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Category:GENERAL EXTERNAL TECHNICAL REPORTS
MONTHYEARML17292B2641998-03-0404 March 1998 Performance Self Assessment,WNP-2. ML17292A3921996-06-30030 June 1996 WNP-2 Ten Mile EPZ Evacuation Time Estimate Study. ML17291B2931995-12-31031 December 1995 Adjustable-Speed Drive Retrofit for Ormond Beach Fd Fans. ML17291B1401995-07-0606 July 1995 Technical Evaluation Rept,Wppss Plant No 2,Pump & Valve Ist,Rev 0,Second Ten-Yr Interval. ML17291A9421995-06-30030 June 1995 Rev 0 to IPE of External Events WNP2. ML17291A5691994-12-0707 December 1994 Simulator Facility Certification. ML17291A4481994-10-13013 October 1994 WNP-2 Response to Request for Addl Info on Emergency Classification. ML17290A9181993-12-27027 December 1993 Justification for Revised Tornado Design Criteria,Rev 1. ML17290A6901993-10-0808 October 1993 Revised Significant Hazards Consideration Assessment for WNP-2 Power Uprate W/Elll. ML17290A6861993-09-27027 September 1993 Rev 1 to Evaluation of Sources of Radioactive Matl Found in Cooling Tower Sediments at Washington Nuclear Plant 2. ML17290A3831993-05-18018 May 1993 Rept R-R8-111 Re Flaw in Reactor Recirculation Piping ML17289B0751992-11-23023 November 1992 Rev 0 to Technical Memorandum Tm 2025, Secondary Containment/Standby Gas Treatment Design Basis. ML17289A9881992-10-0707 October 1992 Containment Atmosphere Control Sys (CAC) Summary Issues. ML17289A7251992-06-30030 June 1992 Institutional Custody Fiduciary Svcs. ML17289A7231992-06-30030 June 1992 Institutional Custody Fiduciary Svcs. ML17289A9281992-06-24024 June 1992 WNP-2 Simulator Certification NRC Form 474 Supporting Documentation. ML17289A5351992-05-11011 May 1992 App B, 8X8 Extended Burnup, of EMF-92-040, WNP-2 Cycle 8 Reload Analysis. ML17286B0211991-08-20020 August 1991 Root Cause Analysis Summary, Unsatisfactory Licensed Operator Requalification Program, Reflecting Causes of Operators Continued Inability to Respond to Severe Accident Conditions ML17286A9151991-06-30030 June 1991 Asset Summary 910630. ML17286A9141991-06-30030 June 1991 Summary of Transactions for 900630-910630. ML17285A9631989-12-27027 December 1989 Feedwater Nozzle Insp Rept for Refueling Outage RF89A Spring 1989. ML17285A8871989-08-14014 August 1989 Rev 0 to Commercial Grade Dedication Project for Wppss Contract C-30298. ML17285A6411989-07-31031 July 1989 Instrument Air Sys Review Response to Generic Ltr 88-14. W/Six Oversize Figures ML17285A1971988-12-14014 December 1988 Feedwater Nozzle Insp Rept for Refueling Outage RF88A, Spring,1988. ML20237D3121987-11-30030 November 1987 Final Feedwater Temp Reduction Summary Rept ML17279A6251987-04-30030 April 1987 Rev 2A to Wnp 1,2 10-Mile EPZ Evacuation Time Assessment Study. ML17279A1911987-04-0707 April 1987 Comparision of Electrical Design of Wye Pattern Globe Valve Actuator W/Ball Valve,Hanford 2 & River Bend Design. Five Oversize Drawings Encl ML17279A2341987-03-31031 March 1987 Washington Nuclear Plant 2 Performance Indicator Rept. ML20207N2661986-12-31031 December 1986 Assessment of Fire Protection Program Responsibilities & Administration ML20215B7271986-11-25025 November 1986 Feedwater Nozzle Insp Rept for Refueling Outage RF86A, Spring 1986 ML17278B0001986-08-22022 August 1986 Results of Insp of WPPSS-2 Cycle 1 Discharge Fuel. ML17279A6481986-05-0101 May 1986 Draft Lead Test Assembly Program,Wpps 2. ML17278A8051986-03-31031 March 1986 Safety Review of Wppss Nuclear Project 2 at Core Flow Conditions Above Rated Flow Throughout Cycle 1 & Final Feedwater Temp Reduction. ML17278A4721985-09-30030 September 1985 Crdr & Emergency Procedure Functional Task