L-PI-12-078, PWR (Pressurized Water Reactor) Vessel Internals Program for Fulfillment of License Renewal Commitment 25

PWR (Pressurized Water Reactor) Vessel Internals Program for Fulfillment of License Renewal Commitment 25

ML12276A041
Person / Time
Site:	Prairie Island
Issue date:	10/01/2012
From:	Sorensen J Northern States Power Co, Xcel Energy
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-PI-12-078
Download: ML12276A041 (18)

Text

@ Xcel Energym U S Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Prairie Island Nuclear Generating Plant Units 1 and 2 Dockets 50-282 and 50-306 Renewed License Nos. DPR-42 and DPR-60 PWR [Pressurized Water Reactor1Vessel lnternals Program for Fulfillment of Prairie Island Nuclear Generating Plant (PINGP) License Renewal Commitment 25 By letter dated April 11,2008 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML081130666), the Nuclear Management Company, LLC, (NMC') submitted an Application for Renewed Operating Licenses (LRA) for PINGP, Units 1 and 2. The LRA included commitment 25 related to the submittal of the PINGP PWR Vessel lnternals Program (PVIP) for NRC review and approval. In a letter dated May 12,2009 (ML091470263), NSPM updated the LRA to incorporate information regarding the new PWR vessel internals program. Renewed operating licenses DPR-42 and DPR-60 were issued June 27,201 1 including commitment 25.

The implementation schedule for part B of commitment 25 was August 9, 201 1 (Unit 1) and October 29,2012 (Unit 2). The NRC issued Regulatory Issue Summary (RIS) 201 1-07, "License Renewal Submittal Information for Pressurized Water Reactor lnternals Aging Management," (MLI 11990086) on July 21, 201 1. In accordance with the guidance of RIS 201 1-07, by letter dated August 8, 201 1 (MLI 12210299), NSPM revised the date for submittal of the PINGP PVlP to October 1, 2012. , "PWR Vessel lnternals Program", provides the PINGP PVlP in fulfillment of commitment 25, part B.

The PINGP PVlP is based on ERPl Report 1016596, "Materials Reliability

• On September 22, 2008, NMC transferred its operating authority to Northern States Power Company, a Minnesota corporation, doing business as Xcel Energy (hereafter "NSPM"). By letter dated September 3, 2008 (ML082470648), NSPM assumed responsibility for actions and commitments previously submitted by NMC.

1717 Wakonade Drive East e Welch, Minnesota 55089-9642 Telephone: 651.388.1121

Document Control Desk Page 2 Program (MRP): Pressurized Water Reactor lnternals Inspection and Evaluation Guidelines" (MRP-227-A), which has been endorsed by the NRC (ML120270374). The NRC December 16, 201 1 safety evaluation for MRP-227, Rev 0 (MLI 1308A770),

contained eight licensee action items for licensees to consider. NSPM will provide the considerations of these eight licensee action items to the NRC by April I, 2013.

If there are any questions or if additional information is needed, please contact Mr. Dale Vincent, P.E., at 651-388-1 121, Summary of Commitments This letter contains no new commitments and no revisions to existing commitments.

This letter fulfills the requirements of license renewal commitment 25, part B.

L Joel P. Sorensen Acting Site Vice President, Prairie Island Nuclear Generating Plant Northern States Power Company - Minnesota Enclosures (1) cc: Administrator, Region Ill, USNRC Project Manager, PINGP, USNRC Resident Inspector, PINGP, USNRC

Enclosure 1 Prairie Island Nuclear Generating Plant, Units 1 and 2 PWR Vessel lnternals Program Page 1 of 16

MRP-227-A Primary Inspection Components Expansion Link Examination Item Applicability Effect (Mechanism) Examination Coverage (Note 1) MethodlFrequency (Note 1)

Control Rod Guide All Plants Loss of Material (Wear) None Visual (VT-3) examination no later 20% examination of the number Tube Assembly than 2 refueling outages from the of CRGT assemblies, with all Guide plates (cards) beginning of the license renewal guide cards within each period, and no earlier than two selected CRGT assembly refueling outages prior to the start of examined.

the license renewal period.

Subsequent examinations are required on a ten-year interval.

