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Category:CORRESPONDENCE-LETTERS
MONTHYEARML20217M3371999-10-20020 October 1999 Forwards Notice of Docketing of License SNM-2506 Amend Application.Notice Has Been Forwarded to Ofc of Fr for Publication ML20217M1111999-10-19019 October 1999 Forwards Insp Repts 50-282/99-14 & 50-306/99-14 on 990920- 22.One Violation Noted & Being Treated as Ncv.Insp Focused on Testing & Maint of Heat Exchangers in High Risk Sys ML20217F4331999-10-15015 October 1999 Forwards Rev 39 to Security Plan.Changes Do Not Decrease Effectiveness of Security Plan.Rev Withheld,Per 10CFR73.21 ML20217C2351999-10-0606 October 1999 Forwards Insp Repts 50-282/99-12 & 50-306/99-12 on 990823-0917.No Violations Noted.Insp Consisted of Selected Exam of Procedures & Representative Records,Observation of Activities & Interviews with Personnel ML20212J8811999-09-28028 September 1999 Forwards Preliminary Accident Sequence Precurson Analysis of Operational Event That Occurred at Plant,Unit 1 on 990105, for Review & Comment.Comment Requested within 30 Days of Receipt of Ltr IR 05000272/19990071999-09-28028 September 1999 Forwards Insp Repts 50-272/99-07 & 50-306/99-07 on 990721- 0831.One Potentially Safety Significant Issue Identified Dealing with Control Room Special Ventilation System.Four Addl Issues of Low Safety Significance Identified ML20212G7171999-09-24024 September 1999 Submits Semiannual Status Update on Project Plans for USAR Review Project & Conversion to Its.Conversion Package Submittal Continues to Be Targeted for Aug of 2000 ML20212G9801999-09-23023 September 1999 Refers to Resolution of Unresolved Items Identified Re Security Alarm Station Operations at Both Monitcello & Prairie Island ML20212F5121999-09-20020 September 1999 Forwards Response to NRC , Preparation & Scheduling of Operator Licensing Examinations ML20212D8401999-09-16016 September 1999 Discusses 990902 Telcon Between D Wesphal & R Bailey Re Administeration of Retake Exam at Prairie Island During Wk of 991206.NRC May Make Exam Validation Visit to Facility During Wk of 991116 ML20217H2331999-09-10010 September 1999 Forwards Security Insp Repts 50-282/99-10 & 50-306/99-10 on 990809-12.Two Findings,Each of Low Risk Significance Identified & Being Treated as non-cited Violations Consistent with App C of Enforcement Policy ML20217H5661999-09-0909 September 1999 Discusses 990907 Pilot Plan Mgt Meeting Re Results to-date of Pilot Implementation of NRC Revised Reactor Oversight Process at Prairie Island & Quad Cities.Agenda & Handouts Provided by Utils Encl ML20212A9241999-09-0909 September 1999 Discusses Plans Made During 990902 Telephone Conversation to Inspect Licensed Operator Requalification Program at Prairie Island During Weeks of 991101 & 991108.Requests That Written Exams & Operating Tests Be Submitted by 991022 ML20212B0511999-09-0909 September 1999 Forwards Insp Repts 50-282/99-11 & 50-306/99-11 on 990816-20.One Issue of Low Safety Significance Was Identified & Being Treated as Ncb ML20211Q7641999-09-0808 September 1999 Informs That NRC Tentatively Scheduled Initial Licensing Exam for Plant Operator License Applicants During Wk of 000515,in Response to D Westphal ML20211N8631999-09-0707 September 1999 Withdraws 970814 Request for Exemption from 10CFR50,App R, Section III.G.2, Fire Protection of Safe Shutdown Capabilities ML20211K5911999-09-0101 September 1999 Informs That Util Reviewed Rvid Data Base,As Requested in NRC .Summary of Proposed Changes & Observed Differences Are Included in Encl Tables ML20211L0211999-09-0101 September 1999 Provides Notification That License Amends 141 & 132 & Associated License Conditions 6 & 7 Have Been Fully Implemented ML20211K5931999-08-31031 August 1999 Forwards License Amend Request for License SNM-2506, Proposing Change to License Conditions 6,7 & 8 & TSs App a of License by Permitting Inclusion of Bpras & Thimble Plug Devices in Sf