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Category:GENERAL EXTERNAL TECHNICAL REPORTS
MONTHYEARML20205L0541999-04-0101 April 1999 Nonproprietary Replacement Pages to HI-91738,consisting of Section 5.0, Thermal-Hydraulic Analysis ML17059C5501999-01-31031 January 1999 Rev 0 to MPR-1966(NP), NMP Unit 1 Core Shroud Vertical Weld Repair Design Rept. ML20151P1751998-06-16016 June 1998 Rev 0 to SIR-98-067, Evaluation of NMP Unit 2 Feedwater Nozzle-to-Safe End Weld Butter Indication (Weld 2RPV-KB20, N4D) ML20198B4991998-05-15015 May 1998 Non-proprietary Replacement Pages for Attachment F to Which Proposed to Change TS 5.5, Storage of Unirradiated & Sf ML17059C1681998-03-19019 March 1998 Revised Niagara Mohawk Powerchoice Settlement Document for NMPC PSC Case Numbers 94-E-0098 & 94-E-0099, Vols 1 & 2 ML18040A3301998-02-28028 February 1998 Rev 0 to Technical Rept 97181-TR-03, EPR Testing of Boat Samples from Core Shroud Vertical Welds V-9 & V-10 at NMP Unit 1. ML17059B9051998-02-28028 February 1998 NMP Unit 1 Boat Samples Analyses Part Iii:Tension Tests, RDD:98:55863-004-000:01 ML17059B9061998-02-28028 February 1998 Non-proprietary Rev 0 to GE-NE-523-B13-01869-113NP, Assessment of Crack Growth Rates Applicable to NMP Unit 1 Vertical Weld Indications. ML17059B9071998-02-28028 February 1998 Rev 0 to Technical Rept 97181-TR-02,Vol 1 to Interpretive Metallurgical Rept on Core Shroud Vertical Weld Boat Samples from NMP Unit 1. ML20217F1201997-09-30030 September 1997 Rev 1 to Boat Sample Analyses at NMP Unit 1 ML17059B6771997-08-11011 August 1997 Rev 0 to Evaluation of Overlay for RWCU Weld 33-FW-22. ML17059B5901997-06-30030 June 1997 Rev 0 to Metallurgical Evaluation of Failed Shroud Tie Rod Lower Spring Contact Wedge Latches, for June 1997 ML17059B4861997-04-30030 April 1997 Non-proprietary Rev 0 to GE-NE-523-B13-01869-043, Assessment of Vertical Weld Cracking on NMP1 Shroud. ML17059B4881997-04-30030 April 1997 Non-proprietary Rev 0 to Gene B13-01739-40, Shroud Repair Anomalies NMP1,RF014. ML17059B5111997-04-30030 April 1997 Non-proprietary Version of Rev 1 to GE-NE-523-B13-01869-043, Assessment of Vertical Weld Cracking on NMP1 Shroud. ML17059B4891997-04-30030 April 1997 Non-proprietary Rev 0 to Gene B13-01739-22, Design Rept for Improved Shroud Repair Lower Support Latches. ML17059B5071997-04-30030 April 1997 Final Rept, Analysis of Nine Mile Point Unit 1 Shroud Weld V9 & Weld V10 Cracking. ML17059B4931997-04-0303 April 1997 Core Shroud Cracking Evaluation. ML17059B2411996-08-13013 August 1996 NMP-1 Core Shroud Repair Mod Summary Rept. ML17059B2441996-08-13013 August 1996 Non Proprietary Version of Suppl 1 NMP-1 Seismic Analysis, Core Shroud Repair Mod. ML17059B2421996-08-13013 August 1996 Suppl 4 NMP-1 Shroud Repair Hardware Stress Analysis. ML17059B2431996-08-0909 August 1996 Rev 4 to Stabilizer Installation. ML18040A1801996-08-0101 August 1996 Rev 5 to Reactor. Drawings Encl ML17059B1221996-04-29029 April 1996 Nonproprietary Core Shroud Repair 270 Degree Tie Rod Assembly Assessment. ML17059B0091995-11-29029 November 1995 NMP Unit 2 Safety Evaluation Summary Rept. ML18040A1671995-09-29029 September 1995 NMP Nine Mile Point Unit 1 Nuclear Power