ML053470476

Request for Authorization to Utilize Code Case N-513-2

ML053470476
Person / Time
Site:	Monticello, Palisades, Point Beach, Prairie Island, Duane Arnold
Issue date:	12/12/2005
From:	Weinkam E Nuclear Management Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-HU-05-24
Download: ML053470476 (22)

Text

Committed to Nuclear Excellence Nuclear Management Company, LLC December 12,2005 US Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Duane Arnold Energy Center Docket 50-331 License No. DPR-49 L-HU-05-24 10 CFR 50.55a Palisades Nuclear Plant Docket 50-255 License No. DPR-20 Point Beach Nuclear Plant Units 1 and 2 Monticello Nuclear Generating Plant Dockets 50-266 and 50-301 Docket 50-263 License Nos. DPR-24 and DPR-27 License No. DPR-22 Prairie Island Nuclear Generating Plant Units 1 And 2 Dockets 50-282 and 50-306 License Nos. DPR-40 And DPR-60 Request For Authorization To Utilize Code Case N-513-2 Pursuant to 10 CFR 50.55a(a)(3)(i), Nuclear Management Company, LLC (NMC) requests Nuclear Regulatory Commission (NRC) approval of the enclosed relief request for the In-service Inspection Program for the licensees identified above. Approval is requested to use the alternative requirements of Code Case N-513-2, "Evaluation Criteria for Temporary Acceptance of Flaws in Moderate Energy Class 2 or 3 Piping," in lieu of certain American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, IWA-4000 requirements. The use of the proposed alternative will provide an acceptable level of quality and safety, as described in Enclosure 1. A copy of Code Case N-513-2 is provided as Enclosure 2.

NMC requests approval by June 30,2006. NMC will use Code Case N-513-2 under the approved relief only until such time as the code case is published in a future version of the applicable Regulatory Guide as stated in 10 CFR 50.55a(b).

700 First Street Hudson, Wisconsin 54016 Telephone: 71 5.377.3300

Document Control Desk Page 2 Summarv of Commitments This letter contains no new commitments and no revisions to existing commitments.

Director, w e a r Licensing & Regulatory Services Nuclear Management Company, LLC Enclosures (2)

CC:

Administrator, Region Ill USNRC Project Managers, Duane Arnold Energy Center, Monticello Nuclear Generating Plant, Palisades Nuclear Plant, Point Beach Nuclear Plant, Prairie Island Nuclear Generating Plant. USNRC Senior Resident Inspectors Duane Arnold Energy Center, Monticello Nuclear Generating Plant, Palisades Nuclear Plant, Point Beach Nuclear Plant, Prairie Island Nuclear Generating Plant. USNRC

ENCLOSURE 1 REQUEST FOR AUTHORIZATION TO UTILIZE CODE CASE N-513-2 I. ASME Code Component(s) Affected ASME Section XI, Moderate Energy Class 2 and Class 3 Piping

2. Applicable ASME Section XI Code Edition and Addenda The applicabfe code editions are as follows:

Flaws that exceed the acceptance criteria of the above code editions/addenda are required to be accepted by either a repairlreplacernent activity or an analytical evaluation.

MMC Site Monticello Prairie Island Point Beach Palisades Duane Arnold

3. Applicable Code Requirements

The applicable code requirements are as follows:

Inservice Inspection 1995 Edition with the 1996 Addenda 1998 Edition with the 2000 Addenda ASME Section XI 1989 Edition CLASS 3 RepairlReplacement 2001 Edition 1998 Edition with the 2000 Addenda IWD-3000 states, "This article is in course of preparation. The rules of IWB-3000 may be used."

IWB-3132 provides four ways in which an inservice volumetric or surface examination may be accepted.

1998 Edition with the 2000 Addenda 1989 Edition 1989 Edition

1. IWB-3132.4, "Acceptance by Volumetric or Surface Examination"

2. IWB-3132.2, "Acceptance by Repair" 1998 Edition with the 2000 Addenda 1989 Edition 1992 Edition with the 1992 Addenda Page 1 of 8

3. IWB-3132.3, "Acceptance by Replacement"

4. IWB-3132.4, "Acceptance by Analytical Evaluation" IWB-3132.2 states, "Components whose volumetric or surface examination reveals flaws that exceed the acceptance standards listed in Table IWB-3410-1 shall be unacceptable for continued service until the additional examination requirements of IWB-2430 are satisfied, and the flaw shall be either removed by mechanical methods or the component repaired to the extent necessary to meet the acceptance standards of IWB-3000."

IWB-3132.3 states, "As an alternative to the repair requirement of IWB-3132.2, the component or the portion of the component containing the flaw shall be replaced."

IWB-3142 provides five ways in which an inservice visual examination may be accepted.

1. IWB-3142.7, "Acceptance by Visual Examination"

2. IWB-3142.2, "Acceptance by Supplemental Examination"

3. IWB-3142.3, "Acceptance by Corrective Measures or Repairs"

4. IWB-3142.4, "Acceptance by Analytical Evaluation"

5. IWB-3142.5, "Acceptance by Replacement" IWB-3142.3 states, "Components containing relevant conditions shall be acceptable for continued service if the relevant conditions are corrected or the components are repaired to the extent necessary to meet the acceptance standards specified in Table IWB-3410-1."

