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

{{Adams
| number = ML12276A041
| issue date = 10/01/2012
| title = PWR (Pressurized Water Reactor) Vessel Internals Program for Fulfillment of License Renewal Commitment 25
| author name = Sorensen J
| author affiliation = Northern States Power Co, Xcel Energy
| addressee name = 
| addressee affiliation = NRC/Document Control Desk, NRC/NRR
| docket = 05000282, 05000306
| license number = DPR-042, DPR-060
| contact person = 
| case reference number = L-PI-12-078
| document type = Letter type:L, Graphics incl Charts and Tables
| page count = 18
| project = 
| stage = Other
}}

=Text=
{{#Wiki_filter:@ 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)
Page 7 of 16

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.
Page 16 of 16}}