Station Rept of RPV FW & CRD Return Line Nozzle Exams Performed for NUREG-0619...at Culmination of Refueling Outage 13 Which Ended on 950404. ML17059B0181995-01-20020 January 1995 Feedwater Nozzle Analysis. ML18040A1621995-01-16016 January 1995 Rev 2 to 25A5583, Shroud Repair Hardware. ML17059A5781994-12-31031 December 1994 Non-proprietary Version of Final Rept Plant-Specific Charpy Shift Model for Nine Mile Point Unit 1. ML17059A5041994-12-31031 December 1994 Unit 2 Safety Evaluation Summary Rept 1994. ML18040A2971994-10-31031 October 1994 Final Rept Entitled Fracture Mechanics Assessment of Nine Mile Point Unit 1 Shroud H4 Weld. ML18040A2271994-08-19019 August 1994 Nuclear Engineering Rept, Nine Mile Point Unit 1 Shroud Cracking Safety Assessment for GL 94-03. ML17059A3611994-07-0606 July 1994 Emergency Action Level Verification & Validation Rept. ML17059A3531994-06-10010 June 1994 Ny State EAL Upgrade Project Nine Mile Point Unit 1 EAL Generation Package. ML17059A3551994-06-10010 June 1994 Eals. ML17311A0181994-05-13013 May 1994 New York State EAL Upgrade Project Verification & Validation Rept. ML17059A3401994-04-30030 April 1994 Rev 0 to Nine Mile Point Unit 1 Feedwater Nozzle Fatigue Evaluation. ML17059A3411994-04-30030 April 1994 Rev 0 to Nine Mile Point Unit 1 CRD Return Nozzle Fatigue Evaluation. ML17059A0881993-12-31031 December 1993 Safety Evaluation Summary Rept 1993. ML17059A0311993-08-31031 August 1993 Elastic Plastic Fracture Mechanics Assessment...Nine Mile Point,Unit 1:Response to NRC RAI Re GL 92-01 ML18038A7381993-03-17017 March 1993 Upper Shelf Energy Uncertainty Analysis for Nine Mile Point Unit 1 Beltline Welds Final Rept ML18038A7351993-02-22022 February 1993 Final Rept, Elastic-Plastic Fracture Mechanics Assessment of Nine Mile Point Unit 1 Beltline Plates for Service Level C & D Loadings. ML18038A7361993-02-19019 February 1993 Beltline Plate Orientation Determination, Final Rept ML18037A0831992-12-16016 December 1992 Elastic-Plastic Fracture Mechanics Assessment of Nine Mile Point Unit 1 Beltline Plates for Svc Level a & B Loadings. ML18038A7261992-11-19019 November 1992 Technical Response to SE by NRR Related to Proposed Deferment of Torus Mods, Nmp,Nmpns,Unit 1 Docket 50-220 ML17056C1091992-10-29029 October 1992 NMP Unit 2 Safety Evaluation Summary Rept. ML18038A7141992-10-16016 October 1992 Final Rept Entitled, Elastic-Plastic Fracture Mechanics Assessment of Nine Mile Point Unit 1 Beltline Plates for Service Level a & B Loadings. ML18038A5181992-06-12012 June 1992 Response to GL 92-01 for Nine Mile Point Unit 1. ML17056B4781991-12-31031 December 1991 Unit 2 Safety Evaluation Rept 1991. ML18038A3741991-09-0909 September 1991 Rev 1 to Root Cause Rept for Exide UPS 1A,B,C,D & G Trip Event of 910813. Electrical Fault on B Phase Main step-up Transformer Occurred Due to Improper Design.Logic Power Supply for Subj UPS Units to Be Modified 1999-04-01
