ju ELECTRIC POWER RESEARCH INSTITUTE MRP Materials Reliability Program MRP 2010-065 (via email) October 27, 2010 Document Control Desk U.S. Nuclear Regulatory Commission 11555 Rockville Pike Rockville, MD 20852 Subject: Document Transmittal: MRP Letter 2008-036 dated June 12, 2008; Subject: Minutes of the Expert Panel Meetings on Expansion Criteria for Reactor Internals I&E Guidelines Reference: 1) EPRI report "Materials Reliability Program: Pressurized Water ReactorInternals Inspection and Evaluation Guidelines (MiRP-22 7-Rev. 0)" EPRI Palo Alto, CA, 2008, 1016596. 2) REQUEST FOR ADDITIONAL INFORMATION NUMBER 4, RE: ELECTRIC POWER RESEARCH INSTITUTE TOPICAL REPORT 1006596,'MATERIALS RELIABILITY PROGRAM: PRESSURIZED WATER REACTOR INTERNALS INSPECTION AND EVALUATION GUIDELINES (MRP-227-REV. 0)' (TAC NO. ME0680) To Whom It May Concern: Two copies of the subject document are being forwarded to assist the NRC Staff in its review of MRP- 227, Reference 1. Specifically, the document is being provided to supplement the response to RAI 26 of Reference 2. If you have any questions on this subject, please contact Anne Demma at 650-855-2026. Sincerely, Terry McAlister SCANA Chairman, Materials Reliability Program Cc: James Lash, First Energy Sheldon Stuchell, NRC (with 8 copies of Subject document) Victoria Anderson, NEI Chuck Welty, EPRI Anne Demma, EPRI Together ... Shaping the Future of Electricity PALO ALTO OFFICE 3420 Hillview Avenue, Palo Alto, CA 94304-1338 USA * 650.855.2000 * Customer Service 800.313.3774 * www.epri.com
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ju ELECTRIC POWERRESEARCH INSTITUTE
MRP Materials Reliability Program MRP 2010-065
(via email)
October 27, 2010
Document Control DeskU.S. Nuclear Regulatory Commission11555 Rockville PikeRockville, MD 20852
Subject: Document Transmittal: MRP Letter 2008-036 dated June 12, 2008; Subject: Minutes of theExpert Panel Meetings on Expansion Criteria for Reactor Internals I&E Guidelines
Reference:1) EPRI report "Materials Reliability Program: Pressurized Water Reactor Internals Inspection and
2) REQUEST FOR ADDITIONAL INFORMATION NUMBER 4, RE: ELECTRIC POWERRESEARCH INSTITUTE TOPICAL REPORT 1006596,'MATERIALS RELIABILITYPROGRAM: PRESSURIZED WATER REACTOR INTERNALS INSPECTION ANDEVALUATION GUIDELINES (MRP-227-REV. 0)' (TAC NO. ME0680)
To Whom It May Concern:
Two copies of the subject document are being forwarded to assist the NRC Staff in its review of MRP-227, Reference 1. Specifically, the document is being provided to supplement the response to RAI 26 ofReference 2.
If you have any questions on this subject, please contact Anne Demma at 650-855-2026.
Sincerely,
Terry McAlisterSCANAChairman, Materials Reliability Program
Cc: James Lash, First EnergySheldon Stuchell, NRC (with 8 copies of Subject document)Victoria Anderson, NEIChuck Welty, EPRIAnne Demma, EPRI
Together ... Shaping the Future of Electricity
PALO ALTO OFFICE3420 Hillview Avenue, Palo Alto, CA 94304-1338 USA * 650.855.2000 * Customer Service 800.313.3774 * www.epri.com
M R P Materials Reliability Program MRP 2008-036
(Via email)
June 12, 2008
To: Reactor Internals Focus Group
Subject: Minutes of the Expert Panel Meetings on Expansion Criteria for Reactor Internals I&EGuidelines
Expert panel meetings were held at the EPRI office in Charlotte to generate expansion criteriafor the Reactor Internals I&E Guidelines for the Westinghouse and CE components on April 3 0 th
and for the B&W components on May 1s 2008.