Control Rod Guide All Plants Cracking (SCC, Fatigue) Bottom-mounted Enhanced visual (EVT-1) 100% of outer (accessible)

Tube Assembly Aging instrumentation examination to determine the CRGT lower flange weld Lower flange welds Management (IE and (BMI) column bodies, presence of crack-like surface flaws surfaces and adjacent base TE) Lower support in flange welds no later than 2 metal on the individual column bodies (cast) refueling outages from the beginning periphery CRGT assemblies.

Upper core plate of the license renewal period and (Note 2).

Lower support subsequent examination on a ten-forginglcasting year interval.

Core Barrel Assembly All Plants Cracking (SCC) Lower Support Periodic enhanced visual (EVT-1) 100% of one side of the Upper core barrel flange column bodies (non examination, no later than 2 refueling accessible surfaces of the weld cast) outages from the beginning of the selected weld and adjacent Core barrel outlet license renewal period and base metal (Note 4).

nozzle welds. subsequent examination on a ten-year interval.

Core Barrel Assembly All Plants Cracking (SCC, IASCC, Upper and lower core Periodic enhanced visual (EVT-1) 100% of one side of the Upper and lower core Fatigue) barrel cylinder axial welds examination, no later than 2 refueling accessible surfaces of the barrel cylinder girth outages from the beginning of the selected weld and adjacent welds license renewal period and base metal (Note 4).

subsequent examination on a ten-year interval.

Page 2 of 16

MRP-227-A Primary Inspection Components Expansion Link Examination Item Applicability Effect (Mechanism) Examination Coverage (Note 1) MethodlFrequency (Note 1)

Core Barrel Assembly All plants Cracking (SCC, Fatigue) None Periodic enhanced visual (EVT-1) 100% of one side of the Lower core barrel flange examination, no later than refueling accessible surfaces of the weld (Note 5) outages from the beginning of the selected weld and adjacent license renewal period and base metal (Note 4).

subsequent examination on a ten-year interval.

Baffle-Former All plants with Cracking (IASCC, None Visual (VT-3) examination, with Bolts and locking devices on Assembly baffle-edge bolts Fatigue) that results in: baseline examination between 20 high fluence seams. 100% of Baffle-edge bolts Lost or broken and 40 EFPY and subsequent components accessible from locking devices examinations and a ten-year interval. core side (Note 3).

Failed or missing bolts Protrusion of bolt heads Aging Management (IE and ISR) (Note 6)

Baffle-Former All plants Cracking (IASCC, Lower support column Baseline volumetric (UT) examination 100% of accessible bolts (Note Assembly Fatigue) Aging bolts, Barrel-former bolts between 25 and 35 EFPY, with 3). Heads accessible from the Baffle-former bolts Management (IE and ISR) subsequent examination on a ten- core side. UT accessibility may (Note 6) year interval. be affected by complexity of head and locking device designs.

Page 3 of 16

MRP-227-A Primary Inspection Components Item Expansion Link Examination Applicability Effect (Mechanism) Examination Coverage (Note 1) MethodlFrequency (Note 1)

Baffle-Former All plants Distortion (Void Swelling), None Visual ((VT-3) examination to check Core side surface as indicated.

Assembly or Cracking (IASCC) that for evidence of distortion, with Assembly results in: baseline examination between 20 (includes: Baffle plates, *Abnormal and 40 EFPY and subsequent baffle edge bolts and interaction with examinations on a ten-year interval.

indirect effects of void fuel assemblies swelling in former *Gaps along high plates) fluence baffle joint

-Vertical displacement of baffle plates near high fluence joint Broken or damaged edge bolt locking systems along high fluence baffle joint Alignment and All plants with 304 Distortion (Loss of load) None Direct measurement of spring height Measurements should be taken Interfacing stainless steel hold within three cycles of the beginning of at several points around the components down springs Note: This mechanism the license renewal period. If the first circumference of the spring, Internals hold down was not strictly identified set of measurements is not sufficient with a statistically adequate spring in the original 'list of age- to determine life, spring height number of measurements at related degradation measurements must be taken during each point to minimize mechanisms' [7]. the next two outages, in order to uncertainty.

extrapolate the expected spring height to 60 years.

Page 4 of 16

MRP-227-A Primary Inspection Components Expansion Link Examination Item Applicability Effect (Mechanism) Examination Coverage (Note 1) MethodlFrequency (Note 1)

Thermal Shield All plants with Cracking (Fatigue) or Loss None Visual (VT-3) no later than 2 refueling 100% of thermal shield Assembly thermal shields of Material (Wear) that outages from the beginning of the flexures.

