reference [1] WRS procedure to model natural convection to an air environment Radiative bOlmdary conditions are not considered since radiation losses from the molten weld pool are included in the weld efficiency. Page 21

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Figure 3*11: Insulated Surfaces at Cut Planes 0.000 10.000 On) I 5.000 3.3.2 Structural Analysis - Welding Simulation The temperature history from the thermal analysis is used as the thermal load in the structural analysis. Friction-less support boundary conditions are maintained on all external "cut" surfaces of the finite element mode as shown in Figure 3-12. Page 22

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Figure 3*12: Structural Model Constraints 0.00 20.00 (in) I 10.00 4.0 ASSUMPTIONS 4.1 Assumptions Requiring Verifications This calculation contains no major assumptions that must be verified prior to use on safety-related work. 4.2 Modeling Simplifications The following is a list of modeling simplification that were used in this document to simplify the mesh: I) A half-symmetric geometric model is considered appropriate to represent geometry for the welding simulation.

2) Weld passes are assumed to be deposited as full 360° weld passes.

3) No external piping loads are considered in this analysis. If external piping loads are suspected to impact the stresses used in subsequent flaw evaluations then the flaw evaluations should account for the external piping loads directly.

Page 23

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary 4.3 Engineering Approximations The following is a list of engineering approximations that have no significant effect on the accuracy of the results calculated in this document.

1) Post-Weld Heat treatment (PWHT) if any is not simulated. This is a conservative assumption since any PWHT relieves the stresses in the weld.

2) Part of the Alloy 82 portion of the sulfur mitigation layer was modeled using Alloy 52M material as first specified for this project. Since the relevant thermal and mechanical properties of Alloy 82 and 52M are comparable, this approximation will have no significant effect on the results.

3) During the thermal analysis, thermal properties of low alloy steel were used instead of carbon steel thermal properties for the cold leg. This inadvertent error is determined to have virtually no effect on the results primarily because the cold leg is sufficiently removed from the welds that there is hardly any heating of the cold leg during the welding process.

5.0 COMPUTER USAGE 5.1 Software and Hardware ANSYS Version 13.0 SP2 [3] was used 10 this calculation. Verification test cases were performed and documented herein.

Computer program tested: ANSYS Version 13.0, verification tests vm32mod2D.vrt, vm32mod3D.vrt, vm38mod2D.vrt, and vm38mod3D.vrt.
Error notices for ANSYS Version 13.0 SP2 were reviewed and none apply for this analysis.
Computer hardware used: The computer hardware used for the stress runs is DELL (Service Tag #

600003). The hardware platform is Intel Xeon CPU E5645 at 2.4 GHz, 24 GB RAM and operating system is Microsoft Windows 7 Enterprise x64 Edition, Service Pack 1.

Name of person running the test: Silvester Noronha
Date of test: 11-05-2012
Acceptability: For ANSYS 13.0 SP2, test cases vm32mod2D, vm32mod3D, vm38mod2D, vm38mod3D obtained from Reference [1] are run to verify that the answers are correct. The files vm32mod2D.vrt, vm32mod3D.vrt, vm38mod2D.vrt, and vm38mod3D.vrt contain output from the test cases. Review of the output shows that the answers are identical to those contained in Reference

[1]. Appendix B lists the output from the test cases. 5.2 Computer Files All ANSYS input files are collected and listed in Table 5-1. All computer runs and post processing data are documented in the ColdStor storage path [ 1. ANSYS verification input/output files are also listed. Page 24

A AFU!VA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Table 5-1: Listing of Computer Files Page 25

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary 6.0 CALCULATIONS/RESULTS As discussed in Section 3.0, following the completion of the two DM welds, repair welds and the SWOL simulation, three steady state loading cycles were applied to the finite element model to obtain a stable state of stress after shakedown. This stress state is referred to as the residual stresses at cold conditions. The hoop and axial stress contours are shown in Figure 6-1 and Figure 6-2, respectively for shutdown conditions. Figure 6-3 and Figure 6-4 show hoop and axial stress contours, respectively for the operating conditions. The results are presented in a cy lindrical coordinate system aligned with the axis of the nozzle. Figure 6-5 shows the six path lines at the symmetric planes along which hoop and axial stresses are obtained. Hoop and axial stress distributions at shutdown conditions (70°F) are shown in Figure 6-6 and Figure 6-7 respectively. Figure 6-8 shows the hoop and Figure 6-9 shows the axial stress at steady state operating conditions ( [ ] OF). The values of stresses plotted in Figure 6-6 through Figure 6-9 are also tabulated in Appendix A. Page 26

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Figure 6*1: Hoop stress contours at shutdown (70°F). Obtained by applying three steady state loading cycles following the completion of the SWOL NODAL SOLUTION STEP=3709 SUB =1 TIME=8920 SY (AVG) RSYS=31 DMX =.183003 SMN =-66483.5 SMX =54147.2 NODAL SOLUTION NOV 4 2012 STEP=3709 08:58:26 SUB =1 TIME=8920 SY (AVG) RSYS=31 DMX = .183003 SMN =-66483.5 SMX =54147.2 60000 Page 27

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Figure 6*2: Axial stress contours at shutdown (70°F). Obtained by applying three steady state loading cycles following the completion of the SWOL NODAL SOLUTION STEP=3709 SUB =1 TIME=6920 SZ (AVG) RSYS=31 DMX =.183003 SMN =-43464.7 SMX =45697.2 NODAL SOLUTION NOV 4 2012 STEP=3709 08:56:02 SUB =1 TIME=8920 SZ (AVG) RSYS=31 DMX =.183003 SMN =-43464.7 SMX =45697.2 50000 Page 28

A. AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Figure 6*3: Hoop stress contours at steady state ([ ] OF). Obtained by applying two and a half steady state loading cycles following the completion of the SWOL NODAL SOLUTION STEP=3708 SUB =3 TlME=8919 SY (AVG) RSYS=31 DMX =.104531 SMN =-52670.3 SMX =47298 NODAL SOLUTION NOV 4 2012 STEP=3708 09: 00: 18 SUB =3 TIME=8919 SY (AVG) RSYS=31 DMX =.104531 SHN =-52670.3 SMX =47298 50000 Page 29

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Figure 6*4: Axial stress contours at steady state ([ ] OF). Obtained by applying two and a half steady state loading cycles following the completion of the SWOL NODAL SOLUTION NOV 4 2012 STEP;3708 08: 43: 48 SUB =3 TIME=8919 SZ (AVG) RSYS;31 DMX ;.104531 SMN ;-33950.8 SMX ;38601. 9 NODAL SOLUTION NOV 4 2012 STEP=3708 09:02:38 SUB ;3 TIME=8919 SZ (AVG) RSYS=31 DMX =.104531 SMN =-33950.8 SMX =38601. 9 40000 30000 Page 30

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Figure 6-5: Path lines for hoop and axial stress distribution in the OM welds and safe end region The node numbers corresponding to each path line are as follows: Path ID OD line Node Node FR1 7954 25230 FR2 28714 39031 FR3 26021 38991 FR4 7024 23498 FR5 28580 39138 FR6 26087 39128 Page 31

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Figure 6-6: Hoop stress distributions at shutdown (70°F). Obtained by applying three steady state loading cycles following the completion of the SWOl Figure 6-7: Axial stress distributions at shutdown (70°F). Obtained by applying three steady state loading cycles following the completion of the SWOl Page 32

A AFU!VA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Figure 6-8: Hoop stress distributions at steady state ( [ ] OF). Obtained by applying two-and-a-half steady state loading cycles following the completion of the SWOL Figure 6-9: Axial stress distributions at steady state ( [ ] OF). Obtained by applying two-and-a-half steady state loading cycles following the completion of the SWOL Page 33

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary

7.0 REFERENCES

1. AREVA NP Document 32-2500013-001, "Technical Basis for Numerical Simulation of Welding Residual Stresses."

2. AREVA NP Document 18-1173549-006, "Functional Specification for RCS for Three Mile Island Unit One"

3. ANSYS Finite Element Computer Code, Version 13.0 SP2, ANSYS Inc., Canonsburg, PA.

4. AREVA NP Drawing 02-91 85282C-000, "TMI Letdown Nozzle Existing Configuration"

5. AREVA NP Drawing 02-8059673D-003, "TMI Letdown Nozzle Weld Overlay Design"

6. AREVA NP Document 38-9194834-000, "Customer Supplied Documents - Three Mile Island Cold Leg Letdown Nozzle Weld Overlay"

7. AREV A NP Document 55-WP8/81F6A W3-008, "Metallic Gas Tungsten Arc Welding - Welding Procedure Specification WP8/8/F6AW3-008"

8. AREVA NP Document 55-WP1I8/43/F430LTBSCa3-003, Welding Procedure Specification WP1I8/431F430LTBSCa3"

9. AREVA Document 08-9182964-002, "TMI 'C' Cold leg Letdown Nozzle Weld Overlay" 10 . AREVA NP Document 32-2500012-002, "Materials Database for Weld Residual Stress Finite Element Analysis"

11. ASME Boiler and Pressure Vessel Code, Section II, 2004 Edition with No Addenda Page 34

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary APPENDIX A: HOOP AND AXIAL STRESS TABLES Figure 6-5 shows the path lines along which the stress results are obtained. The hoop and stress distribution at shutdown (70 OF), obtained by applying three steady state loading cycles subsequent to SWOL, and at steady state operating conditions ( 11°F), obtained by applying two-and-a-half steady state loading cycles subsequent to SWOL, are listed in Table A-I and Table A-2, respectively. Table A-1: Hoop and Axial Stress Distributions at Shutdown Condition (70°F) Along Path Line "FR1" Alon Path Line "FR2" Alon Path Line "FR3" Distance Distance Along Along Path Line Hoop Axial Hoop Axial Path Line Hoop Axial Measured stress stress stress stress Measured stress stress from (ksi) (ksi) (ksi) (ksi) from (ksi) (ksi) the 10 the 10 Page 35

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Alan Path Line "FR4" Alan Path Line "FRS" Alan Path Line "FR6" Distance Distance Distance Along Along Along Path Line Hoop Axial Path Line Hoop Axial Path Line Hoop Axial Measured stress stress Measured stress stress Measured stress stress from (ksi) (ksi) from (ksi) (ksi) from (ksi) (ksi) the ID the ID the ID Page 36

A ARI!VA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Table A-2: Hoop and Axial Stress Distributions at Steady state Operating Condition ([ ] OF) ath Line "FR1" Alon Path Line "FRau Alon Path Line "FR3" Distance Distance Distance Along Along Along Path Line Hoop Axial Path Line Hoop Axial Path Line Hoop Axial Measured stress stress Measured stress stress Measured stress stress from (ksi) (ksi) from (ksi) (ksi) from (ksi) (ksi) the 10 the 10 the 10 (inches) inches Page 37

A ARBVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Alon Path Line "FR4" Alon Path Line "FR5" Alon Path Line "FR6" Distance Along Hoop Axial Hoop Axial Path line Hoop Axial stress stress stress stress Measured stress stress (ksi) (ksi) (ksi) (ksi) from (ksi) (ksi) the 10 inches Page 38

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary APPENDIX B: VERIFICATION OF ANSYS COMPUTER CODE Four verification problems were selected to test key features of the ANSYS finite element computer program [3] used in the current numerical welding simulations, the development of thermal stress in a cylinder and the elastic-plastic response of a cylinder under pressure loading. The standard ANSYS verification manual test case VM32 exercises thermal and elastic stress analysis features of the axisymmetric two-dimensional 4-node PLANE55 and PLANE42 elements, respectively, using a long thick-walled cylinder subjected to a linear through-wall temperature gradient. This test case was been modified (vm32mod2D) by increasing the mesh refinement and changing the structural element type from PLANE42 to the 4-node PLANE182, which is used to verify 2D models. A companion three-dimensional test case (vm32mod3D) was created which utilizes the SOLID 70 thermal element and the SOLID185 structural element, which are used in the current welding simulations. ANSYS verification manual test case VM38 determines stresses in a long thick-walled cylinder subjected to internal pressure using the PLANE42 axisymmetric structural element and an elastic-perfectly plastic material. Two pressure loads are considered; the first pressure of 12,990 psi loads the cylinder elastically to just below the yield strength of the material (30,000 psi), and the second puts the entire cylinder into a state of plastic flow (von Mises equivalent stress 30,000 psi) at an ultimate pressure load of 24,011 psi (Pult). Test case VM38 was modified (vm38mod2D) to use the PLANE182 element. The stress-strain hardening model was changed from bilinear kinematic (BKIN) to multilinear kinematic (KINH) to better represent the current welding simulations. A companion three-dimensional test case (vm38mod3D) exercises the SOLID185 structural element. The error measure for the modified VM38 test cases is the ratio of the applied pressure to the theoretical value (24011 psi) ofPult such that the entire cylinder experiences an equivalent, or effective, stress of 30,000 psi. All test cases executed properly, as demonstrated on the following pages. Page 39

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Verification Problem VM32MOD Thermal Stresses in a Long Cylinder Two-Dimensional Analysis File: vm32mod2D.vrt

        --------------- VM32MOD2D RESULTS COMPARISON ----------------

TARGET ANSYS RATIO PLANE55 THERMAL ANALYSIS: T (C) X=.1875 in -1.00000 -1.00000 1. 000 T (C) X=.2788 in -0.67037 -0.67039 1. 000 T (C) X=0.625 in 0.00000 0.00000 0.000 PLANE182 STATIC ANALYSIS: A STS psi X=.187 420.42 429.99 1. 023 T STS psi X=.187 420.42 429.61 1. 022 A STS psi X=.625 -194.58 -205.15 1. 054 T STS psi X=.625 -194.58 -205.08 1. 054 Three-Dimensional Analysis File: vm32mod3D.vrt

        --------------- VM32MOD3D RESULTS COMPARISON ----------------

TARGET ANSYS RATIO SOLID70 THERMAL ANALYSIS: T (C) X=.1875 in -1. 00000 -1.00000 1. 000 T (C) X=.2788 in -0.67037 -0.67039 1. 000 T (C) X=0.625 in 0.00000 0.00000 0.000 SOLID185 STATIC ANALYSIS: A STS psi X=.187 420.42 429.67 1. 022 T STS psi X=.187 420.42 430.04 1. 023 A STS psi X=.625 -194.58 -205.11 1.054 T STS psi X=.625 -194.58 -205.17 1. 054 Page 40

A AREVA Document No. 32-9196236-000 TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay - Non Proprietary Verification Problem VM38MOD Plastic loading of a Thick-Walled Cylinder Two-Dimensional Analysis File: vm38mod2D.vrt

        --------------- VM38MOD2D RESULTS COMPARISON ----------------

TARGET ANSYS RATIO PLANE182 FULLY ELASTIC ANALYSIS (psi): SIGR LEFT END -9984. -10103. 1.012 SIGT LEFT END 18645. 18763. 1.006 SIGR RIGHT END -468. -481. 1. 028 SIGT RIGHT END 9128. 9141. 1. 001 PLANE182 FULLY PLASTIC ANALYSIS (psi): SIGEFF LEFT END 30000. 30000. 1.000 SIGEFF RIGHT END 30000. 30000. 1.000 Pult 24011. 23350. 0.972 Three-Dimensional Analysis File: vm38mod3D.vrt

        --------------- VM38MOD3D RESULTS COMPARISON ----------------

TARGET ANSYS RATIO SOLID185 FULLY ELASTIC ANALYSIS (psi): SIGR LEFT END -9984. -10066.1.008 SIGT LEFT END 18645. 18776. 1. 007 SIGR RIGHT END -468. -475. 1.014 SIGT RIGHT END 9128. 9128. 1.000 SOLID185 FULLY PLASTIC ANALYSIS (psi): SIGEFF LEFT END 30000. 30000. 1.000 SIGEFF RIGHT END 30000. 30000. 1. 000 Pult 24011. 23360. 0.973 Page 41

0402-01-F01 (Rev. 017,11/19/2012) A. CALCULATION

SUMMARY

SHEET (eSS) AREVA Document No. 32 - 9196234 - 000 Safety Related: I:8J Yes D No TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Title __P:....r:..::o::.tp~ri::::e~ta:.:.ryL-__________________________ PURPOSE AND

SUMMARY

OF RESULTS: AREVA NP Inc. proprietary information in the document are removed and their locations are indicated by pairs of braces "[ ]". This document is the non-proprietary version of AREVA Document 32-9186194-001.