The participants on the April 30'h meeting were: Glenn Gardner, Dominion; Tim Wells, SouthernNuclear; David Whitaker, Duke Energy; Ted Huminski, Progress Energy; Cheryl Boggess,Westinghouse; Randy Lott, Westinghouse; John Keilb, Westinghouse; Bob Nickell, Anatech;and Anne Demma, EPRI.
The participants on the May lst meeting were: Glenn Gardner, Dominion; Tim Wells, SouthernNuclear; David Whitaker, Duke Energy; Steve Fyfitch, Areva; Hongqing Xu, Areva; BillBehnke, Areva; Brad Thigpen, Areva; Bob Nickell, Anatech; and Anne Demma, EPRI.
The objectives of the meetings were to review the inputs provided by the NSSS vendors onexpansion criteria prior to the meetings and to make decisions on expansion criteria during thesemeetings.
The process used to generate the expansion criteria was consistent and repetitive to supportconsistency in decision making.
The process steps are outlined below:- Perform integrated review of information for the specific components- Define key contributors- Consider impacts from key contributors- Generate consensus recommendation
Page I of 2 MRP 2008-036
The results from these steps were recorded in specific sections of a worksheet for eachcomponent and the information that each section contains is explained below.
Section Definition
SECTION 1 Expansion This section contains information describing the component, theComponent degradation and effect, and the Inspection Examination MethodIndentification and Coverage.
SECTION 2 Linked This section contains information describing ihe PrimaryPrimary Component Component, Inspection characteristics, and Disposition/Evaluation
of inspection results.
SECTION 3 Comparison This subsection identifies key factors between the Primary andof Key Factors Expansion components that contribute to the expansion
recommendation.
SECTION 4 Other This subsection identifies additional considerations that support theConsiderations expansion criteria and timing not captured already. Items such as
the impacts of plant modifications or design differences that mightaffect the generic recommendation.
SECTION 5 Expansion This subsection identifies the Expansion Recommendation andRecommendation summarizes the Basis supporting the recommendation. The
information in this section is the culmination of the analysis,information, and results presented in the entire worksheet and theexpert panel process. The expansion recommendation and thebasis for that conclusion are documented in this section.
The panel worksheet descriptions for Westinghouse, CE, and B&W components are attached inAttachments 1, 2 and 3, respectively.
If you have any questions or concerns, please contact Anne Demma (ademma(iaýepri.com, 650-855-2026).
Best Regards,Anne ODenmnaProject ManagerEPRI Materials Reliability Program
Cc: Christine King
Page 2 of 2 MRP 2008-036
ATTACHMENT 1
Westinghouse Expansion Components
Expansion Criteria Determination Expert Panel Worksheets:Lower support column bolts
Component Description and Data Sources
Section 1: Expansion Component Identification
Name: Lower Support Assembly Lower support column bolts MRP-232 DRAFT
Description/Figure: Figure 4-41 and 4-42 MRP-227 Draft C
When: no later than five refueling cycles following 25 EFPY, MRP-227 DRAFT Cwith subsequent examination after 10 to 15 additional EFPYto confirm stability of bolting pattern. Re-examination forhigh-leakage core designs requires continuing examinationson a ten-year interval.
Inspection Data: 100% of accessible bolts or as supported by MRP-232 DRAFTplant-specific justification. Heads accessible from the coreside. UT accessibility may be affected by complexity of headand locking device designs. Any detectable recordable flaw isconsidered.
Operating Experience: observed industry failures in primary MRP- 191component
Plant Specific Considerations:
Additional Considerations: All plants MRP-232 DRAFT
Section 5: Final Expansion Recommendation
Recommendation: >5% of baffle-former bolts confirmed failedon four baffle plates the largest distance from the core(presumed to be lowest dose location). UT Inspection oflower support column bolts within next 3 fuel cycles.Percentage is based only on bolts inspected.