Thermal Shield results in thermal shield license renewal period. Subsequent Assembly flexures excessive wear, examinations on a ten-year interval.

fracture, or complete separation.

Notes to Table 4-3:

1. Examination acceptance criteria and expansion criteria for the Westinghouse components are in Table 5-3.

2. A minimum of 75% of the total identified sample population must be examined.

3. A minimum of 75% of the total population (examined + unexamined), including coverage consistent with the Expansion criteria in Table 5-3, must be examined for inspection credit.

4. A minimum of 75% of the total weld length (examined + unexamined), including coverage consistent with the Expansion criteria in Table 5-3, must be examined from either the inner or outer diameter for inspection credit.

5. The lower core barrel flange weld may be alternatively designated as the core barrel-to-support plate weld in some Westinghouse plant designs.

6. Void swelling effects on this component is managed through management of void swelling on the entire baffle-former assembly.

MRP-227-A Primary Inspection Components Expansion Link Examination Item Applicability Effect (Mechanism) Examination Coverage (Note 1) MethodlFrequency (Note 1)

Upper lnternals All plants Cracking CRGT lower flange weld Enhanced visual (EVT-1) 100% of accessible surfaces Assembly (Fatigue, Wear) examination. (Note 2).

Upper core plate Re-inspection every 10 years following initial inspection.

Lower lnternals All plants Cracking CRGT lower flange weld Enhanced visual (EVT-1) 100% of accessible surfaces Assembly Aging management (TE examination. (Note 2).

Lower support forging or in Casting) Re-inspection every 10 years castings following initial inspection.

Core Barrel Assembly All plants Cracking Baffle-former bolts Volumetric (UT) examination. 100% of accessible bolts.

Barrel-former bolts (IASCC, Fatigue) Re-inspection every 10 years Accessibility may be limited by Aging Management (IE. following initial inspection. presence of thermal shields or Void Swelling and ISR) neutron pads (Note 2).

Lower Support All plants Cracking Baffle-former bolts Volumetric (UT) examination. 100% of accessible bolts or as Assembly (IASCC, Fatigue) Re-inspection every 10 years supported by plant-specific Lower support column Aging Management (IE following initial inspection. justification (Note 2).

bolts and ISR)

MRP-227-A Primary Inspection Components Item Expansion Link Examination Applicability Effect (Mechanism) Examination Coverage (Note 1) MethodlFrequency (Note 1)

Core Barrel Assembly All plants Cracking (SCC, Fatigue) Upper core barrel flange Enhanced visual (Em-1) 100% of one side of the Core barrel outlet nozzle Aging Management (IE of weld examination. accessible surfaces of the welds lower sections) Re-inspection every 10 years selected weld and adjacent following initial inspection. base metal (Note 2).

Core Barrel Assembly All plants Cracking (SCC, IASCC) Upper and lower core Enhanced visual (EVT-1) 100% of one side of the Upper and lower core Aging Management (IE) barrel cylinder girth examination. accessible surfaces of the barrel cylinder axial welds Re-inspection every 10 years selected weld and adjacent welds following initial inspection. base metal (Note 2).

Lower Support All plants Cracking (IASCC) Upper core barrel flange Enhanced visual (EVT-1) 100% of accessible surfaces Assembly Aging Management (IE) weld examination. (Note 2).

Lower support column Re-inspection every 10 years bodes (non cast) following initial inspection.

Lower Support All plants Cracking (IASCC) Control rod guide tube Visual (Em-1) examination. 100% of accessible support Assembly including the detection of (CRGT) lower flanges Re-inspection every 10 years columns (Note 2).

Lower support column fractured support following initial inspection.

bodes (cast) columns Aging Management (IE)

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MRP-227-A Primary Inspection Components Expansion Link Examination Item Applicability Effect (Mechanism) Examination Coverage (Note 1) MethodlFrequency (Note 1)

Bottom Mounted All plants Cracking (Fatigue) Control rod guide tube Visual (VT-3) examination of BMI 100% of BMI column bodies for Instrumentation System including the detection of (CRGT) lower flanges column bodies as indicated by which difficulty is detected Bottom-mounted completely fractured difficulty of insertion/withdrawal of during flux thimble instrumentation (BMI) column flux thimbles. insertionlwithdrawal.

column bodies Aging Management Re-inspection every 10 years (IE). following initial inspection.