Purpose:

The purpose of this calculation is to evaluate the fatigue and primary water stress corrosion crack growth of postulated, inside surface-connected, 360° circumferential and semi-elliptical axial flaws in the weld overlaid cold leg letdown nozzle DMW and safe end at Three Mile Island Unit 1 in order to assess whether these worst case flaws in the repair configuration meet the ASME Boiler and Pressure Vessel Code, Section XI Appendix C acceptance criteria [11. Results/Conclusions: The results from the fracture mechanics analysis performed to evaluate the worst case flaws in the repair configuration show that the final flaw depth after 22 years of service is less than the allowable flaw depth per Section XI [1J acceptance criteria. THE DOCUMENT CONTAINS ASSUMPTIONS THAT MUST BE THE FOlLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT: VERIFIED PRIOR TO USE ON SAFElY-RElATED WORK CODENERSIONIREV CODENERSIONIREV DYES AREVACGC.5.0 I?SI NO Page 1 of29

0402-01-F01 (Rev. 017, 11/19/2012) Document No. 32~g196234-000 TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary Review Method: [gJ 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 Silvester Noronha Engineer IV ~~ p rh /13 ALL Samet" Mahmoud Principal Engineer ~/- R L-1-{J ALL Tim Wiger Unit Manager 7U/~ * ........ J....-r A Y'¥/3 ALL

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 N/A N/A N/A Mentoring Information (not required per 0402"01) Name Title Mentor to: (printed or typed) (printed or typed) (P/R) Signature Date N/A

                                                        --   ,-,~,~---,

N/A Page 2

A 0402-01-F01 (Rev. 017, 11/19/2012) AREVA Document No. 32-9196234-000 TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary Record of Revision Revision Pages/Sectionsl No. Paragraphs Changed Brief Description / Change Authorization 000 All Original Release Page 3

A Document No. 32-9196234-000 AREVA TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary Table of Contents Page SIGNATURE BLOCK ................................................................................................................................2 RECORD OF REVISION ..........................................................................................................................3 LIST OF TABLES .....................................................................................................................................6 LIST OF FIGURES ...................................................................................................................................7 1.0 PURPOSE .....................................................................................................................................8 2.0 ANALYTICAL METHODOLOGY ...................................................................................................9 3.0 KEY ASSUMPTIONS ....................................................................................................................9 3.1 Minor assumptions ......................................................................................................................... 10 4.0 CALCULATIONS .........................................................................................................................10 4.1 Postulated Flaw Shapes ................................................................................................................ 10 4.2 Geometry ........................................................................................................................................ 11 4.3 Crack Growth Mechanisms ............................................................................................................ 13 4.3.1 PWSCC Crack Growth (Alloy 82/182) ............................................................................. 13 4.3.2 Fatigue Crack Growth in Alloy 82/182 ............................................................................. 14 4.3.3 Fatigue Crack Growth in Alloy 52M ................................................................................. 14 4.4 Applied Stress Intensity Factor Calculation .................................................................................... 15 4.5 Applied Stresses ............................................................................................................................ 15 4.5.1 Residual Stress in Welds ................................................................................................. 15 4.5.2 Sustained Stresses due to Piping Loads ......................................................................... 15 4.5.3 Transient Stresses ........................................................................................................... 16 4.5.4 Seismic Event .................................................................................................................. 17 4.5.5 Letdown Nozzle Pressure and Primary Bending Loads .................................................. 18 4.6 Methodology for Flaw Growth Analysis .......................................................................................... 19 4.7 Methodology for Establishing Acceptance Flaw Sizes ................................................................... 20 5.0 RESULTS ....................................................................................................................................21 5.1 Flaw Growth Analysis ..................................................................................................................... 21 5.2 Allowable Flaw Size Estimation ..................................................................................................... 22 6.0

SUMMARY

AND CONCLUSIONS ..............................................................................................27 Page 4

A Document No. 32-9196234-000 AREVA TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary Table of Contents (continued) Page 7.0 COMPUTER OUTPUT ................................................................................................................28 7.1 Computer Software and Hardware ................................................................................................. 28 7.2 Computer Files ............................................................................................................................... 28

8.0 REFERENCES

............................................................................................................................29 Page 5

A Document No. 32-9196234-000 AREVA TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary List of Tables Page Table 4-1: SWOL Geometry dimensions ............................................................................................... 13 Table 4-2: Sustained Loads at the OM Weld (1) ************************************.************************************************* 16 Table 4-3: Summary of Transient Events for cold leg letdown nozzle ................................................... 17 Table 4-4: Seismic Loads ......................................................................................................................17 Table 4-5: Axial Stresses Due to Seismic Loads ................................................................................... 18 Table 4-6: Primary Bending Loads ........................................................................................................ 18 Table 4-7: Relevant Sources of Stress for Fatigue and PWSCC ........................................................... 19 Table 5-1: Results of Flaw Growth Analysis-Inside Surface-Connected 3600 Circumferential Flaw in DMW / Safe end ...............................................................................................................................21 Table 5-2: Results of Flaw Growth Analysis- Inside Surface Semi-Elliptical Axial Flaw in DMW / Safe end ...................................................................................................................................................21 Table 5-3: Allowable Flaw Size - Inside Surface-Connected 3600 Circumferential Flaw in DMW ........ 23 Table 5-4: Allowable Flaw Size -Inside Surface Semi-elliptical Axial Flaw in DMW ............................ 24 Table 5-5: Allowable Flaw Size - Inside Surface-Connected 3600 Circumferential Flaw in Safe end ... 25 Table 5-6: Allowable Flaw Size -Inside Surface Semi-Elliptical Axial Flaw in Safe end ....................... 26 Table 7-1: Computer Files for Crack Growth Evaluation ....................................................................... 28 Page 6

A Document No. 32-9196234-000 AREVA TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary List of Figures Page Figure 1-1: Cold leg letdown nozzle SWOL Configuration ....................................................................... 9 Figure 4-1: Inside Surface-Connected, Partial Through-Wall, 360 0 Circumferential Flaw ..................... 10 Figure 4-2: Inside Surface-Connected, Partial Through-Wall, Semi-Elliptical Axial Flaw ...................... 11 Figure 4-3: Path lines for hoop and axial stress distribution in the OM welds and safe end region ....... 12 Figure 4-4: Coordinate System for Applied Loads Three Mile Island Unit 1 .......................................... 16 Page 7

A AREVA Document No. 32-9196234-000 TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary 1.0 PURPOSE Primary water stress corrosion cracking (PWSCC) of Alloy 600/82/182 materials is a well-documented phenomenon in the nuclear power industry. High temperature components, such as those associated with the cold leg letdown nozzle, have risk for PWSCC. During the upcoming Three Mile Island Unit 1 refueling outage (T1R20), AREVA NP is planning to apply a full structural weld overlay (FSWOL) over the cold leg letdown nozzle Alloy 82/182/600 safe end and dissimilar metal welds (DMW). Exelon plans to mitigate the Three Mile Island Unit 1 cold leg letdown nozzle Alloy 82/182 dissimilar metal weld (DMW) with an SWOL during the 2013 fall refueling outage #20 (T1 R20). A repair procedure has been developed where the safe end and dissimilar metal (DM) Alloy 82/182 welds and a portion of the nozzle and stainless steel pipe/elbow are overlaid with PWSCC resistant Alloy 52M material, as shown in Figure 1-1. This repair design is more fully described by the overlay design drawing [2]. The weld residual stress analysis that were evaluated in Reference [3], which reflect the deposition of the SWOL are used as input in this document. It is postulated that inside surface-connected, partial through-wall, 360 0 circumferential flaw(s) and semi-elliptical axial flaw(s) would propagate by PWSCC and fatigue through the thickness of the DM weld. If the postulated flaws grow through the original DM weld, fatigue crack growth analysis will be performed to determine the amount of crack growth into the PWSCC-resistant Alloy 52 overlay. Since Alloy 52M overlay is resistant to PWSCC, extensions of the postulated flaws into the SWOL would only be due to fatigue crack growth under cyclic loading conditions. A fracture mechanics analysis is performed to evaluate these worst case flaws in the repair configuration. This evaluation will consider sustained and normal/upset condition transient stresses [4] with the associated number of transient cycles to predict the final flaw sizes at the end of license extension at Three Mile Island Unit 1, which equates conservatively to a service life of 22 years. This analysis is performed for Alloy 82/182 DM welds and Alloy 600 safe end with SWOL. Page 8

A Document No. 32-9196234-000 AREVA TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary Figure 1-1: Cold leg letdown nozzle SWOL Configuration 2.0 ANALYTICAL METHODOLOGY This analysis postulates both circumferential and axial flaws which propagate by PWSCC and fatigue crack growth through the existing DM weld. The crack growth is governed by crack growth rates and stress intensity factors as detailed in Section 4.0. Fatigue crack growth analysis in the overlay will be performed if the postulated flaws grow through the original DM weld before the remaining service life of 22 years is reached. Applied stresses include both transient and sustained normal operating loads. The analysis will determine the total amount of flaw growth. In this calculation, the acceptability of the postulated worst case flaws in the weld overlaid cold leg letdown nozzle shall be assessed using the methodology provided in Appendix C of Reference [1]. Details of the methodology presented in this section are provided in Section 4.0 of this document. 3.0 KEY ASSUMPTIONS There are no major assumptions for this calculation. Minor assumptions are noted where applicable. Page 9

A Document No. 32-9196234-000 AREVA TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary 3.1 Minor assumptions The total number of seismic cycles during the life time that is assumed is 400. This assumption had no impact on the results of this document since no flaw growth was observed and flaw growth would be calculated even if a different number of seismic cycles is used. 4.0 CALCULATIONS 4.1 Postulated Flaw Shapes An inside surface-connected, partial through-wall, full (360°) circumferential flaw in a cylinder as shown in Figure 4-1 and an inside surface-connected, partial through-wall, semi-elliptical axial flaw as shown in Figure 4-2 are postulated to exist at the time the overlay is applied. The initial flaw depths for the circumferential and axial flaws are taken to be 75% of the thickness of the original welds from the inside surface. In this analysis, a flaw aspect ratio (flaw length to depth) of 2:1 is used to represent the postulated axial flaws in the DM weld. The flaw growth analysis contained herein addresses the growth of the postulated flaws by cyclic and sustained loads. Figure 4-1: Inside Surface-Connected, Partial Through-Wall, 3600 Circumferential Flaw Postulated 3600 Circumferential Flaw SWOL Original Weld Page 10

II A Document No. 32-9196234-000 AREVA TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary Figure 4-2: Inside Surface-Connected, Partial Through-Wall, Semi-Elliptical Axial Flaw 1~P~o:s:ru:la:te:d~S~e=m:j~-------~~--'---~~--------------~ r-;ft Elliptical Axial Raw li t a 4.2 Geometry Path lines were selected in each of the Nozzle-ta-safe end OM weld, safe end, and safe end to elbow to sample the representative stress states in the alloy 821 alloy 600 regions. Two path lines were selected in each region as shown in Figure 4-3. The orientation of Paths FR1 and FR4 along the nickel alloy weld joining safe end to the nozzle material is chosen to evaluate any potential flaws in the Alloy 82 weld. Paths FR2 and FRS are chosen to evaluate flaws that could be present in Alloy 600 safe end. Any flaws that may be present in the Alloy 82 weld joining the safe end to the elbow are evaluated by choosing paths FR3 and FR6. Crack growth analyses will be performed along these path lines. Page 11

A ARE:VA Document No. 32-9196234-000 TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary Figure 4-3: Path lines for hoop and axial stress distribution in the OM welds and safe end region The basic dimensions for the path lines (Figure 4-3) are taken from the finite element model that is used for the welding residual stress analysis, Reference [3]. The finite element model was constructed using the existing configuration dimensions as well as the minimum design thickness at the defined locations on the nozzle side and on the pipe end based on References [2,5]. Table 4-1 lists the SWOL geometry and section properties employed for the flaw growth analysis. The SWOL thickness at each location of interest is obtained by the difference between the SWOL outside diameter and the existing configuration outside diameter. Likewise, the existing wall thickness at each location of interest is obtained by the difference between the piping outside and inside diameters. All pertinent dimensions that are essential for the calculations performed in this document are best estimates from the design drawing [2] and the finite element model construed in Reference [3]. Page 12

A Document No. 32-9196234-000 AREVA TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary Table 4-1: SWOL Geometry dimensions Path Line FR1 FR2 FR3 FR4 FR5 FR6 Diameter of outside surface (including weld overiay). 00 (inch):: Diameter of inside surface, DI (inch) :: Wall thickness prior to weld overiay, 10 (inch) :: Overall wall thickness post weld overiay, t (inch) = Weld overiay thickness, w (inch) = Cross-sectional area, A (inch2):: Moment of inertia, I (inch4) = Section modulus at OD So (inch3 ) = 4.3 Crack Growth Mechanisms 4.3.1 PWSCC Crack Growth (Alloy 821182) PWSCC growth is calculated using the MRP Alloy 821182 crack growth rate from (MRP-115) with an activation energy of 31,000 calories/mole [6]. This crack growth rate model is based on industry data for stress corrosion cracking of Alloy 821182 material. The activation energy is utilized to adjust crack growth rates for temperatures other than the test temperature of 325°C or 61rF. Since the equation is for a temperature of 325°C (617°F), the equation is modified for the applied temperature by a temperature correction term that reduces to unity at 325°C. The crack growth rate equation is: da =Co(1.5x10-12)KI1.6 mlsec dt where Kr is the applied stress intensity factor in MPavm. The temperature correction coeffiCient, Co, is defined as where Q:: 31,000 calories/mole R = 1.987 calories/mole-K (=8.314 kJ/mole-K) and T1 = Test temperature (325°C) in degrees kelvin T2 = Operating temperature in degrees kelvin The Co term is calculated as a function of temperature. The normal operating temperature for the cold leg letdown nozzle is [ ]oF [7]. Page 13

A Document No. 32-9196234-000 AREVA TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary 4.3.2 Fatigue Crack Growth in Alloy 82/182 Flaw growth due to cyclic loading is calculated using the fatigue crack growth model in the NRC flaw evaluation guidelines for Alloy 600 in a PWR environment [8,9], which is based on the work that was presented in NUREG/CR-6721 [10]. Reference [10] shows that Alloy 82/182 weldments may exhibit the enhanced corrosion fatigue crack growth behavior in simulated 320°C PWR water. To be conservative, a multiplier of 10 is applied to the Alloy 600 crack growth rate. Crack growth analysis is then conducted on a cycle-by-cycle basis to the end of design life. The crack growth rate equation for Alloy 82/182 to be used is then given by:

                                          ~ =10

CSRS ENV (LlK)n dN where LlK is the stress intensity factor range in terms of MPavm and da/dN is the crack growth rate in terms of m/cycle.