Basis: 60 year irradiation doses in low fluence plate bolts 13-45 MRP-230 DRAFTdpa (former levels 1-8). Majority of support column boltsbelow 10 dpa at 60 years. Fluence distribution flatter on coreplate. Structure is generally a flaw tolerant design and highlyredundant.
When: no later than five refueling cycles following 25 EFPY, MRP-227 DRAFT Cwith subsequent examination after 10 to 15 additional EFPYto confirm stability of bolting pattern. Re-examination forhigh-leakage core designs requires continuing examinationson a ten-year interval.
Inspection Data: 100% of accessible bolts or as supported by MRP-232 DRAFTplant-specific justification. Heads accessible from the coreside. UT accessibility may be affected by complexity of headand locking device designs. Any detectable recordable flaw isconsidered.
Operating Experience: Observed industry failures in baffle-former bolts. French experience correlates with high fluenceseams. Limited experience in US plants more random.
Plant Specific Considerations:
Additional Considerations: Not all bolts are accessible due topresence of thermal shield or neutron pads. More areaccessible if neutron pads are used. Ability to inspectbarrel-former bolts otherwise is the same as for baffle-formerbolts.
Section 5: Final Expansion Recommendation
Recommendation: >5% of baffle-former bolts confirmed failedon four plates at the largest distance from the core (presumedto be lowest dose location). UT Inspection of lower supportcolumn bolts within next 3 fuel cycles. If>5% of coresupport column bolts then UT inspection of core barrel bolts.Percentage is based only on bolts inspected.
Basis: 60 year irradiation doses in low fluence plate bolts 13-45 MRP-230 DRAFTdpa (former levels 1-8). Majority of barrel-former boltsbelow 5 dpa at 60 years. Fluence distribution flatter on coreplate. Structure is a highly redundant design.
When: no later than 2 refueling outages from the beginning of MRP-227 DRAFT Cthe license renewal period and subsequent examination on aten-year interval.
Inspection Data: 100 % of one side of the accessible surfaces of MRP-232 DRAFTthe selected weld and adjacent base metal.
Additional Considerations: All plants MRP-232 DRAFT
Section 5: Final Expansion Recommendation
Recommendation: If an observed surface breaking indication>2" in the Primary component is confirmed then a VT-1inspection of the core barrel to support plate weld isperfoined within completion of one refueling outage.Extensive confirmed indications require further expansion.
Basis: SCC is projected as a slowly progressing degradation.Fluence at both flanges well below IA.SCC threshold.Structure is flaw tolerant.
Plant Specific Considerations: Majority of core supportstructure should be in compression under normal operatingconditions. However, some designs with "winged" structuremay have local tensile stresses.
Additional Considerations: All plants MRP-232 DRAFT
Section 5: Final Expansion Recommendation
Recommendation: Any visual indication >2" in the Primarycomponent if confirmed would require complete visual (VT-1) or volumetric (UT) inspection of core barrel to lowersupport plate weld within completion of one refueling outage.Extensive cracking in the expanded welds would requirevisual (VT-1) inspection of the uipper six inches of accessiblesurfaces of the lower support column body within three fuelcycles of original observation.
Basis: The upper six inches of this component includes the MRP-230 DRAFTportion that is susceptible to IASCC.
Action: Change I&E Guidelines Table 4-3 and 4-6 to remove expansion link. Also revise text insections 3 and 5.Assigned: Demma/Nickell
Name: Core Barrel Assembly Lower support column bodies MRP-232 DRAFT
Description/Figure: Figure 4-42 MRP-227 Draft C
Degradation/Effect: IASCC/Cracking MRP-232 DRAFT
Section 2: Linked Primary Component
Name: Control Rod Guide Tube Assembly Lower flanges MRP-232 DRAFT
How (Inspection Technique): VT-i MRP-232 DRAFT
When: no later than 2 refueling outages from the beginning of MRP-227 DRAFT Cthe license renewal period and subsequent examination on aten-year interval.
Inspection Data: 100 % of accessible weld surfaces and adjacent MRP-232 DRAFTbase metal to determine the presence of crack-like surfaceflaws in flange welds.