IWB-3142.5 states, "As an alternative to either the supplemental examinations of IWB-3142.2, the corrective measures or repairs of IWB-3142.3, or the evaluation of IWB-3142.4, the component or that part of the component containing the relevant condition shall be replaced."

CLASS 2 IWC-3122 provides four ways in which an inservice volumetric and surface examination may be accepted.

1. IWC-3122.1, "Acceptance by Examinationn

2. IWC-3122.2, "Acceptance by Repair"

3. IWC-3122.3, "Acceptance by Replacement

4. IWC-3122.4, "Acceptance by Evaluation" IWC-3122.2 states, "Components whose examination reveals flaws that exceed the acceptance standards listed in Table IWC-3410-1 shall be unacceptable for continued service until the additional examination Page 2 of 8

requirements of IWC-2430 are satisfied, and the flaw shall be either removed by mechanical methods or the component repaired to the extent necessary to meet the acceptance standards of IWC-3000."

IWC-3122.3 states, "As an alternative to the repair requirements of IWC-3122.2, a component or the portion of the component containing the flaw shall be replaced."

IWC-3132 provides four ways in which an inservice visual examination may be accepted.

1. IWC-3132.1, "Acceptance by Supplemental Examination"

2. IWC-3132.2, "Acceptance by Corrective Measures or Repairs"

3. IWC-3132.3, "Acceptance by Evaluation"

4. IWC-3132.4, "Acceptance by Replacement" IWC-3132.2 states, "Components containing relevant conditions shall be acceptable for continued service if the relevant conditions are corrected or the components are repaired to the extent necessary to meet the acceptance standards specified in Table IWC-3410-1."

IWC-3132.4 states, "As an alternative to the supplemental examinations of IWC-3132.1, the corrective measures or repairs of IWC-3132.2, or the evaluation of IWC-3132.3, a component or part of a component containing the relevant condition shall be replaced."

ASME Section XI 1995 Edition with the 1996 Addenda CLASS 3 IWD-3000 states, "This Article is in course of preparation. The rules of IWB-3000 may be used."

IWB-3132 provides three ways in which an insewice volumetric or surface examination may be accepted.

1.

IWB-3132.1, "Acceptance by Volumetric or Surface Examination",

2.

IWB-3132.2, "Acceptance by RepairJReplacement Activity", or

3.

IWB-3132.3, "Acceptance by Analytical Evaluation".

IWB-3132.2 states, "A component whose volumetric or surface examination detects flaws that exceed the acceptance standards of Table IWB-3410-1 is unacceptable for continued service until the additional examination requirements of IWB-2430 are satisfied and the component is corrected by a repairireplacement activity to the extent necessary to meet the acceptance standards of IW B-3000."

Page 3 of 8

IWB-3142 provides four ways in which an inservice visual examination may be accepted.

1. IWB-3142.1, "Acceptance by Visual Examination"

2. IWB-3142.2, "Acceptance by Supplemental Examination"

3. IWB-3142.3, "Acceptance by Corrective Measures or RepairlReplacement Activity"

4. IWB-3142.4, "Acceptance by Analytical Evaluation" IWB-3142.3 states, "A component containing relevant conditions is acceptable for continued service if the relevant conditions are corrected by a repairlreplacement activity or by corrective measure to the extent necessary to meet the acceptance standards of Table IWB-3410-1."

CLASS 2 IWC-3122 provides three ways in which an Inservice Volumetric and Surface Examinations may be accepted.

1. IWC-3122.1, "Acceptance by Examination"

2. IWC-3122.2, "Acceptance by RepairlReplacement Activityn

3. IWC-3122.3, "Acceptance by Analytical Evaluation" IWC-3122.2 states, "A component whose examination detects flaws that exceed the acceptance standards of Table IWC-3410-1 is unacceptable for continued service until the additional examination requirements of IWC-2430 are satisfied and the component is corrected by a repair/replacement activity to the extent necessary to meet the acceptance standards of IWC-3000."

IWC-3132 provides four ways in which an inservice visual examinations may be accepted.

I. IWC-3132, "Acceptance"

2. IWC-3132.1, "Acceptance by Supplemental Examination"

3. IWC-3132.2, "Acceptance by Corrective Measures or RepairlReplacement Activity"

4. IWC-3132.3, "Acceptance by Analytical Evaluation" IWC-3132.2 states, "A component containing relevant conditions is acceptable for continued service if the relevant conditions are corrected by a repairlre placement activity or by corrective measures to the extent necessary to meet the acceptance standards of Table IWC-3410-1."

Page 4 of 8

ASME Section XI 1998 Edition with the 2000 Addenda CLASS 3 IWD-3000 states, "This Article is in course of preparation. The rules of IWB-3000 may be used."

IWB-3132 provides three ways in which an lnservice Volumetric or Surface Examination may be accepted.