C = 4.835x1 0. 14 + 1.622x1 0* 16T - 1.490x1 0* 18T2 + 4.355x1 0*21 T3 SR = [1 - 0.82Rr2.2 A =4.4x10*7 m =0.33 n =4.1 T =degrees C R = K min 1 Kmax TR =rise time, limited to 5000 seconds [10]. For PWR environment, Reference [9] recommends to use a rise time value 30 seconds. 4.3.3 Fatigue Crack Growth in Alloy 52M Flaw growth in the SWOL (Alloy 52M material) due to cyclic loading is calculated using the fatigue crack growth model in the NRC flaw evaluation guidelines for Alloy 600 in a PWR environment [8, 9], which is based on the work that was presented in NUREG/CR-6721 [10]. Reference [10] shows that Alloy 52M materials do not exhibit the enhanced corrosion fatigue crack growth behavior of Alloy 82/182 materials in simulated 320°C PWR water. Instead, Alloy 52M behaves quite similarly to Alloy 600 in PWR water. However, to be conservative, a multiplier of 2 is applied to the Alloy 600 crack growth rate. Crack growth analysis is then conducted on a cycle-by-cycle basis to the end of service life. The crack growth rate equation for Alloy 52M to be used is then given by:

                                           ~ = 2 C SR     SE N v LlK n

dN where LlK is the stress intensity factor range in terms of MPavm and da/dN is the crack growth rate in terms of m/cycle, and C =4.835x1 0.14 + 1.622x1 0*16T - 1.490x1 0* 18T2 + 4.355x1 0*21 T3 Page 14

A AREVA Document No. 32-9196234-000 TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary SR =[1 - 0.82Rr2.2 SENV =1 + A[CSRLlKn]m-1TR1-m A =4.4x10-7 m =0.33 n = 4.1 T =degrees C R = Kmin / Kmax TR =rise time, limited to 5000 seconds [10]. For PWR environment, Reference [9] recommends to use a rise time value 30 seconds. 4.4 Applied Stress Intensity Factor Calculation For highly nonlinear stress fields such as those due to weld residual stresses, standard stress intensity factor (K) formulas based on third order polynomials are usually not adequate in representing the stresses. This deficiency can be overcome by using the weight function method. This is a well-established fracture mechanics methodology which AREVA NP has implemented in a Microsoft Excel macro. The technical basis for this implementation is given in Reference [11]. The weight function methodology is used to compute K for the flaw and nozzle geometries considered in this analysis, which have been described in Sections 4.1 and 4.2. 4.5 Applied Stresses The categories of applied stresses that need to be considered are discussed below in this section 4.5.1 Residual Stress in Welds The residual stress profiles through the thickness of the OM welds and SWOL are obtained from an analysis performed for the Three Mile Island Unit 1 cold leg letdown nozzle [3]. Axial and hoop residual stresses are determined over six path lines through the thickness of the OM welds and SWOL as shown in Figure 4-3. The residual stresses at the shutdown condition are combined with the sustained stresses and transient stress results to obtain the combined stresses over each path line. These results are used to perform the fatigue crack growth calculation. For PWSCC crack growth calculations, the stresses used for each path line are the combination of residual stresses at the normal operating condition and the sustained stresses such as piping loads due to dead weight and thermal expansion, and pressure acting on the crack faces of the postulated flaws. 4.5.2 Sustained Stresses due to Piping Loads All the force and moment components are given in the local coordinate system shown in Figure 4-4. Page 15

A AREVA Document No. 32-9196234-000 TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary Figure 4*4: Coordinate System for Applied Loads Three Mile Island Unit 1 The deadweight (OW) and OW plus normal operation thermal (TH) loads that are applied at the OM weld are obtained from Reference [12]. They are given in Table 4-2 below: Table 4*2: Sustained Loads at the DM Weld (1) Fx(Axial) Fy Fz Mx(Torsion) Mv Mz Ibs Ibs Ibs in-Ibs in-Ibs in-Ibs OW - - - - - -

                         -             -                -           [         ]    [         ]    [

t TH OW+TH - - - [ ] [ ] [ Note: (1) The forces and moments in Reference [12] are applied on the nozzle end of the DWM as shown in Figure 4-4. These sustained loads are converted to axial stresses as follows:

                                         .             F    SRSSbending AXIal Stress == _x +             r A         I where A and I are the cross-sectional area and moment of inertia, respectively, as given in Section 4.2, and r is the radial distance from the point where the stress is considered to pipe center line, and the resultant bending moment is calculated as SRSSbending            = ~My 2 + M z2. These axial stresses are applied to all path lines for the flaw growth evaluation.

4.5.3 Transient Stresses The cyclic operating stresses needed to calculate fatigue crack growth are obtained from a linear, thermo-elastic finite element analysis [4]. These cyclic stresses are developed for all the transients at a Page 16

A Document No. 32-9196234-000 AREVA TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary number of time points to capture the maximum and minimum stresses due to fluctuations in pressure and temperature. Per Reference [7], the number of RCS design transients is established for 60 years of design life. Cyclic operating stresses were generated in Reference [4] for the transients listed in Table 4-3. The transients that have trivial contribution to fatigue are not considered per Reference [41. The transient cycle counts used in the fracture mechanics calculations are obtained from Reference [4]. Table 4-3: Summary of Transient Events for cold leg letdown nozzle Transient Transient no. of Loading no. 1 2 Nama 1A 1B

cvcles

                                        -f-                   -

Description

                                                                   -                      -    Condition Normal Normal 4

5 2A 28 -- Normal Normal 6 3

                                          -                                                      Normal 7               4
                                          -                                                      Normal 8               5
                                         --                                                      Normal 9

10 6 7 -- Normal Upset 11 9(1) Upset 12 10(1) Upset 13 14(1) Upset 14 8C

                                        -                                                         Upset 15             11(2)                                                                      Upset 16             15(2}                                                                      Upset 17A(2) 17 Notes..                   -

(1) These transients are enveloped with transient 7 [4]. Upset (2) These transients are enveloped with transient BC [4]. 4.5.4 Seismic Event The effect of the seismic loads on fatigue crack growth is addressed by modeling the seismic event as a transient event. The seismic loads as obtained from Reference [12] are shown in Table 4-4. Table 4-4: Seismic Loads SRSS Fx(Axial) Fy Fz Mx(Torsion) My Mz (bending) OBE (+1-) Ibs Ibs Ibs in-Ibs in-Ibs in-Ibs in-Ibs

                    -            -           -           [        1     [        1    [        1   [        .1 These seismic loads are converted to axial stresses according to Page 17

A AREVA Document No. 32-9196234-000 TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary

                                        .           IFx I SRSSbending AXIal Stress = - + ----"'-

A So where the absolute sign denotes the magnitude of the axial force and So is the 00 section modulus used in the calculation for conservatism. The results are given in Table 4-S. Table 4*5: Axial Stresses Due to Seismic Loads aBE (+/-) FR1 FR2 FR3 FR4 FRS FR6 Axial Stress. psi [ ] [ ] [ ] [ ] [ ] [ ] The baseline through-wall axial stress distribution for each path line is obtained from the stress state at the steady state conditions. This corresponds to the first time point of Transient 4 - Power Unloading 100 to 8%. The total lifetime number of seismic cycles assumed is 400. 4.5.5 Letdown Nozzle Pressure and Primary Bending Loads For the fatigue crack growth analysis, it is conservatively assumed that primary water can get into the flaw and apply pressure load to the crack faces. Per Reference [4], the normal operating pressure is [ ] psia. Thus a pressure load of [ ] psig will be applied to the crack faces during crack growth analysis in addition to the other sources of stress described in Sections 4.S.1 through 4.S.3. For the determination of allowable flaw sizes, to be discussed in Section 4.7, maximum pressures for normal/upset/test and emergency/faulted conditions are required. Per IWB-SOOO of Reference [1], the test pressure shall be no higher than 10% of the normal operating pressure. Thus for allowable flaw size determination, a pressure of [ ] psia will be used for both the normal/upset/test conditions and emergency/faulted conditions. Per article C-2S00 of Appendix C of Reference [1], information on primary and secondary bending moment acting on the cross-section of interest under normal/upset/test and emergency/faulted conditions is required to determine the allowable flaw sizes for circumferential flaws. Loads from OW and operational basis earthquake (OBE) are required for the normal/upset/test conditions and OW and safe shutdown earthquake (SSE) for the emergency/faulted conditions of the cold leg letdown nozzle. The results of the bounding loads and primary bending moments for the normal/upset/test and emergency/faulted conditions are given in Table 4-6. Table 4*6: Primary Bending Loads My Mz SRSS (bending) in-Ibs in-Ibs in-Ibs Normal/Upset/Test Emergency/Faulted Page 18

A AREVA Document No. 32-9196234-000 TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary 4.6 Methodology for Flaw Growth Analysis For the crack growth analysis, the applied stress intensity factor is driven by axial stress for 360 0 circumferential flaws, and by hoop stress for axial flaws. The relevant sources of stress for fatigue and PWSCC crack growth analysis are summarized below in Table 4-7. Table 4-7: Relevant Sources of Stress for Fatigue and PWSCC Inside Surface-Connected, Partial Through-Wall, 360 0 Circumferential Flaw Residual Axial Stress at Shutdown Axial Stress from Transients Fatigue Crack Growth Sustained Axial Stress due to Pipe Loads (Deadweight if applicable) Sustained Axial Stress due to Normal/Upset Pressure (Acting on Crack Face) Residual and Operating Axial Stress at Steady State Conditions PWSCC Sustained Axial Stress due to Pipe Loads (Deadweight and/or Thermal Expansion) Crack Growth Sustained Axial Stress due to Normal System Pressure (Acting on Crack Face) Inside Surface-Connected, Partial Through-Wall, Semi-Elliptical Axial Flaw Residual Hoop Stress at Shutdown Fatigue Crack Hoop Stress from Transients Growth Sustained Hoop Stress due to Normal/Upset Pressure (Acting on Crack Face) Residual and Operating Hoop Stress at Steady State Conditions PWSCC Crack Growth Sustained Hoop Stress due to Normal System Pressure (Acting on Crack Face) For each transient, the cycles are assumed to be uniformly distributed along the design life time. The cycles from all the transients are sorted by the time that they are assumed to occur. Fatigue flaw growth is calculated by considering the assumed sequence of total transient stresses which may consist of a collection of subcycles (peaks and valleys) within any transient. The service life is conservatively taken to be 22 years for a 60-year plant life extension since the plant first came online on April 19, 1974. Through-wall metal temperatures are provided by the Section III analysis [4]. The PWSCC and fatigue crack growth mechanisms are considered to be active simultaneously. Following the guidance in article C-3230 of Section XI, Appendix C of Reference [1], the PWSCC and fatigue crack growths are coupled in an incremental manner at selected time points throughout the service life. Page 19

II A Document No. 32-9196234-000 AREVA TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary The PWSCC and fatigue crack growth of the inside surface-connected, partial through-wall, semi-elliptical axial flaw is controlled by the values of K and ilK at the flaw depth location. The axial flaw growth is conservatively taken to be self-similar so that the initial flaw aspect ratio of the axial flaw is retained during flaw growth. The coupled PWSCC and fatigue crack growth calculations in the DM weld, and if necessary, the fatigue crack growth calculations in the SWOl, are performed by the AREVA NP Excel-based macro AREVACGC [13], which is verified for use in the present analysis by running the verification case. The results generated by the test run are identical to those documented in Reference [13]. 4.7 Methodology for Establishing Acceptance Flaw Sizes The methodology in establishing the allowable flaw sizes per ASME B&PV Code, Section XI [1], for austenitic stainless steel and Ni-Cr-Fe alloy base metals and associated weld materials can be summarized as follows. First a flaw growth analysis is performed to establish the end-of-evaluation-period flaw depth af and flaw length If. Then the allowable flaw sizes are determined for (1) Normal operating (including upset and test) conditions, and (2) Postulated emergency and faulted conditions. The allowable flaw sizes can be determined from the equations given in C-5300 and C-5400 or C-6300 and C-6400 of Section XI, Appendix C of Reference [1]. Per article IWB-3641 of Reference [1], the postulated flaws are acceptable for continued service until the end of the evaluation period if the end-of-evaluation-period flaw sizes are less than the maximum allowable flaw sizes determined as discussed above. In Section 5.0, the maximum allowable flaw sizes will be determined using the equations given in C-5300 and C-5400 or C-6300 and C-6400 of Section XI, Appendix C of Reference [1]. Page 20

A Document No. 32-9196234-000 AREVA TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary 5.0 RESULTS 5.1 Flaw Growth Analysis Results of the flaw growth analysis from AREVACGC are summarized in Table 5-1 and Table 5-2 for the postulated inside surface-connected, 3600 circumferential and semi-elliptical axial flaws in the DMW and safe end, respectively_ It is seen in Table 5-1 that an inside surface-connected, 360 0 circumferential flaw does not grow along any of the analyzed paths (FR1 through FR6) during the remaining life time 22 years of the Three Mile Island Unit 1 nuclear power reactor. For an inside surface-connected semi-elliptical axial flaw in the DMW. the results of the flaw growth analysis from AREVACGC, summarized in Table 5-2, show that that an inside surface-connected semi-elliptical axial flaw(s) will not grow by fatigue or PWSCC for the end of the license extension at Three Mile Island Unit 1, which is 22 years. Table 5-1: Results of Flaw Growth Analysis- Inside Surface-Connected 3600 Circumferential Flaw in DMW I Safe end Paths _ FR1 FR2 FR3 FR4 FRS FR6 Initial Flaw Depth (in) = Initial alt ratio = Final Flaw Depth (in) = Final alt ratio = Total Amount of Fatigue + PWSCC Crack Growth (in) = -'- -'- - - - .ill Table 5-2: Results of Flaw Growth Analysis- Inside Surface Semi-Elliptical Axial Flaw in DMW I Safe end Paths FR1 FR2 FR3 FR4 FRS FR6 Initial Flaw Depth (in) = Initial Flaw Length (in) = Initial aft ratio = Final Flaw Depth (in) = Final alt ratio = Total Amount of Fatigue + PWSCC Crack Growth (in) = Page 21

A AREVA Document No. 32-9196234-000 TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary 5.2 Allowable Flaw Size Estimation Allowable flaw sizes were determined in accordance with Appendix C of Reference [1] for both circumferential and axial crack orientations. For each crack orientation, allowable crack sizes were determined. The first set (paths FR1, FR3, FR4 and FR6) considered a flaw to exist in the DMW in which case the ductile fracture effects were considered using the EPFM criteria for ductile fracture as mandated by Article C-6000, Appendix C of Reference [1]. Results of circumferential flaw evaluation are shown in Table 5-3 and that of axial flaw evaluations are shown in Table 5-4. The postulated flaws in the safe end (paths FR2 and FRS) were evaluated using the limit load solution (Article 5000 of Appendix C [1]). Results of circumferential flaw and axial flaw evaluations are presented respectively in Tables 5-5 and 5-6. Page 22

A Document No. 32-9196234-000 AREVA TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary Table 5-3: Allowable Flaw Size - Inside Surface-Connected 3600 CIrcumferential Flaw In DMW Paths FR 1 FR3 FR4 FR6 r--N/UIT____

~------~~~~~~~~~,.

Operating Condition Final Flaw Depth, a" (inch) = N/UIT

                                                        ---- ElF _   N/UIT_      ElF _   NlUIT____    ElF                 ElF.....___--t SWOL Outer Diameter, Do, (inch) =

Inner Diameter, 0;, (inch) = Mean Radius, Rm (inch) = Total Wall Thickness, t, (inch) = SWOL Thickness, w, (inch) = Cross-sectional Area, A, (inch2) = Moment of Inertia, I. (inch4) =

Section Modulus. S 211D0 * (inch3) = Temperature (F) = a,. (psi) = Pressure, p, (psi) = Bending Safety Factor, SFb = C-2621 Membrane Safety Factor. SFm = C-2621 Zl factor = C-6330(8) am = pDoI(4t). (psi) = Mb* (in-Ibf) = ab =M~S. (psi) = C-2500 Me, (in-Ibf) = Stress, a.=M.lS, (psi) = -- - -- - -- - -- C-25OO

p 1t/(2-a.uowlt)[1-a..,.Jt-a,./a,)), (rad) = C-5321

             %c=2at!lt(2sinp -alt sine)(psi)    =                                                                                C-5321
                                                =

Sc = 1/SFb(crbcJZ-a.)-o"m(1-1/ZSFm) (psi) tjI = asin (0.5 (aft) sin e), (rad) =

                                                         --      r-       --        -- --                  -        --           C-6321 (9)

C-5322 O"mC(psi) = C-5322

St(psi) aallow lt =

                                                         --      I---     --        -I---     --           -        --           C-6322(9)

Allowable Flaw Depth. aallow. (inch) = Page 23

A Document No. 32-9196234-000 AREVA TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary Table 5-4: Allowable Flaw Size -Inside Surface Seml-elllptical Axial Flaw In DMW Paths FR 1 FR3 FR4 FR6 ~------~~~~~~~~-+.. Operating Condition Final Flaw Depth, a" (inch) = SWOL Outer Diameter, Do, (inch) = N/Urr

                                                        ---    ElF I--Nlurr_      ElF I--Nlurr_        ElF _   N/UIT_      EIF.....________-t Flow strength, 0", (ksi) =

Pressure, p (ksi) = Outside Radius, R.,(inch) = Inside Radius, R;(inch) = Mean Radius, Rm (inch) = Thickness, t (inch) = Final Flaw Depth, iij(inch} = Final Flaw Length, 4 (inch) = O"h=pR.,It (ksi) = t..1ow=1.58(R."t)D.S[(crh 10",)2_1]05 (inch) = M2=[1+(1.61/4Rmt) t?)]112= Safety Factor, SFm = C-2622 Stress Ratio =SFm*crwO"r= C-2500 Nondimensional Flaw Length,41..fR."t= aa/lowl t = Table C-641Q-1 Allowable Flaw Depth, aa/low, (inch) = Page 24

