ML100330138

Submittal of Relief Request I3R-14 Concerning Nozzle-to-Vessel Weld and Inner Radii Examinations

ML100330138
Person / Time
Site:	Limerick
Issue date:	02/01/2010
From:	Cowan P Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML100330138 (11)

Text

{{#Wiki_filter:Exelon Nuclear 200 Exelon Way Kennett Square, PA 19348 February1, 2010 www.exeloncorp.com Nuclear 10 CFR 50.55a U.S.Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Units 1 and 2 Facility Operating License Nos.NPF-39 and NPF-85 NRC Docket Nos.50-352 and 50-353

Subject:

Submittal of Relief Request 13R-14 Concerning Nozzle-to-Vessel Weld and Inner Radii Examinations In accordance with 10 CFR 50 55a,"Codes and standards," paragraph (a)(3)(i), Exelon Generation Company, LLC (EGC), is requesting relief from the American Society of Mechanical Engineers (ASME)Boiler and Pressure Vessel (B&PV)Code, Section XI, IIRules for Inservice Inspection of Nuclear Power Plant Components. 1I Relief Request 13R-14 proposes an alternative to the requirements contained in Table IWB-2500-1 concerning nozzle-to-vessel weld and nozzle inner radii examination requirements. This relief applies to the third 10-year Inservice Inspection (lSI)interval.The third interval for Limerick Generating Station (LGS), Units 1 and 2 began on February 1, 2007 and will conclude January 31, 2017.The third 10-year lSI interval complies with theASMEB&PV Code, Section XI, 2001 Edition through 2003 Addenda.We request your review and approval by February 1,2011.No regulatory commitments are contained in this letter.Should you have any questions concerning this letter, please contact Tom Loomis at (610)5510.Sincerely, tfal1#!fJ11aif (Pamela B.Cowan Director-Licensing&Regulatory Affairs Exelon Generation Company, LLC

Attachment:

Relief Request 13R-14 cc: USNRC Region I, Regional Administrator USNRC Senior Resident Inspector, LGS USNRC Project Manager, LGS R.R.Janati, Bureau of Radiation Protection Attachment Relief Request 13R-14 Relief Request 13R-14 to Implement an Alternative Concerning Nozzle-to-Vessel Weld and Inner Radii Examination Requirements in Accordance with 10 CFR 50.55a(a)(3)(i)(Page 1 of 9)1.0 ASME CODE COMPONENTS AFFECTED Code Class: Component Numbers: Examination Category: Item Number:

Description:

1 Reactor Vessel Nozzles:N2,N3,N5, N6, N7, N8, and N17 (See Enclosure 1 for complete list of nozzle identifications) B-D (Inspection Program B)B3.90 and B3.100 Alternative to ASME Section XI, Table IWB-2500-1 2.0 APPLICABLE CODE EDITION AND ADDENDA The third 10-year Inservice Inspection (lSI)Program at Limerick Generating Station (LGS), Units 1 and 2 is based on the American Society of Mechanical Engineers (AS ME)Boiler and Pressure Vessel (B&PV)Code, Section XI, 2001 Edition through the 2003 Addenda.Additionally, for ultrasonic examinations, ASME Section XI, Appendix VIII,"Performance Demonstration for Ultrasonic Examination Systems," of the 2001 Edition is implemented, as required and modified by 10 CFR 50.55a(b)(2)(xv). 3.0 APPLICABLE CODE REQUIREMENTS The applicable requirements are contained in Table IWB-2500-1,"Examination Category B-D, Full Penetration Welded Nozzle in Vessels-Inspection Program B." Class 1to-vessel weld and nozzle inner radii examination requirements are delineated in Item Number B3.90,"Nozzle-to-Vessel Welds," and B3.100,"Nozzle Inside Radius Section." The required method of examination is volumetric. All nozzles with full penetration welds to the vessel shell (or head)and integrally cast nozzles are examined each interval.All of the nozzle assemblies identified in Enclosure 1 are full penetration welds.4.0 REASON FOR REQUEST Enclosure 1 provides a complete listing of the applicable Reactor Pressure Vessel (RPV)nozzlesfor LGS, Units 1 and 2.The proposed alternative provides an acceptable level of quality and safety, and the reduction in scope could provide a dose savings of as much as 24.1 Person-Rem for Unit 1 and 11.9 Person-Rem for Unit 2 over the remainder of the interval.5.0 PROPOSED ALTERNATIVE AND BASIS FOR USE In accordance with 10 CFR 50.55a(a)(3)(i), relief is requested from performing the required examinations on 100 percent of the nozzle assemblies identified in Tables 5-1 and 5-2 below (see Enclosure 1 for complete list of RPV Nozzles).As an alternative for all welds and inner radii identified in Tables 5-1 and 5-2, Exelon Generation Company, LLC Relief Request 13R-14 to Implement an Alternative Concerning Nozzle-to-Vessel Weld and Inner Radii Examination Requirements in Accordance with 10 CFR 50.55a(a)(3)(i)(Page 2 of 9)(EGC)proposes to examine a minimum of 25 percent of the LGS, Units 1 and 2 vessel welds and inner radii sections, including at least one nozzle from each system and nominal pipe size, in accordance with Code Case N-702 ("Alternative Requirements for Boiling Water Reactor (BWR)Nozzle Inner Radius and Nozzle-to-Shell Welds Section XI, Division 1").For the nozzle assemblies identified in Enclosure 1, this would mean 25 percent from each of the groups identified below: Table 5-1 LGS U"t1S, nl ummary Total Minimum Group Number Number to be Comments*Examined Recirculation Inlet 10 3 Two (2)nozzles inspected this interval (N2)(two (2)completed in1R 12 (2008>>Main Steam 4 1 One (1)nozzle inspected this interval (N3)(one (1)completed in 1R12 (2008>>Core Spray 2 1 Two (2)nozzles inspected this interval (N5)(two (2)completed in 1 R12 (2008>>Nozzles On Top Head 3 1 No nozzles have been inspected this (NG and N7)interval Jet Pump Instrument 2 1 No nozzles have been inspected this (N8)interval Residual Heat Removal 4 1 One (1)nozzle inspected this interval (N17)(one (1)completed in 1 R12 (2008>>*The nozzle-to-vessel weld and inner radius examinations are performed together.Table 5-2 LGSU"2S , nit ummary Total Minimum Group Number Number to Comments*be Examined Recirculation Inlet Five (5)nozzles inspected this interval (N2)10 3 (two (2)completed in 2R09 (2007), and three (3)completed in 2R10 (2009>>Main Steam 4 1 Two (2)nozzles inspected this interval (N3)(two (2)completed in 2R09 (2007>>Core