Assemblies Stored in TN-40 Casks ML20211Q6041999-08-31031 August 1999 Forwards Rev 19 to USAR for Pingp,Per 10CFR50.71(e).Rev Brings USAR up-to-date as of 990228,though Some Info Is More Recent.Attachment 1 Contains Descriptions & Summaries of SE for Changes,Tests & Experiments,Per 10CFR50.59 ML20211K2591999-08-27027 August 1999 Forwards NSP Co Fitness for Duty Program Performance Data for Six Month Period Ending 990630 ML20211D3541999-08-24024 August 1999 Discusses GL 95-07 Re Pressure Locking & Thermal Binding of safety-related Power Operated Gate Valves.Forwards SE Re Response to GL 95-07 ML20211C7601999-08-19019 August 1999 Confirms NRC Intent to Meet with NSP & Ceco on 990807 in Lisle,Il to Discuss with Region III Pilot Plants,Any Observations,Feedback,Lessons Learned & Recommendations Relative to Implementation of Pilot Program ML20211B8311999-08-19019 August 1999 Forwards Request for Relief 8 Re Limited Exams Associated with Unit 1 Third ten-year Interval Inservice Insp Program. Licensee Requests Relief Due to Impractibility of Obtaining 100% Exam Coverage for Affected Items ML20211B5711999-08-19019 August 1999 Forwards Second 90-day Rept for Implementation of Voltage Based Repair Criteria at Prairie Island Unit 1.Rept Fulfills Requirements of Section 6.b of Attachment 1 to GL 95-05 ML20211C2311999-08-19019 August 1999 Forwards Unit 1 ISI Summary Rept,Interval 3,Period 2 Refueling Outage Dates 990425-0526,Cycle 19 971212-990526. Rept Identifies Components Examined,Exam Methods Used,Exam Number & Summarizes Results ML20211B0561999-08-18018 August 1999 Provides Addl Info on Proposed Rev to Main Steam Line Break Methodology ,in Response to NRC Staff Request Made in 990416 Telcon.Nuclear Svcs Corp Rept PIO-01-06, Analysis Rept Structural Analyses of Main Steam Check... Encl ML20211B2621999-08-17017 August 1999 Forwards Insp Repts 50-282/99-09 & 50-306/99-09 on 990719-22.No Violations Noted.Insp Included Review & Evaluation of Current Emergency Preparedness Performance Indicators ML20211C7371999-08-17017 August 1999 Discusses Closure of Staff Review Re Generic Implication of Part Length Control Rod Drive Mechanism Housing Leak on 980123.Enclosed NRC 980811 & 1223 Ltrs Responded to WOG Positions Re Corrective Actions ML20210T5661999-08-12012 August 1999 Forwards RAI Re & Suppl ,which Requested Exemptions from TSs of Section III.G.2 of 10CFR50 App R,To Extent That Specifies Separation of Certain Redundant Safe Shutdown Circuits with fire-related Barriers ML20210R7021999-08-12012 August 1999 Forwards Insp Repts 50-282/99-06 & 50-306/99-06 on 990601- 0720.One NCV Occurred,Consistent with App C of Enforcement Policy ML20210P5191999-08-11011 August 1999 Discusses GL 92-01,Rev 1,Supp 1, Rv Integrity, Issued by NRC on 950519 & NSP Responses for PINGP & 951117. Staff Reviewed Info in Rvid & Released Info as Rvid Version 2.Requests Submittal of Comments Re Revised Rvid by 990901 ML20210G5061999-07-30030 July 1999 Responds to Administrative Ltr 99-02, Operating Reactor Licensing Action Estimates 05000282/LER-1999-007, Forwards LER 99-007-00,re Loss of CR Special Ventilation Function.One New Commitment Was Made in Rept as Indicated in Corrective Action Section Statement in Bold Italics1999-07-23023 July 1999 Forwards LER 99-007-00,re Loss of CR Special Ventilation Function.One New Commitment Was Made in Rept as Indicated in Corrective Action Section Statement in Bold Italics ML20210J4991999-07-22022 July 1999 Forwards Rev 18 to USAR for Pingp,Bringing USAR up-to-date as of 990228,though Some Info More Recent.Safety Evaluation Summaries Also Encl ML20209J0941999-07-15015 July 1999 Forwards SER Finding Rev 7 to Topical Rept NSPNAD-8102, Reload Safety Evaluation Methods for Application to PI Units, Acceptable for Ref in Plant Licensing Actions ML20209H8051999-07-14014 July 1999 Forwards Summary of non-modification Safety Evaluation Number 515 Re Storage of Fuel Inserts,Per