A Document No. 32-9196234-000 AREVA TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary Table 5-5: Allowable Flaw Size - Inside Surface-Connected 360 0 Circumferential Flaw in Safe end Paths FR2 FR5 Operating Condition N/UfT ElF N/UfT ElF Final Flaw Depth, at, (inch) = SWOL Outer Diameter, Do, (inch) = Inner Diameter, OJ, (inch) = Mean Radius, Rm (inch) = Total Wall Thickness, t, (inch) = SWOL Thickness, w, (inch) = Cross-sectional Area, A, (inch2) = Moment of Inertia, I, (inch4) = 3 Section Modulus, S = 21100' (inch ) = Temperature (F) = O't, (psi) = Pressure, p, (psi) = Bending Safety Factor, SF b = C-2621 Membrane Safety Factor, SFm = C-2621 O'm = pDoI(4t), (psi) = Mb, (in-Ibf) = O'b =MJS, (psi) = C-2500 Me, (in-Ibf) = Stress, O'e=M.,IS, (psi) = C-2500 J3 = lt/(2-aallowlt)[1-aallow/t-O'mlO't)], (rad) =

                                                                           --     -f--     --      C-5321 O'bC =20'Ilt(2sinJ3 -a/t sin8)(psi) =                                  C-5321 Sc = O'bc/SFb -O'm(1-1/SF m) (psi) =                                     C-5321 (5)
                            = asin( 0.5 (alt) sin 8), (rad) =                                   C-5322 O'mc(psi) =                                 C-5322 St(psi)=                                 C-5322(6) aallowl t =

Allowable Flaw Depth, aatlow, (inch) = Page 25
A Document No. 32-9196234-000 AREVA TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary Table 5-6: Allowable Flaw Size -Inside Surface Semi-Elliptical Axial Flaw in Safe end Paths FR2 FRS Operating Condition Final Flaw Depth, af, (inch) = N/U/T
-- ElF - N/U/T -- ElF SWOL Outer Diameter, Do, (inch) =
Flow strength, O'f (ksi) = Pressure, p (ksi) = Outside Radius, Ro (inch) = Inside Radius, R; (inch) = Mean Radius, Rm (inch) = Thickness, t (inch) = Final Flaw Depth, af(inch) = Final Flaw Length, 4 (inch) = O'h=pRmlt (ksi) = lallow=1.58(Rmt)0.5[(O'h IO'f)2_1]0.5 (inch) = M 2=[1+(1.61/4Rmt) 42)]112= Safety Factor, SFm = C-2622 Stress Ratio =SFm*O'JO't= C-2500 Nondimensional Flaw Length, 41-.JRmt= aallowl t = Table C-541 0-1 Allowable Flaw Depth, aallow, (inch) = Page 26
A Document No. 32-9196234-000 AREVA TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary 6.0
SUMMARY
AND CONCLUSIONS As presented in section 5, none of the postulated circumferential or axial cracks exhibit any crack growth during the evaluation period of 22 years. Final sizes of all postulated flaws at the end of license duration remain smaller than the allowable flaws sizes. Page 27
A Document No. 32-9196234-000 AREVA TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary 7.0 COMPUTER OUTPUT 7.1 Computer Software and Hardware AREVACGC 5.0 was used in this document to compute PWSCC and fatigue crack growth. AREVACGC 5.0 installation was verified by running test cases 1 and 2 as documented below:
Computer program tested: AREVACGC 5.0.

Computer Hardware: Intel Core i7-2640M CPU @ 2.8 GHz Tag# 5VKW5S1

Name of person running test: Silvester Noronha

Date of test: 10/17/2012.

Results of the test: Both test cases produced were acceptable 7.2 Computer Files Computer files of all analysis contained in this document are listed in Table 7-1. These files have been stored in COLDSTOR server within the directory [
] ". All files were uploaded to COLDSTOR on 11/15/2012.
Table 7-1: Computer Files for Crack Growth Evaluation Checksum File Size Date and time File Name Page 28
A Document No. 32-9196234-000 AREVA TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis - Non Proprietary
8.0 REFERENCES
1. ASME B&PV Code Section XI, "Boiler and Pressure Vessel Code, Section XI, Rules for In-service Inspection of Nuclear Power Plant Components", 2004 Edition with No Addenda

2. AREVA Drawing 02-8059673D-003, "Three Mile Letdown Nozzle Weld Overlay Design"

3. AREVA NP Document 32-9186192-001, "TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay"

4. AREVA Document 32- 9185635-001, "TMI-1 Letdown Nozzle Weld Overlay Section III Analysis"

5. AREVA NP Drawing 02-9185282C-000, "TMI Letdown Nozzle Existing Configuration"

6. Material Reliability Program: Crack Growth Rates for Evaluating Primary Water Stress Corrosion Cracking (PWSCC) of Alloy 82, 182, and 132 Welds (MRP-115), EPRI, Palo Alto, CA, 2004, 1006696.

7. AREVA NP Document 18-1173549-006, "Functional Specification for Reactor Coolant System for three Mile Island Unit One"

8. NRC Letter from Richard Barrett, Director Division of Engineering, Office of NRR to Alex Marion of Nuclear Energy Institute, "Flaw Evaluation Guidelines," April 11, 2003, Accession Number ML030980322.

9. Enclosure 2 to [8], "Appendix A: Evaluation of Flaws in PWR Reactor Vessel Upper Head Penetration Nozzles," Accession Number ML030980333.

10. 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.