Disposition/Evaluation:
Section 3: Comparison of Key Factors
Primary Expansion
Irradiation dose: 7 x 1020 to 1 x < 5 x 1021 MRP-1911021
Plant Specific Considerations: Although drawings of lowerflange weld on CRGT assemblies indicate cast stainless steel,a preliminary review of manufacturing records indicates thatthese components were often fabricated from 304 plate.
Additional Considerations: All plants MRP-232 DRAFT
Section'5: Final Expansion Recommendation
Recommendation: Cracking confirmed in two or more CRGTflanges should expand to a visual inspection for failures inlower support columns within three fuel cycles of originalobservation.
Basis: Primary cracking concern is SCC. (High fluence limitedto upper sections of support.) Operating stresses tend to becompressive and system is highly redundant. CRGTconfiguration has similarities to support column. Welds inCRGT should have similar duplex structure to castings.
How (Inspection Technique): VT-I MRP-232 DRAFTWhen: no later than 2 refueling outages from the beginning of MRP-227 DRAFT C
the license renewal period and subsequent examination on aten-year interval.
Inspection Data: 100 % of accessible weld surfaces and adjacent MRP-232 DRAFTbase metal to determine the presence of crack-like surfaceflaws in flange welds.
Disposition/Evaluation:
Section 3: Comparison of Key Factors
Primary Expansion
Irradiation dose: 7 x 1020 to 1 x 1 x 1022 to 5 x MRP-1911021 1022
Temperature: T-hot >608 MRP-191
Mechanical Load: Weld Weld MRP-191
Material: CF8 304 SS/Weld 308 MRP-191
Other:
ATTACHMENT 1
Westinghouse Expansion Components
Section 4: Other Considerations
Operating Experience:
Plant Specific Considerations:
Additional Considerations: All plants MRP-232 DRAFT
Section 5: Final Expansion Recommendation
Recommendation: Flux thimble insertion/withdrawal to bemonitored at each inspection interval. Visual (VT-3)examination of BMI column bodies as indicated by difficultyof insertion/withdrawal of flux thimbles or observed crackingin two or more CRGT lower flanges.
Basis: The BMI column bodies guide BMI flux thimbles intocore. There is no significant structural or pressure boundaryfunction for these columns. Failure of a BMI colunm bodywould result in a misalignment of the structure and difficultieswith insertion. Observation of cracking in CRGT flanges orlower support columns would indicate an active mechanismthat might also affect the BMI columns.
Action: Re-evaluate. Eliminate from Expansion and re-categorize BMI column bodies.Action: Westinghouse
Operating Experience: Generally Good. Recent experience isaccess is fairly achievable for Primary
Plant Specific Considerations:
Additional Considerations: Applies to non-bolted core shroudplants. Fatigue in this weld is substantially less than in theflexure weld so it is not a significant concern for this weld
Section 5: Final Expansion Recommendation
Recommendation: If an observed surface breaking indication>2" in the Primary component is confirmed then a VT-Iinspection of the lower flange welds is performed bycompletion of the next refueling outage.
Basis: SCC is projected as a slowly progressing degradation.Fluence at both flanges well below IASCC threshold.Structure is flaw tolerant. Need an estimate of crack growthrate.
Observation: should use caution in determining supplementary examination. Should not presumeacceptance criteria.
Observation: Fatigue assessment could provide insights for lower flange.
Action: Primary component inspection recommendation should be investigated and changed ifneeded to provide clarity on inspection for single or dual side inspection. Driver in determiningfinal recommendation is to determine surface or full penetration.
Name: Core Support Barrel Assembly Core barrel welds MRP-232 DRAFT
Description/Figure: Figure 4-15, 4-20, 4-22 MRP-227 Draft C
Degradation/Effect: SCC - Cracking MR-P-232 DRAFT
Examination Method/Coverage: Visual (VT-1), 100 % of one MRP-232 DRAFTside of the accessible weld and adjacent base metal surfacesfor the weld with the highest calculated operating stress.
