ML12335A476: Difference between revisions
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Revision as of 20:23, 1 March 2020
| ML12335A476 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 12/31/2008 |
| From: | Electric Power Research Institute |
| To: | Atomic Safety and Licensing Board Panel |
| SECY RAS | |
| References | |
| RAS 21618, 50-247-LR, ASLBP 07-858-03-LR-BD01, 50-286-LR, 1016596 | |
| Download: ML12335A476 (60) | |
Text
{{#Wiki_filter:United States Nuclear Regulatory Commission Official Hearing Exhibit NYS00307C Entergy Nuclear Operations, Inc. Submitted: December 22, 2011 In the Matter of: (Indian Point Nuclear Generating Units 2 and 3) c:..\,.~""R REGlI~;. ASLBP #: 07-858-03-LR-BD01
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Docket #: 05000247 l 05000286 Exhibit #: NYS00307C-00-BD01 Identified: 10/15/2012
- 0 Admitted: 10/15/2012 Withdrawn:
~ ~ Aging Management Requirements
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Guide Lug P late Top Plate Ring Brace Rib Bottom Plate Figure 4-13 CE welded core shroud with full height panels 4-47
Aging Management Mw!u.gement Requirements Requiremenis Inspect for Separation of Upper and Lower Shroud Sections Figure 4-14 Locations of potential separation between core shroud sections caused by swelling induced warping of thick flange plates in CE welded core shroud assembled in stacked sections 4-48 IPEC_PA_OAG0000104
Aging Agillg Management Reqlljrement.~ Mallagemellt Requirements Flange Fl Weldd ange Wel Axial A Weld xial We ld
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Aging Management Requirements
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Flange and Flexllre I * , Core Support Columns without "Winged" Design Figure 4-16 CE lower support structures for welded core shrouds: shrouds: separate core barrel and lower support structure assembly with lower flange and core support plate 4-50 IPEC_PA_OAG0000106
Reqlliremenl.~ Aging Management Requirements (a) UGS SUPPORT PLATE s c D E CEA GUIDE TUBES FUEL CEA GUIDE TUBE ALIGNMENT EXTENSIONS PLATE (b) Figure 4-17 (a) Schematic illustration of a portion of the fuel alignment plate, and (b) Radial-view schematic illustration of the guide tubes protruding through the plate in upper internals assembly of CE core shrouds with full-height shroud plates 4-511 4-5 IPEC_PA_OAG0000107
Aging Management Mmwgel1lelll Requirements Req/l;remelllJ
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vV I vV Figure 4-18 CE control element assembly (CEA) shroud instrument tubes (circled in red) are shown, along with the welded supports attaching them to the CEA shroud tube, in this schematic illustration 4-52 IPEC_PA_OAG0000108
Aging Agil/g Management Mal/agemelll Requirements Illustrates the deep beam grid strllcture structure (number 3). 3), as well as the fuel fu el alignmen alignmentt pins (numbers 1 and 2) Figure 4-19 Isometric view of the lower support structure in the CE core shrouds with full-height shroud plates units. Fuel rests on alignment pins 4-53 IPEC_PA_OAG0000109
Aging Management Requirements Requiremellts Wear Area Figure 4-20 Typical Westinghouse control rod guide card (17x17 fuel assembly) 4-54 IPEC_PA_OAG0000110
Aging Agillg Management Reqllirelllent.~ M anagemelll Requirements Lower L ower Flange F1unge Weld Figure 4-21 Typical Westinghouse control rod guide tube assembly 4-55 IPEC_PA_OAG0000111
Aging Management Requirements Requiremenis o Flange Weld Axial Axial Weld o o o Upper Core Barrel to
~r Lower Core Barrel Circumferential Weld Cf!'Cumlerential lLower ower Barrel Axial Weld Axial lower Lower Barre Barrell Circumferential Cirtumferential Weld Lower Barrel A;i(ial Axial Weld Core Barrel to Support Plate Weld Figure 4-22 Major fabrication welds in typical Westinghouse core barrel 4-56 IPEC_PA_OAG0000112
Reqlliremenl.~ Aging Management Requirements
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CORE BARREL "TOTO R>R.Mr;:R.BOLT FOP.f&:RBOLT HAFFI..E TE P1.A11i HAFfl.E PI..A EDGEBOtT EDGE BOLT BAFFLE TO FORMER BOLT (LONG&: SHORl) BOLT(l.ONGA: SHORT) COP.NE:R COANER EDGE BRACXET BAFFLE TO FORMER. FORMER BOLT Figure 4-23 Bolt locations in typical Westinghouse baffle-former-barrel structure. In CE plants with bolted shrouds, the core shroud bolts are equivalent to baffle-former bolts and barrel-shroud bolts are equivalent to barrel-former bolts 4-57 IPEC_PA_OAG0000113
Aging Management Requirements Requiremenis
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Figure 4-24 Baffle-edge bolt and baffle-former bolt locations at high fluence seams in bolted baffle-former assembly (note: equivalent baffle-former bolt locations in bolted CE shroud designs are core shroud bolts) 4-58 IPEC_PA_OAG0000114
Aging Agillg Management Reqlljrement.~ M allagemelll Requirements High Fluence Seams Flucncc Scams Figure 4-25 High fluence seam locations in Westinghouse baffle-former assembly 4-59 IPEC_PA_OAG0000115
Aging Management Requirements Requiremenis
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Potential Bowing Along t High Fluence Seam Figure 4-26 Exaggerated view of void swelling induced distortion in Westinghouse baffle-former assembly. This figure also applies to bolted CE shroud designs 4-60 IPEC_PA_OAG0000116
Aging Management Requirements o Vertical Figure 4-27 Vertical displacement of Westinghouse baffle plates caused by void swelling. This figure also applies to bolted CE shroud designs 4-61 IPEC_PA_OAG0000117
Aging Management Maul/gement Requirements
// TOP SUPPORT PLA PLATE lE VESSEl V ESSEL HEAD
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Hold-down spring VESSEL CORE BARRElL BARREL Figure 4-28 Schematic cross-sections of the Westinghouse hold-down springs 4-62 IPEC_PA_OAG0000118
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Figure 4-30 CE lower support structure assembly for plants with integrated core barrel and lower support structure with a core support plate (this design does not contain a lower core barrel flange) esp a) b) c) a) Early support colu columnmn design deslgn b) b) "Winged" support colu column mn design and plants with with second generalion generation core support assemblies c) Later su art coili mn desi ort column lanls with desi n used in lants with second eneration core su ort assembli es assemblies Figure 4-31 CE core support columns 4-64 IPEC_PA_OAG0000120
Aging Agillg Management Mal/agemel1l Requirements Lm." c ",~ Core Plate Lower Core LO\IIIt'tr i!W Su,.port Support SIN""'" Structure Core Support Suppcrt Plate (Forging) Figure 4-32 Schematic indicating location of Westinghouse lower core support structure. Additional details shown in Figure 4-33 LOWER CORE PLATE Dl FFUSER PLATE DIFFUSER CORE SUPPORT PLATE/FORGING CORE~ CORE ':, SUPPORT COLUMN ~
\_BOTTOM BOTTOM MOUNTED INSTRUMENTATION COLUMN Figure 4-33 Westinghouse lower core support structure and bottom mounted instrumentation columns. Core support column bolts fasten the core support columns to the lower core plate 4-65 IPEC_PA_OAG0000121
Aging Management Requirements Figure 4-34 Typical Westinghouse core support column. Core support column bolts fasten the top of the support column to the lower core plate Figure 4-35 Examples of Westinghouse bottom mounted instrumentation column designs 4-66 IPEC_PA_OAG0000122
Aging Agillg Management Mal/agell/el1l Requirements Figure 4-36 Typical Westinghouse thermal shield flexure 4.4 Existing Programs Component Requirements Existing Ex istin g Programs components are those PWR PW"R internals inte rn als for which current aging management acti viti es required to activities 1,0 maintain functionality are being be ing implemented. imple mented. The continuatio continuationn of these activities activiti es is credited within these guidelines for adequate agin agingg management manageme nt for specifi specificc components. components. Ex isting Programs are PWR internals Included in the Existing inlernal s that classified th ai are class i.fied as removable removab le core support structW'es. SUppOlt structures. ASME Section XI, Xl, IWB-2500, lWB-2500, Examination Category B-N-3 8-N-3 [2] [2] does not list component specific exami examination nati on requirements for removable removabl e core support structures. Accordingly, fac tors such as original Accordi ngly, factors orig in al design, licensing and code of construction variability could result in significa nt difference significant differencess in an individual indi vidual plant's plant' s ccurrent urrent B-N-3 8 -N-3 requirements. These guideli nes credit specifi guidelines specificc components contained within the general B-N-3 8-N-3 class ificatio n fo classification forr maintainin g functionality. maintaining functionality . These examination requirements, as applied to !.he the components designated in Tables 4-7, 4-8, and 4-9, have been determined to provide sufficient agi agingng management for these components. Table 4-7 B&W plants Existing Programs components No existing generic industry indu stry programs were considered sufficie sufficientnl, for monitoring the aging guide lines forB& effects addressed by these guidelines for B&W pla nts. Therefore, no co W plants. mponents for components B&W forB& W plants were placed into Existin g Programs group. inlo the Existing group . 4-67 IPEC_PA_OAG0000123
Aging Management Requirements Table 4-8 CE plants Existing Programs components Effect Item Applicability Primary link Link Examination Method Examination Coverage (Mechanism) Core Shroud Assembly All plants Loss of material ASM ASME E Code Visual (VT-3) First 10-year 10-year lSI lSI after 40 (Wear) Section XI XI examination, general years of operation, operation, and at Guide lugs condition examination each subsequent Guide lug inserts and for detection of inspection interval. bolts excessive or asymmetrical wear. Lower Support lower All plants with (SCC, Cracking (SCC, ASME ASM E Code Visual (VT-3) Accessible surfaces at Structure core shrouds IASCC, Fatigue) Section XI XI examination to detect specified frequency. frequency. assembled with severed fuel alignment Fuel alignment pins full-height pins, missi pins, missing ng locking shroud plates tabs, or excessive wear on the fuel alignment pin flange. nose or flange. lower Lower Support All plants with Loss of material ASME ASM E Code Visual (VT-3) Accessible surfaces at Structure core shrouds (Wear) Section XI XI examination. specified frequency. frequency. assembled in Fuel alignment pins two vertical sections Core Barrel Assembly All plants Loss of material ASME ASM E Code Visual (VT-3) Area of the upper flange (Wear) Section XI XI examination. potentially susceptible to Upper flange wear. 4-68 IPEC_PA_OAG0000124
Aging Agillg Management Mallagemellt Requirements Requiremellts Table 4-9 Westinghouse plants Existing Programs components Effect Item Applicability Primary Link Examination Method Examination Coverage (Mechanism) Core Barrel Assembly All plants Loss of material ASME ASM E Code Visual (VT (VT-3)3) All accessible surfaces surtaces at Core barrel flange (Wear) Section XI XI examination to specified frequency. determine general condition for excessive wear. Upper Internals Assembly All plants (SCC, Cracking (SCC, ASME ASM E Code Visual (VT-3) All accessible surfaces surtaces at Upper support ring or skirt Fatigue) Fatiguef Section XI XI examination. specified frequency. Lower Internals Assembly All plants Cracking (IASCC, ASME ASM E Code Visual (VT-3) All accessible surfaces surtaces at Lower core plate Fatigue) Section XI XI examination of the lower specified frequency. frequency. XL lower core plate (Note 1) core plates to detect evidence of distortion and/or loss of bolt integrity. inteqritv. Lower Internals Assembly All plants Loss of material ASME ASM E Code Visual (VT-3) All accessible surfaces surtaces at Lower core plate (Wear) Section XI XI examination. specified frequency. frequency. XL lower core plate (Note 1) Bottom Mounted All plants Loss of material NUREG-1801 NUREG* 1801 Surface (ET) Surtace Eddy current surface surtace Instrumentation System (Wear) Rev. 1 Rev. examination. examination as defined in Flux thimble tubes plant response to IEB 88-09. 09. Alignment and Interfacing All plants Loss of material ASME ASM E Code Visual (VT-3) All accessible surfaces surtaces at Components (Wear) Section XI XI examination. specified frequency. Clevis insert bolts (Note 2) Alignment and Interfacing All plants Loss of material ASME ASM E Code Visual (VT-3) All accessible surfaces surtaces at Components (Wear) Section XI XI examination. specified frequency. frequency. Upper core plate alignment pins Notes: Notes:
- 1. XL = "Extra Long*
XL= Long" referring to Westinghouse plants with 14-foot cores.