11. AREVA Document 32-9052958-003, "Evaluation of Stress Intensity Factors Using the Weight Function Method"

12. AREVA Drawing 02-163313E-03, "Reactor Coolant System Nozzle Loadings"

13. AREVA Document 32-9055891-006, "Fatigue and PWSCC Crack Growth Evaluation Tool AREVACGC" Page 29
0402-01-F01 (Rev. 016, 03/31/2011) A CALCULATION
SUMMARY
SHEET (CSS) AREVA Document No. 32 - 9196161 -
----~----~~~~--~~~---------------
000 Safety Related: ~ Yes D No Title TMI-1 Letdown Nozzle Weld Overlay Sizing Calculation (Non-Proprietary) PURPOSE AND
SUMMARY
OF RESULTS: AREVA NP Inc. Proprietary information in the document is indicated by pairs of braces" [ 1".
Purpose:
The purpose of this report is to calculate the weld overlay size (thickness and length) at the two weld locations for the letdown nozzle on the cold leg at TMI Unit 1 per ASME B&PV Code, Section XI, Division 1 (References [2]) and Code Case N-740-2 (Reference [3]). Summary: The minimum full structural weld overlay thickness is determined to be [ 1for both welds. The weld overlay length is [ 1 for both welds. The overlay length is measured from the intersection of the weld material with the adjacent base material on the outside surface. 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 DYES
~ NO Page 1 of 13
A 0402-01-F01 (Rev. 016, 03/31/2011) AREVA Document No. 32-9196161-000 TMI-1 Letdown Nozzle Weld Overlay Sizing Calculation (Non-Proprietary) Review Method: r8J Design Review (Detailed Check) o Alternate Calculation Signature Block P/RlA Name and Title and Pages/Sections (printed or typed) Signature LP/LR Date Prepared/Reviewed/Approved Kaihong Wang, Principal Engineer rJflifv --3 P 1/1/13 All. Lingyah Yen, SupervisorylAdvisory ~"'~ 11 v~ R 1/7/ I?> All. Engineer '\I'"" Lkl -\1 Tim Wiger, Manager IP D.~ T. t,);, ........ A /7/13 All.
~;J~
,Note: PIR/A designates Preparer (P), Reviewer (R), Approver (A); LPILR 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 N/A N/A N/A Mentoring Information (not required per 0402-01) Name Title Mentor to: (printed or typed) (printed or typed) (P/R) Signature Date N/A N/A N/A N/A N/A Page 2
A 0402-01-F01 (Rev. 016, 03/31/2011) AREVA Document No. 32-9196161-000 TMI-1 Letdown Nozzle Weld Overlay Sizing Calculation (Non-Proprietary) Record of Revision Revision Pages/Sections/Paragraphs No. Changed Brief Description / Change Authorization 000 All Initial release. Page 3
A AREVA Document No. 32-9196161-000 TMI-1 Letdown Nozzle Weld Overlay Sizing Calculation (Non-Proprietary) Table of Contents Page SIGNATURE BLOCK ................................................................................................................................2 RECORD OF REVISION ..........................................................................................................................3 LIST OF TABLES .....................................................................................................................................5
1.0 INTRODUCTION
...........................................................................................................................6 2.0 PURPOSE AND SCOPE ...............................................................................................................6 3.0 ANALYTICAL METHODOLOGY ...................................................................................................6 3.1 FSWOL Thickness by Circumferential Flaw Criteria ........................................................................ 6 3.2 FSWOL Thickness by Axial Flaw Criteria ........................................................................................ 8 3.3 FSWOL Length ................................................................................................................................. 8 4.0 ASSUMPTIONS ............................................................................................................................8 5.0 DESIGN INPUTS ..........................................................................................................................9 6.0 COMPUTER USAGE .................................................................................................................. 10 7.0 CALCULATIONS ......................................................................................................................... 10 8.0 RESULTS,
SUMMARY
/CONCLUSIONS .................................................................................... 13
9.0 REFERENCES
............................................................................................................................ 13 Page 4
A AREVA Document No. 32-9196161-000 TMI-1 Letdown Nozzle Weld Overlay Sizing Calculation (Non-Proprietary) List of Tables Page Table 5*1 Loading Conditions at the Nozzle/Safe End ...................................................................... 10 Table 7*1 FSWOL Thickness at the Nozzle End (Circumferential Flaw) .......................................... 11 Table 7*2 FSWOL Thickness at the Nozzle End (Axial Flaw) .... ........................................................ 12 Page 5
A AREVA Document No. 32-9196161-000 TMI-1 Letdown Nozzle Weld Overlay Sizing Calculation (Non-Proprietary)
1.0 INTRODUCTION
Primary water stress corrosion cracking (PWSCC) of [ ] materials is a well recognized phenomenon in the nuclear power industry. High temperature components such as those nozzles connected to the cold leg have higher risk to PWSCC at these dissimilar metal (DM) welds, i.e., the [ ] welds. Three Mile Island Unit 1 (TMI-l) plans to mitigate the cold leg letdown nozzle [ ] DM welds with full structural weld overlays (FSWOL) during the TlR20 outage in the fall of20l3. The corresponding DM welds to be overlaid are located at the [ ] letdown nozzle. Since the weld between the nozzle safe end and the pipe elbow is connected to the weld between the nozzle and safe end, the weld overlay has to extend onto both welds that are [ ] (Reference [1]). The letdown nozzle material is [ ], the piping is [ ], and the nozzle safe end material is [ ] (Reference [1]). In the following, nozzle weld refers to the weld between the nozzle and safe end, and safe end weld refers to the weld between the safe end and the piping elbow. 2.0 PURPOSE AND SCOPE The purpose of this calculation is to determine the minimum structural weld overlay length and thickness required for the repair of the letdown nozzle at TMI-l, in accordance with the Design Specification (Reference [1]) and References [2] and [3] criteria related to the weld overlay sizing. Specifically, this calculation determines the minimum structural requirements for the weld overlay size (thickness and length) for the two weld locations (nozzle weld and safe end weld) at the cold leg letdown nozzle per References [2] and [3]. The minimum structural requirement on the thickness calculated herein does not include any allowance for possible crack growth, weld material dilution layers or surface machining. 3.0 ANALYTICAL METHODOLOGY According to Reference [3], paragraph 2(b)(4), the combined wall thickness at the weld overlay with the flaw size assumptions given in paragraph 2(b)(3) shall be evaluated as well as meet the requirements set forth in IWB-3640 of Reference [2]. For the assumed circumferential and axial flaws, IWB-3640 of Reference [2] instructs to use formula given in Appendix C of the same reference to calculate the corresponding stresses with a flaw present either circumferentially or axially. 3.1 FSWOL Thickness by Circumferential Flaw Criteria As above mentioned, the required thickness of weld overlay repair with the assumption of the circumferential flaw (paragraph 2(b)(3)(a) of Reference [3]) can then be determined by formulas given in Appendix C of Reference [2]. The criterion is based on net section plastic collapse, which predicts adequate load capacity of flawed pipes repaired by weld overlays for given applied stresses, am and abo Here am is the pipe primary membrane stress and ab is the pipe primary bending stress. Note that only the applied loads such as pressure, deadweight and seismic loads are needed in evaluating am and abo Stresses due to temperature gradients and Page 6
A AREVA Document No. 32-9196161-000 TMI-1 Letdown Nozzle Weld Overlay Sizing Calculation (Non-Proprietary) thermal expansion need not be considered since these loads cause stresses that are self limiting, and therefore do not affect the net section plastic collapse. For a circumferentially flawed pipe, the relation between the applied loads in term of bending stress and the flaw depth at incipient plastic collapse per Reference [2], Section C-5321 is given by: (1) where t is the pipe thickness including the overlay, fJ is the angle that defines the location of the neutral axis (for details see Figure C-4310-1 of Reference [2]), a is the flaw depth. The flow stress O"fis the average of the material ultimate tensile strength (Su) and yield strength (Sy) (Section C-8200 of Reference [2]). The value for Su [ 1)and Sy (= [ 1)both at [ 1OF are taken from Reference [4] for the overlay material [ 1, and therefore O"f= [ 1 ksi. The assumed circumferential through-wall flaw penetrates the compressive bending region such that [ 1, where () is one-half of the flaw angle ( [ 1), and therefore the angle fJ per Reference [2] is given by: (2) where O"m is the pipe primary membrane stress in the axial direction in the unflawed section of the pipe. The allowable bending stress Sc is given by: Sc CJC
= S;b -CJ m
( 1- SFm 1 J (3) where SFb and SFm are specified in C-2621 of Reference [2] for service levels A to D. For a circumferentially flawed pipe, the relation between the applied membrane stress and the flaw depth at incipient plastic collapse bending stress per Reference [2], Section C-5322 is given by: CJ~ = CJ f (1- a .!!... _ 2rp) t TC TC (4) where, rp = arCSin( 0.5* ~ . sin ()) (5) The allowable membrane stress Sf for each service level is given by: (6) Page 7
A AREVA Document No. 32-9196161-000 TMI-1 Letdown Nozzle Weld Overlay Sizing Calculation (Non-Proprietary) Additionally, Section C-5300 of Reference [2] also states that in no case shall the resulting flaw depth be greater than a = 0.75t, and the weld overlay thickness should be adjusted to satisfy this criterion if necessary. 3.2 FSWOL Thickness by Axial Flaw Criteria Similarly, when the flaw is assumed to be in the axial direction (paragraph 2(b)(3)(b) of Reference [3]), the pipe hoop stresses shall be evaluated according to C-5400 of Reference [2]. The flawed pipe in this case is the original weld combined with the weld overlay, considering now the flaw depth as the original weld thickness (i.e., the original weld is completely cracked in the axial direction). The required thickness of the weld overlay repairs with the presence of the axial flaw in the assumed size can then be determined by formula given in Appendix C-5420 of Reference [2]. The allowable hoop stress aha is given by: (7) 0.5 where M = l+~.f ( (8) 2 4R m t J with Rm the mean radius of the overlaid pipe and t the pipe thickness including the overlay, and I is the assumed axial length of the flaw. The safety factor SFm is specified in C-2622 of Reference [2] for service levels A to D. The applied hoop stress under internal pressure of P is calculated by: PR m CJ h =-- (9) t Again, Section C-5400 of Reference [2] also states that in no case shall the resulting flaw depth be greater than a = 0.75t, and the weld overlay thickness should be adjusted to satisfy this criterion if necessary. 3.3 FSWOL Length Per Reference [3], paragraph 2(b)(l), to provide for load redistribution from the item into the weld overlay and back into the item without violating applicable stress limits of NB-3200, the length of the weld overlay should extend at least 0.75(Rtn)'h beyond each end of the observed flaw where Rand tn are the outside radius and the nominal wall thickness of the pipe prior to depositing the weld overlay. 4.0 ASSUMPTIONS This calculation contains no assumptions that must be verified prior to use on safety-related work. Simplifications in modeling and simulation used in the calculation are due to the acceptability requirement specified in Reference [1] for the following two assumptions stated in Reference [3]: Circumferential Flaw - [ ] through wall (original weld) for the entire circumference. Page 8
A AREVA Document No. 32-9196161-000 TMI-1 Letdown Nozzle Weld Overlay Sizing Calculation (Non-Proprietary) Axial Flaw - [ ] through wall (original weld) for a length of [ ] , or the combined width of the weld plus buttering, whichever is greater. Since the two [ ] welds (letdown nozzle to safe end weld and elbow to safe end weld) are close to each other (Reference [5]), the combined length of the two welds (including the short safe end in between) is [ ] at maximum. To be conservative, the total length of [ ] is considered as the axial flaw length in the following calculation. 5.0 DESIGN INPUTS 5.1 Geometry Based on the geometry given in Reference [6], the nozzle weld has an inside diameter of [ ] and the outside diameter is [ ] at the nozzle end; the safe end weld has an inside diameter of [ ] and the outside diameter is [ ] at the piping connection for the [ ] pipe. As illustrated in Reference [5], the two [ ] welds (letdown nozzle to safe end weld and elbow to safe end weld) are close to each other with a short safe end in between; the total length of the combined welds is [ ] at maximum. 5.2 Materials and Properties Per Reference [1], the nozzle is welded to the cold leg and fabricated from [ ] . The safe end material is [ ] . The letdown nozzle to safe end and elbow to safe end welds are both [ ] . The weld overlay material is [ ] with material properties equivalent to [
].
The ultimate strength and yield strength of the overlay material [ ] is Su = [ ] and Sy = [ ] , both at [ ] OF are taken from Reference [4] for the overlay material. 5.3 Applied Loads As identified in Reference [2], Appendix C, only primary stresses (O'm - maximum applied pipe primary membrane stress, O'b - maximum applied pipe primary bending stress and O'h - maximum applied hoop stress) are needed to determine the acceptability of a flawed pipe for continued service. The primary stresses considered in this application result from internal pressure, dead weight (DW), seismic loads (OBE or SSE). Section C-2620 of the same reference also specifies safety factors SFm and SFb applied individually to membrane and bending stresses respectively, for each Service Level: A (Normal), B (Upset), C (Emergency), and D (Faulted). Below are the required safety factors as specified in Reference [2], Sections C-2621 and C-2622: Service Level A: SFm =2.7 SFb = 2.3 Service Level B: SFm = 2.4 SFb = 2.0 Service Level C: SFm = 1.8 SFb = 1.6 Service Level D: SFm = 1.3 SFb = 1.4 The limiting load combinations for the ASME Code Service Level conditions are as follows: Page 9
II A AREVA Document No. 32-9196161-000 TMI-1 Letdown Nozzle Weld Overlay Sizing Calculation (Non-Proprietary) Service Level A: Service Level B: Service Level C: Service Level D: Note that [ ] combination is conservatively used for both Normal and Emergency conditions. The piping loads at the safe end are taken from Reference [7]. The axial membrane stress due to the internal pressure is determined by PDI4t, where P is the maximum specified service level pressure presented in Reference [8] and D is the outside diameter of the pipe. The SRSS (square root of the sum of squares) moment is conservatively defined as ~Torsion2 + M: + M; . The maximum pressures approximated from the thermal design transients documented in Reference [8] are collected as follows: Normal- [ ] psi [ ] Upset- [ ] psi [ ] Emergency- [ ] psi [ ] Faulted - [ ] psi [ ] Table 5-1 lists the total loads to be used for both the nozzle and safe end weld overlays. Table 5-1 Loading Conditions at the Nozzle/Safe End Moments (in-Ibt) Load Case Torsion My Mz SRSS 6.0 COMPUTER USAGE No engineering software is used in the sizing calculation. 7.0 CALCULATIONS 7.1 FSWOL Thickness As above mentioned in Section 3.0, the weld overlay thickness with the flaw size assumptions given in paragraph 2(b)(3) shall be evaluated as well as meet the requirements set forth in IWB-3640 of Reference [2], which directs Page 10
A AREVA Document No. 32-9196161-000 TMI-1 Letdown Nozzle Weld Overlay Sizing Calculation (Non-Proprietary) to use formula given in Appendix C of the same reference to calculate the corresponding stresses with a flaw present either circumferentially or axially. 7.1.1 Circumferential Flaw Evaluation The weld overlay thickness is determined through an iterative approach. The outside diameter at the weld overlay location is obtained by postulating an overlay thickness; the primary stresses O'm and O'b are then calculated for the applied loads; the allowable stresses Se and St obtained by Equations (3) and (6) should be equal to or greater than respective applied stresses when an allowable flaw depth is reached. Sections C-5300 and C-5400 (Reference [2]) also state that in no case shall the resulting flaw depth be greater than a = 0.75/, and the weld overlay thickness should be adjusted to satisfy this criterion if necessary. The results from the iteration along with parameters used in the calculation are listed in Table 7-1. Table 7-1 FSWOL Thickness at the Nozzle End (Circumferential Flaw) Paramo Normal Upset Emergency Faulted The piping loads listed in Table 5-1 are identical for both welds. Since the two welds with the same ID are directly connected from the outside surface while the inside surfaces are separated by the safe end, the combined weld needs to be considered by using the maximum weld thickness (which is the weld between the nozzle and safe end) in the calculation of the overlay thickness. Page 11
A AREVA Document No. 32-9196161-000 TMI-1 Letdown Nozzle Weld Overlay Sizing Calculation (Non-Proprietary) 7.1.2 Axial Flaw Evaluation The previously determined weld overlay thickness shown in Table 7-1 is used in Equations (7) through (9) to ensure acceptability of the WOL for axial flaw criteria. The results along with the parameters used in the calculation are listed in Table 7-2 for the nozzle weld, which remains bounding for the safe end weld. Table 7*2 FSWOL Thickness at the Nozzle End (Axial Flaw) Paramo Description Normal Upset Emergency Faulted As shown in Table 7-1 to Table 7-2, the minimum overlay thickness is [ ] for both welds, controlled by the thickness ratio criterion. 7.2 FSWOL Length To meet the requirement of Reference [3], paragraph 2(b)(1), with R = [ ] and tn = [
] for the nozzle weld, the full thickness weld overlay length shall be at least: ]
Note that the weld overlay length is to be conservatively measured in full thickness from the intersection of the weld material with the adjacent base material (nozzle or elbow) on the outside surfaces. Page 12
A AREVA Document No. 32-9196161-000 TMI-1 Letdown Nozzle Weld Overlay Sizing Calculation (Non-Proprietary) 8.0 RESULIS,
SUMMARY
/CONCLUSIONS In accordance with References [1], [2] and [3], the minimum weld overlay size is calculated as follows: Thickness - [ ] for both the nozzle and safe end welds Length - [ ] for both the nozzle and safe end welds The length is all measured in full thickness on each side of the weld intersection, as noted in Section 7.2. Note that the weld overlay thickness is the minimum required by the applicable acceptance criteria for primary sources of loading. The final weld overlay thickness should additionally consider fatigue crack growth, weld material dilution, and machining allowance in the final overlay design.
9.0 REFERENCES
[1] AREVA NP Inc Design Specification 08-9182964-002, "TMI-l 'C' Cold Leg Letdown Nozzle Weld Overlay." [2] ASME Boiler Pressure Vessel Code, 2004 Edition with no Addenda, Section XI, Division I. [3] Code Case N-740-2, "Full Structural Dissimilar Metal Weld Overlay for Repair or Mitigation of Class 1,2, and 3 Items, Section XI, Division I." [4] ASME Boiler and Pressure Vessel Code, 2004 Edition with no Addenda, Section II, Part D - Properties. [5] AREVA NP Inc. Drawing 02-9185282C-000, "TMI-l Letdown Nozzle, Existing Configuration." [6] AREVA NP Inc. Drawing 02-131964E-06, "Assembly and Details for 1 Y:z" TEMP. CONN's, 1" Drain Nozzle and 2 Y:z" Drain Nozzle." [7] AREVA NP Inc. Drawing 02-163313E-03, "Reactor Coolant System Nozzle Loadings." [8] AREVE NP Inc. Functional Specification 18-1173549-006, "Functional Specification for Reactor Coolant System for TMI-l." Page 13
0402-01-F01 (Rev. 016, 03/31/2011) A CALCULATION
SUMMARY
SHEET (CSS) AREVA Document No. 32 - 9196160 - 000
----~----~~~~--~~---------------
Safety Related: ~ Yes D No Title TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) PURPOSE AND
SUMMARY
OF RESULTS: AREVA NP Inc. Proprietary information in the document is indicated by pairs of braces II [ ] ". PURPOSE: This document presents the thermal and structural analyses of the TMI-1 cold leg letdown nozzle with a weld overlay. The purpose of this calculation is to qualify the weld overlay design to the requirements of the ASME B&PV Code Section III, Division 1, 2004 Edition with no addenda (Reference [2]).
SUMMARY
The thermal and structural analyses demonstrate that the cold leg letdown nozzle weld overlay design satisfies the ASME Code (Reference [2]) primary and primary plus secondary stress requirements as well as criteria against fatigue failure. Based on the loads and cycles specified in References [1], [11], and [12], the fatigue analyses performed in this document indicate that the maximum fatigue usage factor for the cold leg letdown nozzle weld overlay design is [ ] . This document contains 60 pages including pages 1 - 56, Appendix A (3 Pages), and Appendix B (1 Pages). 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 DYES [ ]
~ NO Page 1 of60
0402-01-F01 (Rev, 016, 03/31/2011) Document No, 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Review Method: IZI Design Review (Detailed Check) o Alternate Calculation Signature Block PJRlA Name and Title and Pages/Sections (printed or typed) Signature LP/LR Date Prepared/Reviewed/Approved
~~
Kristine Barnes P All Engineer IV '}':l- Jl'b Kaihong Wang R All Principal Engineer ~'~~ t/1/13
~ ;/9}J Tim Wiger ---..;, A All Manager l:>.K",- ..(:.. T. 'f"J; 1'"4-'"
Note: PIR/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 Page 2
A 0402-01-F01 (Rev. 016, 03/31/2011) AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Record of Revision Revision Pages/Sections/Paragraphs No. Changed Brief Description / Change Authorization 000 All Initial Issue Page 3
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Table of Contents Page SIGNATURE BLOCK ................................................................................................................................2 RECORD OF REVISION ..........................................................................................................................3 LIST OF TABLES .....................................................................................................................................6 LIST OF FIGURES ...................................................................................................................................8
1.0 INTRODUCTION
...........................................................................................................................9
1.1 Purpose and Scope
.......................................................................................................................... 9 2.0 ANALYTICAL METHODOLOGY ................................................................................................. 10 3.0 ASSUMPTIONS .......................................................................................................................... 11 3.1 Unverified Assumptions .................................................................................................................. 11 3.2 Justified Assumptions ..................................................................................................................... 11 3.3 Modeling Simplifications ................................................................................................................. 11 4.0 DESIGN INPUTS ........................................................................................................................ 12 4.1 Geometry ........................................................................................................................................ 12 4.2 Finite Element Model ...................................................................................................................... 13 4.3 Materials ......................................................................................................................................... 14 4.4 Boundary Conditions ...................................................................................................................... 18 4.4.1 Thermal Analysis ............................................................................................................. 18 4.4.2 Structural Analysis ........................................................................................................... 20 4.5 Loads .............................................................................................................................................. 22 4.5.1 External Loads ................................................................................................................. 22 4.5.2 Design Conditions ............................................................................................................ 23 4.5.3 Operational Transient Loads ........................................................................................... 23 5.0 COMPUTER USAGE ..................................................................................................................24 5.1 Hardware ........................................................................................................................................ 24 5.2 Software Verification ...................................................................................................................... 24 5.3 Analysis Generated Files ............................................................................................................... 24 6.0 CALCULATION ...........................................................................................................................28 Page 4
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Table of Contents (continued) Page 6.1 Design Condition ............................................................................................................................ 28 6.2 Thermal Analysis ............................................................................................................................ 30 6.3 Structural Analysis .......................................................................................................................... 37 6.4 ASME Code Criteria ....................................................................................................................... 44 6.4.1 ASME Code Primary Stress Intensity Criteria ................................................................. 44 6.4.2 ASME Code Primary + Secondary Stress Intensity Range and Fatigue Usage Criteria 44 7.0 RESUL TS/CONCLUSIONS .........................................................................................................55
8.0 REFERENCES
............................................................................................................................56 APPENDIX A: PIPE THICKNESS COMPARISON ........................................................................................... A-1 APPENDIX 8 : STRESSES FOR FRACTURE ANALySiS ................................................................................ 8-1 Page 5
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) List of Tables Page Table 4-1: Cold Leg Piping .. .................................................................................................................. 15 Table 4-2: Letdown Nozzle .................................................................................................................... 15 Table 4-3: Nozzle to Safe End Weld / Safe End / Safe End to Pipe Weld ............................................. 16 Table 4-4: Letdown Piping .....................................................................................................................16 Table 4-5: Cladding ............................................................................................................................... 17 Table 4-6: Weld Overlay ........................................................................................................................ 17 Table 4-7: External Loads ......................................................................................................................22 Table 4-8: Transients and Number of Cycles ........................................................................................ 23 Table 5-1: Software Verification Runs ...................................................................................................24 Table 5-2: Analysis Computer Files ....................................................................................................... 24 Table 6-1: Transient Temperature Files ................................................................................................. 30 Table 6-2: Thermal Analysis Output Files .............................................................................................. 30 Table 6-3: Locations for Temperature Gradients ................................................................................... 30 Table 6-4: Transient Pressure and Time Point Files .............................................................................. 37 Table 6-5: Structural Analysis Output Files ............................................................................................ 37 Table 6-6: Time Points of Interest for [ ] ..........................................................................................37 Table 6-7: Time Points of Interest for [ ] ..........................................................................................38 Table 6-8: Time Points of Interest for [ ] .......................................................................................... 39 Table 6-9: Time Points of Interest for [ ] ..........................................................................................39 Table 6-10: Time Points of Interest for [ ] ...........................................................................................40 Table 6-11: Time Points of Interest for [ ] ...........................................................................................40 Table 6-12: Time Points of Interest for [ ] ...........................................................................................41 Table 6-13: Time Points of Interest for [ ] ...........................................................................................41 Table 6-14: Time Points of Interest for [ ] ...........................................................................................42 Table 6-15: Time Points of Interest for [ ] ....................................................................................... .43 Table 6-16: Path Lines for Linearized Stresses .....................................................................................45 Table 6-17: Stress Intensity Ranges ......................................................................................................46 Table 6-18: Geometric Characteristics of Path Line Cross Section ...................................................... .47 Table 6-19: Stress Intensities due to External Loads (ksi) .................................................................... .48 Table 6-20: Membrane + Bending Stress Intensity Range Summary (ksi) ........................................... .49 Table 6-21: Total Maximum Primary + Secondary Stress Intensity Range Summary (ksi) ................... 51 Page 6
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) List of Tables (continued) Page Table 6-22: ] Material CFUF (Path3/3a) ................................................................................. 53 Table 6-23: ] Material CFUF (Path11/11a) .............................................. 53 Table 6-24: ] Material CFUF (Path8) ......................................................................................... 54 Table 6-25: ] Material CFUF (Path13b) ................................................................................ 54 Table 7-1: M+B Stress Intensity Ranges and CFUFs ............................................................................ 55 Table A-1: Summary of Thin vs. Thick Comparison ............................................................................ A-2 Table A-2: Thick VS. Thin Stress Intensities (ksi) ................................................................................. A-3 Table B-1: Paths for Fracture Mechanics Evaluation ........................................................................... B-1 Table B-2: File Names and Units of ANSYS Output.. .......................................................................... B-1 Page 7
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) List of Figures Page Figure 4-1: Nozzle-FSWOL Geometry ................................................................................................... 12 Figure 4-2: Finite Element Model (FEM) ................................................................................................ 13 Figure 4-3: Thermal Boundary Conditions ............................................................................................. 19 Figure 4-4: Structural Boundary Conditions ........................................................................................... 21 Figure 4-5: External Load Orientation (Reference [13]) ......................................................................... 22 Figure 6-1: Deformed Shape for Design Condition ................................................................................ 28 Figure 6-2: Stress Intensity Contours for Design Condition ................................................................... 29 Figure 6-3: Approximate Locations for Temperature Gradient Evaluation ............................................. 31 Figure 6-4: Thermal Gradients at Selected Locations ( [ ] ) .............................................. 32 Figure 6-5: Thermal Gradients at Selected Locations ( [ ] ) .............................................. 32 Figure 6-6: Thermal Gradients at Selected Locations ( [ ] ) .............................................. 33 Figure 6-7: Thermal Gradients at Selected Locations ( [, ] ) .............................................. 33 Figure 6-8: Thermal Gradients at Selected Locations ( [ ]) ................................................ 34 Figure 6-9: Thermal Gradients at Selected Locations ( [ ]) ................................................ 34 Figure 6-10: Thermal Gradients at Selected Locations ( [ ] ) .............................................. 35 Figure 6-11: Thermal Gradients at Selected Locations ( [ ]) .............................................. 35 Figure 6-12: Thermal Gradients at Selected Locations ( [ ] ) .............................................. 36 Figure 6-13: Thermal Gradients at Selected Locations ( [ ]) ........................................... 36 Figure 6-14: Approximate Locations of Path Lines for Stress Analysis ................................................ .46 Figure A-1: Pipe Thickness Difference ................................................................................................ A-1 Page 8
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary)
1.0 INTRODUCTION
It is well recognized that the [ ] dissimilar metal welds (DMWs) are susceptible to the primary water stress corrosion cracking (PWSCC), especially those in high temperature components such as cold leg nozzles. The possibility ofPWSCC at the DMWs escalates with increased plant service time. Three Mile Island Unit 1 (TMI-l) plans to mitigate the PWSCC in the cold leg letdown [ ] dissimilar metal (DM) welds with full structural weld overlays (FSWOLs). The weld overlay is designed to cover the [ ] welds between the nozzle safe end and the elbow. Application of the weld overlays alters the local stress distribution. A detailed finite element analysis (FEA) is performed to investigate stress conditions under various operational transients. The results are summarized to certify that criteria per ASME Code Section III for Class I components are satisfied for the letdown nozzle with overlay. The analysis is focused on the overlaid region for requirements on both stress distribution and fatigue failure criteria.
1.1 Purpose and Scope
As required by the Design Specification (Reference [1]), the purpose of this calculation is to perform a structural assessment of the TMI-lietdown nozzle repaired by weld overlay, following the requirements of the ASME Code Section III. The results of the calculation is documented in this report to certify that the repair meets the stress criteria and fatigue requirements of the ASME Code Section III 2004 Edition (Reference [2]). The analysis is focused on the weld overlaid region for requirements on both stress distribution and fatigue failure criteria. The scope ofthe analysis includes the weld overlay, letdown elbow, weld between the elbow and the safe end, safe end, dissimilar metal weld between the safe end and the nozzle, letdown nozzle, and a portion of the cold leg. A detailed finite element analysis (FEA) is performed to determine stress conditions under various operational transients. Two models are created due to the variations of the pipe wall thickness of the existing bent pipe configuration as documented in Reference [5]. One side is measured as [ ] thick (intrados) and the other side is measured as [ ] (extrados). Because of the difference in thickness, a test case is run to determine if a model with uniform pipe thickness of [ ] or [ ] gives the highest stress results. The more critical model is used for stress and fatigue evaluations. Page 9
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) 2.0 ANALYTICAL METHODOLOGY The general methodology of the stress analysis consists of following steps:
1. Develop two 3D finite element model of the nozzle (with unifonn pipe thicknesses of [ ] and
[ ] ,respectively) with a welded curved pipe from the weld overlay drawings. Only the minimum overlay design configuration is used to develop the model in performing the analysis required by Reference [1] (see Section 3.0 for more details). The model incorporates the geometry of the CL letdown nozzle (including adjacent cold leg, nozzle, safe end, welds, weld overlay and the curved pipe), appropriate materials and boundary conditions. There are two finite element models consisting ofthennal and structural elements, respectively so as to enable the thennal and structural analysis using ANSYS R13.0 (Reference [3]).
2. Run a test case using the heat up and cool down transients to detennine which model (thick or thin pipe thickness) is most critical, see Appendix A.