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20217G2161999-10-15015 October 1999 Errata Pages 2 & 3 for Safety Evaluation Supporting Amend 168 Issued to FOL DPR-63 Issued on 990921.New Pages Change Description of Flow Control Trip Ref Cards to Be Consistent with Application for Amend ML20217K4631999-09-30030 September 1999 Monthly Operating Rept for Sept 1999 for Nine Mile Point, Unit 1.With ML20216J9251999-09-30030 September 1999 Suppl to Special Rept:On 990621,11 Containment Hydrogen Monitoring Sys Chart Recorder Was Indicating Below Normal Operating Range.Caused by Excessive Wear on Valve Body & Discs of Bypass Pump.Sample Pump Replaced ML20212F7301999-09-21021 September 1999 Special Rept:On 990907,CR Operators Declared 12 Containment Hydrogen Monitoring Sys Inoperable for Planned Maint.Cause of Low Flow Condition Was Determined to Be Foreign Matl. Replaced Sample Pump Valve Discs ML20212B9081999-09-14014 September 1999 Special Rept:On 990901, 12 Containment Hydrogen Monitoring Sys Was Declared Inoperable for Planned Maint.Caused by Planned Maint Being Performed as Corrective Action.Check Valves with O Rings Were Replaced ML20212C4601999-08-31031 August 1999 Monthly Operating Rept for Aug 1999 for Nine Mile Point Nuclear Station,Unit 1.With ML20216F5141999-08-31031 August 1999 Rept on Status of Public Petitions Under 10CFR2.206 ML20210U4591999-07-31031 July 1999 Monthly Operating Rept for July 1999 for Nine Mile Point, Unit 1.With ML20209D0291999-07-0202 July 1999 Special Rept:On 990621,operator Identified That Number 11 Hydrogen Monitoring Sys (Hms) Chart Recorder Was Indicating Below Normal Operating Range.Cause Indeterminate.Licensee Will Complete Troubleshooting of Subject Hms by 990709 ML20210B9081999-06-30030 June 1999 Monthly Operating Rept for June 1999 for Nine Mile Point Unit 1.With ML20209F8811999-06-0808 June 1999 Rev 1 to NMP Unit 1 COLR for Cycle 14 ML20207G2261999-06-0707 June 1999 SER Accepting Proposed Mod to Each of Four Core Shroud Stabilizers for Implementation During Current 1999 Refueling Outage at Plant,Unit 1 ML20196E2111999-05-31031 May 1999 Monthly Operating Rept for May 1999 for Nmp,Unit 1.With ML20207B0241999-05-18018 May 1999 Safety Evaluation of Topical Rept TR-107285, BWR Vessel & Intervals Project,Bwr Top Guide Insp & Flaw Evaluation Guidelines (BWRVIP-26), Dtd December 1996.Rept Acceptable ML20206U5351999-05-17017 May 1999 SER Accepting GL 95-07, Pressure Locking & Thermal Binding of Safety-Related Power-Operated Gate Valves, for Plant, Units 1 & 2 ML20196L2301999-04-30030 April 1999 Monthly Operating Rept for Apr 1999 for Nmp,Unit 1.With ML20205L0541999-04-0101 April 1999 Nonproprietary Replacement Pages to HI-91738,consisting of Section 5.0, Thermal-Hydraulic Analysis ML20205S5701999-03-31031 March 1999 Monthly Operating Rept for Mar 1999 for NMP Unit 1.With ML20207M9231999-03-12012 March 1999 Amended Part 21 Rept Re Cooper-Bessemer Ksv EDG Power Piston Failure.Total of 198 or More Pistons Have Been Measured at Seven Different Sites.All Potentially Defective Pistons Have Been Removed from Svc Based on Encl Results ML20207G2671999-03-0101 March 1999 Special Rept:On 990315,Nine Mile Point,Unit 1 Declared Number 12 Containment Hydrogen Monitoring Sys Inoperable. Caused by Degraded Encapsulated Reed Switch within Flow Switch FS-201.2-1495.Technicians Replaced Flow Switch ML20204C9971999-02-28028 February 1999 Monthly Operating Rept for Feb 1999 for Nine Mile Point,Unit 1.With