- 2. Bolt was screened in because of stress relaxation and associated cracking; cracking; however, wear of the clevis/insert is the issue.
4-69 IPEC_PA_OAG0000125
Aging Management Requirements Requiremenis Ex isting Programs Also included in Existing Progmms are those components for which ex isting guidance has existing been issued (e.g., from the nuclear steam suppl supplyy system (NSSS) vendors or Owners Groups) to address degradation that manifested itself during the current operational life of the PWR fleet. fl eet. imple mentation of this The continued implementation thi s guidance has been detennined determined to adequate adequately ly manage the aging effects for these components. 4.4. 1 B& W Components Table 4-7 describes the PWR internals inte mals in the Existing Exi sting Programs Progmms for B& B&W W plants. No existing generic industry programs contain the specificity considered sufficient for monitoring the ag ing effects addressed by these guidelines for B&W plants. Therefore, no aging components forB& for B&W plants were placed pl aced into the Existing Programs group. 4.4.2 CE Components Table 4-8 describes the PWR internals in the Existing Ex isting Programs Progmms forCE fo r CE plants. pl ants. The following fo llowing is a listli st of the CE Existing Ex isting Programs Prog rams Components.
- ASME Section XI Existing:
Ex isting: Guide Gu ide lugs and guide lug inserts and bolts (applicable to aJi all plants)
- Fuel alignment pins (applicable to all plants with core shrouds assembled with full- fu ll-height shroud plates and all plants with core shrouds asse section s) mbled in two vertical sections) assembled
- Upper flange (applicable to all plants)
These component items may be considered core support SUppOl1 stllletures li stings that are typically structures listings typicall y examined during the 10-year inservice inserv iee inspection per ASME Code Section XI Table IWB-2510, IW8-25 10, 8-N-3 [2]. B-N-3 ['2 ]. For these component items,ite ms, the requirements require ments of B-N-3 8-N-3 (v isual VT-3) arc (visual are considered sufficient to monitor for the aging effects addressed by these guidelines.
- Plant-specific The guidance for ICI thimble tubes and thermaJ thermal shield positioning pins is limited to plant specific recommendations recommendation s and thus have no generic reference, nor are they included in Tab Table le 4-8.
The owner should review rev iew their spec ific des specific ign, upgrade status, and plant design, pl ant commitments for fo r CE ICI thimble tubes. 4-70 IPEC_PA_OAG0000126
Reqlliremenl.~ Aging Management Requirements 4.4.3 Westinghouse Components Table 4-9 desc ribes the PWR internals describes inte l11 als in the Existing Ex isting Programs Progra ms for Westinghouse plants. pl ants. The following is a list li st of the Westinghouse Existing Exi sting Programs Components.
- ASM ASME E Section XI Ex isting:
Existing:
- Core barrel flange flan ge (applicable to all plants)pl ants)
- Upper support ring or skiJ1 skirt (applicable to all plants)
- Lower core platepl ate and XL lower core plate (applicable to all plants) pl ants)
- Clev is insert Clevis in sert bolts (applicable (a pplicable to all plants) pl ants)
- Upper core platepl ate ali gnment pins (applicable to all plants) alignment These component items are considered core support structu res that are typically structures typicall y examined during IO-year inservice inspection the 10-year in spection per ASME AS ME Code Section XI Table IWB-2510, 8-N-3 [21.
rWB-25 10, B-N-3 [2]. For these component items, ite ms, the requirements require ments of B-N-3 8-N-3 (v isual VT-3) (visual VT- 3) are considered sufficient to monitor fo forr the aging effects addressed by these guidelines.
- Plant-specific The guidance for flux flu x thimble tubes is included in Table 4-9 and is based on owner commitments.
The guidance guidan ce for guide tube support pins (split pins) is limited to plant pl ant spec ific recommendations specific and thus have no generic reference. Subsequent performance perfonnance monitoring should follow the supplierr recommendations. They thus are not included in Table 4-9. The owner should review supplie rev iew their specific design, upgrade status, and asset management plans pl ans for Westinghouse guide tube support pins (split pins). 4.5 No Additional Measures Components It has been determined that no additional ag ing management is necessary for compone aging components nts in thi thiss group. In no case does this thi s determination relieve utilities of ofthe AS ME Code Section XI [2] IWB the ASME JWB Examination Category B-N-3 8 -N-3 inservice inspection in spection requirements for fo r components from this thi s group cl assified as core support structures unless specific classified spec if ic relief is granted as allowed by 10CFR50.55a IOCFR50. 55a [[41. 4]. 4-71 4* 71 IPEC_PA_OAG0000127
IPEC_PA_OAG0000128 5 EXAMINATION ACCEPTANCE CRITERIA AND EXPANSION CRITERIA The purpose of this thi s section is to provide prov ide both examination acceptance criteri criteriaa for fo r conditions detected as a result of the exa examination minatio n requirements in Section Sectio n 4, Tables 4-14~ J through 4-6, as well as criteri criteriaa for expanding fo r ex panding examinations examinatio ns to the Expansion Ex pansion components co mpo ne nts when warranted by the level of degradation detected in the Primary components. components. Examination Examinatio n acceptance criteria identify ide ntify the visual examinatio examinationn relevant condition(s) or signal-based level or relevance re levance of an indication indi catio n that requires formal disposition fo nnal di spos itio n for acceptability. Based conditio n, and supplemental examinations if required, the di oonn the identified condition, spos itio n process disposition results in an evaluation and determination of whether to accept the condition until the next nex t examinationn oorr repair oorr replace examinatio repl ace the item. item. An acceptable di disposition spos ition process is described in Sectionn 6. Section 5. Sectio 5.11 provides prov ides a didiscussion scussion of relevant conditions applicable to the visual visuaJ examinatio examinationn methods and of relevant indications indicati ons applicable applica ble to the volumetric vo lumetric exa minations examinations employed in the guide guidelines. lines. Section 5.2 provides prov ides examination acce acceptance criteriaa for physical ptance criteri phys ical measurements. measurements. These crite criteria ria are contained in Tables 5-1, 5~ I, 5-2, 5~2, and 5~3 5-3 for B&W, 8&W, CE, and Westinghouse plants, respectively. respectivel y. Additionally, Additio nall y, Tables 5- 5-1, 5~2, and 5* 1, 5-2, 5-33 contain ex expansion pansion criteria forfo r B&W, 8 &W, CE, and Westinghouse plants, respectively. respectivel y. Expansion criteriaa are intended to form Expansio n criteri fO lm the basis for decisions fo r decis ions about exexpanding panding the set of compo components ne nts selected for examinationn or other aging fo r examinatio ag ing management activity, acti vity, in order to determine whether the level degradationn represented by the detected leve l of degmdatio conditions has extended ex tended to other components compo nents judged to be less affected by the degmdatio degradation. n. 5-11 5* IPEC_PA_OAG0000129
Examination E.xamillatioll Acceptance Criteria alld and Expansion Ex pallsioll Criteria Table 5-1 B&W plants examination acceptance and expansion criteria Examination Acceptance Expansion Additional Examination Hem Item Applicability Expansion Criteria Criteria (Note 1) Link(s) Acceptance Criteria Plenum Cover All plants One-time physical None N/A N/A Assembly & & Core measurement. In addition, addition, a Support Shield visual visual (VT-3) examination is Assembly conducted for these items. Plenum cover weldment rib pads The measu measured red differential Plenum cover support height from the top of the flange plenum rib pads to the vessel seating surface shall CSS top flange average less than 0.004 inches compared to the as-bu built ill condition. The specific relevant condition for these items is wear that may lead to a loss function. of function. Core Support Shield ONS-3, ONS-3. DB Visual (VT-3) examination. CRGT CRGT Confirmed evidence of relevant The specific relevant re levant Assembly spacer conditions for a single CSS cast condition is evidence of castings outlet nozzle shall require oullet requ ire that the fractured fractu red spacers or CSS cast oullet outlet nozzles The specific relevant VT-3 examination be expanded to missing screws. condition is evidence of include 100% of the accessible surface irregularities, irregularities, such surfaces at the 4 screw locations as damaged or fractured (at every 90°) of the C RGT spacer CRGT nozzle material. castings casti ngs by the completion of the next refueling outage. 5-2 IPEC_PA_OAG0000130
Examination
/:,).:amination Acceptance Criteria and Expansion E..'7Jansion Criteria Table 5-1 B&W plants examination acceptance and expansion criteria (continued)
Examination Acceptance Expansion Additional Examination Hem Item Applicability Expansion Criteria Criteria (Note 1) Link(s) Acceptance Criteria Core Support Shield All plants Visual (VT-3) examination. CRGT CRGT Confirmed evidence of relevant The specific relevant Assembly spacer conditions in two or more CSS condition is evidence of castings vent valve discs shall require that fractu fracturedred spacers or CSS vent valve discs the VT-3 examination be missing screws. The specific relevant condition is evidence of expanded to include 100% of the irregularities, such surface irregularities, accessible surfaces at the 4 screw as damaged or fractured locations (at every 90*) 90°) of the disc material. CRGT spacer castings by the completion of the next refueling outage. outage. Core Support Shield All plants Visual (VT-3) examination. None NiA N/A NiA N/A Assembly CSS vent valve top The specific relevant retaining ring condition is evidence of CSS vent valve bottom damaged or fractured retaining ring material, material , and missing items. CSS vent valve disc shaft shall or hinge pin 5-3 IPEC_PA_OAG0000131