Spray 2 1 One (1)nozzle inspected this interval (N5)(one (1)completed in 2R09 (2007>>Nozzles On Top Head 3 1 No nozzles have been inspected this (NG and N7)interval Jet Pump Instrument 2 1 Two (2)nozzles inspected this interval (N8)(Two (2)completed in 2R10 (2009>>Residual Heat Removal Two (2)nozzles inspected this interval (N17)4 1 (one (1)completed in 2R09 (2007), and one (1)completed in 2R10 (2009>>*The nozzle-to-vessel weld and inner radius examinations are performed together. Relief Request 13R-14 to Implement an Alternative Concerning Nozzle-to-Vessel Weld and Inner Radii Examination Requirements in Accordance with 10 CFR 50.55a(a)(3)(i)(Page 3 of 9)The exams in Tables 5-1 and 5-2 will be scheduled in accordance with Table IWB-2412-1, Inspection Program B.Code Case N-702 stipulates that a VT-1 examination may be used in lieu of the volumetric examination for the inner radii (Le., Item No.B3.100,"Nozzle Inside Radius Section"). This VT-1 examination is outlined in Code Case N-648-1 ("Alternative Requirements for Inner Radius Examinations of Class 1 Reactor Vessel Nozzles Section XI, Division 1").However, EGC is not currently using Code Case N-648-1 at LGS for the identified components utilizing enhanced magnification visual examination, and has no plans of using Code Case N-648-1 on those components in the future.Volumetricexaminations of all nozzle inside radius sections will be completed.ElectricPower Research Institute (EPRI)Technical Report 1003557,"BWRVIP-108: Boiling Water Reactor Vessel and Internals Project Technical Basis for the Reduction of Inspection Requirements for the Boiling Water Reactor Nozzle-to-Vessel Shell Welds and Nozzle Blend Radii," provides the basis for Code Case N-702.The evaluation found that failure probabilities at the nozzle blend radius region and nozzle-to-vessel shell weld due to a Low Temperature Overpressure event are very low (Le.,<1 x 10-6 for 40 years)with or without inservice inspection. The report concludes that inspection of 25 percent of each nozzle type is technically justified. This EPRI report was approved by the NRC in a Safety Evaluation (SE)dated December 19, 2007 (Le., ADAMS Accession No.ML073600374). Section 5.0,"Plant-Specific Applicability," of the SE indicates that each licensee who plans to request relief from ASME Code, Section XI requirements for RPV nozzle-to-vessel shell welds and nozzle inner radii sections may reference the BWRVIP-108 report as the technical basis for the use of ASME Code Case N-702 as an alternative. However, each licensee should demonstrate the plant specific applicability criteria from the BWRVIP-108 report to its units in the relief request by showing that all the general and nozzle-specific criteria addressed below are satisfied (Le., as described in Enclosure 2).(1)The maximum RPV heatup/cooldown rate is limited to less than 115°F/hour. LGS, Units 1 and 2 Technical Specification (TS)3.4.6.1,"Pressure/Temperature Limits," provides a limiting condition for operation (LCO)of 100°F in any 1-hour period.The heatup/cooldown rate is referenced in the LGS operating procedures. This heatup/cooldown rate is also described in the LGS Updated Final Safety Analysis Report (UFSAR), Section 5.3.3.6,"OperatingConditions." (2)For the Recirculation Inlet Nozzles, the following criteria must be met: a.(pr/t)/C RPv<1.15;the calculation for the LGS, Units 1 and 2 N2 Nozzle results in 1.064, which is less than 1.15.b.[p(r o 2+rj 2)/(r o 2-r?)VCNOZZLE<1.15; the calculation for the LGS, Units 1 and 2 N2 Nozzle results in 0.976, which is less than 1.15. Relief Request 13R-14 to Implement an Alternative Concerning Nozzle-to-Vessel Weld and Inner Radii Examination Requirements in Accordance with 10 CFR 50.55a(a)(3)(i)(Page 4 of 9)(3)For the Recirculation Outlet Nozzles, the following criteria must be met: a.