Analysis Summary Rept. ML17278A4281985-07-31031 July 1985 Washington Nuclear Plant Unit 2 Spray Pond Drift Loss Rept. ML17277B6191985-01-31031 January 1985 Rev 2 to Description of Early Warning Sys for Wppss Nuclear Plants 1 & 2. ML17277B5241984-10-0808 October 1984 Feedwater Piping Thermal Deflection Events, Final Design Engineering Rept ML17277B2451983-12-30030 December 1983 RHR Addendum to Design Verification Program. ML17277B2201983-12-11011 December 1983 Qualification of Purge & Vent Valves at WPPSS-2, Vols 1 & 2 ML20080N1941983-12-0707 December 1983 Excerpt from Qvp Overview Rept,Vol I,Book 1 of 1.Related Info Encl ML17277B2961983-11-30030 November 1983 Rept to Governor J Spellman of State of Wa & Governor V Atiyeh of State of Or. ML17277B2231983-11-0808 November 1983 Qualification of Purge & Vent Valves at WPPSS-2, Vol 4: Rev 4 to Equipment Seismic & Hydrodynamic Requalification of 24-Inch Cylinder Operated Butterfly Valves for CSP-V-3, 4,5,6 & 9 & CEP-V-3A & 4A. ML17277B2221983-11-0404 November 1983 Qualification of Purge & Vent Valves at WPPSS-2, Vol 3: Rev 2 to Equipment Seismic & Hydrodynamic Requalification of 30-Inch Cylinder Operated Butterfly Valves CSP-V-1 & 2 & CEP-V-1A & 2A. ML17277A9431983-10-0707 October 1983 Response to NRC Human Factors Engineering Preliminary Design Assessment Audit Rept of 830826. ML17277A8701983-09-30030 September 1983 Design Reverification Program, Vols 1 & 2,final Assessment Rept ML20078M2661983-09-30030 September 1983 Independent Evaluation of Plant Verification Program at WPPSS-2:Vol I Quality Verification ML20080T2071983-09-22022 September 1983 Engineering Insp & Evaluation of Quality Class Ii/Seismic Category I Pipe Supports ML17277A8541983-09-21021 September 1983 Quality Verification Program,Vol 1:Overview Rept,Jul-Sept 1983. ML17292A8091983-09-20020 September 1983 Sheet 1 to Reactor Protection Sys. ML17277A9961983-09-0909 September 1983 Hanford 2 Power Generation Control Complex (Pgcc) Floor Plate Design. 1998-03-04
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML17284A9001999-10-31031 October 1999 Rev 0 to COLR 99-15, WNP-2 Cycle 15,COLR GO2-99-177, LER 99-S01-00:on 990903,failure to Take Compensatory Measure within Required Time Upon Failure of Isolation Zone Microwave Unit,Was Noted.Caused by Personnel Error.Provided Refresher Training on Compensatory Measures.With1999-10-0101 October 1999 LER 99-S01-00:on 990903,failure to Take Compensatory Measure within Required Time Upon Failure of Isolation Zone Microwave Unit,Was Noted.Caused by Personnel Error.Provided Refresher Training on Compensatory Measures.With ML17284A8941999-09-30030 September 1999 Monthly Operating Rept for Sept 1999 for WNP-2.With 991012 Ltr ML17284A8801999-08-31031 August 1999 Monthly Operating Rept for Aug 1999 for WNP-2.With 990910 Ltr ML17284A8691999-07-31031 July 1999 Monthly Operating Rept for July 1999 for WNP-2.With 990813 Ltr ML17292B7421999-07-20020 July 1999 LER 99-001-00:on 990628,ESF Signal Closed All Eight MSIVs While Plant Was Shutdown.Caused by Failure of Relay RPS-RLY-K10D.Subject Relay Was Replaced & Tested on 990630. with 990720 Ltr ML17292B7271999-06-30030 June 1999 Monthly Operating Rept for June 1999 for WNP-2.With 990707 Ltr ML17292B6961999-05-31031 May 1999 Monthly Operating Repts for May 1999 for WNP-2.With 990608 Ltr ML17292B6641999-04-30030 April 1999 Monthly Operating Rept for Apr 1999 for WNP-2.With 990507 Ltr ML17292B6391999-03-31031 March 1999 Monthly Operating Rept for Mar 1999 for WNP-2.With 990413 Ltr ML17292B5871999-02-28028 February 1999 Monthly Operating Rept for Feb 1999 for WNP-2.With 990311 Ltr ML17292B5571999-01-31031 