1. IWB-3132.1, "Acceptance by Volumetric or Surface Examination",

2. IWB-3132.2, "Acceptance by RepairlReplacement Activity", or

3. IWB-3132.3, "Acceptance by Analytical Evaluation".

IWB-3132.2 states, "A component whose volumetric or surface examination detects flaws that exceed the acceptance standards of Table IWB-3410-1 is unacceptable for continued service until the additional examination requirements of IWB-2430 are satisfied and the component is corrected by a repair/replacement activity to the extent necessary to meet the acceptance standards of IWB-3000."

IWB-3142 provides four ways in which an Insewice visual examination may be accepted.

1. IWB-3142.1 "~cce~tance' by Visual Examination"

2. IWB-3142.2 "Acceptance by Supplemental Examination"

3. fWB-3142.3 "Acceptance by Corrective Measures or RepairlReplacement Activity"

4. IWB-3142.4 "Acceptance by Analytical Evaluation" IWB-3142.3 states, "A component containing relevant conditions is acceptable for continued service if the relevant conditions are corrected by a repair/repIacement activity or by corrective measure to the extent necessary to meet the acceptance standards of Table IWB-3410-1."

CLASS 2 IWC-3122 provides three ways in which an lnservice Volumetric and Surface Examinations may be accepted.

1. IWC-3122.1, "Acceptance by Examination"

2. IWC-3122.2, "Acceptance by RepairJReplacernent Activity"

3. IWC-3122.3, rrAcceptance by Analytical Evaluation" IWC-3122.2 states, "A component whose examination detects flaws that exceed the acceptance standards of Table IWC-3410-1 is unacceptable for continued service until the additional examination requirements of IWC-2430 Page 5 of 8

are satisfied and the component is corrected by a repairlreplacernent activity to the extent necessary to meet the acceptance standards of IWC-3000."

IWC-3132 provides four ways in which an inservice visual examination may be accepted.

I.

IWC-3132, "Acceptance"

2. IWC-3132.1, "Acceptance by Supplemental Examination"

3. IWC-3132.2, "Acceptance by Corrective Measures or Repair/Replacernent Activity"

4. IWC-3132.3, "Acceptance by Analytical Evaluation" IWC-3132.2 states, "A component containing relevant conditions is acceptable for continued service if the relevant conditions are corrected by a repairlreplacement activity or by corrective measures to the extent necessary to meet the acceptance standards of Table IWC-3410-1."

4. Reason for Request

Relief is requested from replacement or internal weld repair of wall thinning conditions resulting from various wall thinning degradation mechanisms such as erosion, corrosion, cavitation, and pitting in moderate energy Class 2 and 3 piping systems in accordance with the design specification and the original construction code. The use of Code Case N-513-2 will provide an acceptable method to evaluate flaws on a temporary basis until the next scheduied outage.

5. Proposed Alternative and Basis for Use

The Nuclear Regulatory Commission in Regulatory Guide 1.147, "Insewice Inspection Code Case Acceptability," Revision 14, has accepted Code Case N-513-1 with the following limitations:

Specific safety factors in paragraph 4.0 must be satisfied.

Code Case N-513 may not be applied to:

i. Components other than pipe and tube.

ii. Leakage through a gasket iii. Threaded connections employing nonstructural seal welds for leakage prevention (through seal weld leakage is not a structural flaw; thread integrity must be maintained).

iv. Degraded socket welds Page 6 of 8

Code Case N-513-1 permits flaws in Class 2 and 3 moderate energy piping on a temporary basis until the next outage if it can be demonstrated that adequate pipe integrity and leakage containment are maintained. The Code Case is currently applicable to part-through and through wall planar flaws and part-through nonplanar flaws. Service experience has shown that some piping can suffer degradation from nonplanar flaws, such as pitting and microbiological attack, where local inconsequential leakage can occur.

The Code Case can be used for nonplanar through-wall flaws but in a restrictive situation where nonplanar geometry is dominant in one plane.

Some plants have used the intent of N-513 for nonplanar leaking flaws; however, relief requests from code requirements are still required because of the stated limited scope of N-513 in section 3.0 of the Code Case. The Code Case was revised (N-513-2) to extend the application to cover all types of nonplanar flaws. The analysis procedures were expanded to address the generai case of through-wall degradation. Code Case N-513-2 has broader applications and therefore has a real direct benefit for operating plants.

Code Case N-513-2 includes the incorporation of the improved flaw evaluation procedures for piping that are provided in the new Appendix C of Section XI in the 2002 Addenda.

Code Case N-513-2 addresses the limitations posed in Regulatory Guide 1.A47 as follows:

1 Paragraph 4.0 was revised to incorporate references to Appendix C for acceptance and eliminated the provision that lower safety factors may be used.

2. I

.O(a) was revised to limit the application of the code case as specified in the limitation applied in Regulatory Guide 1.147.

NMC considers the proposed alternative of using Code Case N-513-2 to provide an acceptable level of quality and safety in accordance with 10 CFR 50.55a(3)(i).