Examination E.x amillatioll Acceptance Criteria alld and Expansion Ex pallsioll Criteria Table 5-1 B&W plants examination acceptance and expansion criteria (continued) (c ontinued) Examination Acceptance Expansion Additional Examination Item Applicability Expansion Criteria Criteria (Note 1) Link(s) Acceptance Criteria Core Support Shield All plants 1) Volumetric (UT) LCB bolts 1) Confirmed unacceptable 1) The examination Assembly examination of the UCB (Note 2) indications exceeding 10% of the acceptance criteria for Upper core barrel (UCB) bolts. bolts. require UCB bolts shall requi re that the UT the UT of the expansion bolts and their locking UTS, LTS. UTS. LTS, examination be expanded by the bolting shall be devices The examination acceptance and FD bolts completion of the next refueling established as part of the criteria for the UT of the outage to include: include : examination technical UCB bolts shall be SSHT bolts For all plants justification. established as part of the (C R-3 and (CR-3 100% of the accessible UTS, L TS, LTS, examination technical DB only) and FD bolts, 2) The specific relevant justification. Additionally for TMI-1 TMf-1 condition for the Lower grid UT examination to include 100% of expansion of the VT-3
- 2) Visual (VT-3) examination shock pad the accessible lower grid shock locking devices is of the UCB bolt locking bolts (TMI-1 bolls (TM 1-1 pad bolts, bolts, evidence of broken or devices. only) Additionally for CR-3 and DB missing bolt locking UT examination to include 100% of devices.
The specific relevant the accessible SSHT bolts. bolts. condition for the VT -3 of the UCB bolt locking devices is 2) Confirmed evidence of relevant evidence of broken or conditions exceeding 10% of the missing bolt locking devices. UCB bolt locking devices shall require that the VT-3 examination be expanded by the completion of the next refueling outage to include: For all plants 100% of the accessible UTS, L TS, LTS, and FD bolt locking devices, Additionally for TMI-1 TMf- 1 100% of the accessible lower grid 100% shock pad bolt locking devices, Additionally for CR-3 and DB 100% of the accessible SSHT bolt devices. locking devices. 5-4 IPEC_PA_OAG0000132
Examination
/:,).:amination Acceptance Criteria and Expansion E..'7Jansion Criteria Table 5-1 B&W plants examination acceptance and expansion criteria (continued)
Examination Acceptance Expansion Additional Examination Item Applicability Expansion Criteria Criteria (Note '1 1)) Link(s) Acceptance Criteria Core Barrel Assembly All plants 1) Volumetric (UT) UTS, LTS. UTS. LTS, 1) Confirmed unacceptable 1) The examination Lower core barrel (LCB) examination of the LCB and FD bolls bolts indications exceeding 10% of the acceptance criteria for bolts bolls and their locking bolts. bolls. bolts shall require that the UT LCB bolls the UT of the expansion devices SSHT bolls bolts examination be expanded by the bolting shall be boiling The examination acceptance (C R-3 and (CR-3 completion of the next refueli refueling ng established as part of the criteria for the UT of the LCB DB only) outage to include include:: examination technical bolts shall be established as For all plants justification. part of the examination Lower grid 100% of the accessible UTS, LTS, LTS, technical justification. shock pad and FD bolls, bolts, (TMI-1 Additionally for TMI-1 bolts (TMI-1 2) The specific relevant
- 2) Visual (VT-3) examination only) 1 00% of the accessible lower grid 100% condition for the of the LCB boll bolt locking shock pad bolts, bolls, expansion of the VT -3 of 01 devices. Additionally for CR-3 and DB the locking devices is 100% of the accessible SSHT evidence of broken or The specific relevant bolts.
bolls. bolt locking missing boll condition for the VT -3 of the devices. devices. LCB bolt boll locking devices is 2) Confirmed evidence of relevant evidence of broken or conditions exceeding 10% of the missing bolt locking devices. LCB bolt locking devices shall require that the VT-3 examination be expanded by the completion of the next refueling outage to include: For all plants 100% of the accessible UTS, LTS, LTS, devices, and FD bolt locking devices, Additionally for TMI-1 TMI- 1 100% of the accessible lower grid 100% shock pad bolt boll locking devices, devices, Additionally for CR-3 and DB, 100% of the accessible SSHT boll bolt locking devices. 5*5 5-5 IPEC_PA_OAG0000133
Examination E.xamillatioll Acceptance Criteria alld and Expansion Ex pallsioll Criteria Table 5-1 B&W plants examination acceptance and expansion criteria (continued) Examination Acceptance Expansion Additional Examination Hem Item Applicability Expansion Criteria Criteria (Note 1) Link(s) Acceptance Criteria Core Barrel Assembly All plants Baseline volumetric (UT) Baffle-to-baffle Confirmed Confi rmed unacceptable NiA N/A Baffle-to-former bolls bolts examination of the baffle-to- bolts, bolls, indications in greater than or former bolls. bolts. Core barrel-to- equal equal to 5% (or 43) of the baffle-former bolls bolts to-former bolts, bolts, provided that The examination acceptance none of the unacceptable boltsbolls criteria for the UT of the are on former elevations 3, 3, 4, 4, baffle-to-former baffl e-to-former bolts shall and 5, or greater than 25% of the be established as part of the bolts on a single former plate, plate, examination technical shall requ require ire an evaluation of the justification. justification. internal baffle-to-baffle bolls bolts for the purpose of determining whether to examine or replace the internal baffle-to-baffle bolts. bolls. The evaluation may incl include ude external external baffle-to-baffle baffle-to-baffl e bolts bolls and bolts for the core barrel-to-former bolls purpose of determ ining whether determining to replace them. Core Barrel Assembly All plants Visual (VT-3) examination. a. Former b. Confirmed cracking in a and b. a and b. N/A Baffle plates plates multiple (2 or more) locations in The specific relevant the baffle plates shall require condition is readily b. Core barrel expansion, with continued detectable cracking in the cylinder operation of former plates and baffle plates. (incl (including uding the core barrel cylinder justified vertical and by evaluation or by replacement circumferential by the completion of the next seam welds) refueling outage. 5-6 IPEC_PA_OAG0000134
Examination
/:,).:amination Acceptance Criteria and Expansion E..'7Jansion Criteria Table 5-1 B&W plants examination acceptance and expansion criteria (continued)
Examination Acceptance Expansion Additional Examination Hem Item Applicability Expansion Criteria Criteria (Note 1) Link(s) Acceptance Criteria Core Barrel Assembly All plants Visual (VT-3) examination. Locking Confirmed Confi rmed relevant conditions in NiA N/A Locking Locki devices, ng devices, devices for greater than or equal to 1 1%% (or 11) including locking welds, The specific relevant the external of the baffle-to-former or internal of baffle-Io-former baffle-to-former bolls bolts condition is missing, non- baffle-to- baffle-to-baffle bolt locking devices and internal baffle-Io-baffle-to- functional, or removed baffle bolts shall require an evaluation of the baffle bolts locking devices. barrel-- and barrel external baffle-to-baffle and core to-former barrel-to-former bolt locking bolts devices for the pu purpose rpose of determining determini ng continued operation or replacement. Lower Grid Assembly All plants Initial visual (VT-3) Alloy X-750 Confirmed evidence of relevant The specific relevant Alloy X-750 dowel-to- examination. examination. dowel conditions at two or more locations condition is separated or guide block welds locking shall require that the VT-3 missing locking weld, or The specific relevant welds to the examination be expanded to missing dowel. condition is separated or upper and include the Alloy X-750 X-7S0 dowel missing locking weld, or lower fuel locking welds to the uppeupperr and missing dowel. assembly lower fuel assembly support pads support pads by the completion of the next refueling outage. outage. 5-7 5*7 IPEC_PA_OAG0000135
Examination E.xamillatioll Acceptance Criteria alldand Expansion Ex pallsioll Criteria Table 5-1 B&W plants examination acceptance and expansion criteria (continued) Examination Acceptance Expansion Additional Examination Hem Item Applicability Expansion Criteria Criteria (Note 1) Link(s) Acceptance Criteria lncore Monitoring Incore All plants Initial visual (VT-3) a. CRGT a. Confi Confirmed rmed evidence of relevant a. For the CRGT spacer Instrumentation (IMI) examination. spacer conditions for two or more IMI IMI castings, the specific Guide Tube Assembly castings guide tube spider locations shall relevant conditions are IMI IMI guide tube spiders The specific relevant require that the VT-3 examination fractu red spacers or fractured IMI IMI guide tube spider-to- conditions for the IMI IMI guide b. Lower fuel be expanded to include 100% of missing screws. lower grid rib section tube spiders are fractured or assembly the accessible surfaces surtaces at the 4 welds missing spider arms. support pad screw locations (at every 90°) of b. For the lower fuel items: pad, the CRGT spacer castings by the assembly support pad The specific relevant pad-to-rib completion of the next refueling items (pads, (pads, pad-to-rib conditions for the IMI IMI spider- section outage. section welds, Alloy X-to-lower grid rib section welds, Alloy screws, 750 dowels, cap screws, welds are separated or X-750 X-7S0 Confirmed
- b. Confi rmed evidence of relevant and their thei r locking welds),
missing welds. dowel,, cap dowel conditions at two or more IMI IMI the specific relevant screw, screw, and guide tube spider locations or IMI conditions are separated spider-to-Iower grid rib their locking guide tube spider-to-lower or missing welds, welds section welds shall require that the missing support pads, VT-3 examination be expanded to dowels, dowels, cap screws and include lower fuel assembly locking welds, or support pad items by the misalignment of the completion of the next refueling support pads. outage. Notes:
- 1. The examination acceptance criterion for visual examination is the absence of the specified relevant condition{s).