Insp Rept 72-0010/99-201 ML20209D4181999-07-0707 July 1999 Informs That Util Has Changed Listed TS Bases Pages Attached for NRC Use.Util Made No New Commitments in Ltr ML20209H8361999-07-0202 July 1999 Forwards Operator Licensing Exam Repts 50-282/99-301(OL) & 50-306/99-301(OL) for Tests Administered During Week of 990517-21.Two Applicants Passed All Sections of Exam & Issued Reactor Operator Licenses to Operate Pings ML20196J9681999-07-0101 July 1999 Informs That in Sept 1998,Region III Received Rev 20 to Portions of Util Emergency Plan Under 10CFR50.54(q).Based on Determination That Changes Do Not Decrease Effectiveness of Licensee Emergency Plan,No NRC Approval Required ML20209C3951999-07-0101 July 1999 Forwards Supplemental Response to GL 95-07, Pressure Locking & Thermal Binding of SR Power-Operated Gate Valves ML20209B7541999-07-0101 July 1999 Final Response to GL 98-01,Suppl 1 Re Y2K Readiness of Computer Sys.Sys Remediated as Required for Plant Operation. Contingency Plans Developed to Mitigate Impact of Y2K-induced Events at Key Rollover Dates ML20196J8941999-06-30030 June 1999 Transmits Util Comments on Draft Regulatory Guide DG-1074, Steam Generator Tube Integrity. Licensee Recommends That NRC Focus on Several Important Listed Areas Considered Principal Concerns & Contentions ML20209F0391999-06-30030 June 1999 Forwards Insp Repts 50-282/99-04 & 50-306/99-04 on 990407-0531.Violation Noted.Notice of Violation or Civil Penalty Will Not Be Issued,Based on NRC Listed Decision to Exercise Discretion ML20209C3011999-06-29029 June 1999 Forwards Annual Rept of Corrections to NSP ECCS Evaluation Models,Iaw 10CFR50.46.Since All Analyses Remain in Compliance,No Reanalysis Is Required or Planned ML20209B5751999-06-24024 June 1999 Submits Revised Relief Request for Limited Examinations Associated with Third 10-yr ISI Examination Plan.Attached Is Unit 1 Relief Request 7,rev 1 Which Addresses Limited Examinations ML20196F3871999-06-23023 June 1999 Forwards Revised Pages 71,72 & 298 of Rev 7 to NSPNAD-8102, Prairie Island Nuclear Power Plant Reload Safety Evaluation Methods for Application to PI Units, Per Discussions with Nrc.Approved Version of Rept Will Be Issued 05000282/LER-1999-006, Forwards LER 99-006-00 Re Discovery That Manual SI Actuation Switch Had Not Been Tested on Staggered Basis During Integrated SI Test.Two New Commitments Are Indicated in Corrective Action Section Statement in Bold Italics1999-06-18018 June 1999 Forwards LER 99-006-00 Re Discovery That Manual SI Actuation Switch Had Not Been Tested on Staggered Basis During Integrated SI Test.Two New Commitments Are Indicated in Corrective Action Section Statement in Bold Italics ML20196D5501999-06-18018 June 1999 Forwards Individual Exam Results for Licensee Applicants Who Took May 1999 Initial License Exam.In Accordance with 10CFR2.790,info Considered, Proprietary. Without Encls ML20196A6741999-06-17017 June 1999 Refers to 990517-20 Meeting with Util in Welch,Minnesota Re Licensee Initiatives in Risk Area & to Establish Dialog Between SRAs & Licensee PRA Staff 1999-09-09
[Table view] Category:INCOMING CORRESPONDENCE
MONTHYEARML20217F4331999-10-15015 October 1999 Forwards Rev 39 to Security Plan.Changes Do Not Decrease Effectiveness of Security Plan.Rev Withheld,Per 10CFR73.21 ML20212G7171999-09-24024 September 1999 Submits Semiannual Status Update on Project Plans for USAR Review Project & Conversion to Its.Conversion Package Submittal Continues to Be Targeted for Aug of 2000 ML20212F5121999-09-20020 September 1999 Forwards Response to NRC , Preparation & Scheduling of Operator Licensing Examinations ML20211N8631999-09-0707 September 1999 Withdraws 970814 Request for Exemption from 10CFR50,App R, Section III.G.2, Fire Protection of Safe Shutdown Capabilities ML20211K5911999-09-0101 September 1999 Informs That Util Reviewed Rvid Data Base,As Requested in NRC .Summary of Proposed Changes & Observed