3. Apply the design conditions (pressure and temperature) to the structural finite element model and obtain the defonnation and stresses in the model. The defonnation field is used to verify the correct behavior of the model and correct modeling of the boundary and load conditions.

4. Apply the thennalloads pertaining to the service level transients in the fonn of transient temperatures and corresponding heat transfer coefficients versus time. Each of the major service level transient requires a separate run on the thennal finite element model.

5. Review the results of the thennal analysis by examining the magnitude of temperature difference between critical locations in the model at all time points. Detennine the critical time points for stress analysis.

6. Apply the corresponding mechanical (pressure) and thennal (nodal temperature) loads at each time point identified in Step 5 to the structural finite element model. Since the weld overlay configuration contains layers of different material having different coefficients of expansion, it is possible that one material is in compression and the other is in tension due to thennal expansion.

7. Define paths and linearize the stresses along the path to compute membrane and membrane+ bending stresses. The standard method in defining a path is to go from a free surface to a free surface. However, using this method ANSYS may average the stresses at the boundary of two material to compute the membrane and membrane + bending stresses. In addition to the free surface to free surface path, two partial paths (one in each material) are defined at the same location to ensure maximum stress intensities are captured. These paths will be used to check the 3S m criteria and to obtain maximum K., factor. It is recognized that no continuous and progressive displacement can occur in one of the materials without the other material restraining that displacement.

8. Calculate stresses due to nozzle extemalloads by manual computation to add to the stress results due to pressure and temperature effect.

9. Compare the primary + secondary stresses to the ASME Code criteria for acceptability. Because weld overlay adds material to the original structure, the primary stresses in the original design will bound those in the weld overlay design. Therefore, the primary stresses in the overlay design need not be checked against the Code allowables (see discussion in Section 6.4.1).
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A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary)
10. Perfonn the fatigue evaluation for each material.

11. Document the stresses and temperature for the fracture mechanics analysis of the letdown nozzle weld overlay design, see Appendix B.
3.0 ASSUMPTIONS 3.1 Unverified Assumptions This analysis contains no assumptions that must be verified prior to use on safety-related work. 3.2 Justified Assumptions Justified assumptions used for the analysis are listed as follows:
1. Since the pipe thickness around the elbow is varying, two finite element models (thick or thin pipe thickness) are built and tested under the transient conditions of heat up and cool down. The results are documented in Appendix A. It is concluded that the results from the thin pipe are bounding for most critical locations, and therefore, the model with thin pipe is used to complete the analysis.

2. The FSWOL design consists of two configurations in tenns of the overlay thickness: the minimum and maximum conditions. Based on similar Section III analyses as well as studies on the nozzle DMW repair with
[ ] , the stress intensity ranges and cumulative fatigue usage factors at most critical locations remain bounding when the analysis is perfonned using the minimum overlay thickness. Therefore, the minimum FSWOL configuration is then used in this analysis. 3.3 Modeling Simplifications Simplifications in modeling and simulation used for the analysis are listed as follows:
1. The outside surface of the letdown nozzle and part of the cold leg modeled is insulated. However, a small heat transfer coefficient of [ ] Btu/hr-in2-oF is used in this calculation to account for imperfect insulation.

2. The weld between the safe end and elbow is considered symmetric and the actual pipe bend starts at the top of the weld.

3. The smaller overlay radius of [ ] taken from the minimum FSWOL thickness (Reference [6]) is modeled in the finite element analysis as it yields higher stress concentration. Element sizes around these transition regions are refined to ensure the convergence in an effort to capture the accurate peak stresses.

4. Based on the evaluation of temperature and pressure fluctuation, some transients are enveloped (see Table 4-8) by the bounding transient and the corresponding numbers of cycles are summed up in the fatigue assessment.
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A AREVA Document No. 32-9185635-001 PROPRIETARY TMI-1 Letdown Nozzle Weld Overlay Section III Analysis 4.0 DESIGN INPUTS 4.1 Geometry The detailed dimensions of the cold leg letdown nozzle existing configuration are shown in Reference [4]. Major dimensions used for building the finite element model include: cold leg inside radius ( [ ] to base metal), cold leg thickness ( [ ] ), nozzle inside diameter ( [ ] ), and outside diameter ( [ ] at nozzle end). Figure 4-1: Nozzle-FSWOL Geometry The pipe elbow is considered to be a [ ] Elbow with a thickness of [ ] . However, NDE results show that the thickness of the elbow ranges from [ ] to [ ] (Reference [5]). Two models are created, one with each thickness, and the resulting stresses for the [
] transients ( [ ] ) are compared in Appendix A, which demonstrates that the thin pipe with the nominal thickness of [ ] bounds the model with the thicker pipe.
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A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) The weld overlay configurations are shown in Reference [6] for the minimum and maximum weld overlay. The minimum thickness of the weld overlay is [ ] . The weld overlay is tapered to the elbow on the extrados side and is angled out on the intrados side. At a distance of [ ] from the safe end to pipe weld, the thickness of the weld overlay is [ ] on the intrados and extrados side. 4.2 Finite Element Model The finite element model is built based on the weld overlay design with the minimum weld overlay size. The model is developed in ANSYS R13.0 Workbench and the geometry file (nodes, elements, and components) created is found in [ ] . The 3D model is meshed with [ ] elements for the structural analysis and [ ] elements for thermal analysis. The meshed model with the minimum weld overlay is shown in Figure 4-2. The meshed model with material properties (Section 4.3) is documented by [ ]. Figure 4-2: Finite Element Model (FEM) Page 13
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) 4.3 Materials Reference [1] provides the material designations for each component of the cold leg letdown nozzle. Material properties are found in References [7] (new material), [8] (existing material), and [9]. Since thermal Conductivity (k) values for original materials are not provided in Reference [8], they are taken from the next code year, Reference [10]. In addition, the piping material [ ] is also not included in Reference [8] and has material properties from the next code year, Reference [10]. The Weld Overlay is the only new material, all others are existing. Cold Leg Piping Letdown Nozzle Nozzle to Safe End Weld Safe End Safe End to Letdown Piping Weld Letdown Piping Weld Overlay The following tables provide the material physical properties - mean coefficient of thermal expansion (a), specific heat (C), thermal conductivity (k), density (P), and the mechanical properties - modulus of elasticity (E), Poisson's ratio (jl). The units of data listed are: Temperature Temp OF Young's Modulus E 106 psi Poisson's Ratio f.l unitless Density p lb/in3 Mean Coefficient of Thermal Expansion a 10-6 inlin-OF Thermal Conductivity k Btu/hr-in-oF Specific Heat C Btu/lb-oF Design Stress Sm ksi Yield Strength Sy ksi Ultimate Strength Su ksi Note that specific heat (C) is a calculated value: C = k / (p
thermal dijJusivity) where thermal diffusivity is taken from the same source as thermal conductivity k.
The material properties are read into the FEM from the ANSYS files: [
].
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A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Table 4*1: Cold Leg Piping [ ] Temp, of fi f.J P a k C 8m 8v 8.u., 70 - f-- - i- - I-- - i-- - - - -- 100
- r-- - r- - r-- - I-- - - - --
200
- r-- - r- - r-- - i-- - - - --
300 - f-- - i- - I-- - i-- - - - -- 400 500
- - - r- - r-- - I-- - - - -- - - - r- - r-- - i-- - - - --
600 650
- - - i- - I-- - i-- - - - --
700
- - - r- -- - I-- - r-- ---
Reference [8] typical [9] [8] [10] calculated [8] [8] [8] Table 4*2: Letdown Nozzle [ ] Temp, of E f.J P a k C 8m 8y 8u 70 - f-- - i- - I-- - i-- - - - -- 100 - r-- - r- - r--- - I-- - - - -- 200 300
- - - r- - r-- - i-- - - - --
400
- - - i- -- - i-- - r-- - --
500
- - - i- -- - i-- - I-- --- - - - - -- - - - r-- ---
600
- - - - -- - - - r-- ---
650
- - - - -- - - - I-- - f---
700 Reference [8] typical [9] [8] [10] Calculated [8] [8] [8] Page 15
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Table 4-3: Nozzle to Safe End Weld I Safe End I Safe End to Pipe Weld [ ] Temp, of E f.1. P a k C 8m 8v 81J. 70 100
- r-- - - -- - - - I-- - r---- - r-- - - -- - - - r-- - r----
200
- f-- - - -- - - - r-- --
300 400
- r-- - - -- - - - I-- - r----
500
- r-- - - -- - - - r-- - r---- - f-- - - -- - - - r-- --
600 650
- I-- - - -- - - - - - -- - r-- - - -- - ,.-- - - - --
700 Reference [8] typical [9] [8] [10] Calculated [8] [8] [8] - Table 4-4: Letdown Piping [ ] Temp, OF E f.1. P a k C 8m 8y
8u 70 100
- - - r- -f - - - - - r-- -- - - - r- -- - - - r-- - r-----
200 300
- c-- - I- -- - - - I-- - r----
400
- r-- - r- -- - - - r-- --
500
- - - r- -- - - - r-- -- - I-- - I- -- - - - I-- - r-----
600 650
- r-- - - -- - - - - - -- - r-- - - -- - c-- - - - --
700 Reference [8] typical [9] [8] [10] Calculated [10] [10] [10]
[ ] is not included in the Sy tables in Reference [10], therefore, the Sy values for the type [ ]
material is used. This is reasonable as the Sy value listed in the Sm table for [ ] , [ ] is [ ] ksi. Page 16
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Table 4-5: Cladding [ ] Temp, of E J1. P a k C 0 100
- I-- - - -- - - I-- - i- -r--- -
200 300
- I-- - r- -I-- - - I-- - '- -'---- -
400 500
- I-- - i- -I-- - - I-- - r- -I-- -
600 - - I-- - r- -I-- 650 700
- - - i- -I-- -
Reference [8] typical [9] [8] [10] Calculated Table 4-6: Weld Overlay [ ] Temp, OF E J1. P a k C Sm Sv Su 70
- I-- - - - f--- - I-- - - - r-- -
100 200
- I - - - i- - I-- - t-- - I-- - I- - - I-- - - - I-- - I-- - - - :- -
300 400
- I-- - c- - f--- - I-- - ,...- - r-- - - - - r- - f--- - I-- - I-- - r-- -
500
- - - i- -- - - - I-- - I- -
600
- - - r- -- - - - I-- - I- -
650 - - - r- -- - - - I-- - - - 700 Reference [7] typical [9] [7] [7] Calculated [7] [7] [7] Page 17
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) 4.4 Boundary Conditions 4.4.1 Thermal Analysis During operation, the inside surfaces of the cold leg, letdown nozzle, nozzle to safe end weld, safe end, safe end to pipe weld, and pipe are in contact with the reactor coolant water coming out of the steam generator on its way back to the reactor. Appropriate heat transfer coefficients (HTCs) for the inside of the cold leg and inside of the letdown nozzle and piping are provided in Reference [11 J. The outside surface of the cold leg, letdown nozzle, pipe, and weld overlay are exposed to ambient temperatures. A small HTC of [ ] Btu! hr-in2 -oF is applied during all transient events to account for imperfect insulation. All thennal boundary conditions are shown in Figure 4-3. Page 18
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Figure 4-3: Thermal Boundary Conditions Page 19
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) 4.4.2 Structural Analysis The reactor coolant system pressure is applied to all interior surfaces of the cold leg, letdown nozzle, nozzle to safe end weld, safe end, safe end to pipe weld, and pipe. The upper end of the pipe has a pressure PPendcap and the back section of the cold leg has a pressure PCLendcap applied to represent the hydrostatic end load. The pressures are calculated (for the design condition) as: PPendcap - (R2 _ 2 pipe 2
- p. r pipe r plpe L- ]
P CLendcap = 2
- P
rcoldleg 2
2 (RcOldleg - rcoldleg
=[ ]
Where: p = pressure applied = [ ] psi* for design condition (Reference [12]) R pipc = OD of the pipe = [ ] in for thickness [ ] (Reference [4]) rpipc = ID of the pipe = [ ] in (Reference [4]) Rcoldleg = OD of cold leg = [ ] in (Reference [4]) rcoldleg = ID of cold leg = [ ] in (Reference [4])
While the design pressure is [ ] psig, the calculated difference in endcap pressures is negligible.
For other transients, the pressure at each time point is used to calculate the corresponding end cap pressures. The boundary conditions for the structural analysis are set to have no displacement in the circumferential direction along the cylindrical planes of the cold leg and the symmetry plane. All structural boundaries are shown in Figure 4-4. Page 20
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Figure 4-4: Structural Boundary Conditions Page 21
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) 4.5 Loads 4.5.1 External Loads Loads applied to the mode include temperatures and heat transfer coefficients for the thermal analysis and internal pressure for the structural analysis. External loads are shown in Table 4-7 per Reference [13] and are applied at the location between the nozzle and piping as shown in Figure 4-5. Table 4*7: External Loads M Loading Condition f-- Dead Load + OBE Dead Load + SSE Max Thermal Max Thermal + OBE Thermal Range OBERange Boundin2 Case Note 1: [ ] Figure 4*5: External Load Orientation (Reference [13]) Page 22
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) 4.5.2 Design Conditions The design pressure and temperature of the TMI-l reactor coolant system is [ ] psig and [ ] of (Reference [12]). These design conditions are simulated on the model by applying a uniform and reference temperature of [ ] OF throughout the model (the temperature is used to determine the material properties, not for thermal expansion) and a uniform pressure of [ ] psig on all inside surfaces of the model. The equivalent endcap pressures on the letdown piping and cold leg are also applied as described in Section 4.4.2. 4.5.3 Operational Transient Loads The letdown nozzle is located on the cold leg. The inside surfaces are subjected to the cold leg temperatures and pressures as defmed in Reference [12]. Temperatures and pressures along with the appropriate heat transfer coefficients (HTCs) are documented in Reference [11]. The applicable transients and number of cycles are listed in Table 4-8. Several transients are enveloped ( [ ] ) since their temperature and pressure fluctuation is bounded by the transient used. Table 4-8: Transients and Number of Cycles Transient Description # Cycles Page 23
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) 5.0 COMPUTER USAGE 5.1 Hardware 5.2 Software Verification Table 5*1: Software Verification Runs File Name Date Description - 5.3 Analysis Generated Files The following table lists the computer files associated with the analysis and qualification of the TMI-l Cold Leg Letdown Weld Overlay analysis. Table 5*2: Analysis Computer Files l- - I- - l-I- I-Page 24
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) roo roo I-l- I-l- I-I- roo Page 25
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) r- - r- - r-r- r-r- r-r- r-r- r-Page 26
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) i-I-- I-- I-- I-- I-- I-- I-- I-- I-- I-- I-- I-- I-- I-- I-- I-- I-- I-- I-- I-- I-- I-- I-- I-- Page 27
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) 6.0 CALCULATION 6.1 Design Condition Stress analysis of the model under the design pressure and temperature provides a basis for verification of the expected behavior of the model, the boundary and load conditions. It also verifies attenuation of stress effects at regions away from the nozzle. The ANSYS output for the design condition is documented in the following file: [ 1 Figure 6-1 shows the deformed shape of the FSWOL model under design pressure. The stress intensity contour plot is shown in Figure 6-2. Figure 6*1: Deformed Shape for Design Condition Page 28
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Figure 6-2: Stress Intensity Contours for Design Condition Page 29
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) 6.2 Thermal Analysis The ANSYS input files containing the transient definitions tabulated in Reference [11] are: Table 6*1: Transient Temperature Files
-I--
The thermal analysis output files including the temperature gradient output are as follows: Table 6*2: Thermal Analysis Output Files The results of the thermal analysis are evaluated to identify the maximum and minimum temperature gradients between critical locations in the model and the corresponding time points. These temperature gradients generate maximum and minimum thermal stresses, which in in turn contribute to the maximum range of stress intensities in the model. The locations for the evaluation of temperature gradients are listed by coordinates in Table 6-3. The locations are shown in Figure 6-3. Table 6*3: Locations for Temperature Gradients Inside Coordinate Outside Coordinate Path X y Z X Y Z A - B C 0 E F Page 30
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Figure 6-3: Approximate Locations for Temperature Gradient Evaluation The temperature of selected nodes versus transient time as well as the temperature gradient are shown in Figure 6-4 to Figure 6-13. These figures are provided to show the trend and visual aid only. Specific data is taken from computer output files. Page 31
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Figure 6-4: Thermal Gradients at Selected Locations ( [ ]) Figure 6-5: Thermal Gradients at Selected Locations ( [ ]) Page 32
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Figure 6*6: Thermal Gradients at Selected Locations ( [ ]) Figure 6*7: Thermal Gradients at Selected Locations ( [ ]) Page 33
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Figure 6*8: Thermal Gradients at Selected Locations ( [ ]) Figure 6*9: Thermal Gradients at Selected Locations ( [ ]) Page 34
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Figure 6*10: Thermal Gradients at Selected Locations ( [ ]) Figure 6*11: Thermal Gradients at Selected Locations ( [ ]) Page 35
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Figure 6-12: Thermal Gradients at Selected Locations ( [ ]) Figure 6-13: Thermal Gradients at Selected Locations ( [ ]) Page 36
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) 6.3 Structural Analysis Nodal temperatures from the thermal analysis are input into the structural model within ANSYS. The time points selected for stress analyses are based on criteria such as pressure extremes, temperature gradient extremes as well as those of analytical interest. The time points of interest for the transient models are listed in Table 6-6 to Table 6-15. Stress analysis is performed for each of the listed time points. The ANSYS output files from the stress analysis are listed in Table 6-5. The ANSYS input files containing the transient pressure definitions tabulated in Reference [11] are: Table 6*4: Transient Pressure and Time Point Files Table 6*5: Structural Analysis Output Files Table 6*6: Time Points of Interest for [ ] Page 37
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Table 6*7: Time Points of Interest for [ ] Page 38
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Table 6-8: Time Points of Interest for [ ] Table 6-9: Time Points of Interest for [ ] Page 39
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Table 6*10: Time Points of Interest for [ ] Table 6*11: Time Points of Interest for [ ] Page 40
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Table 6-12: Time Points of Interest for [ ] Table 6-13: Time Points of Interest for [ ]
*Duplicate time points resulted due to rounding. While this affects the time stamp for each step, the correct thermal and pressure load is applied together at the required intervals.
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A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Table 6-14: Time Points of Interest for [ ] Page 42
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Table 6-15: Time Points of Interest for [ ]
~
Duplicate time points resulted due to rounding. While this affects the time stamp for each step, the correct thermal and pressure load is applied together at the required intervals.
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A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) 6.4 ASME Code Criteria The ASME Code qualification (Reference [2]) involves two basic sets of criteria:
1. Assure that failure does not occur due to the application of the design loads.