condition(s). 2.
- 2. Expansion to LCB applies if the required Pri Primary mary examination of LCB has not been pertormed performed as scheduled in Table 4-1.
4- t . 5-8 IPEC_PA_OAG0000136
Examination
/:,).:amination Acceptance Criteria and Expansion E..'7Jansion Criteria Table 5-2 examination CE plants examinat ion acceptance and expansion criteria Examination Additional Examination Item Applicability Acceptance Criteria Expansion Link(s) Expansion Criteria Acceptance Criteria (Note 1)
Core Shroud Assembly Bolted plant Volumetric (UT) a. Core support a. Confirmation that >5% of the a and b. The (Bolted) designs examination. column bolls bolts core shroud bolts bolls in the four examination acceptance plates at the largest distance criteria for the UT of the Core shroud bolts b. Barrel-shroud from the core contain core support column bolts The examination unacceptable indications shall bolts and barrel-shroud acceptance criteria for require UT examination of the bolts shall be established the UT of the core lower support column bolts as part of the shroud bolls bolts shall be barrel ba rrel within the next 3 refueling examination technical established as part of the cycles. justification. examination technical justification.
- b. Confirmation that >5% of the core support column bolts contain unacceptable indications shall require UT examination of the barrel-shroud bolts within the next 3 refueling cycles.
Core Shroud Assembly Plant designs Visual (EVT-1 (EVT -1)) Remaining axial Confi Confirmation rmation that a surface- The specific relevant (Welded) with core examination. welds breaking indication> 2 inches in condition is a detectable shrouds length has been detected and crack-like surface Core shroud plate-former assembled in sized in the core shroud plate- indication. plate weld two vertical The specific relevant former plate weld at the core sections condition is a detectable shroud re-entrant corners (as crack-like surface visible from the core side of the indication. shroud), within 6 inches of the central flange and horizontal stiffeners, shall require EVT-1 EVT -1 examination of all remaining axial welds by the completion of the next refueling outage. 5-9 IPEC_PA_OAG0000137
Examination E.xamillatioll Acceptance Criteria alld and Expansion Ex pallsioll Criteria Table 5-2 CE plants examination acceptance and expansion criteria (continued) Examination Additional Examination Item Applicability Acceptance Criteria Expansion link(s) Link(s) Expansion Criteria Acceptance Criteria (Note 1) Core Shroud Assembly Plant designs (EVT-1) Visual (EVT -1) Remaining
- a. Remai ning axial a. Confirmation that a surface- The specific relevant (Welded) with core examination. welds breaking indication> 2 inches in condition is a detectable shrouds b. Ribs and rings length has been detected and crack-like surface Shroud plates assembled sized in the axial weld seams at indication.
with full- The specific relevant the core shroud re-entrant height shroud condition is a detectable corners at the core mid-plane plates crack-like surface shall require EVT-1 or UT indication. examination of all remaining axial welds by the completion of the next refueling outage.
- b. If extensive cracking is detected in the remaining axial welds, an EVT-1 welds, EVT-1 examination shall be required of all accessible rib and ring ri ng welds by the completion of the next refueling outage.
5-10 IPEC_PA_OAG0000138
Examination
/:,).:amination Acceptance Criteria and Expansion E..'7Jansion Criteria Table 5-2 CE plants examination acceptance and expansion criteria (continued)
Examination Additional Examination Item Applicability Acceptance Criteria Expansion Link(s) Expansion Criteria Acceptance Criteria (Note 1) Core Shroud Assembly Bolted plant (VT -3) Visual (VT-3) None N/A N/A N/A (Bolted) designs examination. Assembly The specific relevant conditions are evidence of abnormal interaction with fuel assemblies, assemblies, gaps along high fluence shroud plate joints, and vertical displacement of shroud plates near high fluence joints. Core Shroud Assembly Plant designs Visual (VT (VT*1
-1)) None N/A N/A N/A (Welded) with core examination examination..
shrouds Assembly assembled in two vertical The specific relevant sections condition is evidence of physical separation between the upper and lower core shroud sections. sections. 5-11 IPEC_PA_OAG0000139
Examination E.xamillatioll Acceptance Criteria alld and Expansion Expallsioll Criteria Table 5-2 examination CE plants examinat ion acceptance and expansion criteria (continued) Examination Additional Examination Item Applicability Acceptance Criteria Expansion link(s) Link(s) Expansion Criteria Acceptance Criteria (Note 1) Core Support Barrel All plants Visual (EVT-1) Remaining core a. Confirmation that a surface- a and b. The specific Assembly examination. barrel assembly breaking indication >2 inches in relevant condition is a welds beginning length has been detected and detectable crack-like Upper (core support barrel) flange weld with: sized in the upper flange weld surface surlace indication. The specific relevant shall require that an EVT-1 condition is a detectable a. lower flange weld, examination of the lower flange surlace crack-like surface weld be performed perlormed by the c. The specific relevant indication. followed by: completion of the next refueling condition is damaged or
- b. remaining outage. material fractured mate rial of the accessible core cast core support column barrel assembly welds.
welds, and welds, b. Confirmation that a surface-breaking indication >2 inches in
- c. core support length has been detected and column welds sized in the lower flange weld (cast) shall require an EVT-1 EVT-1 examination of all remaining accessible core barrel ba rrel assembly welds by the completion of the next refueling outage.
- c. Confirmation of cracking in any of the remaining accessible core barrel assembly welds shall requi re a VT-3 require examination of cast core support column welds, taking into account the general compressive loading of these columns and the potential for thermal aging embrittlement of the castings.
5-12 IPEC_PA_OAG0000140
Examination
/:,).:amination Acceptance Criteria and Expansion E..'7Jansion Criteria Table 5-2 CE plants examinat examinationion acceptance and expansion criteria (continued)
Examination Additional Examination Item Applicability Acceptance Criteria Expansion link(s) Link(s) Expansion Criteria Acceptance Criteria (Note 1) Core Support Barrel All plants Visual (EVT-1) None N/A N/A N/A Assembly examination. Lower flange weld The specific relevant condition is a detectable crack-like indication. Lower Support All plants Visual (EVT -1) None N/A N/A N/A Structure with a core examination. Core support plate support plate The specific relevant condition is a detectable crack-like surface indication. Upper Internals All plants Visual (EVT-1) (EVT -1) None N/A N/A N/A Assembly with core examination. Fuel alignment plate shrouds assembled The specific relevant with full- condition is a detectable height shroud crack-like surface surtace plates indication. 5-13 IPEC_PA_OAG0000141
Examination E.xamillatioll Acceptance Criteria alld and Expansion Expallsioll Criteria Table 5-2 examination CE plants examinat ion acceptance and expansion criteria (continued) Examination Additional Examination Item Applicability Acceptance Criteria Expansion link(s)Link(s) Expansion Criteria Acceptance Criteria (Note 1) Control Element All plants Visual (VT-3) (VT -3) Remaining Confirmed evidence of missing The specific relevant Assembly with examination.. examination instrument tubes supports or separation at the conditions are missing Instrument gu guide ide tubes instruments within the CEA welded joint between the tubes supports and separation tubes in the shroud assemblies and supports shall require the at the welded joint CEA shroud The specific relevant visual visual (VT-3) examination exam ination to be between the tubes and assembly conditions are missing expanded to the remaining the supports. supports and separation instrument tubes within the CEA at the welded joint shroud assemblies by between the tubes and completion of the next refueli refueling ng the supports. outage. Lower Support All plants Visual Visual (EVT-1 (EVT -1)) None N/A N/A Structure with core examination examination.. Deep beams shrouds assembled with full- The specific relevant height shroud condition is a detectable plates crack-like indication. Notes:
- 1. The examination acceptance criterion for visual examination is the absence of the specified relevant condition(s).
5-14 IPEC_PA_OAG0000142
Examination
/:,).:amination Acceptance Criteria and Expansion E..'7Jansion Criteria Table 5-3 plants Westinghouse plant examination s examinat ion acceptance and expansion ccriteria riteria Examination Additional Examination Item Applicability Criteria Acceptance Criter ia Expansion Link(s) Expansion Criteria Acceptance Criteria (Note 1)
Control Rod Guide All plants (VT -3) Visual (VT-3) None NiA N/A NiA N/A Tube Assembly examination. Guide plates (cards) The specific relevant condition is wear that could lead to loss of control rod alignment and impede control assembly insertion. Control Rod Guide All plants Enhanced visual visual (EVT-1 (EVT-1)) a. Bottom-mounted a. a. Confirmation of surface- a.