January 1999 Monthly Operating Rept for Jan 1999 for WNP-2.With 990210 Ltr ML17292B5621999-01-31031 January 1999 Rev 1 to COLR 98-14, WNP-2 Cycle 14 Colr. ML17292B5341999-01-15015 January 1999 Part 21 Rept Re Incorrect Modeling of BWR Lower Plenum Vol in Bison.Defect Applies Only to Reload Fuel Assemblies Currently in Operation at WNP-2.BISON Code Model for WNP-2 Has Been Revised to Correct Error ML17292B5331999-01-15015 January 1999 Part 21 Rept Re XL-S96 CPR Correlation for SVEA-96 Fuel. Defect Applies Only to WNP-2,during Cycles 12,13 & 14 Operation.Evaluations of Defect Performed by ABB-CE ML17292B4791998-12-31031 December 1998 Washington Public Power Supply Sys 1998 Annual Rept. with 981215 Ltr ML17292B5351998-12-31031 December 1998 Monthly Operating Rept for Dec 1998 for WNP-2.With 990112 Ltr ML17292B5741998-12-31031 December 1998 WNP-2 1998 Annual Operating Rept. with 990225 Ltr ML17284A8231998-11-30030 November 1998 Monthly Operating Rept for Nov 1998 for WNP-2.With 981207 Ltr ML17284A8081998-10-31031 October 1998 Monthly Operating Rept for Oct 1998 for WNP-2.With 981110 Ltr ML17292B4451998-10-27027 October 1998 LER 98-012-01:on 980715,failure to Comply with Requirements of TS SR 3.8.4.7 Was Noted.Caused by Inadequate Work Practices.Training Session Was Held with Personnel.With 981027 Ltr ML17284A7831998-09-30030 September 1998 Monthly Operating Rept for Sept 1998 for WNP-2.With 981007 Ltr ML17284A7491998-09-10010 September 1998 WNP-2 Inservice Insp Summary Rept for Refueling Outage RF13 Spring,1998. ML17284A7561998-09-0303 September 1998 LER 98-013-00:on 980805,ESF Actuations Were Noted Due to Deenergization of Vital Electrical Bus SM-8.Caused by Inadequate Direction in Troubleshooting Plan.Will Conduct Training for Engineering Personnel.With 980903 Ltr ML17284A7571998-09-0202 September 1998 LER 98-014-00:on 980807,completion of TS 3.8.1.F Required Shutdown Due to Inoperability of EDG-2 Was Noted.Caused by Degraded Voltage Regulator for DG-2.Replaced Voltage Regulator & Associated Scrs.With 980902 Ltr ML17284A7551998-09-0202 September 1998 LER 98-015-00:on 980808,discovered Reactor Coolant Pressure Boundary Leak During Shutdown Conditions.Caused by Leakage from Socket Weld (Fwb 63) on Elbow Connection.Failed Piping Connection Was Replaced.With 980902 Ltr ML17284A7681998-08-31031 August 1998 Monthly Operating Rept for Aug 1998 for WNP-2.With 980915 Ltr ML17284A7311998-08-17017 August 1998 LER 98-012-00:on 980716,determined That 24-month SR 3.8.4.7 Had Not Been Fulfilled within Specified Frequency.Caused by Inadequate Work Practices.License Requested & Received Enforcement Discretion Re Battery Svc test.W/980817 Ltr ML17284A7261998-07-31031 July 1998 Monthly Operating Rept for July 1998 for WNP-2.W/980810 Ltr ML17284A7121998-07-23023 July 1998 LER 98-006-01:on 980520,discovered Discrepancies in Low Voltage Bus Calculations During Review of 10CFR50,App R Calculations for High Impedance Faults.Caused by Inadequate Work Practices.Implemented Procedural Changes ML17284A6951998-07-17017 July 1998 LER 98-011-00:on 980617,ECCS Pump Room Flooding Was Noted Due to FP Sys Pipe Break.Caused by Inadequate Design of FP Sys.Detailed Review of FP Sys Design Was Conducted. W/980717 Ltr ML17284A6961998-07-15015 July 1998 LER 98-010-00:on 980615,TS Required Shutdown Due to Inoperability of TIP Sys Isolation Valve Was Noted.Caused by Improper Installation of TIP Tubing.Reattached Affected Tubing & Inspected Other TIP tubing.W/980715 Ltr ML17284A6731998-07-0101 July 1998 LER 98-009-00:on 980606,nuclear Steam Supply Shutoff Sys Group 3 & 4 Isolations During Testing Was Noted.Caused by Procedural