Section 2: Linked Primary Component
Name: Core Support Barrel Assembly Upper flange weld MRP-232 DRAFT
Degradation/Effect: SCC - Cracking MRP-232 DRAFT
How (Inspection Technique): VT-I MRP-232 DRAFTWhen: no later than 2 refueling outages firom the begilming of MRP-227 Draft C
the license renewal period. Subsequent examinations on aten-year interval.
Inspection Data: 100% of the accessible surfaces of the upper MRP-227 Draft Cflange weld.
Additional Considerations: Applies to non-bolted core shroudplants
Section 5: Final Expansion Recommendation
Recommendation: If an observed surface breaking indication>2" in the Primary component is confirmed then a VT-Iinspection of the lower flange welds is performed bycompletion of the next refueling outage. If observed surfaceindication > 2".is confirmed in Lower core barrel flange weldthen perform VT-I inspection of all remaining accessible corebarrel welds by completion of the same refueling outage.
Basis: Barrel is generally flaw tolerant. Through wall crackingrequired for critical crack. Crack growth rate should be smallcompared to size of structure.
ATTACHMENT 2
Combustion Engineering Expansion Components
Expansion Criteria Determination Expert Panel Worksheets:Core support column welds and casting
Component Description and Data Sources
Section 1: Expansion Component Identification
Name: Lower Support Structure Core support column welds MRP-232 DRAFTand castings
Description/Figure: Figure 4-20, 4-21, 4-22 MRP-227 Draft C
How (Inspection Technique): VT-I MRP-232 DRAFTWhen: no later than 2 refueling outages from the beginning of MRP-227 Draft C
the license renewal period. Subsequent examinations on a ten-year interval.
Inspection Data: 100% of the accessible surfaces of the upper MRP-227 Draft Cflange weld.
Disposition/Evaluation:
Section 3: Comparison of Key Factors
Primary Expansion
Irradiation dose: <1020 1 x 1021 to 1x MRP-1911022
Temperature: T-hot T-cold MRP- 191
Mechanical Load: Weld Weld MRP-191
Material: 304 SS/Weld 308 304 SS/CF8 MRP-191
Other:
ATTACHMENT 2
Combustion Engineering Expansion Components
Expansion Criteria Determination Expert Panel Worksheets:Core support column welds and casting
Component Description and Data Sources
Section 4: Other Considerations
Operating Experience: No Indications noted under currentVT-3 practices.
Plant Specific Considerations: Multiple column designs.Location of casting within plant should be identified. PotentialThermal Embrittlement must be accounted for in analysis.
Additional Considerations: All plants except those with coreshrouds assembled with full-height shroud plates
Basis: Primary cracking concern is SCC. (High fluence limited MRP-230 Draftto upper sections of support.) Operating stresses tend to becompressive and system is highly redundant. Large weldsshould have a duplex structure similar to castings.
Parking Lot: Core Group to decide if Cast version should stay as an Expansion component orbecome a Primary component. Potential RAI.
Observation: less rigorous exam from a more rigorous will attract concern under reviews.
Action: Determine distance criteria compatibility to support VT-I examination recommendation.Consider economics. Westinghouse?
Action: White paper to assess recommendation to support a VT-3 versus the current VT-1. IfVT-3 is acceptable move component to Existing category.Assigned: Westinghouse (Kielb)/Gardner (Dominion Millstone)
When: no later than 2 refueling outages from the beginning of MRP-227 Draft Cthe license renewal period and subsequent examination on aten-year interval.
Inspection Data: Axial and horizontal weld seams at the core MRP-227 Draft Cshroud re-entrant corners as visible from the core side of theshroud, within six inches of central flange and horizontalstiffeners.
Disposition/Evaluation:
Section 3: Comparison of Key Factors
Primary Expansion
Irradiation dose: 1 x 1022 to 5 x 1022 1 x 1022 to 5 x 1022 MRP-191
Operating Experience: No observations. Core side visual.Recent VT-i inspections returned no indications.