- a. For BM BMII col column umn Tube Assembly examination examination.. instrumentation breaking indications in two or bodies, bodies, the specific (BMI)I) column bodies more CRGT lower flange (BM relevant condition for the Lower flange welds welds, combined with flux welds, VT-3 examination is The specific relevant thimble insertion/withdrawal completely fractured condition is a detectable b. lLower ower support difficulty, difficulty, visual shall require visual column bodies.
crack-like surface column bodies (cast) (VT-3) examination of BM I BMI indication. column bodies by the completion of the next b. For cast lower support b. refueling refueli outage. ng outage. bodies, the column bodies, specific relevant condition is a detectable
- b. Confirmation of surface-
- b. crack-like surface breaking indications in two or indication.
indication. more CRGT lowerlowe r flange welds shall requ ire EVT-1 require EVT-1 examination of cast lower support column bod bodies ies within three fuel cycles following the initial observation. 5-15 IPEC_PA_OAG0000143
Examination E.x amillatioll Acceptance Criteria alld and Expansion Expallsioll Criteria Table 5-3 Westinghouse plant plants examination s examinat ion acceptance and expansion ccriteria riteria (continued) Examination Additional Examination Item Applicability Acceptance Criteria Expansion Link(s) Expansion Criteria Acceptance Criteria (Note 1) Core Barrel Assembly All plants Periodic enhanced visual visual a. Remaining core a. The confirmed detection and
- a. a and b.
- b. The specific (EVT-1) examination. barrel welds sizing of a surface-breaking relevant condition is a Upper core barrel barrel flange indication with a length greater detectable crack-like weld than two inches in the upper surface surlace indication.
The specific relevant b. lLower ower support core barrel flange weld shall condition is a detectable column bodies (non requ ire that the EVT-1 require EVT-1 crack-like surface surlace cast) examination, examination, and any indication. supplementary UT examination, examination, be expanded to incl ude the core barrel-to-include support plate weld by the completion of the next outage. If extensive refueling outage. ind ications in the confirmed indications core barrel-to-support plate weld are detected, detected, further EVT-1 expansion of the EVT-1 examination shall include the remaining core barrel assembly welds. welds.
- b. If extensive cracking in the b.
remaining core barrel welds is detected, detected, EVT-1 EVT-1 examination shall be expanded to include the upper six inches of the surfaces of the non-accessible surlaces cast lower support column bodies within three fuel cycles following the initial observation. 5-16 IPEC_PA_OAG0000144
Examination
/:,).:amination Acceptance Criteria and Expansion E..'7Jansion Criteria Table 5-3 plants Westinghouse plant examination s examinat ion acceptance and expansion ccriteria riteria (continued)
Examination Additional Examination Item Applicability Acceptance Criteria Expansion Link(s) Expansion Criteria Acceptance Criteria (Note 1) Baffle-Former All plants (VT -3) Visual (VT-3) None NiA N/A NiA N/A Assembly with baffle- examination. edge bolts Baffle-edge bolts bolls The specific relevant conditions are missing or broken locking devices, failed or missing bolts, and protrusion of bolt heads. heads. Baffle-Former All plants Volumetric (UT) a.
- a. Lower support a.
- a. Confirmation Confi rmation that more than a and b.b. The Assembly examination. column bolts
!column 5% of the baffle-former bolts examination acceptance actually examined on the four criteria for the UT of the Baffle-former bolts baffle plates at the largest lower support column The examination b. Barrel-former bolts distance from the core
- b. ba rrel-bolts and the barrel-acceptance criteria for (presumed to be the lowest former bolts shall be the UT of the baffle- dose locations) contain established as part of the former bolts shall be unacceptable indications shall examination technical established as part of require requi re UT examination of the justification.
the examination lower support column bolts technical justification. within the next three fuel cycles.
- b. Confirmation
- b. Confi rmation that more than 5% of the lower support column bolts actually examined contain unacceptable indications shall require UT examination of the barrel-former bolts.
bolts. 5-17 IPEC_PA_OAG0000145
Examination E.x amillatioll Acceptance Criteria alld and Expansion Ex pallsioll Criteria Table 5-3 Westinghouse plants examination acceptance and expansion ccriteria riteria (continued) Examination Additional Examination Item Applicability Acceptance Criteria Expansion Link(s) Expansion Criteria Acceptance Criteria (Note 1) Baffle-Former All plants Visual (VT-3) (VT-3) None N/A N/A N/A Assembly examination. Assembly The specific relevant conditions are evidence of abnormal interaction assemblies, with fuel assemblies, gaps along high fluence shroud plate joints, vertical displacement of shroud plates near high fluence flue joints, and nee joints, broken or damaged edge bolt locking systems along high fluence flue nee baffle plate joints. joints. Alignment and All plants Direct physical None N/A N/A N/A Interfacing Components with 304 measurement of spring stainless height. Internals hold down steel hold spring down springs The examination acceptance criterion for this measurement is that the remaining compressible height of the spring shall provide hold-down forces within the plant-specific design tolerance. tolerance. 5-18 IPEC_PA_OAG0000146
Examination
/:,).:amination Acceptance Criteria and Expansion E..'7Jansion Criteria Table 5-3 Westinghouse plants examination acceptance and expansion criteria (continued)
Examination Additional Examination Item Applicability Acceptance Criteria Expansion Link(s) Expansion Criteria Acceptance Criteria (Note 1) Thermal Shield All plants (VT -3) Visual (VT-3) None NiA N/A NiA N/A Assembly with thermal examination. shields Thermal shield flexures fl exures The specific relevant conditions for thermal thermal shield flexures are wear, fracture, excessive wear, or complete separation. separation . Notes:
- 1. The examination acceptance criterion for visual examination is the absence of the specified relevant condition(s).
5-19 IPEC_PA_OAG0000147
Examination Acceptance AccelJtance Criteria and Expansion ExpallSion Criteria 5.1 Examination Acceptance Criteria 5.1.1 Visual (VT-3) {VT-3) Examination Visual (VT-3) examination has been determined to be an appropriate NDE method for the tion of general deg detection detec degradation radation conditions in many of the susceptible components. The ASME Code Section XI, Examination Category B-N-3 [2], provides a set of relevant conditions cond itions for the visual (VT-3) exami nation of removable core support structures in IWB-3520.2. examination IWB- 3520.2. These arc;are: 1. I. structural distortion or di displacement splacement of parts to the extent that component function may be impaired; mi ss ing, cracked, or fractured parts, bolting, or fastene
- 2. loose, missing, rs; fasteners;
- 3. corrosion or erosion that reduces the nominal section thickness by more than 5%;
- 4. wear of mating sUlfaces surfaces that may lead to loss of function; and
- 5. structural degradation of interior attachments such that the ori ginal ccross-sectional original ross-sectional area is reduced more than 5%.
For components in the Existing Ex isting Programs group, these ge neral relevant conditions are sufficient. general However, for components where visual (VT-3) is specified in the Primary or the Expansion group, more specific desc riptions of the relevant conditions are provided in Tables 5-1, 5-2, and descriptions 5-3 fo forr the benefit of the examiners. Typical examples are "fractured material" and "completely separated material." materi al." One or more of ofthese these specific relevant condition descriptions may be applicable to the Primary and Expansion Expans ion components listed in Tables 5-1 5-1,, 5-2, and 5-3. The examination acceptance criteria for components requiring visual (VT (VT-3)-3) examination is thus the absence of the relevant re levant condition(s) specified in Tables 5-1,5- 1, 5-2, and 5-3. The di disposition sposition can include a supplementary examination exa mination to further characterize fUlthe r characte rize the relevant condition,, an eng condition ineering evaluation engineering evaluat ion to show that the component compone nt is ca pable of continued capable operation with a known relevant cond ition, or repair/replacement to remediate condition, remed iate the relevant condition. {VT-1) Examination 5.1.2 Visual (VT*I) Visual (VT-I) (VT-1) examination is defined in the ASME Code Section XI 121 [2] as an examination "conducted to detect di scontinuities and imperfections on the sUlface discontinuities surface of components, including conditionss as cracks, wear, corrosion, or erosion." For these gu such condition idelines VT--11 has only been guidelines selected to detect di stortion as ev distortion idenced by small gaps between the upper-to-lower evidenced uppe r-to-Iower mating surfaces of CE welded sUlfaces we lded core shrouds assembled in two vertical sections. The examination acceptance criterion is thus the absence of the relevant condition of gaps that would wou ld be indicative of di distortion stortion from void vo id swelling. 5-20 IPEC_PA_OAG0000148
Examination Acceptance Criteria and Expansion Criteria 5.1.3 Enhanced Visual (EVT-l) (EVT-1) Examination Enhanced visual vi sual (EVT (EVT-I -1)) examination has the same requirements as the ASME Code Section XI [2 [2][ visual (YT-I (VT-1)) examination examination,, with additional requirements given in the Inspection In spection Standard [3 [3].[. These enhancements are intended inte nded to improve the detection and characterization of di discontinuities scontinuities taking into account the remote visual aspect of reactor internals inte rnals examinations. As a result, EVT EVT-I -1 examinations are capable of detecting small surface breaking cracks cmcks and sUiface surface crack length siz ing when used in conjunction with sizing aids (e.g. landmarks, ruler, and tape measure). EVT-sizing 1I examination has been se selected lected to be the appropri ate NDE method for detection of cracking in appropriate plates or their welded joints. Thus the relevant condition applied for EVT EVT--1I examination is the same as found for cracking in Reference 2 which is crack-like sUiface surface breaking indications. Therefore, until such time as generic engineering studies develop the basis by which a quantitati quantitative ve amount of degradation can be shown to be tole rable for the specific component, tolerable any relevant condition is to be di spositioned. In the interim, the examination acceptance criterion dispositioned. is thus the abse nce of any detectable surface breaking indication. absence 5.1.4 Surface Examination Surface 5 U1face ET (eddy curre current) nt) examination is specified spec ified as an alternative or as a supplesupplement ment to visual examinations. No spec ific acceptance criteria specific criteri a for surface (ET) examination of PWR internals intemal s locations location s are provided in the ASME Code Sec Section tion XI [2]. Since surface ET is employed as a signal-based exa examination, min ation , a technical justification per the Inspection Standard [3] [3] provides the basis for detection and length sizing of surface-breaking or near-surface cracks. The signal -based signal-based relevant indication for surface (ET) is thus the same as the relevant condition fo forr enhanced visual (EVT-(EVT -1)l ) examination. The acceptance criteri criteriaa for enhanced visual (EVT- (EVT-1) I) examinations in
- 5. 1.3 (and accompanying entries in Tables 5-1, 5.1.3 5-1 , 5-2, and 5-3) are therefore applied when this thi s method is used as an alternative or supple supplement ment to visual examination.