ML20207E9311999-02-26026 February 1999 Part 21 Rept Re Sprague Model TE1302 Aluminum Electrolytic Capacitors with Date Code of 9322H.Caused by Aluminum Electrolytic Capacitors.Affected Capacitors Replaced ML17059C5501999-01-31031 January 1999 Rev 0 to MPR-1966(NP), NMP Unit 1 Core Shroud Vertical Weld Repair Design Rept. ML20199M0891999-01-22022 January 1999 Part 21 Rept Re Failure of Square Root Converters.Caused by Failed Aluminum Electrolytic Capacitory Spargue Electric Co (Model Number TE1302 with Mfg Date Code 9322H).Sent Square Root Converters Back to Mfg,Barker Microfarads,Inc ML20199K9331998-12-31031 December 1998 Monthly Operating Rept for Dec 1998 for Nine Mile Point Nuclear Station,Unit 1.With ML20210R8441998-12-31031 December 1998 1998 Annual Rept for Energy East ML20206P2391998-12-31031 December 1998 Special Rept:On 981222,operators Removed non-TS Channel 12 Drywell Pressure Recorder & Associated TS Pressure Indicator from Svc.Caused by Intermittent Measuring Cable Connection in non-TS Recorder Circuitry.Replaced Cable ML20206P2421998-12-30030 December 1998 Special Rept:On 981219,number 12 Hydrogen Monitoring Sys (Hms) Was Declared Inoperable When Operators Closed Valve 201.2-601.Caused by Indeterminate Failure of Valve 201.2-71. Supplemental Rept Will Be Submitted After Valve Is Repaired ML20198M3571998-12-23023 December 1998 Special Rept:On 981210,operators Declared Number 11 Inoperable,Due to Failure of CR Chart Recorder.Caused by Inverter Board in Power Supply Circuitry of Recorder Due to Component Aging.Maint Personnel Replaced Failed Inverter ML20198D9361998-11-30030 November 1998 Monthly Operating Rept for Nov 1998 for Nine Mile Point,Unit 1.With ML20155E2001998-11-0202 November 1998 Safety Evaluation Approving NMP 980227 Request for Extension of Reinspection Interval for Core Shroud Vertical Welds at NMP1 from 10,600 Hours to 14,500 Hours of Hot Operation ML20195J4141998-10-31031 October 1998 Monthly Operating Rept for Oct 1998 for Nine Mile Point Nuclear Station,Unit 1.With ML20154D8401998-10-0505 October 1998 Safety Evaluation Accepting Proposed Changes Related to PT Limits in Plant,Unit 1 TSs ML20154P1821998-09-30030 September 1998 Monthly Operating Rept for Sept 1998 for Nine Mile Point Nuclear Station,Unit 1.With ML20153B2001998-08-31031 August 1998 Monthly Operating Rept for Aug 1998 for Nmpns,Unit 1.With ML20237C6351998-07-31031 July 1998 Monthly Operating Rept for July 1998 for Nine Mile Point Nuclear Station,Unit 1 ML20236T5911998-07-20020 July 1998 LER 98-S01-00:on 980618,security Force Member Left Nine Mile Point,Unit 2 Vehicle Gate Unattended Without Ensuring,Gate Alarm Had Been Reactivated.Caused by Inadequate Work Practice.Vehicle Gate Alarm Was Activated ML18040A3491998-07-0202 July 1998 LER 98-017-00:on 980602,control Room Ventilation Sys Was Declared Inoperable.Caused by Original Design Deficiency. Mod Designed,Tested & Implemented Prior to Startup from RF06 to Correct Design deficiency.W/980702 Ltr ML20236Q1701998-06-30030 June 1998 Monthly Operating Rept for June 1998 for Nine Mile Point Nuclear Station,Unit 1 ML17059C1011998-06-24024 June 1998 LER 98-014-00:on 980525,noted Differences Between Actual Valve Weights & Weights Shown on Engineering Drawings.Caused by Vendor Failing to Provide Accurate Valve Weights.Revised Valve Drawings & Associated Calculation,Per 10CFR21 ML20151P1751998-06-16016 June 1998 Rev 0 to SIR-98-067, Evaluation of NMP Unit 2 Feedwater Nozzle-to-Safe End Weld Butter Indication (Weld 2RPV-KB20, N4D) ML18040A3451998-06-0404 June 1998 LER 98-004-01:on 980302,TS Required LSFT of Level 8 Trip of Main Turbine Was Missed.Caused by Knowledge Deficiency of EHC Sys.Revised Applicable LSFT Procedures Prior to Refueling Outage 6.W/980604 Ltr ML20249B4971998-05-31031 May 1998 Monthly Operating Rept for May 1998 for Nine Mile Point Nuclear Station,Unit 1 ML20248F3531998-05-21021 May 1998 Part 21 Rept Re Electronic Equipment Repaired or Reworked by Integrated Resources,Inc from Approx 930101-980501.Caused by 1 Capacitor in Each Unit Being Installed W/Reverse Polarity. Policy of Second Checking All Capacitors Is Being Adopted ML20198B4991998-05-15015 May 1998 Non-proprietary Replacement Pages for Attachment F to Which Proposed to Change TS 5.5, Storage of Unirradiated & Sf ML20247R1141998-04-30030 April 1998 Monthly Operating Rept for Apr 1998 for Nine Mile Point Nuclear Station,Unit 1 ML20217B0621998-03-31031 March 1998 Monthly Operating Rept for Mar 1998 for Nine Mile Point Nuclear Station,Unit 1 ML17059C1681998-03-19019 March 1998 Revised Niagara Mohawk Powerchoice Settlement Document for NMPC PSC Case Numbers 94-E-0098 & 94-E-0099, Vols 1 & 2 ML20217F4341998-03-19019 March 1998 SER Related to Proposed Restructuring New York State Electric & Gas Corp,Nine Mile Point Nuclear Station,Unit 2 ML17059B9051998-02-28028 February 1998 NMP Unit 1 Boat Samples Analyses Part Iii:Tension Tests, RDD:98:55863-004-000:01 1999-09-30
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0 ATTACHMENT 8.2 , 0 SUPPLEMENT 4 MILE POINT 1 SHROUD REPAIR HARDWARE STRESS ANALYSIS'6082iOi37 9608i4'DR ADQCK 05000220.P'PDR
GE Nuclear Energy GENE B13-01739-04 Supplement 4 August 1998 Supplement 4 Nine Mile Point 1 Shroud Repair Hardware Stress Analysis Prepared for: Niagara Mohawk Power Corporation Nine Mile Point Unit 1 Prepared by: GE Nuclear Energy Reactor Modification Services 175 Curtner Avenue, N/C 571 San Jose, California 95125
GE Nuclear Energy GENE B13-01739-04 Supplement 4 August 1996 Supplement 4 Nine Mile Point 1 Shroud Repair Hardware Stress Analysis Prepared by: T.'.Gleason, Principal Engineer Reactor Modification Services Reviewed by: A, N Dalcher, Principal Engineer Reactor Modification Services Approved by: S.Ranganath, Engineering Fellow GE Nuclear Engineering
GENE B13-01739-04 Supplement 4 August, 1998 REVISION STATUS SHEET Revision A roval P.Walier Date Jan., 199o Descri tion Shroud Repair Hardware Stress Analysis Suppl.1 H.iVehta Feb., 1995 Crack separation evaluation with 360'hrough wall cracks at H2 and H3.Suppl.2 P.Walier April, 1995 Addresses the changes and deviations in the as-built hardware.Suppl.3 Suppl.4 S.Ranganath S.Ranganath April, 1996 August, 1996 Evaluation of the 270'tabilizer assembly with the lower spring bearing on a nozzle blend radius.(Not re uired if lower s rin is relocated.)
Relocated Lower Spring and Lower Spring Spacer evaluation.