Flux thimble insertion/withdrawal to be monitored at each inspection interval.

Notes to Table 4-6:

1. Examination acceptance criteria and expansion criteria for the Westinghouse components are in Table 5-3.

2. A minimum of 75% coverage of the entire examination area or volume, or a minimum sample size of 75% of the total population of like components of the examination is required (including both the accessible and inaccessible portions).

MRP-227-A Primary Inspection Components Expansion Link Examination Item Applicability Effect (Mechanism) Examination Coverage (Note 1) MethodlFrequency (Note 1)

Core Barrel Assembly All plants Loss of material (Wear) ASME Code Section XI Visual (VT-3) examination to All accessible surfaces at Core barrel flange determine general condition for specified frequency excessive wear.

Upper lnternals All plants Cracking (SCC, Fatigue) ASME Code Section XI Visual (VT-3) examination. All accessible surfaces at Assembly specified frequency Upper support ring or skirt Lower lnternals All plants Cracking (IASCC, ASME Code Section XI Visual (VT-3) examination of the All accessible surfaces at Assembly Fatigue) lower core plates to detect evidence specified frequency Lower core plate Aging Management (IE) of distortion andlor loss of bolt XL lower core plate (Note integrity.

1)

Lower lnternals All plants Loss of material (Wear) ASME Code Section XI Visual (VT-3) examination All accessible surfaces at Assembly specified frequency Lower core plate XL lower core plate (Note 1)

Bottom Mounted All plants Loss of material (Wear) NUREG-1801 Surface (ET) examination. Eddy current surface Instrumentation System Rev. 1 examination as defined in plant Flux thimble tubes response to IEB 88-09.

Alignment and All plants Loss of material (Wear) ASME Code Section XI Visual (VT-3) examination All accessible surfaces at Interfacing specified frequency Components (Note 2)

Clevis insert bolts Alignment and All plants Loss of material (Wear) ASME Code Section XI Visual (VT-3) examination All accessible surfaces at Interfacing specified frequency Components Upper core plate alignment pins Notes to Table 4-9:

1. XL = "Extra Long" referring to Westinghouse plants with 14-foot cores.

2. Bolt was screened in because of stress relaxation and associated cracking; however, wear of the clevislinsert is the issue

MRP-227-A Primary Inspection Components Examination Acceptance Additional Examination Item Applicability Expansion Link(s) Expansion Criteria Criteria (Note 1) Acceptance Criteria Control Rod Guide Tube All plants Visual (VT-3) examination None N/A NIA Assembly Guide plates (cards) The specific relevant condition is wear that could lead to loss of control and alignment and impede control assembly insertion.

Control Rod Guide Tube All plants Enhanced visual (EVT-1) a. Bottom-mounted a. Confirmation of surface- a. For BMI column bodies, the Assembly examination instrumentation (BMI) breaking indications in two specific relevant condition for Lower flange welds column bodies or more CRGT lower flange the VT-3 examination is The specific relevant welds, combined with flux completely fractured column condition is a detectable b. Lower support thimble insertionlwithdrawal bodies.

crack-like surface indication column bodies (cast), difficulty, shall require visual upper core plate and (VT-3) examination of BMI b. For cast lower support lower support forging or column bodies by the column bodies, upper core plate casting completion of the next and lower support refueling outage. forginglcastings, the specific relevant condition is a

b. Confirmation of surface- detectable crack-like surface breaking indications in two indication.

or more CRGT lower flange welds shall require EVT-1 examination of cast lower support column bodies, upper core plate and lower support forginglcastings within three fuel cycles following the initial observation.

Page 10 of 16

MRP-227-A Primary Inspection Components Examination Acceptance Additional Examination Item Applicability Expansion Link(s) Expansion Criteria Criteria (Note 1) Acceptance Criteria Core Barrel Assembly All plants Periodic enhanced visual a. Core barrel outlet a. The confirmed detection a and b. The specific relevant Upper core barrel flange weld (EVT-1) examination. nozzle welds and sizing of a surface- condition for the expansion core breaking indication with a barrel outlet nozzle weld and The specific relevant condition b. Lower support length greater than two lower support column body is a detectable crack-like column bodies (non inches in the upper core examination is a detectable surface indication. cast) barrel flange weld shall crack-like surface indication.

require that the EVT-1 examination be expanded to include the core barrel outlet nozzle welds by the completion of the next refueling outage.

b. If extensive cracking in the core barrel outlet nozzle welds is detected, EVT-1 examination shall be expanded to include the upper six inches of the accessible surfaces of the non-cast lower support column bodies within three fuel cycles following the initial observation.