- 5. 1.5 Volumetric Examination 5.1.5 The intent of volumetric examinations examination s specified spec ified for bolts in Section 4.3 of these I&E guidelinesguide lines is to detect planar defec defects. fl aw sizing measurements are recorded or assumed in the ts. No flaw acceptance or rejection of individual indi vidual bolts or pins. Individual Indi vidual bolts or pins are accepted based on the detec tion of relevant detection releva nt indications established as part of the examination technical justification justification..
Whe n a relevant indication is detected in the cross-sectional area of the bolt or pin, it is assumed When to be non-functional and the indication is recorded. recorded. A bolt or pin that passes the criterion of the examination is assumed to be functional.fun ctional. Because of this thi s pass/fail acceptance of individual bolts or pins, pin s, the examination acceptance criterion for volumetric ((UT) UT) examination of bolts and pins pin s is based on a reliable detection of indications as established by the individual indi vidual technical justification for the proposed examination. Thi Thiss is in keeping with curre current nt industry indu stry practice. pmctice. For example, planar pl anar flaws fla ws on the order of 30% of the cross-sectional area have been demonstrated to be reliably reliabl y detectable in previous bolt NDE technical justifications for baffle-former baffle-fonner bolting. 5-21 IPEC_PA_OAG0000149
Examination Acceptance AccelJtance Criteria and Expansion ExpallSion Criteria Bolted and pinned assemblies are evaluated for acceptance based on meeting a spec ified number specified di stribution of functional bolts and pins. and distribution pin s. As di scussed in Section 6.4, criteri discussed criteriaa for this thi s evaluation can be: 1) I) found in previous Owners Group reports, repol1s, 2) developed for use by the PWROG or 3) developed on a plant-specificpl ant-specific basis by the applicable NSSS vendor.ve ndor. 5.2 Physical Measurements Examination Acceptance Criteria Continued functionality can be confirmed by physical measurements where, for example, loss of material materi al caused by wear, loss of pre-load of clamping force caused by various degradation mechani sms, or di mechanisms, stortion/defl ection caused by void swelling distortion/deflection swe lling may occur. Where appropriate, appropri ate, phys ica l measurements these physical measure ments are arc described in Section 4.3, with limits applicable to the various des igns. ForB& designs. For 8 &W des igns, the acceptable tolerance for the measured differential height from the designs, top ofthe of the plenum rib pads to the vessel seatjng seating sUlface generi cally established and is surface has been generically provided in Table 5- 1. For Westinghouse designs, 5-1. des igns, tolerances are available on a des ign or plant-design plallt-specific spec genericall y in these guidelines. ForCE ific basis and thus are not provided generically designs, For CE des igns, no physical phys ical measurements are spec specified. ified. 5.3 Expansion Criteria The ccriteria riteri a for fo r ex panding the scope of examination from the Primary components to their linked expanding Expansion components is contained in Tables 5-1, 5-1 , 5-2, and 5-3 for B&W, 8 & W, CE, and Westinghouse respectivel y. The logic plants, respectively. log ic and basis for the levels leve ls of degradation warranting expansion is docume documented nted in an MRP letter [15]. ["1 5 1. Y*22 5-22 IPEC_PA_OAG0000150
6 EVALUATION METHODOLOGIES There are various options that are avaj lable for the disposition of condition available conditionss detected during examinations (Section 4) that are unable to satisfy the examination acceptance criteri criteriaa (Section 5). These options include, but are (1) supple arc not limited to: (I) mental examinations, supplemental exami nation s, such as a surface exa sUifacc examination, mination , to supple supplement (VT-1) or an enhanced visual (EVT ment a visual (VT-I) (EVT-l)-1) examination, exami nation, to further characteri characterize ze and potentially dispose of a detected condition; (2) engineering engi neeri ng evaluation demonstrates the acceptability of a detected condition; (3) repair, in order to restore a that dcmonstmtcs component with a detected condition to acceptable statu s; or (4) status; (4) replacement of a co mponent component with an unacceptable detected condition. The first option involves in volves the re-examination re+examination of a co mponent with an unacceptable detected component condition with an alternative examination method that has the potential capability to further fUl1her confirm with greater precision the component physical condition. This additional define or confu'm zation may enable the more precise character of that detected condition to be found characterization characteri acceptable for continued service. An example would be the volumetric (UT) exa mination to examination depth size a surface+break surface-breaking ing flaw fla w detected by eeither ither visual (VT+ I) or enhanced visual (EVT-1) (VT -1) examination. Section 6 concentrates on the second option, evaluation methodologies that ca cann be used for evaluating eva luating flaws fl aws detected during the examinations described in Section 4 that exceed the examination acceptance ccriteria riteria described in Section 5. The evaluation process depends upon the loading applied to the component, assembly, or system. Typical loading information to be considered is provided in Section 6.1 and evaluation methodology options are described in subsequent section sections. s. These methodologies range from the sati sfaction of limit load requirements satisfaction for the internals assembly or co mpone nt cross section to the sati component sfaction of flaw stability satisfaction requirements using eithereithe r linear elastic fracture mechanics mechani cs (LEFM) or elastic-plastic fracture mechanics (EPFM), depending upon applicability. In addition, recommendations for flaw depth assumptions, in the absence of fla flaww depth sizing during examination examination,, and flaw growth assumptions for subsequent operation until the next examination,exa mination, are described. Justification for flaw evaluation fracture toughness limits is also provided. Design-specific or fleet-specific flaw handbook s may be used as an engineering evaluation tool. handbooks 6.1 Loading Conditions The purpose of thisthi s section is to describe the typical loading co nditions that govern the conditions evaluation of fla ws exceedi flaws exceeding ng the examination acceptance criteria of Section 5. 6-1 IPEC_PA_OAG0000151
Evaluation Em/l/atiOIl Methodologies support Core suppo rt structures are des designed igned to a set of defined loading conditions that typicall typicallyy include deadweight, such as the weight we ight of the structure itself and an assigned portion po rtio n of the weight we ight of the fuel assemblies; mechanical loads, such as fuel assembl assemblyy spring forces and control rod actuation loads; hydraulic loads; loadings caused by flow-induced flo w- induced vibration; vibratio n; loss-of-coolant acc ident accident (LOCA) loads; thermalthennalloads, loads, such as those from both normal operation thermal tran sients and transients upset condition thermal transients, tra nsients, as well as gamma heating; operating basis earthquake (O BE) (OBE) and safe shutdown earthquake (SSE) seismic loads; handling loads that might occur during refueling and internals internal s removal remova l for inservice inserv ice examinatio examinations; ns; and interference conditions, friction forces, and dynamic insertion loads. Confirmationn of required loading and combinatio load s. Confirmatio combinationn requirements oonn an individual individu al plant basis is essenti essential al prior prio r to conducting any assessment. assess ment. For the case of many bolts bo lts and pins, pin s, the defined loading conditio conditionsns include interference interfe rence conditions, friction forces forces due to differential thermal growth, and dynamic insertion insertio n loads, in addition to dead weight, se seismic, ismic, and vibration loadings. load ings. The loading conditions co nditio ns for internal inte rnal structures that are not core suppo support rt structures are less well documented docume nted publicly. publicl y. However, should an engi engineering evaluationn be required for any internals nee ring evaluatio internal s structure (both core SUppOl1support structures and other internals), intemals), the original design basis bas is should be examined, in order to determine the availability avai lability of actual or potential pote nti al loading conditions. 6.2 Evaluation Requirements The evaluation of component conditions that do not satisfy the examination acceptance criteriaa of Section 5 must criteri mu st be performed perfo nned for a future state that corresponds to the next nex t required examinationn or later. examinatio This late r. Th is future state should be determined based on the observed conditio conditionn and a projection of future condition based oonn progressing progress ing degradation. The progressing progress ing degradationn estim degradatio ate should be based on a combination of operating experience estimate ex perience (bolt failure hi stories), applicable testing data (crack growth rates in plate histories), pl ate material), and available analytical results for fo r that component. Uncertainties in predictive measures should be considered where applicable. Options for performing perfolming evaluations evaluation s are contained in the following fo llow ing sub-sections. sub-section s. 6.2. 1 Limit Load Evaluation Evaluation Requirement An assembly or compo componentnent that cannot meet the examination exa mination acceptance criteri criteriaa of Section 5 of these I&E I& E guidelines may be subject to limit load requirements requireme nts as an evaluation dispositiondi sposition option, in order to continue in serv ice in the ex service isting condition. For PWR internals, existing intern als, the threshold for limit load requirements only is based on the accumulated neutron fluence exposure identified BWRVlP-I OO-A (191 in BWRVIP-100-A [19].. Thi Thiss requirement states that, for accumulated neutron fluence less than 20 2 3xl0 n/cm! (E > 1I MeV), or approximately 0.5 dpa 3x I 020 n/cm dpa,, oonly nl y a limit load evaluation requirement must be met fo forr continued serv ice of the internals assembly or individual co service component. mpo nent. A discussion di scuss ion and ex explanation pl anation of thi thiss requirement requireme nt is contained in the following follo wing paragraphs. 6-2 IPEC_PA_OAG0000152