(pr/t)/C RPV<1.15;the calculation for the LGS, Units 1 and 2 N1 Nozzle results in 1.272, which is higher than 1.15.b.[p(r o 2+rj 2)/(r o 2-rj2)]/CNOZZLE<1.15; the calculation for the LGS, Units 1 and 2 N1 Nozzle results in 1.044, which is less than 1.15.Based upon the above information, all LGS RPV nozzle-to-vessel shell full penetration welds and nozzle inner radii sections, with the exception of the Recirculation Outlet Nozzles, meet the general and nozzle-specific criteria in BWRVIP-108. Therefore, Code Case N-702 is applicable. Therefore, use of Code Case N-702 provides an acceptable level of quality and safety in accordance with 10 CFR 50.55a(a)(3)(i) for all the RPV nozzle-to-vessel shell full penetration welds and nozzle inner radii sections, with the exception of the Recirculation Outlet Nozzles.6.0 DURATION OF PROPOSED ALTERNATIVE The third interval for LGS, Units 1 and 2 began on February 1, 2007, and will conclude January 31, 2017.The proposed alternative will be used for the remainder of the thirdyear interval of the LGS lSI Program.7.0 PRECEDENTS 1.Letter from L.James (U.S.Nuclear Regulatory Commission) to R.L.Anderson (Duane Arnold Energy Center),"Duane Arnold Energy Center-Safety Evaluation for Request for Alternative to Reactor Pressure Vessel Nozzle to Vessel Weld and Inner Radius Examinations (TAC NO.MD8193)," dated August 29, 2008.2.Letter from R.Gibbs (U.S.Nuclear Regulatory Commission) to M.B.Bezilla (FirstEnergy Nuclear Operating Company),"Perry Nuclear Power Plant, Unit No.1Request for Relief Related to Inservice Inspection Relief Request IR-054 (TAC NO.MD8458)," dated December 29, 2008. Relief Request 13R-14 to Implement an Alternative Concerning Nozzle-to-Vessel Weld and Inner Radii Examination Requirements in Accordance with 10 CFR 50.55a(a)(3)(i)(Page 5 of 9)Enclosure 1 Applicable LGS, Unit 1 Nozzles Page 1 of 2 Component Category Item System Nominal Comments 10 Number Number Pipe Size N2A Nozzle B-O B3.90 Reeire Inlet 12" POI examination 1 R12 (2008)N2A IRS*B-O B3.100 Reeire Inlet 12" POI examination 1 R12 (2008)N2B Nozzle B-O B3.90 Reeire Inlet 12" N2BIRS B-O B3.100 Reeire Inlet 12" N2C Nozzle B-O B3.90 Reeire Inlet 12" N2CIRS B-O B3.100 Reeire Inlet 12" N20 Nozzle B-O B3.90 Reeire Inlet 12" N20lRS B-O B3.100 Reeire Inlet 12" N2E Nozzle B-O B3.90 Reeire Inlet 12" N2EIRS B-O B3.100 Reeire Inlet 12" N2F Nozzle B-O B3.90 Reeire Inlet 12" POI examination 1 R12 (2008)N2F IRS B-O B3.100 Reeire Inlet 12" POI examination 1 R12 (2008)N2G Nozzle B-O B3.90 Reeire Inlet 12" N2GIRS B-O B3.100 Reeire Inlet 12" N2H Nozzle B-O B3.90 Reeire Inlet 12" N2HIRS B-O B3.100 Reeire Inlet 12" N2J Nozzle B-O B3.90 Reeire Inlet 12" N2J IRS B-O B3.100 Reeire Inlet 12" N2K Nozzle B-O B3.90 Reeire Inlet 12" N2KIRS B-O B3.100 Reeire Inlet 12" N3A Nozzle B-O B3.90 Main Steam 26" N3AIRS B-O B3.100 Main Steam 26" N3B Nozzle B-O B3.90 Main Steam 26" N3BIRS B-O B3.100 Main Steam 26" N3C Nozzle B-O B3.90 Main Steam 26" N3CIRS B-O B3.100 Main Steam 26" N30 Nozzle B-O B3.90 Main Steam 26" POI examination 1R12 (2008)N30lRS B-O B3.100 Main Steam 26" POI examination 1 R12 (2008)N5A Nozzle B-O B3.90 Core Spray 10" POI examination 1R12 (2008)N5AIRS B-O B3.100 Core Spray 10" POI examination 1R12 (2008)N5B Nozzle B-O B3.90 Core Spray 10" POI examination 1R12 (2008)N5BIRS B-O B3.100 Core Spray 10" POI examination 1R12 (2008)N6A Nozzle B-O B3.90 Head Spray 6" N6AIRS B-O B3.100 Head Spray 6" N6B Nozzle B-O B3.90 Head Spray 6" N6BIRS B-O B3.100 Head Spray 6" N7A Nozzle B-O B3.90 Head Vent 6" N7AIRS B-O B3.100 Head Vent 6" N8A Nozzle B-O B3.90 Jet Pump 6" Instrumentation N8AIRS B-O B3.100 Jet Pump 6" Instrumentation N8B Nozzle B-O B3.90 Jet Pump 6" I nstrum entation N8BIRS B-O B3.100 Jet Pump 6" Instrumentation