6. Duration of Proposed Alternative

NMC requests approval of Code Case N-513-2 to be used for each plant's 10-year iSI interval (see table 1 below) or until the NRC publishes Code Case N-513-2 in a future revision of Regulatory Guide 1.147. Upon incorporation into the Regulatory Guide, NMC will review and follow the conditions specified. All other ASME Code,Section XI requirements for which relief was not specifically requested and authorized by the NRC staff will remain applicable including third party review by the Authorized Nuclear Inservice Inspector.

Page 7 of 8

7. Precedent Plant Monticello Nuclear Generating Plant 50-263 Prairie Island Nuclear Generating Plant 50-282 (Unit 1 ) & 50-306 (Unit 2)

Point Beach Nuclear Plant Units I

& 2 (50-266 &

50-301 )

Palisades Nuclear Plant 50-255 Tennessee Valley Authority (TVA) submitted a relief request pursuant to 10 CFR 50.55a(a)(3)(i), for Browns Ferry Nuclear Plant, Units I, 2 and 3; Sequoyah Nuclear Plant, Units 1 and 2; and Watts Bar Nuclear Plant, Unit ?,

dated November 23,2003 (ADAMS Accession #ML033320222). TVA requested relief from using the specific formula in Code Case N-513, for the maximum allowable flaw width when planar flaw evaluation rules may be applied. As an alternative, TVA proposed the use of the formula for maximum allowable flaw width from Code Case N-513-1, with applicable errata while retaining the use of all the other provisions and requirements in Code Case N-513. The NRC approved this relief request by letter October 6, 2004 (ADAMS Accession #ML042150438). The TVA relief request is similar to the NMC relief request in that the request involves Code Case N-513. However, NMC is requesting relief to use Code Case N-513-2, which incorporates the limitations specified in Regulatory Guide 1.I47 on Code Case N-513-1. In addition, Code Case N-513-2 added a procedure for evaluating non-planar through-wall flaws in moderate energy piping. This revision also includes the improved flaw evaluation procedures for piping added to Section XI, Appendix C, in the 2002 Addenda.

Page 8 of 8 Applicable ASME Section XI 1995 Edition with the A996 Addenda 1998 Edition with the 2000 Addenda 1998 Edition with the 2000 Addenda 1989 Edition IS1 Interval Fourth Fourth Fourth Third Duane Arnold Energy Center 50-331 Interval Dates 05/0'l103 - 05/31 11 2 12/21 104 - 1 2/20/14 07/01 102 - 06/30/12 0511 2/95 - 1211 2/06 Third 1989 Edition 11/01196 - 10131106

ENCLOSURE 2 ASME CODE CASE N-513-2, "EVALUATION CRITERIA FOR TEMPORARY ACCEPTANCE OF FLAWS IN MODERATE ENERGY CLASS 2 OR 3 PIPING" 11 Pages Follow

CASES OF A S m BOlLERhND PRESSURE VESSEL CODE CASE M-5 % 3-2 Approval Date: kbrusry 20,2004 See Numerri: Index for explmtion end any reaifimetion dates.

Case N.513-2 Eyaluntion Criteria for 'femporary Acceptance of Flaws in Moderate Energy Class 2 or 3 Piping Section XI, Division 1 Inquiry: What requirements may be used for tempo-rary acceptance of Raws, including through-wall flaws, in moderate energy Class 2 or 3 piping, without performing a repairlreplacement activity?

Reply: 11 is the opinion of the Cornminee that the following requirements may be used to accept Raws, including through-wall flaws, in moderate energy Class 2 or 3 piping, without performing a repairireplacement activity for a limited time, not exceeding the time to the next scheduled outage.

1.0 SCOPE (a) These ~equirements apply to the ASME Secrion TII, ANSI B31.1, and ANSI B31.7 piping, cIassified by the Owner as CIass 2 or 3. The provisions of this Case do not apply 10 the following:

(1) pumps, valves, expansion joints and heat ex-changers; (2) socket welds; (3) leakage through a flange joint:

(4) threaded connections employing nonsbuctural seal welds for leakage protection.

(6) The provisions of the Case apply to Class 2 or 3 piping whose maximum operating temperature does not exceed 200°F (93OC) aid whose maximum operating pressure does not exceed 275 psig (1.9 MPa).

k) The Following flaw evaluation criteria are permit-ted for pipe and tube. The fiaw evaluation criteria are permitted for adjoining fittings and flanges to s distance of (&t)" from the weld centerline.

(d) Tile provisions of this Case demonstratc the integ-rity of the item and not the consequences of leakage. It is the responsibility of the Owner to demonstrate system operability considering effects of leakage.

(a) The Raw gconletry shall be characterized by volu-metric inspection methods or by physicaI measurement.

The fuB pipe circumference at the flaw location shall be inspected to characterize the tength and depth of all flaws in the pipe section.

{b) Flaw shall be classified as plnnar or nonplanar.

(c) When multiple flaws, including irregular (com-pound) shape flaws, are detected, the interaction and com-bined area loss of fiaws in a given pipe section shall bc accounted for in the flaw evaluation.

(df A flaw evaluation shalI be performed to determine the conditions for flaw acceptance, Scction 3.0 provides accepted methods for conducting the required analysis.