Differences Are Included in Encl Tables ML20211L0211999-09-0101 September 1999 Provides Notification That License Amends 141 & 132 & Associated License Conditions 6 & 7 Have Been Fully Implemented ML20211Q6041999-08-31031 August 1999 Forwards Rev 19 to USAR for Pingp,Per 10CFR50.71(e).Rev Brings USAR up-to-date as of 990228,though Some Info Is More Recent.Attachment 1 Contains Descriptions & Summaries of SE for Changes,Tests & Experiments,Per 10CFR50.59 ML20211K5931999-08-31031 August 1999 Forwards License Amend Request for License SNM-2506, Proposing Change to License Conditions 6,7 & 8 & TSs App a of License by Permitting Inclusion of Bpras & Thimble Plug Devices in Sf Assemblies Stored in TN-40 Casks ML20211K2591999-08-27027 August 1999 Forwards NSP Co Fitness for Duty Program Performance Data for Six Month Period Ending 990630 ML20211C2311999-08-19019 August 1999 Forwards Unit 1 ISI Summary Rept,Interval 3,Period 2 Refueling Outage Dates 990425-0526,Cycle 19 971212-990526. Rept Identifies Components Examined,Exam Methods Used,Exam Number & Summarizes Results ML20211B8311999-08-19019 August 1999 Forwards Request for Relief 8 Re Limited Exams Associated with Unit 1 Third ten-year Interval Inservice Insp Program. Licensee Requests Relief Due to Impractibility of Obtaining 100% Exam Coverage for Affected Items ML20211B5711999-08-19019 August 1999 Forwards Second 90-day Rept for Implementation of Voltage Based Repair Criteria at Prairie Island Unit 1.Rept Fulfills Requirements of Section 6.b of Attachment 1 to GL 95-05 ML20211B0561999-08-18018 August 1999 Provides Addl Info on Proposed Rev to Main Steam Line Break Methodology ,in Response to NRC Staff Request Made in 990416 Telcon.Nuclear Svcs Corp Rept PIO-01-06, Analysis Rept Structural Analyses of Main Steam Check... Encl ML20210G5061999-07-30030 July 1999 Responds to Administrative Ltr 99-02, Operating Reactor Licensing Action Estimates 05000282/LER-1999-007, Forwards LER 99-007-00,re Loss of CR Special Ventilation Function.One New Commitment Was Made in Rept as Indicated in Corrective Action Section Statement in Bold Italics1999-07-23023 July 1999 Forwards LER 99-007-00,re Loss of CR Special Ventilation Function.One New Commitment Was Made in Rept as Indicated in Corrective Action Section Statement in Bold Italics ML20210J4991999-07-22022 July 1999 Forwards Rev 18 to USAR for Pingp,Bringing USAR up-to-date as of 990228,though Some Info More Recent.Safety Evaluation Summaries Also Encl ML20209H8051999-07-14014 July 1999 Forwards Summary of non-modification Safety Evaluation Number 515 Re Storage of Fuel Inserts,Per Insp Rept 72-0010/99-201 ML20209D4181999-07-0707 July 1999 Informs That Util Has Changed Listed TS Bases Pages Attached for NRC Use.Util Made No New Commitments in Ltr ML20209C3951999-07-0101 July 1999 Forwards Supplemental Response to GL 95-07, Pressure Locking & Thermal Binding of SR Power-Operated Gate Valves ML20209B7541999-07-0101 July 1999 Final Response to GL 98-01,Suppl 1 Re Y2K Readiness of Computer Sys.Sys Remediated as Required for Plant Operation. Contingency Plans Developed to Mitigate Impact of Y2K-induced Events at Key Rollover Dates ML20196J8941999-06-30030 June 1999 Transmits Util Comments on Draft Regulatory Guide DG-1074, Steam Generator Tube Integrity. Licensee Recommends That NRC Focus on Several Important Listed Areas Considered Principal Concerns & Contentions ML20209C3011999-06-29029 June 1999 Forwards Annual Rept of Corrections to NSP ECCS Evaluation Models,Iaw 10CFR50.46.Since All Analyses Remain in Compliance,No Reanalysis Is Required or Planned ML20209B5751999-06-24024 June 1999 Submits Revised Relief Request for Limited Examinations Associated with Third 10-yr ISI Examination Plan.Attached Is Unit 1 Relief Request 7,rev 1 Which Addresses Limited Examinations ML20196F3871999-06-23023 June 1999 Forwards Revised Pages 71,72 & 298 of Rev 7 to NSPNAD-8102, Prairie