GENE B13-01739-04 Supplement 4 August, 1998 IMPORTANT NOTICE REGARDING CONTENTS OF THIS REPORT Please read carefully The only undertakings of the General Electric Company (GE)respecting information in this document are contained in the contract between Niagara Mohawk Power Corporation (NMPC)and GE, and nothing contained in this document shall be construed as changing the contract.The use of this information by anyone other than NMPC, or for any purpose other than that for which it is intended is not authorized; and with respect to any unauthorized use, GE makes no representation or warranty, express or implied, and assumes no liability as to the completeness, accuracy, or usefulness of the information contained in this document, or that its use may not infringe upon privately owned rights.
GENE B13-01739-04 Supplement 4 August, 1998 CONTENTS
1.0 INTRODUCTION
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SUMMARY
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6 3o2 CORE PLATE DISPLACEMENTe
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GENE B13-01739-04 Supplement 4 August, 1996 1.INTRODUCTION The purpose of this stress report supplement is to address the addition of the Bottom Spring Spacer (148C6912) to the shroud repair hardware and to address the affects of relocating the 270'ottom spring to the opposite side of the tie rod.The addition of the Bottom Spring Spacer extends the lower spring contact b'eyond weld H6A and restores the function of the lower contact to its intended design condition.
Relocating the lower spring changes the equivalent spring characteristics which affects the seismic response for several assumed shroud cracked conditions.
Reference 5.1 addresses the loads and displacements for the revised configuration.
2.
SUMMARY
AND CONCLUSION Adding the Bottom Spring Spacer restores the lower spring to its intended design function.The Bottom Spring Spacer limits possible temporary and permanent shroud displacements at weld H6A to less than the allowable values.The added piece is captured in all directions and is held firmly in place by a spring loaded clamping force.The stresses in the added part are well below the allowable values for all operating conditions and accident events.Moving the lower spring on the 270'ie rod changes the lower spring loads and displacements for certain assumed shroud cracked conditions.
The loads on the stabilizer hardware were calculated and found to remain less than the bounding loads used in the original stress analysis.The core plate displacement for certain accident conditions exceed those previously calculated, but remain well below the allowable values.3.EVALUATION 3.1 Bottom Spring Spacer (148C6912)
The Bottom Spring Spacer rests on the existing lower contact and extends beyond the potential crack location at weld H6A.The 3 inch extension accounts for the weld height, the heat affected zone (HAZ)and the calculated vertical weld separation during a steam line LOCA.The extended length also accounts for the initial mismatch, bearing area and margin.The weld dimension and HAZ are based on the design drawings and the inspection videos of this area.
GENE B13-01739-04 Supplement 4 August, 1998 The Bottom Spring Spacer is attached to the existing lower contact and includes features which capture it in all directions.
The steps at the end of each leg fit under the existing lower contact to prevent vertical movement.A tang at the back of the contact block fits in the gap between the lower contact and the lower spring to prevent horizontal movement.A positive spring loaded clamping force (40 to 50 pound)against the sides of the lower contact prevent vibrations or any free movements.
The Bottom Spring Spacer is made of Inconel X-750.When installed, the legs of the Bottom Spring Spacer are sprung up to 0.215 inches to provided the clamping load on the lower contact.The resulting bending stress: Bending Stress=3E5c/L'42,500 lb/in.'=modulus of elasticity
=28.85 x 10'si 5=deflection
=0.215 in..c=spring thickness/2
=0.205/2=0.1025 in.L=spring leg length=6.7 in.The allowable bending stress for normal conditions is 1.5 Sm or 71,250 lb/in'.The installation tooling may temporarily hold the legs sprung out to a maximum of 0.405 inches.Accounting for the greater deflection and the elastic modulus at the installation temperature, the bending stress during installation is: Installation Bending Stress=(0.405/0.215) x(31.00/28.85) x 42,500=86,024 lb/in'his remains well below the 120,000 lb/in'ield stress for this material.There will be no permanent set during installation.