Plant Specific Considerations:
Additional Considerations: Plant designs with core shroudsassembled in two vertical sections
Section 5: Final Expansion Recommendation
Recommendation: Any visual indication >2" in an axial weldseam if confirmed would require complete visual (VT-i) orvolumetric (UT) inspection of the axial weld seams at the coremid-plane within completion of one refueling outage.
Basis: Initial crack growth rate is expected to be high within theexamination region. Driving force for 'crack growth expectedto drop sharply beyond the examination region.
Observation: Concern on initial 1" detection ability (opening and length)f
Action: Verify gap permitted in axial joint for Millstone. Confirm drawings used consistent.Assigned: Westinghouse (Kielb)/Gardner (Dominion Millstone). Glenn's drawings show non-weldedseam with permitted .016 gap, dwg E-STD-164-25 sheets 1 and 2, Rev. 5
Examination Method/Coverage: Visual (VT-1), Axial weld MRP-232 DRAFTseams other than the core shroud re-entrant comer welds atthe core mid-plane, plus ribs and rings
When: no later than 2 refueling outages from the beginning of MRP-227 Draft Cthe license renewal period and subsequent examination on aten-year interval.
Inspection Data: Axial weld seams at the core shroud re-entrant MRP-227 Draft Ccorners, at the core mid-plane (± three feet in height) asvisible from the core side of the shroud.
Disposition/Evaluation:
Section 3: Comparison of Key Factors
Primary Expansion
Irradiation dose: I x 1022 to 5 x 1022 1 x 1022 to 5 x 1022 MRP-191
Operating Experience: There are a large number of ribs, ringsand other stiffeners welded to the back side of this coreshroud. Irradiation induced stress relaxation should eliminateweld residual stresses present at the beginning of operation.
Plant Specific Considerations:
Additional Considerations: Plant designs with core shroudsassembled with full-height shroud plates.
Section 5: Final Expansion Recommendation
Recommendation: Any visual indication >2" in an axial weldseam if confirmed would require complete visual (VT-1) orvolumetric (UT) inspection of the axial weld seams at the coremid-plane within completion of one refueling outage.Extensive cracking in the expanded axial welds would requirevisual (VT-1) inspection of accessible ribs and rings welds.
Basis: Axial welds are the initial inspection component.Structure is generally a flaw tolerant design. Ribs and ringsare redundant and do not represent a single point componentitem failure that would prevent continued function.
Examination Method/Coverage: Ultrasonic (UT), 100 % (or as MRP-232 DRAFTsupported by plant-specific analysis) of core support columnbolts with neutron fluence exposures > 3 dpa.
When: no later than five refueling cycles following 25 EFPY. MRP-227 Draft CFollow-up examination after additional 10-15 EFPY toconfirm stability of bolting pattern. Re-examination for high-leakage core designs requires continuing inspections on a ten-year interval.
Inspection Data: 100% of accessible bolts, or as supported by MRP-227 Draft Cplant-specific justification. Heads are accessible from thecore side. UT accessibility may be affected by complexity ofhead and locking device designs.
Disposition/Evaluation:
Section 3: Comparison of Key Factors
Primary Expansion
hTadiation dose: 1 X 1021 to 1 X 1 X 1021 to 1 x MRP-1911022 1022
Plant Specific Considerations: verify bolts are present in design
Additional Considerations: Applies to Bolted designs. There isno current requirement for inspecting lower support columnbolts in plants with welded core shrouds. Industry trendsshould be evaluated for possible revisions to I&E Guidelines.
Section 5: Final Expansion Recommendation
Recommendation: : >5% of bolts confirmed failed on fourplates at the largest distance from the core (presumed to belowest dose location). UT Inspection of lower support columnbolts within next 3 fuel cycles.
Basis: The lowest dose core shroud bolts are roughly equivalent MRP-230 Draftto leading core support column bolts. Temperatures andstresses are lower.
Observation: Vendor to ensure inspection examination detection rate is high.