Island Nuclear Power Plant Reload Safety Evaluation Methods for Application to PI Units, Per Discussions with Nrc.Approved Version of Rept Will Be Issued 05000282/LER-1999-006, Forwards LER 99-006-00 Re Discovery That Manual SI Actuation Switch Had Not Been Tested on Staggered Basis During Integrated SI Test.Two New Commitments Are Indicated in Corrective Action Section Statement in Bold Italics1999-06-18018 June 1999 Forwards LER 99-006-00 Re Discovery That Manual SI Actuation Switch Had Not Been Tested on Staggered Basis During Integrated SI Test.Two New Commitments Are Indicated in Corrective Action Section Statement in Bold Italics ML20195G4281999-06-0909 June 1999 Notifies That Amsac/Dss Mods Completed & TS 138/129 Has Been Fully Implemented 05000282/LER-1999-005, Forwards LER 99-005-00 Re Containment Inservice Purge Sys Not Isolated During Heavy Load Movement Over Fuel.Event Has Indicated That Level of Performance Expected by Mgt Has Not Yet Been Achieved1999-06-0707 June 1999 Forwards LER 99-005-00 Re Containment Inservice Purge Sys Not Isolated During Heavy Load Movement Over Fuel.Event Has Indicated That Level of Performance Expected by Mgt Has Not Yet Been Achieved ML20207F4301999-06-0101 June 1999 Forwards 1999 Unit 1 SG Insp Results,Per TS 4.12.E.1. Following Insp 84 Tubes Were Plugged for First Time ML20196L2461999-05-21021 May 1999 Forwards Rev 0 to COLR for Pingp,Unit 1 Cycle 20, IAW TS Section 6.7.A.6 ML20195C6861999-05-21021 May 1999 Forwards Rev 17 to USAR for Prairie Island Nuclear Generating Plant.Attachment 1 Contains Descriptions & Summaries of SEs for Changes,Tests & Experiments Made Under Provisions of 10CFR50.59 During Period Since Last Update ML20206U6781999-05-17017 May 1999 Forwards Revised Emergency Response Plan Implementing Procedures,Including Rev 15 to F3-3,rev 15 to F3-16,rev 14 to F3-22 & Table of Contents ML20206U7131999-05-17017 May 1999 Forwards Revised EOF Emergency Plan Implementing Procedures, Including Table of Contents & Rev 2 to F8-10, Record Keeping in Eof. with Updating Instructions ML20206T2461999-05-17017 May 1999 Forwards Off-Site Radiation Dose Assessment for Jan-Dec 1998, Rev 0 to Annual Radiactive Effluent Rept for 980105- 990103 & Effluent & Waste Disposal Annual Rept Solid Waste & Irradiated Fuel Shipments,Jan-Dec 1998 ML20206R0401999-05-13013 May 1999 Forwards Application for Amends to Licenses DPR-42 & DPR-60, Removing Plant Organization Requirement,Imposed in Amend 141/132 That Plant Manager,Who Has Responsibility for Overall Safe Operation of Plant,Report to Corporate Officer ML20206Q0871999-05-13013 May 1999 Forwards Result of Evaluation Re Ultrasonic Exams of SG Number 22 Performed in Accordance with ASME Boiler & Pressure Vessel Code Section Xi.Procedure Used for Evaluation Contained in WCAP-14166,submitted for Review ML20206F9381999-05-0303 May 1999 Forwards Response to NRC 990304 RAI Re GL 96-05 Program at Pingp.Licensee Commitments Are Identified in Encl as Statements in Italics ML20206J3851999-05-0303 May 1999 Forwards 1998 Annual Radiological Environmental Monitoring Rept 05000282/LER-1999-004, Forwards LER 99-004-00 Re Discovery of Inadequate Sp That Demonstrates Operability of SFP Special Ventilation Sys.Two New NRC Commitments Are Contained in Corrective Action Section of Rept in Bold Italics1999-05-0303 May 1999 Forwards LER 99-004-00 Re Discovery of Inadequate Sp That Demonstrates Operability of SFP Special Ventilation Sys.Two New NRC Commitments Are Contained in Corrective Action Section of Rept in Bold Italics ML20206E1761999-04-28028 April 1999 Forwards Revised TS Pages for Amends 144 & 135 to Licenses DPR-42 & DPR-60,respectively,to Update Controlled Manual or File ML20205S3221999-04-20020 April 1999 Forwards Application for Amends to Licenses DPR-42 & DPR-60, Changing Implementation Date for Relocation from TS to UFSAR of Requirements in TS 3.1.E & Flooding Shutdown Requirements of TS 