2. Assure that failure does not occur due to repetitive loading.
In general, the primary stress intensity criteria of the ASME Code assure that the design is adequate for application of the design loads. The ASME Code criteria for cumulative fatigue usage factor assures that the design is adequate for repetitive loadings. 6.4.1 ASME Code Primary Stress Intensity Criteria Per NB-32 13.8 of Reference [2], the primary stresses are those normal or shear stresses developed by an imposed loading such as internal pressure and external loadings. A thermal stress is not classified as a primary stress. The classification as well as the limit of primary stress intensity is specified in NB-3221 of Reference [2] for design condition. The limit of primary stress intensity of Level B (Upset), Level C (Emergency), Level D (Faulted), and Test Conditions are specified in NB-3223, NB-3224, NB-3224, and NB-3225 of Reference [2] respectively. The primary stress intensity criteria are the basic requirements in calculating the weld overlay size which is under the assumption that a 360 0 circumferential flaw has grown through the original weld. Loading conditions in each service level have been considered in the weld overlay sizing calculation. The nozzle to pipe region has been reinforced by the weld overlay since adding material to the nozzle outside region reduces primary stresses resulting from internal pressure and external loads. The overlay further reduces stress concentrations by eliminating the outside surface discontinuity. Therefore, the primary stress requirement for the nozzle, welds with overlay, safe end, and pipe have been satisfied for all service level loadings without the need for further evaluation. Other related criteria include the minimum required thickness (NB-3324 of Reference [2]), and reinforcement area (NB-3330 of Reference [2]), which were addressed in the original nozzle/cold leg designs. Adding weld overlay will increase the nozzle wall thickness, and therefore, these requirements are satisfied. 6.4.2 ASME Code Primary + Secondary Stress Intensity Range and Fatigue Usage Criteria The stress analysis for transient conditions is required for a component to satisfy the requirements for repetitive loadings. Computer runs for each transient time point selected for stress analysis are contained in the computer output files listed in Section 5.3. The overall stress profile is then reviewed to determine the critical locations that require detailed stress/fatigue analysis. The objective to assure that (1) the most severely stressed locations are evaluated and (2) the specified region is quantitatively qualified. Once the specific locations for detailed stress evaluation are established, the related path lines can be defined for input to ANSYS. ANSYS post-processor POST! is used to linearize stresses along the path lines. The path lines selected for primary plus secondary stress range calculation and fatigue failure evaluation are listed in Table 6-16. The approximate location of the full paths and partial paths is shown in Figure 6-14. Page 44
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Table 6-16: Path Lines for Linearized Stresses Inside Coordinate Outside Coordinate Material(l) _X y Z X Y Z Inside OutsiL Path 1(2) Path2 Path3 Path3a Path3b Path4 Path4a Path4b Path5 Path5a Path5b Path6 Path6a Path6b Path7 Path7a Path7b Path8(3) Path9 Path9a Path9b Path 10 PathlOa Path lOb Path 11 Pathlla
- I- -
Pathllb Path12 Path12a Path12b Pathl3 Path13a Path13b Path14(3) (l) Materials: [ ] (2) Node for the inside of Path 1 is selected 1 element in excluding the cladding. The affect is negligible as this is not a critical location. (3) Nodes on Path8 and Path 14 are selected to ensure that the highest Total stress ranges are obtained. Page 45
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Figure 6-14: Approximate Locations of Path Lines for Stress Analysis The definition of these path lines, linearized stress components, and stress intensity ranges (M+B and Total) for these paths are contained in the following output files: Table 6-17: Stress Intensity Ranges 6.4.2.1 Maximum Primary + Secondary Stress Intensity Range NB-3222.2 The enveloped external loads are listed in Table 4-7. These loads which cause periodic stress changes need to be included in calculating the maximum stress intensity ranges. Except for PATH 1 where the stress variation due to external loads is negligible, the stress intensities due to enveloping external load is calculated at all other path locations. The geometric characteristics of each cross section at these path locations are listed in Table 6-18. Page 46
A AREVA Document No. 32-9185635-001 PROPRIETARY TMI-1 Letdown Nozzle Weld Overlay Section III Analysis Where: D - Outside diameter (in) d - Inside diameter (in) I =~(D4 _d 4) - Moment of inertia (in4) 64 I S OD
=D/2 - - Section modulus of the nozzle: outside diameter (in3)
S =~ - Section modulus of the nozzle: inside diameter (in3) ID d/2 Table 6-18: Geometric Characteristics of Path Line Cross Section N ode Coordinates Node Coordinates (Inside) (Outside) X y Z X Y Z ID OD I SOD SID Path2 Path3
- - - - - I- - r- -
Path4/Path9 Path5/Path! 0 Path6 Path7 1
- !-- - f- - - - - -
Path8IPath142
- I- - i- - - - - -
Path 1 1
- i- - i- - - - - -
Path12 1
- i- - i- - - - - -
Path13 1 Note 1: The ID 0 the path is the same as the ID of the pp -thoIS ca1-1
1. e. T h e OD 0 fth e p a cu ate d as 2 th e-cf
_'-:c-* - Istance between the inside and outside nodes (2 '~(Xin - XOlll )2 + (Yin - Yo )2 ) + ID. lll Note 2: The ID and OD are the nominal dimensions of a [ ] . The membrane + bending stress intensities due to external loads are calculated as follows: Mb (J'ax_Mb =-S - Axial bending stress due to external bending moment (Mb) (ksi) r ___ MI
- Shear stress due to external torsion moment (Mt ) (ksi) sMI-2*S - Membrane + Bending stress intensity range (ksi)
Where S = SID for the inside diameter and SOD for the outside diameter. Stress intensities at the inside and outside nodes of the selected path lines are computed and listed in Table 6-19. Page 47
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Table 6-19: Stress Intensities due to External Loads (ksi) Inside Node Outside Node (jax Mb Ts Mt Sint (jax Mb Ts Mt Sint Path2 Path3 Path4/Path9 PathS/Path I ° Path6 Path7 Path8/Pathl4 Path I I Pathl2 Path I 3 The summary of maximum stress intensity ranges including extemalloads is listed in Table 6-20. As shown in Table 6-20, the 3S m Primary + Secondary stress intensity limit (NB-3222.2 of Reference [2]) has been met for all locations. Page 48
II A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Table 6*20: Membrane + Bending Stress Intensity Range Summary (ksi) Inside Node Outside Node Ext. Total Ext. Total M+B SI 3S m Limit M+B SI 3S m Limit Load SI M+BSI Load SI M+BSI Range @650°F Range @650°F Range Range Range Range Path I Path2
- I-- - - - I-- - I-- -
Path3
- r--- - - - r--- - I-- -
Path3a Path3b
- - - - - r--- - I-- - - - - - - - - I-- -
Path4
- - - - - - - I-- -
Path4a Path4b PathS Path5a
- - - I-- - - - - - - - - r--- - - - - -
Path5b
- - - r--- - - - - -
Path6
- - - I-- - - - - -
Path6a
- - - r--- - - - - -
Path6b
- - - r--- - - - - -
Path7
- - - r--- - - - - - - -
Path7a
- - - I-- - - - ,.-- - - -
Path7b
- r--- - r--- - - - r--- - - -
Path8
- r--- - r--- - r--- - I-- -
Path9
- r--- - - - I-- - I-- -
Path9a Path9b
- r--- - - - r--- - I-- - - r--- - - - r--- - I-- -
PathlO
- r--- - - - r--- - I-- -
PathlOa
- I-- - - - I-- - I-- -
PathlOb
- - - - - - - I-- -
Pathll Pathlla
- - - - - f-- - - - - - - - - r--- - - - - -
Pathllb
- - - r--- - - - - -
Path I 2
- - - r--- - - - - - - -
Pathl2a
- - - r--- - - - - - - -
Pathl2b
- - - I-- - - - - - - -
Path 13
- - - r--- - '-- - - -
Path13a
- r--- - r--- - f-- - - -
Path13b
- I-- - I-- - I-- - I-- -
Pathl4
Note: As documented in [ ] ,the maximum range is between [ ] ,time point 16 and [ ] ,
time point 20. The maximum temperature of those two time points is [ ] OF and is used to fmd the 3Sm allowable limit of [ ] ksi (= [ ] ). Page 49
II A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) 6.4.2.2 Fatigue Usage Factor NB-3222.4 In order to calculate the fatigue usage factors per Section NB-3222.4 of the ASME Code (Reference [2]), the total stress intensity ranges are computed and documented in the following ANSYS files: l J Total stress is used to ensure peak stresses are accounted for that may not be depicted in membrane plus bending stress intensity ranges. The summary of total stress intensity ranges for all paths is shown in Table 6-21. Since the extemalload stress intensity is calculated as the membrane + bending load a stress concentration factor is applied to them before being added to the transient total stress intensity range. Per Reference [14], a stress concentration factor for a bar with fillets between the transition is approximately [ ] for a member with an rid ratio [ ] . A review of the total stress ratio to membrane + bending stress at critical time points in the 1A transient produces a stress concentration ratio closer to [ ] . Therefore, a factor of [ ] is conservatively applied to the external loads. Page 50
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Table 6-21: Total Maximum Primary + Secondary Stress Intensity Range Summary (ksi) Inside Node Outside Node Ext. Total + Ext. Total + Total SI Total SI Load SI Ext. SI Load SI Ext. SI Range Range Path I
- Range Range Range Rang~
Path2 Path3 j Path3a 1 Path3b Path4 Path4a Path4b Path5 Path5a Path5b Path6 Path6a Path6b Path7 Path7a Path7b Path8 Path9 Path9a Path9b PathlO Path lOa Path lOb Pathll 1 Pathlla 1 Pathllb Pathl2 Pathl2a Pathl2b Pathl3 Pathl3a Pathl3b : Pathl4 Page 51
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Based on a review of the Stress Intensity range results in Table 6-20 the following paths will produce the highest cumulative fatigue usage factors (CFUF):
1. Path3/3a Inside Node for [ ] material [ ]