In the event of separation at weld H6A, (only during a steam line LOCA)the Bottom Spring Spacer limits the possible shroud movement and, together with, the core plate spacers, provide a redundant load path for the horizontal seismic loads.(The core support structure is also held in position by the core support bolts and by the core support aligner pins.)Without taking credit for the core support bolts or aligner pins, the limiting load on the Bottom Spring Spacer is the entire 63,800 Ib maximum horizontal seismic load.The Bottom Spring Spacer bears against the 4 inch wide lower spring and carries the load over the portion extending beyond weld H6A.A 1.2 square inch load carrying area is a conservative value.Bearing Stress=P/A=63,800 lb/1.2 in'53,170 lb/in'he allowable bearing stress during a faulted event is 3 Sy or 276,900 psi.
GENE B13-01739-04 Supplement 4 August, 1998 3.2 Core Support Displacement The lower stabilizer spring bears against the shroud at the core support ledge and on the H6B weld crown.The contact extends beyond the H6A weld, but there is up to a 0.28 inch spacing between the contact surface and shroud above weld H6A.The 0.28 inches includes an estimated 0.13 inch weld crown height.The spacing above weld H6A means the shroud can move 0.28 inch in the direction of the spring before contact is made If the movement is in the direction midway between the contacts 108'part, the shroud movement may be up to 0.48 inches[0.28/COS(108'/2)
=0.48]before contact is made.The maximum transient core plate displacement midway between the springs for Upset and Emergency events is 0.26 inches as reported in Reference 5.1.The allowable transient displacements for these events is 0.75 inches and 1.12 inches respectively.
There is no permanent displacement for these events.A Faulted event may include permanent displacement if there is separation at weld H6A and the shroud moves before contact is made with the spring.With separation at weld H6A the shroud cylinder bears against the spring and its affects are included in the net spring characteristics.
For this case, the maximum spring compression increases to 0.37 inches as shown in Table 1 of Reference 5.1.Including the permanent displacement, the maximum transient displacement during the faulted event is 0.85 inches (0.48+0.37=0.85).The maximum permanent displacement is 0.48 inches.During a faulted event, the allowable transient displacement is 1.49 inches and the allowable permanent displacement is 0.66 inches.These core support displacements supercede the displacement values reported in Table 4.8 of the original stress report, GE-NE-B13-01739-04, Rev.0.3.3.Hardware Stresses Reference 5.1 calculates the spring loads and displacements assuming the bottom springs are located 108'part and again with the bottom springs spaced 76'part.The equivalent spring constants are 2782 k/ft and 5,000 k/ft respectively.
There is no change to the tie rod spacing or to the upper spring spacing.The loads calculated in Reference 5.1 are the resultant of the loads applied by the two adjacent springs.Since two springs are actually sharing the total load, the load on any one spring is less than the load calculated in Reference 1.
GENE B13-01739-04 Supplement 4 August, 1996 9.9.1 Lower Spring The highest equivalent load at the lower spring is 68.33k and occurs midway between the lower springs 76'part.The load on the two adjacent springs is: P=68.33k/2 COS (76'/2)=43.36k The 63.8k load used in the previous analysis remains the bounding load condition.
The shroud contact on the replacement 270'ower spring is modified to extend beyond the H6A weld and remains 316 SST.The bearing area on this contact is greater than 2.5 square inches.Bearing stress=63,800 lb/2.5 in'25,520 lb/in'he allowable bearing stress for a faulted event is 3 Sy or 46,350 psi.3.3.2 Upper Spring The analysis in Reference 5.1 show there are no changes to the loads at the upper spring and there are no changes to the previous stress analysis.9.9.3 Tie Rod Repositioning the lower spring has no eQ'ect on the maximum tie rod load.The maximum tie rod load is governed by the MSLB uplift and any change in spring coefficient has insignificant affect on the net load.The bounding 92k tie rod load used in the original analysis remains valid.4.CORE SPRAY PIPING The analysis in Reference 5.1 show there is no changes in the horizontal displacements at the upper spring.There is no changes in the core spray piping loads as result of the lower spring relocation.
5.REFERENCES 5.1 Supplement 1, Nine Mile Point 1, Seismic Analysis, Core Shroud Repair Modification, GENE-B13-01739-03, Rev.0 5.2 Nine Mile Point 1, Seismic Analysis, Core Shroud Repair Modification, GENE-B13-01739-03, Rev.0