5.1 ML20205P9891999-04-12012 April 1999 Requests Approval for Proposed Alternatives to Liquid Penetrant Requirements of N-518.4 of 1968 ASME Boiler & Pressure Vessel Code.Results of Analysis & Summary of Tests Performed & Tests Results Are Encl ML20205Q0191999-04-12012 April 1999 Forwards Application for Amend to License DPR-42 & DPR-60, Relocating Shutdown Margin Requirements from TS to COLR 05000282/LER-1998-010, Forwards LER 98-010-01 Re Discovery That 32 App R Related MOVs Are Susceptible to Physical Damage by Fire Induced Hot Shorts.Rept Provides Addl Details on Current Plans for Completing C/As Committed to in Original LER1999-04-0808 April 1999 Forwards LER 98-010-01 Re Discovery That 32 App R Related MOVs Are Susceptible to Physical Damage by Fire Induced Hot Shorts.Rept Provides Addl Details on Current Plans for Completing C/As Committed to in Original LER ML20205P9221999-04-0101 April 1999 Submits Relief Request 8,rev 0 Which Addresses Limited Exams Associated with Unit 2 Third ten-year Interval Inservice Insp Program.Util Requests Relief Per 10CFR50.55a(q)(5)(iii) Due to Impracticality of Obtaining 100% Exam Coverage ML20205E8371999-03-31031 March 1999 Submits Four Copies of Rev 38 to Prairie Island Security Plan,Per 10CFR50.54(p).Changes Do Not Decrease Effectiveness of Security Plan.Encl Withheld,Per 10CFR73.21 ML20196K7831999-03-31031 March 1999 Forwards Decommissioning Funding Status Rept for Monticello & Prairie Island Nuclear Generating Plants,Per Requirements of 10CFR50.75(f)(1) ML20205Q5051999-03-30030 March 1999 Forwards Inservice Insp Summary Rept Interval 3,Period 1 & 2 Refueling Outage Dates 981109-1229 Cycle 19,970327- 981229. Rept Identifies Components Examined,Exam Methods Used,Exam Number & Summarized Results ML20205H5731999-03-29029 March 1999 Submits Required 1998 Actual & 1999 Projected Cash Flow Statements for Monticello Nuclear Generating Plant & PINGP, Units 1 & 2.Encl Contains Proprietary Info.Proprietary Info Withheld,Per 10CFR2.790(b)(1) ML20205C6561999-03-26026 March 1999 Submits Semiannual Update on Project Plans for USAR Review Project & Conversion to ITS ML20204H3371999-03-19019 March 1999 Forwards Application for Amend to Licenses DPR-42 & DPR-60, Removing Dates of Two NRC SERs & Correcting Date of One SER Listed in Section 2.C.4, Fire Protection 1999-09-07
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Northern States Power Company Pralrle Island Nuclear Generating Plant 1717 Wakonade Dr. East Welch, Mannesota Sf489
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February 13,1998 10 CFR 50.55a(a)(3)
U S Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket Nos. 50 282 License Nos. DPR 42 50-300 DPR-60 E Reauest for Approval of Alternative to ASME Code Reauirements O
Prairie Island Unit 2 shut down on January 24,1998 to repair a small RCS leak. The source of this leakage has been identified as a flaw in the wall of the part length control rod drive mechanism (CRDM) at location G9 on the reactor vessel head (Attachment )
3). The flaw is located on the CRDM motor tube base approximately 1.5 inches above the intermediate canopy seal weld.
Because the part length CRDMs are not used and are abandoned in piace, it was decided that the part length CRDM at location G9, would be permaner.tly removed. l This would eliminate the need for repair of the flaw and would facilitate the metallurgical evaluation of the flaw. Removal of the G9 part length CRDM was completed on February 8,1998. The part length CRDMs at locations I-7 and E-7 have also been removed and plans are to remove the last part length CRDM st G-5 during the current Unit 2 forced outage. Removal of the part length CRDMs requires capping of the associated reactor vessel head penetrations. The preferred method for capping of the penetrations is the installation of a cap which would be screwed onto the threaded end of the penetration and then seal welded.