(e) Frequent periodic inspections of no more than 30 day intervds shall be used to detezmine ifflaws are grow-ing and to establish the time at which the detected flaw willreach the allowable size, Alternatively, aflaw grow&

evaIuation may be performed to predict the time at which the detected flaw will grow to the allowable size. The flaw growth analysis shall consider the relevant growth mechanisms such as general corrosion or wastage. fa-tigue, or sttess corrosion cracking. When a fiaw growth analysis is used to establish the allowable time for tempo-rary operation, periodic examinations of no more than 90 day intervals shall be conducted to verify thc Raw growrh analysis predictions.

@ For throughwall leaking flaws. leakage shall be observed by daily walkdowns to confirm the analysis conditions used in the evaluation remain valid.

(gf If examinations reveal flaw growth rate to bc unoc-ceptable, a repair or replacement shall be performed.

BJ Repair or replacement shall be performed no later than when the predicted flaw size from either pen'odic inspection or by flaw growth analysis exceeds the acccpt-ance Miteria of 4,0, or the next scheduled outage, which-ever occurs first. Repair or repIscement shall be in accor-dance with IWA-4000 or IWA-7000, respectiuely, in Editions and Addenda prior to tl~e 1991 Addenda; and, in the 1991 Addend11 and later, in accordance with WA-4000.

The Commiltee'a funclion is to oslabllrh mlas or slaty. ~~ileIRp only lo procsuro inlegdty, govemlng cha corutnrctlon of bbn7.r~. prcrrura vcssals, u e n s p ~

ranks and nucIearcPmjmnent$, and ~nservico inspoclion for prsauro fnlclgrily of nurlanr componmn and iranspon bnb, and to I~srpral thoso rulos whon quertlanr adso reganUnptholrintcnLThit Codedoes notaddrsrsa~erssfo(yi*;uesRlnrin#torhaconwrucltan of bpilars, prersur@vas~ls,trsospor~

ten$ and nuclcm cornpormnrr.

and the lnrawb lnrpeaion of nudenr wmDenum$ and Ifansporc ranks. Tha umr of tho Cado should mnf-to ollwr osnlnenl cotlo.. vtundnrde. law..

rcguIodonr or mntr relevam oocumrna 1 (W.513-2)

SUPP. 1 -

NC I Reprinted from ASME 2004 Editian Code Cases, Nuclear Components, by permission of The American Society of Mechanical Engineers. All rights reserved.

CASE (continued)

!!!-5 1 3-2 CASES OF ASME BOILm AND PRESSURE VESSEL CODE

{b} For planar Baws in austenitic piping, the evaluation procedure in Appendix C shall be used. Flaw depths up to 100% of wdl thickness may be evaluated. When through-wall circumferential flaws are evaiuated, the for-mulas for evaluation given in C-5320 of Appendix C may be used, with the Raw penetration (olf) qua1 to unip.

When through-wall axial flaws are evaluated, the allow-able flaw length is:

I q = (S, + S,)/2 (3) la) Circumferential Flaw where FIG. 1 THROUGH-WALL FLAW GEOMETRY (i] Evaluations and examination shall be documented in accordance with IWA63M1. The Owner shall docu-ment the use of this Case on the applicable data report form.

3.0 FLAW EVALUATION (a) For planar flaws, the flaw shaII be bounded by a rectangular or circumferential planar area in accordance with the methods described in Appendix C. IWA-3300 shall be used to determine when multiple pmximate Raws axe to be evaluated as a single fiaw. The. geometzy of a through-wall planar flaw is shown in Fig. 1.

p = pressure for the loading condition Do = pipe outside diameter a f = flow S h S S S, = Code specified yield strength S, = Code specified ultimate tensile strength and SF, = structural factor on primary rncmbrane stress as specified in G2622 Materid properties at the temperamre of interest shall be used.

(c) For planar flaws in femtic piping, the evaluation procedure of Appendix C shall be used. Raw depths up to 100% of wall thickness nay be evaluated. When through-wall circumfercntid Raws are evaluated in accor-dance with C-5300 or (2-6300, the flaw penetration (alt) shall be set to unity. When through-wall axial fiaws ore evaluated in accordance with C-5400, the aflowable length is defined by Eqs. (1) through (3), with the appro-priate stmctural factors from Appendix C, C-2622. When through-wall flaws are evaluated in accordance with C-7300 or C-7400, the fonnulas for evaluation given in C-4300 may be used, but with values for F,, Fb, and F applicable to through-wall flaws. Relations For F,, Fb, and F that take into account ff aw shape and pipe geometry (R/t ratio) shall be used. The appendix to this Case pro-vides cquations for F,, Fb, and F for a selecled range of Rit. Gcometry of a through-wall crack is shown in Fig. I.

(dl For nonplanar Raws. the pipe is acceptable when the remaining pipe thickness (I,,) is greater than or equat to the minimum wall thickness bi,:

where p = maximum operaling pressure at Raw location I

Reprinted from ASME 2004 Edition Code Cases, Nuclear Components, by permission of The American Society of Mechanical Engineers. All rights reserved.