Evaluation Me/lwdologie.~ Emlua/ion Methodologies Discussion and Explanation Inespective of the level Irrespective leve l of neutron irradiation ex posure, limit load requirements exposure, require ments can be sati sfi ed satisfied for the affected asse mbl y or component, in order to continue service until the end of the current assembly in se rvice inspection interval. inservice intervaL Therefore, the affec affectedted assembly or component co mpone nt can be shown to satisfy limit load requirements which may fo follow llow procedures similar to those given in the ASME AS ME Section Code Secti on XI, Appendix C [20] [20].. The limit load calculation is carried out to find the critical degree of degradation within the elements of the assembly, or the progress of flaw fl aw parameters (location of ofthe re maining ccross the remaining ross sec tion neutral axis section ax is and the effec ti ve flaw effective fl aw length) that cause cau se the cross sec tion to reach its limit load. section load. For austenitic stainless steel, the stress limits for primary prim ary loading may be based on the irradiated inadiated mechanical strength properties fo forr the minimum estimated fluence accumulaccumulated ated at the loaded section. A safety factor of 2.77 on the limit load for ex pected loadings (ASME expected (AS ME Service Loadings A and B) and a safety factor of 1.39 on the limit load for unexpected loadings (AS (ASME ME Service Loadings C and D) must be met fo forr the applied load on the asse mbl y, or on the membrane assembly, me mbrane and bending stresses in the co mponent. The component analys component. analysis is must demonstrate that a plastic pl astic hinge does not fo formrm in the remaining ligamentli gament of the cross section. For sections that have relatively rel ati vely unifonn loss of material, uniform materi al, and for unflawed unfl awed sections th thatat ex perience increased loading due to experience fa ilure in other secti failure ons, the limiting primary stress and defl sections, ec tions for ASME deflections AS ME Level C and D 0 combin ations should meet the plant des combinations ign basis, or alternatively, design alternati vely, meet the requirements of ASME Sectionn Ill, AS M E Sectio ILl , Appendix Appendi x F 1211 [21].. 20 2 If the neutron fluence exposure is less than 3x10 3x 10 n/cm n/c m (E > 1 MeV), or approximately approx imatel y 0.5 dpa, thi s is the only evaluation that needs to be met for acce this ptance of the PWR internals assembly or acceptance indi vidual component. No fracture toughness requirements individual require ments need to be met for neutron flu ence fluence ex posures less than this exposures thi s value. 6.2.2 Fracture Mechanics Evaluation For neutron fluence levels exceeding 0.5 dpa, either eithe r an elastic-plastic fracturefrac ture mechanics (EPFM) evaluation or a linear elastic fracture mechanics (LEFM) evaluation must be performed to assure continued stlUctura l integrity in the presence of detected flaws co ntinued structural fl aws that exceed the examination acceptance crite ria of Section 5. For neutron fluence above 0.5 dpa and below 5 criteria dpa, EPFM is the preferred method. For neutron fluence fl ue nce above 5 dpa, LEFM should be utilized. utili zed. Non-mandatory Appendix Appendi x C of the ASME AS ME Code Section XI [20.1 prov ides general guidance [20] provides fo llowed for performing such evaluations. Although the appendi which may be followed appendixx strictl strictlyy applies to austenitic stainless steel piping, the discuss discussion ion of flawfl aw growth due to fatigue, fa ti gue, or due to stress corrosion cracking (SCC), or due to a combination of the two is relevant. Note, however, that fatigue crack growth rates in Article C-8000 are limited to air environments onl only,y, and that fatigue crack growth in water environments and SCC crack growth rates are not available yet. For the case of IASCC, lASee, considerable research has been conducted on the effects of various levels of irradiation irradi ation exposure on crack growth resistance, res istance, primarily primaril y by the Boiling Water Reactor Vessel & Internals Internal s Project (BWRVIP) [19]. 1"1 91. Reference 19 also provides prov ides the technical basis for the recommendation of eeither ither LEFM or EPFM. Figure Fi gure 6-1, 6-1 , reproduced from Reference Refere nce 19, shows the data that were used to produce a set of conservative J-R curves (crack growth 6-3 IPEC_PA_OAG0000153
Evaluation Em/llation Methodologies res istance curves) for various exposure levels. Figures resistance Fi gures 6-2 and 6-3, also reproduced from Reference 19, show the lower bound for the power law parameter, C, and the upper bound for the power law parameter, n, in the curve fit to the crack growth resistance res istance curve data given by Jmat = C (~a)" Equation 6-1
~a is in mm.
2 where J and C are in KJ/m Care KJ/ml and Lla mm . The lower bound express expressionion for power law parameter C Cis is given by (121 7.9*6.697* 10'"10 + 0. C = (1217.9*6.697*10 3908 *F~')I(6.697* 0.3908*F 05563
)/(6.697*10 10'"10 + FF"05563
'~)) Equation 6-2 The upper bound express expressionion for power law parameter n is given by 0.02439
- F" ~"))
9976 n = 1/(4.962-1/(4.962 - 0.02439*p0° Equation 6-3 The term F in the above ex expressions press ions is the neutron fluence. flu ence. At accumulated fluence flu ence values of approximately 1I dpa, the material materi al has relatively rel atively highhi gh elastic-elastic-plastic plastic crack growth resistance. For example, at 1I dpa, the upper bound power law parameter C equals equal s 177 and the lower bound power law parameter n equals 0.492. Then, the crack growth resistance at 1.5 mm (0.059") of 2 1 2 crack growth is 2216 16 KJ/mm , or 1,609 in-lb/in in-Iblin
- Elastic-plastic behavior would be ex expected pected at such a low fluence level. leve l.
At an accumul accumulated ated fluence value of 10 dpa dpa,, C equals 55.2 and n equals 0.7833. Then Then,, the crack 2 2 growth resistance at 1.5 mm (0.059") of crack growth is 75.8 KJ/mm , or 565 in-lb/in in-Ib/in
- If the tangent to the crack growth resistance curve at 1.5 1. 5 mm (0.059" (0.059")) is projected back to zero crack growth and converted to K K(1 through the express expression ion Equation 6-4 where E is the elastic modulus, then K1I(c equal equalss 84 MPav'm, M Pa--im, or about 76 ksiv'in. Thiss value ksi--iin. Thi va lue of fracture toughness is in the range that would suggest that LEFM is perhaps more suitable than EPFM, even though some amount of plastic response remains.
However, at 15 dpa, C equal equalss 44.54 and n equals 0.889, so that the crack growth resistance 2 2 at 1.5 mm (0.059") of crack growth is onl onlyy 64 KJ/mm , or 476 in-lb/in in-Ib/in .* Extrapolating the tangent of the crack growth resistance curve back to zero ze ro crack growth and converting gives K1,Cc ==5555 MPav'm, MPa--im, or 50 ksiv'in. ksi--iin. Further analysis of more recent fracture toughness data at higher hi gher irradiation irrad iation exposures for fo r irradiated irrad iated stainless steels has ha s determined [25 [25]J that an appropriately conservative value for the fracture toughness of 38 MPav'm MPa--im (34.6 ksiv'in)ksi--iin) should be used for high neutron fluencefiuence exposure. Therefore, for fluencefiuence levels below 5 dpa, the elastic-plastic crack growth resistance res istance curves based on Equations 6-1 to 6-3 should be used. Equation s 6-1 used. For neutron fiuence fluence greater than 5 dpa, LEFM analyses should be used with w ith a limiting fracture toughness K1I(c = =55 55 MPav'm MPa--im (50 ksiv'in) ksi--iin) for ex posure levels between 5 and 15 dpa, and with a limiting fracture toughness K1I(c == 38 MPav'm exposure MPa--im greate r than 15 dpa. ksi..Jin) for exposure levels greater (34.6 ksiv'in) 6-4 IPEC_PA_OAG0000154
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Evaluation Eva luatioll Methodologies Metlwdologie.f The most recent information on flaw fla w growth rates for irradiated au austenitic steelss in stenitic stainless steel BWR eenvironments nvironm ents is provided in BWRVIP-99 BWRVfP+99 124]. [24]. The information in BWRVIP-99 BWRV I P~ 99 is based on both laboratory data and on field measurements measurement s of crack growth gro wth rates in BWR core shroud beltline welds, as measured by ultrasonic ultrason ic testing. The data arc are considered con sidered proprietary. The major tJ 6 5 findings findings were that field-measured field-m easured crack growth rates varied from 2x10 2x 10* to 5.25x 5.25x1010 S inches per hour (about 0.5 mm to 11 11 mm per year), with the ccrack rack growth rate as a function fun ction of depth much lower lo wer than the crack growth gro wth rate as a function fun ction of length. le ngth. Laboratory crack growth rates depe dependednded upon electro-chemical potential pOI.e nti al (ECP), with the growth rates substantially lower lowe r in a HWC environment that is more typical typi cal of a PWR environment. The HWC crack growth rates varied vari ed from 1x10 J x 10.17 to 4x 4x10 5 I O ~ inches per hour (0.02 mm to 9 mm per year). The nominal no minal reduction in crack growth rate for the HWC environment was found to be approximately 20 times lower than t.h an the cOITesponding corresponding crack growth rates in nominal no minal BWR environments. However, the scatter in the data is very large. For HWe HWC environments, t.he the recommended curve is given by da/dt = 8 25 daJdt = 2.72 Xx 10 ' (K)" (K) Equation 6-5 Figure 6-4 shows that this curve approx approximates imates an upper bound bo und to the relevant laboratory HWC HWe data. The BWR HWC curve is seen to be representative for PWR water enviro nme nts, compared environments, to limited crack growth rate data in PWR envi.ronment environment shown in Figure 6-5 [25] [25].. Therefore, the HWC curve may be used for all al l PWR IASCC IASCe and SCC sec anal analyses yses until generic curves are. are established establi shed for IASCC IASee and SCC sec in PWR environment. The use of ahernative alternative cmckcrack growth rate correlationss in correlation ill any analysis must mu st be accompanied by an appropriare appropriate technical justification justification.. 1.00E-03 1.0DE'()3 1.00E-04 1.DOE-04
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6-7 IPEC_PA_OAG0000157
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1.00E-09 1.00E-1 0 1.00E-10 a0 5 10 15 20 25 30 35 40 45 50 55 60 Stress Intensity K (MPa" ( MPavlm) m) Figure 6-5 Effect of stress intensity on IASCC crack growth rate [25) [25] 6.3 Evaluation of Flaws in Bolts and Pins For bolts and pins, pins. no evaluarion evaluation of individual items itcms is required.required. Individual bolts or pins that are found to be unacceptable during the UT examination should be assumed to be non-functional, non-fun ctional , and the acceptance criterion for continued operation of the assembly that contains one or more non-functional bolts or pins are based ba sed on the functioning fun ctioning of the assembly, assembly. not the individual bolt or pin. In [n addition, addjt ion, no evaluation evaluat.ion of individual indi vidual items is required requ ired where visual examinations are dercrmin ing functionality of bolts, the basis for determining bolls, pins or locking devices. Assessments in cases loc king devices. 6-8 IPEC_PA_OAG0000158