Deficiency.Counseled Individuals Involved in preparation.W/980701 Ltr ML17284A6751998-06-30030 June 1998 Ro:On 980617,flooding of RB Northeast Stairwell with Consequential Flooding of Two ECCS Pump Rooms.Caused by Inadequate Fire Protection Sys Design.Pumped Out Water from Affected Areas to Point Below Berm Areas of Pump Rooms ML17284A6641998-06-24024 June 1998 LER 98-008-00:on 980531,inadvertent Full Scram During RPV Leak Testing in Mode 4 Was Noted.Caused by Change in Mgt Techniques.Revised Procedures to Take Into Account Addl Water Head in Pressure Sensing lines.W/980624 Ltr ML17284A6651998-06-24024 June 1998 LER 98-007-00:on 980530,inadvertent Full Scram & Division 1 ECCS Injection Was Noted.Caused by Failure to Meet Mgt Work Practice Expectation When Encountering Deficient Procedure. Incident Review Board Convened to Review event.W/980624 Ltr ML17284A6631998-06-19019 June 1998 LER 98-006-00:on 980520,discovered Discrepancies in Low Voltage Bus Calculations During Review of App R Calculations for High Impedance Fault Analysis.Caused Indeterminate. Implemented Procedural Changes Involving Operator Action ML17284A6551998-06-0404 June 1998 LER 98-005-00:on 980506,potential for Failure of RHR Sys Valve to Close on Isolation Signal Was Noted.Caused by Design Deficiency.Caution Tag Was Placed on RHR-V-40 Control Switch to Inform Plant Operators of limitation.W/980604 Ltr ML17284A6421998-06-0101 June 1998 LER 98-004-00:on 980502,determined That Primary Containment Penetration Overcurrent Protection Does Not Meet Reg Guide 1.63 Requirements.Caused by Inadequate Design Changes. Installed Addl Fuse in RHR-MO-9 circuit.W/980601 Ltr ML17284A6491998-05-31031 May 1998 Rev 0 to COLR 98-14, WNP-2,Cycle 14 Colr. ML17292B4031998-05-31031 May 1998 Monthly Operating Rept for May 1998 for WNP-2.W/980608 Ltr ML17292B3921998-04-30030 April 1998 Monthly Operating Rept for Apr 1998 for WNP-2.W/980513 Ltr ML17292B3291998-04-0909 April 1998 LER 98-003-00:on 980311,WNP-2 Experienced SCRAM Signal as Result of Low Rpv.Caused by Less than post-SCRAM Operational Strategy for Resetting SCRAM Signal in Conditions.Changes in post-SCRAM Operational Strategy implemented.W/980409 Ltr ML17292B3281998-04-0909 April 1998 LER 98-002-00:on 980311,reactor Scram & Plant Transient Occurred,Due to Failed Closed Main Steam Isolation Valve. Caused by Loss of Pneumatic Actuating Supply Pressure. Problem Evaluation Request Written for Failure of MS-V-22D ML17292B3371998-03-31031 March 1998 Monthly Operating Rept for Mar 1998 for WNP-2.W/980409 Ltr ML17292B2641998-03-0404 March 1998 Performance Self Assessment,WNP-2. ML17292B2661998-03-0404 March 1998 LER 98-001-00:on 980203,automatic Start of HPCS EDG Was Noted.Caused by Operator Error.Operations Crew Stabilized Plant at Approximately 75% Reactor Power & Investigation of Event Was initiated.W/980304 Ltr ML17292B2911998-02-28028 February 1998 Monthly Operating Rept for Feb 1998 for WNP-2.W/980313 Ltr ML17284A7971998-02-17017 February 1998 Rev 28 to Operational QA Program Description, WPPSS-QA-004.With Proposed Rev 29 ML17292B3591998-02-12012 February 1998 WNP-2 Cycle 14 Reload Design Rept. 1999-09-30
[Table view] |
Text
EMF-92-040
( 9205180068 920511 Page B-1 PDR ADOCK 05000397 P POR APPENDIX B 8X8 EXTENDED BURNUP
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EMF-92-040 Page B-2 APPENDIX B X EXTENDED BURN P B.1 INTRODUCTION This appendix documents the mechanical design analyses performed to extend the assembly exposure limit of the WNP-2 SxS fuel to 37,000 MWd/MTU. Reference is made to the NRC-approved document XN-NF-85-67(P)(A), Revision 1 which supported a fuel assembly exposure of 35,000 MWd/MTU for the SxS fuel design. The results of design calculations support the irradiation of the SxS fuel to the following exposure values:
Fuel Assembly 37,000 Mwd/MTU Fuel Rod 42,300 Mwd/MTU Peak Pellet 50,700 Mwd/MTU Planar Exposure 48,100 MWd/MTU B.2
SUMMARY
The results of the design calculations performed to extend the SxS assembly exposure limit demonstrates full compliance with the design criteria.
B.2.1 De i n D seri i n S mmar The SNP 8xS fuel design uses 62 fuel rods and two centrally located water rods, one of which functions as a spacer capture rod. Seven spacers maintain fuel rod spacing. The design uses a quick-removable upper tie plate design to facilitate fuel inspection and bundle reconstitution of irradiated assemblies.
The fuel rods are pressurized and utilize 0.035 inch thick Zircaloy-2 cladding. The rods contain either UO2-Gd203 of UO2 with a nominal density of 94.5% TD Natural uranium axial fuel blankets are provided at the top and bottom of the fuel column for greater neutron economy.
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EMF-92-040 Page B-3 B.2.2 0 i n Anal i mmar The mechanical design analyses were performed to evaluate cladding steady-state strain and stress, transient strain and stress, fatigue damage, creep collapse, corrosion, hydrogen absorption, fuel rod internal pressure, differential fuel rod growth, and creep bow.
The analyses justify irradiation to an assembly exposure of 37,000 MWd/MTU. The following summarizes the analysis results:
The maximum end-of-life (EOL) steady-state cladding strain is calculated to be below the 1.0% design limit.
Cladding steady-state stresses are calculated to be below the material strength limits.
The cladding strain during anticipated operating occurrences (AOOs) does not exceed 1.0%.
The maximum fuel rod internal rod pressure remains below the design limit, The fuel centerline temperature remains below the melting point during AOOs.
The cladding fatigue usage factor is within the 0.67 design limit.
Structural members have adequate strength to support handling and hydraulic loads.
The cladding diameter reduction due to uniform creepdown, plus creep ovality at maximum densification, is less than the minimum initial gap. Compliance to this criterion prevents the formation of fuel column gaps and the possibility of creep collapse, Evaluations of assembly growth and differential fuel rod growths show that the design provides adequate clearances for compatibility with the fuel assembly channel. Also, there is adequate nominal engagement of the end caps in the upper tie plate and lower tie plate throughout the fuel design life.
The initial fuel rod design spacing is anticipated to accommodate expected rod-to-rod gap closure throughout the fuel design life.
The maximum EOL reduction in cladding thickness due to corrosion and the maximum concentration of hydrogen in the cladding are calculated to be weil within the design limits.
EMF-92-040 Page B-4 The fuel rod plenum spring and other miscellaneous components are shown to meet the respective design bases.
The spacer spring meets all the design requirements and can accommodate the expected relaxation at the respective EOL exposures.
B.3 DESIGN ANALYSES The design analyses for the 8x8 fuel were performed using the approved codes and methods in Reference 9.2. Design calculations were performed to extend the assembly exposure limit above that previously reported. Figure B3.1 is the LHGR limit used in the steady- state fuel rod performance evaluation. Figure B3.2 is the limit to protect against fuel damage during anticipated operational occurances (AOOs).