2. Pathl111la Inside Node for [ ] material [ ]

3. Path8 Outside Node for [ ] material [ ]

4. Pathl3b Inside Node for [ ] material [ ]
The CFUF values for these critical locations will bound the CFUF at all other locations. All selected locations use maximum Total stress intensity ranges and have a Ke value of 1.0. Note that only stress intensity ranges and corresponding transient extremes are taken from the output files listed previously in this section since stress intensities due to external loads are not included in the ANSYS output files. The maximum stress intensity due to external loads is conservatively added to every SI range except for the pipe and FSWOL locations. At the pipe and FSWOL locations (Table 6-24 and Table 6-25), the maximum SI range is added to the cycles from transients [ ] and [ ] [( ] ). For all other transients, the thermal range external loads listed in Reference [13] are added to the transient SI range since Note B of Reference [13] states that the thermal range is applicable to thermal transient cycles that are not associated with heat up and cool down. Per Reference [13], the thermal range external loads are half of the maximum external loads. Table 6-22 to Table 6-25 provide the calculation of the CFUFs based on the loads and cycles in Table 4-8. The values of Ecurve and allowable cycles are taken from Figures I-9.l and 1-9.2.1 and Table 1-9.1 of Reference [2]. Page 52
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Table 6*22: [ ] Material CFUF (Path3/3a) ANSYS File: [ ] Path: Path3/3a Inside Ke= 1.0 Material: [ ]
]
UTS (Su) (psi) = E curve (psi) = E mat! (psi @T=[ jOFF [ E mtio = E curvdE matI = [ ] Range Transients Req'd Allowable Usage Index Extreme Cycles SITotal SIExternal Salt Emtio X Salt Cycles Factor I 2 3 Table 6*23: [ ] Material CFUF (Path11/11a) ANSYS File: [ ] Path: Pathl1111a Inside Ke= 1.0 Material: [ ] jOF)~[ ] UTS (Su) (psi) = E curve (psi) = E matI (psi @T=[ E mtio = E curvdE matI = [ ] Range Transients Req'd Allowable Usage Index Extreme Cycles Shotal SIExternal Salt Eratio X Salt Cycles Factor I 2 3 Page 53
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Table 6-24: [ ] Material CFUF (Path8) ANSYS Pile: [ 1 Path: Path8 Outside 1<.,= 1.0 Material: r -:l UTS (Su) (psi) = E curve (psi) = E matl(psi @T=[ lOp) = E ratio = E curv.,lE mati = [ ] Range Transients Req'd Allowable Usage Index _Extreme Shotal SIExtemal* Salt Eratio X Salt Pactor Cycles Cycles 1 2 3 4 5 6 7 8 9
*Maximum external loads added to [ land [ 1.Thermal range external loads (half maximum) added to all other transients.
Table 6-25: [ ] Material CFUF (Path13b) ANSYS Pile: [ 1 Path: Path13b Inside 1<.,= 1.0 Material: [ UTS(Su)(psi@ T=[ lOp) = L - E curve (psi) = lOp) = E ratio = E curve/E mati = [ 1 E mati (psi @ T=[ Range Index Transients Extreme Req'd Cycles Shotal SIExternal* Salt E ratio X Salt Allowable Cycles Usage Pactor I 2 3
*Maximum external loads added to [ 1 and [ 1.Thermal range external loads (half maximum) added to all other transients.
Page 54
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) 7.0 RESUL TS/CONCLUSIONS Stress analysis and design qualification for the TMI-l cold leg letdown nozzle with weld overlay is performed in this calculation following the requirements of the ASME Code (Reference [2]). The TMI-l letdown nozzle with weld overlay satisfies the ASME Code primary and primary plus secondary stress requirements as well as the criteria for fatigue. The primary stress criteria are satisfied as described in Section 6.4.1. The primary plus secondary stress criteria and fatigue requirements are evaluated in Section 6.4.2. The summary of the maximum primary plus secondary, membrane + bending stress intensity ranges and fatigue usage factors are listed in Table 7-1. Table 7-1: M+B Stress Intensity Ranges and CFUFs Maximum M+B Range CFUFs Component Material (ksi) Calculated Allowable Calculated Allow~ Nozzle - Safe End / Safe End Welds - Pipe -
- - - i- I--- -
FSWOL Based on the loads and cycles specified in References [1], [11], and [12], the fatigue analysis performed in this calculation indicates that the maximum fatigue usage factor for the cold leg letdown nozzle weld overlay design is [ ]. Page 55
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary)
8.0 REFERENCES
1. AREVA NP Document 08-9182964-002, "TMI 'C' Cold Leg Letdown Nozzle Weld Overlay."

2. ASME Boiler and Pressure Vessel Code, Section III, Division 1,2004 Edition, No Addenda.

3. ANSYS Release 13.0 SP2, ANSYS Inc., Canonsburg, Pa.

4. AREVA NP Drawing 02-9185282C-000, "TMI Letdown Nozzle Existing Configuration."

5. AREVA NP Document 38-9187200-000, "Letdown Line Nozzle Field Data."

6. AREVA NP Drawing 02-8059673D-003, "TMI Letdown Nozzle Weld Overlay Design."

7. ASME Boiler and Pressure Vessel Code, Section II, Materials, 2004 Edition, No addenda.

8. ASME Boiler and Pressure Vessel Code, Section III, Division 1, 1965 Edition, including Addenda through Summer 1967.

9. AREVA NP Document NPGD-TM-500, Rev D, "NPGMAT-NPGD Material Properties Program User's Manual," March 1985.
1O. ASME Boiler and Pressure Vessel Code, Section III, Division 1, 1971 Edition.
11. AREVA NP Document 51-9187446-001, "TMI Letdown Nozzle Weld Overlay Design Transients."

12. AREVA NP Document 18-1173549-006, "Reactor Coolant System for Three Mile Island Unit One."

13. AREVA NP Drawing 02-l633l3E-03, "Reactor Coolant System Nozzle Loadings."

14. Popov, E.P., "Mechanics of Materials," Second Edition, 1976.
Page 56
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) APPENDIX A: PIPE THICKNESS COMPARISON A.1 Model Comparison Two models were created to compare the nominal pipe thickness of [ ] (thin model) with the maximum thickness measured by the NDE evaluation (Reference [5]) of [ ] (thick model). The only dimension changed between the two models was the pipe thickness. The rest of the dimensions around the Safe End to Pipe weld and the FSWOL were all allowed to land within the confines of the dimensions given in References [4] and [6]. Figure A-1: Pipe Thickness Difference Page A-1
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) The temperatures and pressures for transients [ ] and [ ] (Section 4.5.3) were applied to each model and the linearized stresses along the path lines shown in Section 6.4.2. The Membrane + Bending and Total stress intensities for each model are compared in Table A-2. Table A-I shows the summary of the maximum M+B and Total stress intensities for each material. It also list if the stress comes from the thick or thin model. As seen in Table A-I, most of maximum stresses are found in the thin model with the nominal pipe thickness. For the places where the maximum stress is found in the thick pipe mode, the maximum stresses in the thin pipe model are not significantly lower. Therefore, the nominal pipe thickness will be used for the full qualification as it bounds the thick model. Table A-1: Summary of Thin vs. Thick Comparison Controlling Controlling MaxM+B Max Total Material Path Pipe Material Path Pipe (ksi) (ksi) Thickness Thickness r-- Path 3 Thick Path 3/3a Thick I-- I-- Path lla Thin Path IlIIIa Thin Path 8 Thin Path 14 Thick r-- Path l3b Thin Path l3b Thin Page A-2
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) Table A-2: Thick VS. Thin Stress Intensities (ksi) Path M+B (ksi) M+B (ksi) Total (ksi) Total (ksi) Inside Nodes Outside Nodes Path Inside Nodes Outside Nodes Thin Thick Delta Thin Thick Delta Thin Thick Delta Thin Thick Delta Pathl Pathl
-- -I- - - -- - I- - -- -I- - I- -- - I- -
Path2 Path2
- -I- - - -- -I- - -- -I- - I- -- -I- -
Path3 Path3
- -I- -- - - -I- - -- -I- - I- - - -I- -
Path3a Path3a
-- -I- -I- -- -I- -
Path3b
-- -I- -i- -- -I- -
Path3b
-- -I- -- - - -I- - -- -I- - I- - - -I- -
Path4 Path4
-- -I- -- -- - I- - -- -I- - - -- -I- -
Path4a Path4a Path4b
- -- - - - c- - - -
Path4b
- - -- -- -- -I- - - I- -- - - - I- -- - -- -- - - -- -I- -
Path5 Path5
-I- -- -- - I- - - - - I- -- - - - - -- -
Path5a Path5a
-I- -- -- - I- -- - -I- -- - - - I-- -- -
Path5b Path5b
- I- -- -- - I- - - -
Path6
- I- - - - - - I-- --
Path6
-I- -- - - - I- -- - - I- -- -- -- -- -
Path6a Path6a
-I- -- -- - I- -- - - I- -- -- - I- -- -
Path6b Path6b
- I- -- -- - I- -- - - I- - - -- - I- --
Path7 Path7
-I- -- - i- -I- -- - -I- - - - I- - I- - -
Path7a Path7a
-I- -- - I- -I- - I- - -I- - I- - I- -I- --
Path7b Path7b
-- - c- - I- -- - I- - -- - I- - I- - I- --
Path8 Path8
-- - I- - I- -- - I- - -- - I- - I- -- - I- -
Path9 Path9 Path9a
-- - I- -I- -- - I- -
Path9a
-- - I- - I- -- - I- - -- - I- - I- -- - I- - -- - I- - I- - - - I- -
Path9b Path9b
-- - I- -I- -- - I- - -- - I- -I- -- - I- -
PathlO Path 10
-- - I- -- -- - I- - -- - I- -- -- - I- -
Path lOa PathlOa
-- - I- -- - - - - - -- - - -- -- - I- -
Path lOb Path lOb
-- - - - - - I- - - - - c- - - -- -- - I- -
Pathll Path 11 I- -- -- - I- -- - -I- -- - - - I- - - - Pathlla Pathlla Path11b
-I- -- - - -I- -- -
Path11b
-I- -- - ,... -I- -- - - I- -- - ,- - I- - ,- - - I- -- - I- - I- -- -
Path 12 Pathl2
-I- -- - I- -I- -I- - -I- -I- - I- -I- --
Pathl2a Pathl2a Pathl2b
-I- -- - ~ -I-- - - -
Pathl2b
-I- -- - I- - I-- - - - -I- -- -I- -- -I- -
Path 13
-I- -I- -I- -I- --
Path 13 Pathl3a
-I- -- -i- -- -I- -
Path13a
-- - I- -i- -I- -- - -- - I- -I- -- - I- - -- - I- -I- -- - I- -
Path13b Path13b
-- -I- - i- -- -I- - -- -I- - i- -- -I- -
Pathl4 Pathl4 Page A-3
A AREVA Document No. 32-9196160-000 TMI-1 Letdown Nozzle Weld Overlay Section III Analysis (Non-Proprietary) APPENDIX B: STRESSES FOR FRACTURE ANALYSIS B.1 Component Stresses for Fracture Analysis This section provides supplemental stress and thermal results of the transient analyses for the fracture mechanics analysis of the cold leg letdown weld overlay. For stress and temperature evaluation, the paths are defined through the nozzle at the weld overlay region. The locations are the same as those used in the main body of this calculation for the structural analysis shown in Figure 6-14. Table B-1 lists the new fracture path names. Table B*1: Paths for Fracture Mechanics Evaluation Fracture Path Name Structural Path Name FR 1 Path4 FR 2 Path5 FR 3 Path6 FR 4 Path9 FR 5 PathlO FR 6 Path I I The stresses are evaluated in the global coordinate system with the Y axis oriented along the nozzle axis, X in the radial, and Z in the hoop direction. The axial (Sy) stresses, hoop (Sz) stresses and temperatures are listed at [ 1 equidistant intervals ( [ 1 locations) along the path for all transients and time points. These equidistant intervals (distance along the path from the inside node) for all 6 paths are documented in ,,[ l". Output files containing the stresses (Sy and Sz) and temperature (T) values for all transients are listed in Table 5-2. The units of the tabulated data in the files are provided in Table B-2. Table B*2: File Names and Units of ANSYS Output ANSYS output Unit ANSYS Output File Name Where
is the name of the transient.
Data listed in the stress and temperature output fields are ordered as follows: Page B-1 Affidavit
AFFIDAVIT COMMONWEALTH OF VIRGINIA )
) ss.
CITY OF LYNCHBURG )
1. My name is Gayle F. Elliott. I am Manager, Product Licensing, for AREVA NP Inc. (AREVA NP) and as such I am authorized to execute this Affidavit.

2. I am familiar with the criteria applied by AREVA NP to determine whether certain AREVA NP information is proprietary. I am familiar with the policies established by AREVA NP to ensure the proper application of these criteria.

3. I am familiar with the AREVA NP information contained in the Calculation Summary Sheets (CSS) 32-9183944-002, entitled "TMI-1 Letdown Nozzle Weld Overlay Sizing Calculation," dated January 2013, 32-9185635-001, entitled "TMI-1 Letdown Nozzle Weld Overlay Section III Analysis," dated January 2013,32-9186192-001, entitled, "TMI Unit 1 Weld Residual Stress Analysis for CL Letdown Nozzle Weld Overlay," dated January 2013, and 32-9186194-001, entitled "TMI Unit 1 CL Letdown Nozzle DMW and Safe End Crack Growth Analysis," dated January 2013, and referred to herein as "Documents." Information contained in these Documents has been classified by AREVA NP as proprietary in accordance with the policies established by AREVA NP for the control and protection of proprietary and confidential information.

4. These Documents contain information of a proprietary and confidential nature and is of the type customarily held in confidence by AREVA NP and not made available to the public. Based on my experience, I am aware that other companies regard information of the kind contained in these Documents as proprietary and confidential.

5. These Documents have been made available to the U.S. Nuclear Regulatory Commission in confidence with the request that the information contained in these Documents be withheld from public disclosure. The request for withholding of proprietary information is made in accordance with 10 CFR 2.390. The information for which withholding from disclosure is requested qualifies under 10 CFR 2.390(a)(4) "Trade secrets and commercial or financial information."

6. The following criteria are customarily applied by AREVA NP to determine whether information should be classified as proprietary:
(a) The information reveals details of AREVA NP's research and development plans and programs or their results. (b) Use of the information by a competitor would permit the competitor to significantly reduce its expenditures, in time or resources, to design, produce, or market a similar product or service. (c) The information includes test data or analytical techniques concerning a process, methodology, or component, the application of which results in a competitive advantage for AREVA NP. (d) The information reveals certain distinguishing aspects of a process, methodology, or component, the exclusive use of which provides a competitive advantage for AREVA NP in product optimization or marketability. (e) The information is vital to a competitive advantage held by AREVA NP, would be helpful to competitors to AREVA NP, and would likely cause substantial harm to the competitive position of AREVA NP. The information in these Documents is considered proprietary for the reasons set forth in paragraphs 6(c) and 6(d) above.
7. In accordance with AREVA NP's policies governing the protection and control of information, proprietary information contained in these Documents have been made
available, on a limited basis, to others outside AREVA NP only as required and under suitable agreement providing for nondisclosure and limited use of the information.
8. AREVA NP policy requires that proprietary information be kept in a secured file or area and dfstributed on a need-to-know basis.

9. The foregoing statements are true and correct to the best of my knowledge, information, and belief.
SUBSCRIBED before me this day of ~ ,2013. ~~ Danita R. Kidd NOTARY PUBLIC, STATE OF VIRGINIA MY COMMISSION EXPIRES: 12/31/1*, Reg. # 205569 CcImmIsaIon BIpIrta 12131118 Regfatndlan' 205569}}

v t e Letter Sequence Response to RAI
TAC:ME9818, (Open)
Initiation Request, Request Acceptance Administration Withholding Request Acceptance Questions Answers 17 January 2013 Results Approval... Other: ML13134A467
MONTHYEAR2013-01-17 [Table View]

TMI-13-009, Response to Request for Additional Information - Relief Request RR-12-02 Re Installation of Full Structural Weld Overlay on Lower Cold Leg Letdown Nozzle Dissimilar Metal Welds & Alloy 600 Safe-End

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1.0 INTRODUCTION

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1.1 Purpose and Scope

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