• IRS-Inner Radius Section Relief Request 13R-14 to Implement an Alternative Concerning Nozzle-to-Vessel Weld and Inner Radii Examination Requirements in Accordance with 10 CFR SO.SSa(a)(3)(i)(Page 6 of 9)Enclosure 1 Applicable LGS, Unit 1 Nozzles Page 2 of2 Component Category Item System Nominal Comments 10 Number Number Pipe Size N17A IRS 8-0 83.100 RHR 12" N17A Nozzle 8-0 83.90 RHR 12" N178 IRS 8-0 83.100 RHR 12" POI examination 1 R12 (2008)N178 Nozzle 8-0 83.90 RHR 12" POI examination 1R12 (2008)N17CIRS 8-0 83.100 RHR 12" N17C Nozzle 8-0 83.90 RHR 12" N170lRS 8-0 83.100 RHR 12" N170 Nozzle 8-0 83.90 RHR 12"*IRS-Inner Radius Section Relief Request 13R-14 to Implement an Alternative Concerning Nozzle-to-Vessel Weld and Inner Radii Examination Requirements in Accordance with 10 CFR 50.55a{a){3){i)(Page 7 of 9)Enclosure 1 Applicable LGS, Unit 2 Nozzles Page 1 of 2 Com ponent 10 Category Item System Nominal Comments Number Number Pipe Size N2A Nozzle 8-0 83.90 Recirc Inlet 12" POI examination 2R10 (2009)N2AIRS 8-0 83.100 Recirc Inlet 12" POI examination 2R10 (2009)N28 Nozzle 8-0 83.90 Recirc Inlet 12" N281RS 8-0 83.100 Recirc Inlet 12" N2C Nozzle 8-0 83.90 Recirc Inlet 12" N2CIRS 8-0 83.100 Recirc Inlet 12" N20 Nozzle 8-0 83.90 Recirc Inlet 12" POI examination 2R10 (2009)N20lRS 8-0 83.100 Recirc Inlet 12" POI examination 2R10 (2009)N2E Nozzle 8-0 83.90 Recirc Inlet 12" N2EIRS 8-0 83.100 Recirc Inlet 12" N2F Nozzle 8-0 83.90 Recirc Inlet 12" N2F IRS 8-0 83.100 Recirc Inlet 12" N2G Nozzle 8-0 83.90 Recirc Inlet 12" N2GIRS 8-0 83.100 Recirc Inlet 12" N2H Nozzle 8-0 83.90 Recirc Inlet 12" POI examination 2R09 (2007)N2HIRS 8-0 83.100 Recirc Inlet 12" POI examination 2R09 (2007)N2J Nozzle 8-0 83.90 Recirc Inlet 12" POI examination 2R09 (2007)N2J IRS 8-0 83.100 Recirc Inlet 12" POI examination 2R09 (2007)N2K Nozzle 8-0 83.90 Recirc Inlet 12" POI examination 2R10 (2009)N2KIRS 8-0 83.100 Recirc Inlet 12" POI examination 2R10 (2009)N3A Nozzle 8-0 83.90 Main Steam 26" N3AIRS 8-0 83.100 Main Steam 26" N38 Nozzle 8-0 83.90 Main Steam 26" N381RS 8-0 83.100 Main Steam 26" N3C Nozzle 8-0 83.90 Main Steam 26" POI examination 2R09 (2007)N3CIRS 8-0 83.100 Main Steam 26" POI examination 2R09 (2007)N30 Nozzle 8-0 83.90 Main Steam 26" POI examination 2R09 (2007)N30lRS 8-0 83.100 Main Steam 26" POI examination 2R09 (2007)N5A Nozzle 8-0 83.90 Core Spray 10" N5AIRS 8-0 83.100 Core Spray 10" N58 Nozzle 8-0 83.90 Core Spray 10" POI examination 2R09 (2007)N581RS 8-0 83.100 Core Spray 10" POI examination 2R09 (2007)N6A Nozzle 8-0 83.90 Head Spray 6" N6AIRS 8-0 83.100 Head Spray 6" N68 Nozzle 8-0 83.90 Head Spray 6" N681RS 8-0 83.100 Head Spray 6" N7A Nozzle 8-0 83.90 Head Vent 6" N7AIRS 8-0 83.100 Head Vent 6" N8A Nozzle 8-0 83.90 Jet Pump 6" POI examination 2R1 0 (2009)Instrumentation N8AIRS 8-0 83.100 Jet Pump 6" POI examination 2R10 (2009)Instrumentation N88 Nozzle 8-0 83.90 Jet Pump 6" POI examination 2R1 0 (2009)Instrumentation N881RS 8-0 83.100 Jet Pump 6" POI examination 2R10 (2009)Instrumentation
• IRS-Inner Radius Section Relief Request 13R-14 to Implement an Alternative Concerning Nozzle-to-Vessel Weld and Inner Radii Examination Requirements in Accordance with 10 CFR 50.55a(a)(3)(i)(Page 8 of 9)Enclosure 1 Applicable LGS, Unit 2 Nozzles Page 2 of2 Component Category Item System Nominal Comments 10 Number Number Pipe Size N17A IRS B-O B3.100 RHR 12" N17A Nozzle B-O B3.90 RHR 12" N17B IRS B-O B3.100 RHR 12" POI examination 2R10 (2009)N17B Nozzle B-O B3.90 RHR 12" POI examination 2R10 (2009)N17C IRS B-O B3.100 RHR 12" N17C Nozzle B-O B3.90 RHR 12" N170 IRS B-O B3.100 RHR 12" POI examination 2R09 (2007)N170 Nozzle B-O B3.90 RHR 12" POI examination 2R09 (2007)*IRS-Inner Radius Section Relief Request 13R-14 to Implement an Alternative Concerning Nozzle-to-Vessel Weld and Inner Radii Examination Requirements in Accordance with 10 CFR 50.55a{a){3){i)(Page 9 of 9)Enclosure 2 Plant Specific Applicability (1)The maximum Reactor Pressure Vessel (RPV)heatup/cooldown rate is limited to less than 115°F/hour.