Action: Check fluence distribution to ensure high dose plate assumption.Assigned: Westinghouse (Lott)
Suggest use dpa instead of fluence or cite a conversion factor. Dpa is preferred, since used inMRP-175 i
When: no later than five refueling cycles following 25 EFPY. MRP-227 Draft CFollow-up examination after additional 10-15 EFPY toconfirm stability of bolting pattern. Re-examination for high-leakage core designs requires continuing inspections on a ten-year interval.
Inspection Data: 100% of accessible bolts, or as supported by MRP-227 Draft Cplant-specific justification. Heads are accessible from thecore side. UT accessibility may be affected by complexity ofhead and locking device designs.
Disposition/Evaluation:
Section 3: Comparison of Key Factors
Primar Expansion
Irradiation dose: 1 X 1022 to 5 x 1 X 1021 to 1 x MRP-1911022 1022
Additional Considerations: Applies to Bolted designs
Section 5: Final Expansion Recommendation
Recommendation: >5% of bolts confirmed failed on four lowestplates at the largest distance from the core (presumed to belowest dose location). UT Inspection of lower supportcolumn bolts within next 3 fuel cycles. If>5% of coresupport column bolts then UT inspection of core barrel bolts.
Basis: The lowest dose core shroud bolts still lead fluence onbarrel by factor of 5. Temperatures and stresses are lower.
Additional Considerations: power uprates and baffle-fuelinteraction
Section 5: Final Expansion Recommendation
Recommendation: Confirmed rejectable indications in greaterthan or equal to 5% (or, 43) of the FB bolts, provided none ofthe rejected bolts are in former elevations 3, 4, and 5, or greaterthan 25% of the bolts on a single plate, shall trigger anevaluation of the internal baffle-to-baffle bolts for the purposeof determining whether to inspect or replace them. Thisevaluation may include external baffle-to-baffle bolts and corebarrel-to-former bolts for the purpose of determining whether toreplace them.
Basis: Redundancy; past operability analyses support rows 3-5;functionality analysis supports minimal expected failures; onlyinternal BB bolts are accessible and potentially inspectablewhile the external BB and CB bolts are inaccessible
Recommendation: Confirmed rejectable indications in greaterthan or equal to 1% (or, 11) of the FB or internal BB boltlocking devices shall trigger an evaluation of the lockingdevices for the external baffle-to-baffle bolts and core barrel-to-former bolts for the purpose of determining continued operationor replacement.
Basis: Redundancy; concerns with loose parts and potential fueldamage; only the locking devices of the FB and internal BBbolts are accessible and inspectable while the locking devices ofthe external BB and CB bolts are inaccessible
Recommendation: Confirmed rejectable= indications exceeding10% of either primary component (UCB or LCB bolts) shalltrigger UT inspection of 100% of the accessible LTS bolts andis required by completion of the next refueling outage
Basis: Redundancy; engineering judgment based on flawtolerance of the assembly; no safety consequences with UTSbolts (economic concerns)
Recommendation: Confirmed rejectable indications exceeding10% of either primary component (UCB or LCB bolts) shalltrigger UT inspection of 100% of the accessible FD bolts and isrequired by completion of the next reftieling outage
Basis: Redundancy; engineering judgment based on flawtolerance of the assembly; no safety consequences with UTSbolts (economic concerns)
Recommendation: Confirmed rejectable indications exceeding10% of either primary component (UCB or LCB bolts) shalltrigger UT inspection of 100% of the accessible SSHT bolts andis required by completion of the next refueling outage
Basis: Redundancy; engineering judgment based on flawtolerance of the assembly; no safety consequences with UTSbolts (economic concerns)
Recommendation: Confirmed rejectable indications exceeding10% of either primary component (UCB or LCB bolts) shalltrigger UT inspection of 100% of the accessible UTS bolts andis required by completion of the next refueling outage
Basis: Redundancy; engineering judgment based on flawtolerance of the assembly; no safety consequences with UTSbolts (economic concerns)
the former plates and it is required by completion of the nextrefueling outage. Gross cracking (if confirmed) of the formerplate shall trigger an evaluation of the inspectability of the corebarrel cylinder.