CASE (continued)

CASES OF ASME BOnER AND PRESSURE VESSEL CODE hl-5 'I 3-2 I

Transverse (circumferential) direction FIG. 2 ILLUSTRATION OF NONPLANAR FLAW DUE TO WALL THINNING S = allowable slress at operating ternperamre and theIongitudinal stress limits for theconstruction Code are satisfied for a uniform wall thickness equal to t, Alternatively, an evaluation may be. perfanned as given below. The evaluation procedure is a function of the depth and the extent of the affected area as illustrated in Fig. 2

( I ) Whcn the width of wall thinning W,,,

fhat ex-ceeds I,,,

is less than or equal to 0.5 ( ~ ~ t ) ".

where R,,

is the outside radius and Wm is defined in Fig. 2, the Raw can be classified as a planar flaw and evaluated in accordance with 3.01a) through 3.01~). above. When the above requirement is not satisfied, (2) shall be met.

(2) When the transverse extent of wall thinning that exceeds t,;,, LmI,],

is [lot grater than (R,~,E)\\

tdK is determined from Curve I of Fig. 3, where Lfif0 is defined in Fig. 2. When the above requirement is not satisfied, (3) shall be met.

(3) When the maximum extent of wall thinning that exceeds t,,,

L,, is less than or equal to 265 ( ~, t,,, ~ ) ~

and in, is greater tlian 1.13rmh, fOl, is determined by satisfying both of the following equations:

When the above requirements are not satisfied, (4) shall be met.

(4) When ffw requirements of (1). (2), and (3) above are not satisfied, t,loc is determined from Curve 2 of Fig.

3. In addition, t,~., shall satisfy the foIIowing equation:

where q is the nomind pipe Iongitudinal bending stress resulting from at1 primary pipe loadings.

I Repfinted from ASME 2004 Mition Code Cases, Nuclear Componsnts, by permission ofThe American Society of Mechanical Engineers. Afl rights reserved.

CASE (continued)

!Yu!513-2 CASES OF ASME BOEER AND PRESSURE VESSEL CODE FIG. 3 ALLOWABLE WALL THICKNESS AND LENGTH OF LOCALLY THINNED AREA (e) When here is through-wall penetration along a portion of the thinned wall, as iIIustrated in Fig. 4, thc

.flaw may be evaluated by the branch reinforcement method. The thinned area including the through-watl pen-etration shdl be represented by a circular opening at the flaw location. Only the portion of the flaw lying within

~dj need be considered as illustrated in Fig. 5. When evaluating multiple flaws in accordance with IWA-3330, only the paions of the flaws contained within t d need be considered.

The minimum wall thickness, t ~,,,

shall be determined by Eq. (4). For evaluation purposes, the adjnsted wall Uckness, tdj, is the postulated thickness as shown in Fig. 5. The pipe wall thickness is defined as the thickness of the pipe in the non-deg~aded region as shown in Fig.

5Ca). The diameter of the opening is equal to de# as defined by as shown in Fig Sla). The postulated value for ldj shall be greated than imi, and shall not exceed the pipe wall thickness. The rdj value may bevaried betwecn t,,,, and the pipe wall thickness IO determine whether there is a combination of id& and ddj that satisfies the branch reinforcement requirements.

The required anrc reinforcement for the postulated cir-cular opening, da6 and id, as illusa-ared in Fig. S(b),

shoI1 be calculated in accordance with NC-36433 or ND-3643.3, as appropriate. If a Raw growth analysis is performed, the growth in flaw dimensions shail consider the degradation mecI~anism(s) as reIevant to the applica-tion. The flaw is acceptabtc when them is sufficient thick-ness in the degraded area to provide the rquired area reinforcement. Co~npliance with the primary strcss limits OF the Construction Code shaU be verified. The flow area of the flaw, or the total ofthe Row arcas of multiple Aaws that arc combined into a single flaw for the purpose of evaluation, shall not exceed the lesser of the Row area of the pipe or 20 in.' (130 cm2}.

fl Alternatively, when there is through-wall penetm-tion along a portion of the thinned wall as illustrated in Fig. 4 the Flaw may be evaluated as two independent planar through-wall flaw-one oriented in the axial direc-tion and the othet oriented in the circumferential direc-tion. The minimum wall thickness t,~~, shall be dcter-mined by Eq. (4). The through-wall ienghts for each flaw are the lenghts L&,,, and LC!,, where the local wall rhickness is equal to [,,,I, as projected along tile axial and circumferential planes as shown in Fig. 4. The two planar flaws so constmcted shall be evaluated to 3.0(a) and 3.0@) or 3.0(c), as appropriate. If a flaw growth analysis is performed, the growth in flaw dimensions shaIl con-sider both corrosion aod crack-growth mechanisms as relevant to the application. The Aow area of the flaw, or the told of the flow areas of multiple flaws that me combined into a single flaw for the purpose of euduation, shall not exceed the lesser of the Bow area of h e pipe or 20 in.' (130 cmz).