Based on N-518.4 of the 1968 ASME Boiler and Pressure Vessel Code, a liquid l penetrant examination of the seal weld is required. However, liquid penetrant l
examination of the seal weld would be difficult. The CRDM penetrations being repaired are located in a high radiation area, with radiation fields of approximately 1000 mr/hr.
Additionally, access to the seal welds is difficult duo to the limited clearance between the adjacent control rod drive housings. The separation between the outer rod travel housings is approximately 7.2 inches. This is not adequate clearance to gain complete access to the inner cod travel housings to perform the liquid penetrant examination of f
if I pgg22Soo$ o$o$$a2 e ey_ llf,ll)lll}lll!i'.llp(jcf
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USNRC NORTHERN STATES POWER C@MPANY
, FCbruary 13,1998 Page 2 of 4 the seal we!ds. Final weld surface preparation, the liquid penetrant examination and the subsequent cleanup would be difficult and time consuming due to the limited access, and personnel performing these operations would incur substantial radiation exposure.
While the liquid penetrant examination specified by N-518.4 would provide indication of surface cracks, the processes used to perform the seal welds and the visual l examination of the welds provide the best measure of the seal weld acceptability due to the limited accessibility and high radiation fields. The surface to be seal welded is examined with an 8x camera during weld surface preparation. The weld is deposited using a fully automatic TIG process. A!I welding parameters are controlled within the qualified range from a remote panel. The weld puddle / deposit is observed via an 8x camera during every phase of the welding. A final visual examination of the weld surface is completed using the same 8x camera. Much of the welding is observed at the control panel by an NSP Level ll! inspector, in addition, the post outage hydrostatic test of the reactor coolart system willinclude a VT-2 inspection of the seal weld and CRDM penetration cap for leakage.
10 CFR Part 50, Section 50.55a(e)(3) allows the use of alternatives to the ASME Code
.equirements, when authorized by the Director of the Office of Nuclear Reactor Regulation, if it can be demonstrated that:
'he proposed a;ternatives would provide an acceptable level of quality and safety, or
- 2. Compliance with the specified requiremeres of this section would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety, in accordance with the provisions of 10 CFR Part 59, Section 50.55a(a)(3), we are proposing the following alternatives to the liquid penetrant testing requirements of N-518.4 of the 1968 ASME Boiler and Pressure Vessel Code for the weld repairs described above:
- 1. Use of a controlled automatic welding process.
- 2. Observation of the weld puddle / deposit via a 8x camera during the welding process.
. 3. A final vicual examination of the weld surface using the same 8x camera.
- 4. Performance of a VT-2 inspection of the seal weld and CRDM penetration cap for leakage during the post outage hydrostatic test.
- 5. Authorized Nuclear Inservice inspector approval of alternative testing and NIS-2 acceptance.
ISMST\SEALREQ4 DOC
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USNRC NORTHERN STATES POWER COMPANY
. February 13,1998 Page 3 of 4 A' liquid penetrant examination would provide a more stringent verification of the final weld surface condition and therefore afford an added measure of the quality and safety of the completed seal weld. However, the liquid penetrant examination does not provide a substantial increase in quality and safety above what is provided by the I
measures (controlled process, observation of weld process using 8x camera, final 8x visual inspection and hydrostatic test inspection) that have been and will be taken in 4 lieu of the liquid penetrant mamination, in addition, due to the time consuming nature of the examination r 9rsonnel would incur substantial radiation exposure during the performo ! penetrant examinations.
An analysis was performed by Structural Integrity Associates to demonstrate that a through-wall flaw could be detected by visual examination which has a flaw size which is sufficiently smaller than the critical flaw size, thus assuring sufficient safety margins.
The analysis demonstrated that, under a variety of conservative assumptions, the entical flaw size predicted for the repair geometry is in all cases of significant length. It is likely that a much smaller flaw could be credibly detected by visual examination under 8x magnification. The analysis results are summarized in Attachment 1.
In order to confirm the detectable flaw size, tests were performed by Welding Services Incorporated to evaluate the capabilities of the camera system used in the performance of the weld repair. This testing confirmed that the critical flaw sizes resulting from the Structural Integrity analysis are detectable with margin by the visual inspection technique. A summary of the tests performed and the test results are provided as Attachment 2.
In conclusion, the proposed alternatives (automatic weld process, observation of the process using 8x camera, final 8x visual examination and hydrostatic test inspection) to the liquid penetrant requlrements of N-518.4 of the 1968 ASME Boiler and Pressure Vessel Code provide an acceptable level of quality and safety for the seal welds on the part length CRDM pe ietrations. Furthermore, compliance with the liquid penetrant examination requiren,ents of N-518.4 of the 1968 ASME Boiler and Pressure Vessel Code would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
Because it may be necessary to remove the part length CRDMs from Unit 1 as well, we request that the NRC Staff approve the proposed alternative to ASME Code requirements for both Units 1 and 2.