MRP-227-A Primary Inspection Components Examination Acceptance Additional Examination Applicability Expansion Link(s) Expansion Criteria Criteria (Note 1) Acceptance Criteria All plants Periodic enhanced visual None None None Lower core barrel flange weld (EVT-1) examination (Note 2)

The specific relevant condition is a detectable crack-like All plants Periodic enhanced visual Upper core barrel The confirmed detection The specific relevant condition Upper core barrel cylinder girth (EVT-1) examination cylinder axial welds and sizing of a surface- for the expansion upper core welds breaking indication with a barrel cylinder axial weld The specific relevant condition length greater than two examination is a detectable is a detectable crack-like inches in the upper core crack-like surface indication.

surface indication. barrel cylinder girth welds shall require that the EVT-1 examination be expanded to include the upper core barrel cylinder axial welds by the completion of the next refueling outage.

Page 12 of 16

MRP-227-A Primary Inspection Components Examination Acceptance Additional Examination Item Applicability Expansion Link(s) Expansion Criteria Criteria (Note I) Acceptance Criteria Core Barrel Assembly All plants Periodic enhanced visual Lower core barrel The confirmed detection The specific relevant condition Lower core barrel cylinder girth (EVT-1) examination cylinder axial welds and sizing of a surface- for the expansion lower core welds breaking indicationwith a barrel cylinder axial weld The specific relevant condition length greater than two examination is a detectable is a detectable crack-like inches in the lower core crack-like surface indication.

surface indication. barrel cylinder girth welds shall require that the EVT-1 examination be expanded to include the lower core barrel cylinder axial welds by the completion of the next refueling outage.

Baffle-Former Assembly All plants with Visual (VT-3) examination. None N/A N/A Baffle-edge bolts baffle-edge bolts The specific relevant conditions are missing or broken locking devices.

failed or missing bolts, and protrusion of bolt heads.

Page 13 of 16

MRP-227-A Primary Inspection Components Examination Acceptance Additional Examination Item Applicability Expansion Link(s) Expansion Criteria Criteria (Note 1) Acceptance Criteria Baffle-Former Assembly All plants Volumetric (UT) examination. a. Lower support a. Confirmation that more a and b. The examination Baffle-former bolts column bolts than 5 % of the baffle- acceptance criteria for the UT of The examination acceptance former bolts actually the lower support column bolts criteria for the UT of the b. Barrel-former bolts examined on the four baffle and the barrel-former bolts shall baffle-former bolts shall be plates at the largest be established as part of the established as part of the distance from the core examination technical examination technical (presumed to be the lowest justification.

justification. dose locations) contain unacceptable indications shall require UT examination of the lower support column bolts within the next three fuel cycles.

b. Confirmation that more than 5% of the lower support column bolts actually examined contain unacceptable indications shall require UT examination of the barrel-former bolts.

Page 14 of 16

MRP-227-APrimary Inspection Components Examination Acceptance Additional Examination Item Applicability Expansion Link@) Expansion Criteria Criteria (Note I) Acceptance Criteria Baffle-Former Assembly All plants Visual (VT-3) examination. None NIA NIA Assembly The specific relevant conditions are evidence of abnormal interaction with fuel assemblies, gaps along high fluence shroud plate joints, vertical displacement of shroud plates near high fluence joints, and broken or damaged edge bolt locking systems along high f l uence baffle plate joints.

Alignment and Interfacing All plants with 304 Direct physical measurement None NIA NIA Components stainless steel hold of spring height.

lnternals hold down 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.

Page 15 of 16

MRP-227-A Primary Inspection Components Examination Acceptance Additional Examination Item Applicability Expansion Link@) Expansion Criteria Criteria (Note 1) Acceptance Criteria Thermal Shield Assembly All plants with Visual (VT-3) examination. None N/A N/A Thermal shield fixtures thermal shields The specific relevant conditions for thermal shield flexures are excessive wear, fracture, or complete separation.

Notes to Table 5-3:

1. The examination acceptance criterion for visual examination is the absence of the specified relevant condition(s).

2. The lower core barrel flange weld may alternatively be designated as the core barrel-to-support plate weld in some Westinghouse plant designs.

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