(gj In performing a flaw growth andysis, the proce-dures in C-3000 may be used as guidance. Relevant growth rate mechanisms shall be considered. When stress corrosion cracking (SCC) is active, thefoIlowing growth rate equation shall be used:

SUPP. 1 -

NC 4 (N-513-2) whcs da/dr is flaw growth rate in incheshour, K,,

is the maximum stress intensity factor under ioag-term I Reprinted from ASME 2004 Edition Code Cases, Nuclear Components, by permission of The American Society of MechanicaJ Engineers. All rights reserved.

CASE (contlnudl CASES OF ASME BOILER AND PRESSURE YESSEL CODE N-5 13-2 Through-wall

/ penetration Transverse (circumferential) direction FIG. 4 1LLUSTRATION OF THROUGH-WALL NONPLANAR FLAW DUE TO WALL THINNING 5 (N-513-2)

SUPP. 7 - NC Reprinted from ASME 2004 Edition Code Cases, Nuclear Components, by permission of The American Society of Mechanical Engineers. All rights resewed.

CASE (continued]

N-513-2 i3iSES on ~

M E

Bo~I.,ER m PRESSORE VESSEL C O W f hrough-waif

/ penetration lo1 Adjrartd Walt Thfckness FIG. 5 ILLUSTRATION OF ADJUSTED WALL THICKNESS AND EQUIVALENT HOLE DIAMETER SUPP. t -

NC 6 (N-513-2)

Reprinted from ASME 2004 Edition Code Cases, Nuclear components, by permission of The American Society of Mechanical Engineers. All rights reserved.

CASE (continued) c. 4 ~ ~

OF AS~DS BOILER AND PRESSURE YBSEL. CODE N-5 1 3-2 steady state conditions in ksi in. 0.5 ST is a temperature or, if fewer than five, aII susceptible and accessible loca-correction factor, and C and n are material constants.

tions shall be examined within 30 days of detecting the For intergranular SCC in austenitic steels, where T 5 20O0F (93°C).

For transgranular SCC in austenitic steels, where T S 2OO0F ( 9 3 O C ).

The temperature T is the metal temperature in degrees Fahrenheit. The Raw growth rate curves for the above SCC growth mechanisms are shown in Figs. 6 and 7.

Other growth rate parameters in Eq. 8 may be used, provided they are supported by appropriate data.

(Ii) For nonferrous materials, nonpIanar and planar flaws may be evaluated following the generat approach of 3.0(a) through 3.0(g) above. For pIanar flaws in ductile materials, thc approach given in 3.0(b) and 3.0(g) may be used; otherwise, h e approach given in 3.0(c) and 3.0(g) should be applied. StruceraI factors provided in 4.0 shall be used. It is the responsibility of h e evaluator to establish conservative estimates of strength and fracture toughness for the piping material.

4.0 ACCEPTANCE CRITERIA Piping containing a circumferential planar flaw is ac-ceptable for temporary service when flaw evaluation pro-vides a margin using the structu~al facrors in ~ ~ ~ e i d i x C, C-2621. For axid planar flaws, the structural factors for temporary acceptance are as specified in Appendix C, C-2622. Piping containing a nonplanar part through-wall flaw is acceptable for temporary service if $, > fatm where Idlo, is determined from 3.0(d). Piping containing a nonplanar through-wall flaw is acceptable for temporay service when the Raw conditions of 3.0(e) or 3.OQ are satisfied.

5.0 AUGMENTED EXAMINATION flaw.

(b) When a flaw is detected, an additional sample of the same size as defined in 5(a) $hail be examined.

(c) This process shaIl be repeated within 15 days for each successive sample, until no significant Raw is de-tected or until 10% of susceptible and accessibIe loca-rions have been examined.

6.0 NOMENCLATURE C = coefficient in !he crack growth relationship D, = outside pipe diameter F = nondimensionaf stress intensity factor for through-wall axial flaw under hoop s m s

% = nondimensional stress intensity factor for through-wall circumferential Raw under pipe bending skess F,,, = nondimensional stress intensity factor for through-wali circumferential flaw under membrane stress L = maximum extent of a Iocal thinned area with t < fnom L

= length. of through-wall crack for the hole pen-etration in the axial direction of the pipe Lei, = length of through-wall crack for the hole di-ameter penetration in the circumferential di-rection of the pipe

& = maximum extent of a bcal thinned area with t < fmin LmW = axial extent of wall thinning below rmh L4, = circumferential extent of wall thinning below t,,,,

R = pipe radius Rv = outside pipe radius S = allowable stress at opcnting temperature 5% = structuraI factor on primary membrane stress ST = coefficient for temperature dependence in the crack growth relalionship S,, = Codasaecified ultimate tensile strengm Sy = Code-specified yield strength w,, = maximum extent of a local thinned mea per-An augmented volumetric examination or physical pendicutar lo L,, with I < f,a measurement to assess degradation of the affected system c = half crack Iength shall be performed as follows:

d&

= flaw growth rate for stress corrosion cracking (a) From theengineering evaluation, tltc most suscep-d4 = diameter equivalent circular hole at t,dj tible locations shall be identified. A sample size of nt dmm = diameter of equivalent circular hole at t,,rl,,

least five of the most susccptibie and accessible locations.