Because the G9 part length CRDM has been removed from the reactor vessel head, the request for approval of alternate to ASME Code requirements, dated January 30, 1998, is no longer required and should be considered withdrawn.
LS4s"oEALRE04 DOC 1 --
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. .USNRC NORTHERN STATES POWER COMPANY
, February 13,1998 0 P:gs 4 of 4 m .
We have made no new Nuclear Regulatory Commission commitments in this letter.
Please contact Gene Eckholt (612-388-1121) if you have any questions related to this request.
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Joel P. Sorensen -e Plant Manager Prairie Island Nuclear Genstating Plant c: Regional Administrator - Region ill, NRC Senior Resident inspector, NRC
- NRR Project Manager, NRC J E Silberg Attachments: 1. Calculation Package: Evaluation of Limiting Flaws for Structural Adequacy in CRDM Repair Adapter Plug Fillet Weld Evaluation at Prairie Island Unit 2
- 2. Summary of Camera Testing
- 3. Control Rod Locations b
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ATTACHMENT 1 i
CALCULATION PACKAGE:
EVALUATION OF LIMITING FLAWS FOR STRUCTURAL ADEQUACY IN CRDM REPAIR ADAPTER PLUG FILLET WELD EVALUATION AT PRAIRIE ISLAND UNIT 2
= STRUCTURAL INTEGRITY ASSOCIATES, INC
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e f StructuralIntegrity Associates, Inc.
3315 Almaden Expressway _
sune24 San Jane.CA 95116155r February 12,1998 ," $M
.:_;4tcxrn MLH-98 006 Mr. Dick Cooper Northern States Power Company Prairie Island Nuclear Generation Plant
! 1717 Wakonade Ddve East Welch,MN 55089
Subject:
Evaluation of Critical Flaw Sizes for CRDM Canopy Fillet Weld
Dear Mr,
Cooper; Structural Integrity Associates has performed an evaluation the subject location. The results of thisedevaluation to demonstrate thatcan the be us,to determine critical flaw size is significantly larger than the flaw size observable 'using visual inspection techniques.
This can serve to eliminate the need to perform dye penetrant testing of the fillet weld.
The evaluation was performed using limit load methods since the material is ductile and the fluence at this location is below that needed to impact the matedal fracture toughness. The evaluation was performed assuming a through-wall axial flaw and a through-wall circumferential flaw. The stress in the fillet weld was assumed equal to the design stress intensity of the matedal (S.). The S. for the stainless steel at 650'F was used in this calculation (16.2 ksi), A safety factor of 1.0 was used since the critical flaw size is being calculated.
l The calculations were performed by assuming a pipe with r ius and thickness equal to that at the fillet weld location (0.265" equivalent thickness, mean radiu's =3.3 inches). The resuhs for the
! critical flaw lengths (m terms of fraction of circumference a$d characteristic length parameter, fraction of N'Rt) are independent of the pipe geometry since 'the stress is set to S.. The critical axial flaw was determined using the SI program, p.. CRACK, and the critical circumferential flaw size was determined using the EPRI DLL program.
l The results of the evaluation are shown below.
Critical Through-Wall Axial Flaw Length: 4.17 inch !
Critical Through-Wall Circumferential Flaw Length: 6.95 inch t
It should be noted that this calculation was performed using an applied stress equivalent to the S.
for the stainless steel material, which is conservative. lf the' actual i were used, the critical flaw lengths are expected to be even larger. primarl t 1 sm an.ca air .cn sme sese.no rueme sda.n - mes4. wwu casimm.uc Phormt *n 44+2323 Phone 16M 1F 2781 Ptens02-348 550tt Phone T04473-1359 Phone. 40047&C0 Plass 3304Sblest e9
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.Mr. Dii:k Cooper February 12,1998 Page 2 MLH-95-006 I have inchN he t output li% for the two cases considered in this calculation. I will forward
- the entire calculation package to you shortly as soon as it is prepared.
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w L, errera, P. L
, Senior Coasultant Attachments cc: H. L. Gustin R. A. Mattson G. A. Miessi NSP-27Q 4
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i j ( StructuralIntegrity Assocbtes, Inc.
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