Evaluation Me/lwdologie.~ Emlua/ion Methodologies where the assembl assemblyy is found to be defi cient are most often dri deficient ven by loose parts or reassembly driven intelference evaluations that may be resolved interference resol ved using standard processes to suppOl1 support continued operation. Typically these are part of ex isting plant correcti existing correctiveve action programs and as such di sposition. should be sufficient to disposition. 6.4 Assembly Level Evaluations As indicated in Sections 5. 1. 5, bolts are not accepted or rejected based on flaw 5.1.5, fl aw sizing but on flaw detection. ThuThuss the bolted assembly must mu st be evaluated based on the number of rejected bolts, the minimum number required for functionality and an assumed failure rate until the next examination. Assemblies that sati sfy an evaluation criterion that has been establi satisfy shed established by the NSSS vendor may be di spos itioned. Alternatively, dispositioned. Alte rnativel y, an assembly level evaluation may be performed perfonned to ensure that required functionality is maintained through the period until the next nex t examinatjon. Essenti al features of this type of evaluation are described below. examination. Essential A process that can be followed fo forr those system level evaluations is provided in the following paragraphs. The process builds on the vendor functionality functjonality eva luations [II evaluations [11,, 12]. Othe Otherr approac hes can also be used. approaches used. The finite element models to be used for the system level evaluation could take advantage of geometric and loading symmetry. Examples of such models bee n demonstrated for the B&W-designed have been 8 &W-des igned and Westinghouse-designed Westinghouse-des igned baffle-former assemblies, the CE-designed core shroud asse mbl y, and bottom core plate asse assembly, mblies for assemblies diffe rent vendor designs. The bolts and pins that are ele different ments of the assembly elements asse mbl y should be modeled in suffic ient detail to capture the essential structural behavior needed to demonstrate sufficient de monstrate function or the lack thereof. For example, the assumption that a particular particul ar bolt, pin, or fas tener has failed can fastener be accounted fo forr by modeling the bolt or pin as a one-dimensional finite element with no ax ial axial strength.. If a particular or shear strength partk ular bolt or pin is assumed to maintain at least some or most of its the n the representation preload, then representatjon of material strengthstre ngth must mu st be appropriate. That material strength should account con servati vely for conservatively fo r the local fluence flu ence and temperature for particular pal1icul ar bolts or pins. mode Ung of the bolts and pins for system level evaluations does not require the The geometric modeling level of detail that would be needed to predict localized locali zed failure in a bolt or pin. The number numbe r of bolts or pins that are assumed to be non-functional should bound the estimated number and pattern of non-functional bolts or pins at the end of the eva luation interval. The evaluation estimation process is beyond the scope of this thi s document. A conse rvati ve pattern that diffe conservative rs from differs the actual observed pattern patte rn of non-functional bolts or pins may be used. used. The loads referred refe rred to in Section 6.1 should be applied to this thi s assembly asse mbl y model, model , and the structural response determined. Thiss structural response should then be compared to asse Thi mbly functional assembly fun ctional requirements, require ments, and a determination should be made about the capability to continue to operate the assembl determinatjon assemblyy through the remainder of the inspection interval. intervaL The precise prec ise functionality criteria for each assembly are beyond the scope of this thi s document. doc ument. Refe re nce should be made to vendor-recommended criteria Reference criteria.. 6-9 IPEC_PA_OAG0000159
Evaluation Em/l/atiOIl Methodologies 6.5 Evaluation of Flaws in Other Internals Structures Reference 22 desc describes ribes a methodology to be used to evaluate detected and sized flaws fla ws found internal s - other than bolts or pins - that exceed the exa in PWR internals mination acceptance ccriteria examination riteri a in Section 5.1. Thi Thiss methodology is summari summarized zed in the following steps. First, the neutron fluence for the compone component nt is calculated or deri derived ved from ex existing isting calculations. Second, the applied stresses are found from either ex existing isting stress analyses or from a new stress analysis analys is of the assembly containing the affected component location. location . Third, the detected and sized flaw fl aw from the examination is applied to a representation of the geometry of interest. Reference 22 has provided a number of representative representati ve PWR internal intern al core support geometries of interest. Fourth, the growth of the flaw over the period pe riod of time until the next examination, or until the end of compone component nt life, as applicable, applica ble, is calculated. The flaw fl aw growth calculation will depend on the active mechanism mechani sm dri driving ving the flawfl aw extension (i.e. IASCC, IASee, sec, SCC, or fatigue). fati gue). Reference 22 assumed that negligible flaw fla w growth occurred prior to application of nominal, design-basis, des ign-basis, and bounding loads. requi re ments (for example, limit load) for the flawed geometry after flaw Fifth, load evaluation requirements fl aw growth, subject to both expected and unexpected unex pected loads, should be met. Sixth, applied fracture mechanics stress intensities or applied l-integrals }-integrals are calculated from the combination of the stresses and the grown flaws fl aws for the representative core support geometry of interest, as applicable. LEFM solutions may be obtained from the literature, with a convers conversion ion to an elastic- pl astic crac elastic-plastic crackk driving force valid for localized plasticity pl astic ity at the crack tip tip.. Finally, the applied frac ture mechanics stress intensities fracture inten sities or the applied }-integrals J-integral s must be shown to meet the limits of Section 6.2.2. For LEFM calcul at ions, calculations, the applied fracture mechanics stress mu st be shown to be less than the material fracture toughness. For EPFM calculation intensity must calculation,, the evaluation procedure spec ified in ASME specified AS ME Section XI, XI , non-mandatory Appendix K, Article K-4000, K-4220 [2], can be used to demonstrate flaw Specifically, fl aw stability. Specificall y, Paragraph Paragra ph K-4220 provides a flaw stability criterion that limits the elastic- pl astic crack driving force to less than the elastic-plastic material elastic-plastic crack growth resistance at a crack ex tension of 0.1 inches. The safety extension margi n that is demonstrated in meeting the limits of Section 6.2.2 should be identified and margin justified for the classes of loadingload ing considered. The methodology outlined above has been bee n demonstrated in ReferenceRefe rence 22, where five simple geo metries were geometries we re analyzed with assumed dimensions that represented a w ide variety of PWR wide locations. Because of the uncertainty in the applied stresses and the conservati internal s locations. internals conservatism sm of the materi al fracture toughness, no safety margins bounding material marg in s were applied to the critical flaw fl aw size calculations. calcul ations. The five simple geometries analyzed are described below:
- A semi-elliptica semi-ellipticall surface ccrack rack in a flat fl at plate pl ate that can represent: (i) a semi-elliptical surface in side or outside flat surface of baffle plates; crack at the inside pl ates; (ii) a semi-elliptical sUlfacesurface crack in side or outside flat at the inside fl at surface of a core support barrel; or (i ii) a semi-elliptical (iii) semi -elliptical surface 6-10 6* 10 IPEC_PA_OAG0000160
Evaluation Me/lwdologie.~ Emlua/ion Methodologies crack at the inside smface of a core barrel. The flaw in side or outside sUiface fl aw can be either ccircumferential ircumferential (e.g., in the circumferential weld scam seam of the core barrel) or longitudinal (e.g., in the vertical seam). A flat plate solution is adequate for these cylinders when the radius to thickness weld scam). (R/t) is greater than 36 and loading level ratio (Rlt) leve l is fairly low;
- A through-wall crack in the center of a plate that can represent: (i) a through-wall crack in baffle plates; (ii (ii)) a through-wall crack in the flat surface of a core SUppOl1 support barrel; (iii) a circumferential through-wall crack (e.g. in the circumferential weld seam) in a core barrel; barrel ;
or (iv) a longitudinal through-wall crack (e.g. in the vel1ical vertical weld seam) in a core barrel; ban*eI;
- A through-wall edge crack in a flat plate that can represent: (i) a through-wall ccrack rack emanating from the side edges of baffle plates; or (ii) a through-wall through-wa ll crack eemanating manating from the edge of former plates;
- through-wa ll edge crack emanating from a 1I and 3/8-inch A through-wall 3/S-inch diameter hole that can represent:
(i) two through-wall edge cracks eemanating manating from baffle-to-former baffle-to-fonner bolt holes or cooling holes; or (ii) two through-wall edge cracks emanating from holes in fonner former plates; and
- A quarter-circular corner crack in a rectangular bar that ca cann represent: (i) a quarter-circular crack in the corner of baffle plates; or (ii) a quarter-circu quarter-circular lar crack at the inside in side corner of a core support barrel.
Although no detailed loading/stress information infonnation was available for the various geometries, max imum normal operating stress (2.5 ksi) and the limited information was used to estimate the maximum maximum LOCA stress (10 ksi) in highly irradiated components. For com pleteness, however, completeness, remote tensile stress levels up to 50 ksi were analyzed. For the three types of postulated through-wall flaws, flaws, the analyses showed that the critical flaw is more limiting for a through-wall edge crack or a through-wall edge crack emanating from a hole than for a through-wall centered crack. For a medium-width baffle plate (26-inch), the critical flaw length for a through-wall crack is 22.S22.8 inches at 2.5 ksi and 7.62 inches at 10 ksi. For the same baffle plate, the critical flaw length for a through-wall edge crack is 11.3 I J.3 inches at 2.5 ksi and 2.65 inches at 10 ksi. 6-11 IPEC_PA_OAG0000161
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