The design calculations assumed the following extended exposure values:
Fuel Assembly 37,000 MWd/MTU Fuel Rod 42,300 MWd/MTU Peak Pellet 50,700 Mwd/MTU Planar Exposure 48,100 MWd/MTU These values are consistent with the peaking factors identified in Reference 9.2 and are conservative estimates of the exposures anticipated.
Fuel rod analyses were performed to verify adequate performance of the 8x8 fuel to a fuel rod exposure of 42,300 MWd/MTU and a peak pellet exposure of 50,700 MWd/MTU.
The design power history used in Reference 9.2 was extended to these higher exposure values. The results of the analyses reported herein demonstrate compliance with the design criteria.
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EMF-9 2-040 Page 8-5 8.3.1,1 Maxim m la in r in Durin ra ion The maximum cladding strain during steady-state operation is limited to (1% to avoid ductile cladding fracture. The fuel rod analysis performed with RODEX2A indicates that at a 37,000 MWd/MTU assembly exposure the cladding strain is within the criteria.
8.3.1.2 M xim m I in r 0 rin a r i n Fuel rod cladding stresses during steady-state operation are calculated using linear elasticity theory. The design criteria is in accordance with the ASME pressure vessel code.
Each individual stress is calculated inside and outside the cladding and at both midspan and spacer levels. The applicable stresses at each level are then combined to obtain the maximum stress intensities. The analysis is performed at beginning-of-life (BOL) and end-of-life (EOL) and at cold and hot conditions. The stress analysis assumes maximum fuel rod power, minimum fill gas pressure, and the most conservative fuel rod geometry.
The assumptions made in the analyses reported in Reference 9.2 have been reviewed to determine if additional calculations were required. The review indicated that the only input data affected by the increased exposure is the internal pressure. The internal pressure assumed at EOL is very conservative. The maximum pressure differential across the tube wall is obtained at BOL. The analyses in Reference 9.2 assumed that the rods at EOL had zero gas release. This conservative assumption leads to conservative stress which is also applicable to the 37,000 MWd/MTU assembly burnup. Consequently, the analysis results reported in Table 3.3 of Reference 9.2 are applicable.
8.3.1.3 An i i r inl rrn Two criteria are imposed on the fuel rod to avoid fuel failure during power changes caused by AOOs. These criteria limit the cladding strain to less than 1% and maintain the maximum pellet temperature below melting. The AOOs are assumed to produce a maximum nodal power equal to those defined in Figure 3.4 of Reference 9.2. The analysis consists of calculating the cladding strain and fuel centerline temperature at the power levels defined in Figure 3.4 to verify compliance with the design criteria.
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EMF-92-040 Page B-6 The calculations performed in support of Reference 9.2 were reviewed to determine if the higher exposure requires a reanalysis. Since the exposure at which the margin to the design criteria is the lowest is not at EOL; the results reported in support of Reference 9.2 are applicable.
B,3.1.4 F I R In rn I Pr r (9.2)
The fuel rod internal pressure is limited to 800 psi above system pressure However, if the internal pressure exceeds the system pressure, then the change in the pellet-cladding gap is calculated. The design criteria requires that the gap not open when the fuel rod power increases or when the power remains steady.
The analysis was extended to a fuel assembly exposure of 37,000 Mwd/MTU, and the results indicate that the maximum rod internal pressure is less than 1835 psia, which is below the design criteria. However, since the internal pressure exceeded the system pressure, an evaluation of the gap was performed. This evaluation verified that the incremental pellet swelling with increased powers is greater than the incremental cladding creep, thus complying with the design criteria.
B.3.1.5 Fu I Pell n rline Tem r re The design criteria requires that fuel centerline temperature remain, below the fuel melting point during operation. A fuel pellet centerline temperature analysis was performed using the methodology described in Reference 9.2 while applying the modified LHGR limit curve and higher exposure level ~ The results of the analysis indicated that the fuel pellet centerline temperature will remain below the fuel melting point. Therefore, the design criteria is met.