Basis: Flaws (i.e., Cracking) not detected by VT-3 examination MRP-210having a small COD are considered insignificant and is stillsafely below critical flaw size even if it extends outside the one-inch zone of the baffle plates; baffle plate and former platerelative motion initiates bolt prying action, which is mostprevalent in locations having insignificant ISR/IC (i.e., upperand lower former plate areas), and for cracks to grow, due to thesmall pressure difference across the baffle plates, there wouldhave to be such a prying action that would result in a largeCOD.
Recommendation: Confirmed evidence of damage, grosslycracked, or fractured nozzle material shall trigger VT-3examination of 100% of the accessible surfaces at the 4 screwlocations (at every 90') of the CRGT spacer castings and it isrequired by completion of the next refueling outage
Basis: Higher mechanical stress on the primary item; fabricationdefect unlikely; damage must be service-induced; grossdegradation consequences unacceptable
Other: Potential Need CMTRs for allsynergistic CASSeffect of TE/IE
Section 4: Other Considerations
Operating Experience: none
Plant Specific Considerations:
Additional Considerations:
Section 5: Final Expansion Recommendation
Recommendation: Confirmed evidence of separation, grossdamage, or a missing spider arm for two or more locations shalltrigger VT-3 examination of 100% of the accessible surfaces at
the 4 screw locations (at every 90') of the CRGT spacercastings and it is required by completion of the next refuelingoutage
Basis: Looking for more than a single random fabricationdefect; higher residual stresses present on the primary item;consequences of arm failure are minimal
Inspection Data: 100% of accessible surface to detect surface MRP-231/MRP-227irregularities (including damaged, grossly cracked, or fracturedmaterial)
Disposition/Evaluation: ASME Code MRP-231/MRP-227
Section 3: Comparison of Key Factors
Primary Expansion
Irradiation dose: (not a factor) (not a factor) MRP-229/MRP-231
Temperature: -600 F -600 F MRP-229/MRP-231
Mechanical Load: Low Low MRP-229/MRP-231
Material: CF8 CF3M MRP-229/MRP-231
Other: Need CMTRs for allCASS
Section 4: Other Considerations
Operating Experience: none
Plant Specific Considerations:
Additional Considerations:
Section 5: Final Expansion Recommendation
Recommendation: Confirmed evidence of damage, grosslycracked, or fractured material in two or more vent valve discsshall trigger VT-3 examination of 100% of the accessiblesurfaces at the 4 screw locations (at every 900) of the CRGTspacer castings and it is required by completion of the next
Recommendation: Confirmed evidence of separation, grossdamage, or a missing locking weld for two or more locationsshall trigger VT-3 examination of the expansion categorylocking welds and it is required by completion of the next
Basis: Looking for more than a single random fabricationdefect; potential for PWSCC of the weld (redundancy); lownominal loads to cause complete separation; nonexistent for theguide block bolt; expansion item dowels are captured withoutweld (for lower but not upper)
When: No later than two refueling outages from the beginning MRP-231/MRP-227of the license renewal periodInspection Data: 100% of the locking welds of the 24 dowel-to- MRP-231/MRP-227guide block welds to detect locking weld separation
Recommendation: Confirmed evidence of separation, grossdamage, or a missing locking weld for two or more locationsshall trigger VT-3 examination of the expansion categorylocking welds and it is required by completion of the next
Basis: Looking for more than a single random fabricationdefect; potential for PWSCC of the weld (redundancy); lownominal loads to cause complete separation; nonexistent for theguide block bolt; expansion item dowels are captured withoutweld (for lower support pads but not upper support pads)
Recommendation: Confirmed evidence of separation, grossdamage, or a missing spider arn for two or more locations shalltrigger VT-3 examination of 100% of the accessible expansioncategory lower fuel assembly support pad items and it isrequired by completion of the next refueling outage
Basis: Looking for more than a single random fabricationdefect; primary item is subject to TE/IE and expansion itemonly to IE;