LGS, Units 1 and 2 Technical Specification (TS)3.4.6.1,"PressurefTemperature Limits," provides a limiting condition for operation (LCO)of 100°F in any 1-hour period.The heatup/cooldown rate is referenced in the LGS operating procedures. This heatup/cooldown rate is also described in the LGS Updated Final Safety Analysis Report (UFSAR), Section 5.3.3.6,"Operating Conditions." For Recirculation Inlet Nozzles (N2)(2)(pr/t)/C RPV<1.15 p=RPV Normal Operating Pressure r=RPV inner radius t=RPV wall thickness.Q.RPV=1045 psi 126.6875 in.6.4375 in.19332 (prlt)/C RPV=1.064<1.15 (3)[p(r o 2+ri 2)/(r 02-ri2)]/CNOZZLE< 1.15 p=RPV Normal Operating Pressure 1045 psi r o=nozzle outer radius 13.125 in.ri=nozzle inner radius 6 in..Q.NOZZLE 1637[p{r 0 2+rj 2)/{r 0 2-rj2)]/CNOZZLE =0.976<1.15 For Recirculation Outlet Nozzles (N1)(4)(pr/t)/C RPV<1.15 p=RPV Normal Operating Pressure r=RPV inner radius t=RPV wall thickness.Q.sPV=1045 psi 126.6875 in.6.4375 in.16171{prlt)/C RPV=1.272>1.15 (5)[p(r 0 2+ri 2)/(r 0 2-ri2)]/CNOZZLE< 1.15 p=RPV Normal Operating Pressure 1045 psi r o=nozzle outer radius 22.875 in.ri=nozzle inner radius 13.1 in..Q.NOZZLE 1977[p{r o 2+rj2)/{ro2-rj2)]/CNOZZLE =1.044<1.15}}