+

= total crack length = 2c 7 (h"Si3-2)

SUPP. I -

NC I

Reprinted from ASME 2004 Edition Code Cases, Nudear Componenis, by permission of The American Society of Mechanical Engineers. All rights reserved.

CASE (continued)

N-53 3-2 CASES OF ASME BOILER AND PRESSURP.

VESS~

CODE

= allowable axial through-wall flaw length n = exponent in the crack growth relationship P = maximum operadog pressure at ff aw location t = wall thickness t 4 = adjusted wall thickness which is vacitd for evaluation purposes in the evaluation of a through-wall nonplanar Haw fnh = allowable local thickness for anonplanar flaw t~ = minimum wall thiclmess required for pres-sure loading i

= nominal wail thickness I, = minimum remaining wall thickness A = nondirncnsional half crack length for lhrough-watl axif flaw q = materid flow stress a h = pipe hoop stress due to pressure

= nominal longitudinal bending stress for pri-mary loading without stress intensification factor Q = half crack angle for through-wall circumfer-entiaI Raw This Case is applicable from the 1983 Edition with the Winter 1985 Addenda through the 2001 Edition w i ~

the 2003 Addenda. References in this Case to Appendix C shalI mean Appenidx C of the 2002 Addenda. For editions and addenda prior to 2092 Addenda, Class I pipe flaw evaluation procedures may be used for othcr piping ciasscs. As a matter of definition, the term "smcturaI factor" is equivalent to the tern "safety factur" that is used in earlier editions and addenda.

SUPP. t -

NC 8 ( M 3 - 2 )

I Reprinted from ASME 2004 Edition Code Cases, Nuclear Components, by permission of The American Society of Mechanical Engineers. All rights reserved.

GENERAL NOTE:

CASE (continued)

CASES OF ASME BOILER A.Nil PRESS^^ vES.SEL CODE N-5 1 3-2 Stress tntensity Factor, Kfksi in.o.*l 6 1 conversion: 1.0 inhr = 7.06 x 10.'rnm/sec; 1.0 Ksf 1t1.O.~ = 1.099 MPa moS; 'C = fCF - 3231.8).

FIG. b FLAW GROWTH RATE FOR IGSCC IN AUSTENlTlC PIPING 9 (N-513-2)

SUPP. 1 -

NC I

Reprinted from ASME 2004 Edition Code Cases, Nuclear Components, by permission of The American Society of Mechanical Engineers. All rights reserved.

CASE (continued)

N-5 9 3-2 CASES os AsME BOILER AND wSBS~RE VeSsEL CODE io Stress Intensify Factor, KIksi inP.5)

GENERAL NOTE: IS1 conversion: 1.0 inhr = 7.06 x lw3 mmlsec; 1.0 Ksi in?,' = 1.099 MPa moS; 'C = CaF - 32YL8).

FIG. 7 FLAW GROWTH RATE FOR TGSCC IN AUSTENITIC PIPING SUFP. 1 -

NC 10 (N-513-2)

I Reprinted from ASME 2004 Edition Code Cases, Nuclear Components, by permission of The American Society of Mechanical Engineers. All rights reserved.

CASE (continued}

CASES OF ASME BOILER AND PRESSURE YESSEL CODE No5 1 3-2 RELATIONS FOR F,, Fb, AND F FOR TmOUGH-WALL FLAWS

+ 0.001601 1 (Nt13 Far (hmugh-waU mck depUI be 4 = 11.36322 - 3.91412

.+ 0.18619 (R/~)'

replaced with half crack length (c) in the s@ss intensity factor equalions in C-7300 and C-7400 of Section XI,

- 0.004099 (RI~)?

Appendix C Also. Q will be set equaI to unity in (2-7400.

Cb = -3.1 8609 + 3.84763 (RI!) - 0.18304 ( R A ) ~

+ 0.00403 (~lt)'

Equations for F, and Fb are accurate for Rlt bemcen 1-2.0 CIRCUMl?EXENTIAL FLAWS 5 and 20 and become increasingly conservative for Rli For a range of Rlt between 5 and 20, fol]owing grcater than 20. Alternative solutions for Fm and Fb :bay equations for F, and Fb may be used:

be used when R/t is greater than 20.

where Q = Half mck angle = c/R R = Mean pipe radius r = Pipe wall thickness and A, = -2.02917 + 1.67763 (R/t) - 0.07987 ( ~ / i ) ~

+ 0.00176 (l3fl3 B, = 7.09987 - 4,42394 (Rlr) +- 021036 (f?/tl2

- 0.00463 ( ~ i i f ~

c, = 7.79661 t 5.16676 ( R I ~ ) - 0.245n

( R / I ) ~

+ 0.03541 (!?It)'

1-3.0 AXfAL FLAWS For internal pressure loading, the following equation for F may be used:

where c = half crack lengrh A = c/(~t)'~

The equation for F is accurate for A between O and 5.

Alternative solutions for F may be used when A is greater than 5.

I Reprinted from ASME 2004 Edition Code Cases, Nuclear Components, by permission of The American Society of Mechanical Engineers. All rights reserved.