B.3.1.6 F eIR I in F i u Fuel assembly shuffling, reactor power maneuvering, and anticipated operational occurrences impose cyclic loading on the cladding. To assure that the fuel rod does not fail due to stress cyclic fatigue, a fatigue analysis is performed, The design criteria requires that the cumulative fatigue damage remain below 67%. To conservatively account for the
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EMF-92-040 Page 8-7 additional residence time associated with the higher exposure, the total number of cycles defined in Table 3.5 of Reference 9.2 was increased by over 15%. The maximum cumulative fatigue damage was below the 0.67 design criteria.
Fuel failures due to cladding collapse have been observed in some PWR fuel rods designed and fabricated by other fuel vendors. No SNP fuel rod has ever failed due to this mechanism. The likelihood of a fuel rod failure due to cladding collapse in a BWR is very small due to the lower operating coolant pressure characteristics. Nevertheless, the fuel rods are analyzed to assure that fuel rod collapse will not occur. The design criteria requires that the pellet-cladding gap remains open during the pellet densification stage. This assures that axial gaps will not form in the pellet column. If axial gaps are not formed, the fuel rod cannot fail due to cladding collapse.
Since the pellet densifies at BOL, reverification of the design criteria was not required.
Therefore, the results reported in Table 3.1 of Reference 9.2 are applicable.
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Rod-to-rod and rod-to-channel spacing must not affect the assembly thermal performance. Thermal limits are not affected if the minimum rod-to-rod spacing is greater than 0.090 inch. The analysis performed in Reference 9.2 to calculate the maximum fuel rod bow was evaluated for applicability at higher exposures. The correlation used by SNP to calculate fuel rod bow is exposure dependent. A small incremental increase in rod bow is calculated to occur between 35,000 MWd/MTU and 37,000 MWd/MTU. The maximum fuel rod channel closure at 37,000 MWd/MTU provides ample margin to the channel closure that could affect the assembly thermal performance.
8.3.1.9 I in rroinan H dr nC n enr in The SNP design criteria is to maintain the metal loss due to corrosion to less than 0.002 in. Hydrogen absorption is limited to less than 500 ppm. Using the methodology in Reference 9.2, an analysis was performed using a bundle exposure limit of 37,000 MWd/MTU
II EMF-92-040 Page B-8 MWd/MTU and the modified LHGR limit curve. The results of the analyses indicated that at the increased exposure and modified LHGR limit, the cladding corrosion and hydrogen absorption will remain well below the design criteria.
B.3.2 F I A m I n I The performance of the fuel assembly at 37,000 MWd/MTU was evaluated.
The structural strength of tie plates, locking mechanism, and tie rods is not decreased with exposure. Therefore, the analysis and test results previously reported in Reference 9.2 are applicable..
B.3.2.2 r rin SNP data indicates that spacer spring relaxation occurs with irradiation, However, the relaxation rate tends to decrease with increased exposure and saturate at higher exposure.
In addition, the spacer spring remains in contact with the fuel rod, thus preventing the formation of gaps. Increased exposure does not have a significant effect on spacer spring performance. PWR spacers of essentially the same fuel rod cell design have been irradiated to exposures as high as 50,000 MWd/MTU without experiencing degradation of the spacer performance. The spacer spring design is therefore concluded to be acceptable at assembly exposures up to 37,000 MWd/MTU.
Assembly growth was determined by evaluating differential growth between standard fuel rods and tie rods. The evaluation was based on data obtained on SNP fuel growth extrapolated to 37,000 MWd/MTU. Additionally, an evaluation of channel engagement with the lower tie plate seal as a function of irradiation exposure was performed, The calculations indicate that sufficient channel and end cap engagement was present to EOL.
EMF-92-040 Page 8-9 20 18 16 4
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0 10000 20000 30000 40000 50000 Ave rage P lana r Exposure, MWd/MTU EXP ~HR 0.0 1 6.0 25,400 14.1 43,200 9.0 48,100 8.4 FIGURE 83.1 LINEAR HEAT GENERATION RATE (LHGR) LIMIT VERSUS AVERAGE PLANAR EXPOSURE, SNP 8X8 FUEL
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0 10000 20000 30000 40000 50000 Averoge P lonor Exposure, MWd/MTU EXP LH R 0.0 19.2 25,400 1 6.9 43,200 10.8 48,100 9.98 FIGURE 83.2 PROTECTION AGAINST FUEL FAILURE LIMIT DURING AOO'S
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