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| I "BWR Vessel and Internals Projects, BWR Reactor Vessel Shell Weld Inspection ! | | I "BWR Vessel and Internals Projects, BWR Reactor Vessel Shell Weld Inspection ! |
| Recommendations (Technical Report BWRVIP-05)'' | | Recommendations (Technical Report BWRVIP-05)'' |
| By letter dated September 28,1995,' the Boiling Water Reactor Vessel and Internals Project (BWRVIP), a technical committee of the BWR Owners Group (BWROG), submitted the proprietary report, "BWR Vessel and Internals Project, BWR Reactor Vessel Shell Weld ; | | By {{letter dated|date=September 28, 1995|text=letter dated September 28,1995}},' the Boiling Water Reactor Vessel and Internals Project (BWRVIP), a technical committee of the BWR Owners Group (BWROG), submitted the proprietary report, "BWR Vessel and Internals Project, BWR Reactor Vessel Shell Weld ; |
| Inspection Recommendations (BWRVIP-05)." This report proposed to reduce the scope of inspection of the BWR RPV welds and to eliminate the successive reexamination requirements j in the ASME Code regarding welds with detected indications. The three conditions for the elimination of the successive reexamination r3quirements are: | | Inspection Recommendations (BWRVIP-05)." This report proposed to reduce the scope of inspection of the BWR RPV welds and to eliminate the successive reexamination requirements j in the ASME Code regarding welds with detected indications. The three conditions for the elimination of the successive reexamination r3quirements are: |
| 1 As supplemented by letters dated June 24,1996; October 29,1996; May 16,1997; June 4,1997; June 13, 1997; and December 18,1997. | | 1 As supplemented by letters dated June 24,1996; October 29,1996; May 16,1997; June 4,1997; June 13, 1997; and December 18,1997. |
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Category:SAFETY EVALUATION REPORT--LICENSING & RELATED ISSUES
MONTHYEARML20217L8831999-10-21021 October 1999 Safety Evaluation Supporting Proposed Alternatives to Code Requirements Described in RR-V17 & RR-V18 ML20217G2041999-10-13013 October 1999 Safety Evaluation Supporting Amend 179 to License DPR-28 ML20212C2551999-09-17017 September 1999 Safety Evaluation Supporting Amend 175 to License DPR-28 ML20206E8741999-04-29029 April 1999 SER Determined That Flaw Evaluation Meets Rules of ASME Code & Assumed Crack Growth Rate Adequate for Application ML20205K7581999-04-0707 April 1999 Safety Evaluation Supporting Alternative Proposal for Reexamination of Circumferential Welds with Detected Flaw Indications in Plant RPV ML20203H9881999-02-18018 February 1999 SER Accepting Alternative to 10CFR50.55a(g)(6)(ii)(A) Augmented Reactor Vessel Exam at Vermont Yankee Nuclear Power Station.Technical Ltr Rept Encl ML20199K7151999-01-21021 January 1999 Corrected Safety Evaluation Supporting Amend 163 Issued to FOL DPR-28.Pages 2 & 3 Required Correction & Clarification ML20199K6991999-01-20020 January 1999 Safety Evaluation Concluding That Request to Use YAEC-1339, Yankee Atomic Electric Co Application of FIBWR2 Core Hydraulics Code to BWR Reload Analysis, at Vermont Yankee Acceptable ML20199L5951999-01-14014 January 1999 Safety Evaluation Accepting Licensee Proposed Alternative to Code Requirement,Described in Rev 2 to Pump Relief Request RR-P10 Pursuant to 10CFR50.55a(a)(3)(i) ML20195C4161998-11-0909 November 1998 SER Accepting Request That NRC Approve ASME Code Case N-560, Alternative Exam Requirement for Class 1,Category B-J Piping Welds ML20155B6471998-10-26026 October 1998 Safety Evaluation Accepting Jet Pump Riser Insp Results & Flaw Evaluation,Conducted During 1998 Refueling Outage ML20154B6951998-10-0101 October 1998 SER Re Licensee Response to GL 95-07, Pressure Locking & Thermal Binding of Safety-Related Power-Operated Gate Valves, for Vermont Yankee Nuclear Power Station ML20239A1361998-09-0202 September 1998 SER Re License Request for NRC Review & Concurrence W/Changes to NRC-approved Fire Protection Program ML20216F1001998-04-15015 April 1998 Safety Evaluation Accepting 980331 Licensee Proposal to Perform Alternative Testing for Containment Pressurization Test for Vynp ML20217F3421998-03-25025 March 1998 SER Accepting Plans for 1998 & 1999 Refueling Outages Re Reactor Vessel Internals for Plant ML20212H1521998-03-0606 March 1998 Correction to Page 7 of SE Re Relief Request for Third 10-yr Interval Pump & Valve IST Program for Plant ML20217N4911998-02-27027 February 1998 SER Pertaining to Cracking of EDG Lube Oil Piping at Vermont Yankee ML20198P9941998-01-15015 January 1998 SE Authorizing Relief Requests for Third Interval Pump & Valve Inservice Testing Program ML20141A4151997-06-18018 June 1997 Revised SE Accepting Proposed Onsite Disposal of Slightly Contaminated Silt Removed from Vermont Yankee Cooling Towers ML20135E5401997-03-0303 March 1997 Safety Assessment Accepting Mod of RHR & CS Sys Containment Isolation Function Configuration ML20134N8271996-11-20020 November 1996 Safety Evaluation Accepting Licensee Scope & Insp Methods Proposed for Insp of Core Spray Internal Piping During Fall 1996 Refueling Outage at Plant ML20134F9631996-11-0505 November 1996 Safety Evaluation Re Power/Flow Exclusion Region Calculation Method Using LAPUR5 Computer Code & Implementation of Solomon Stability Monitor for Licensee Facility ML20128N3531996-10-11011 October 1996 Safety Evaluation Accepting Licensee Flaw Evaluation of Indication Found During Reactor Pressure Vessel Insp at Plant ML20129G3611996-10-0202 October 1996 Safety Evaluation Accepting Proposed Repair for Plant Core Shroud ML20057A6991993-09-0303 September 1993 Safety Evaluation of IST Program Relief Requests for Pumps & Valves for Third 10-yr Insp Interval ML20057A2791993-08-12012 August 1993 Safety Evaluation Accepting Licensee Reasons Given for Delay in Completing short-term Actions Requested in Ieb 93-003, Resolution of Issues Re to Rv Water Level Instrumentation in Bwrs ML20246D7731989-08-21021 August 1989 Safety Evaluation Supporting Util Response to Generic Ltr 83-28,Item 2.2.1, Required Actions Based on Generic Implications of Salem ATWS Events. Equipment Classification Program for safety-related Components Acceptable ML20244D0311989-06-0707 June 1989 Safety Evaluation Accepting Util Second 10-yr Interval Inservice Insp Program Plan ML20205T4181988-10-14014 October 1988 Errata to Safety Evaluation Concluding Util Submittal Re Spent Fuel Pool Expansion ML20204F7271988-10-14014 October 1988 Safety Evaluation Supporting Proposed Expansion of Spent Fuel Pool at Facility ML20236N6461987-08-0707 August 1987 Safety Evaluation Re Permanent Elimination of Liquid Penetrant Exam of Feedwater Nozzles at Facility.Due to Lack of Reasonable Assurance That Ultrasonic Exam Can Totally Replace Penetrant Exam,Request Unacceptable ML20214T9891987-05-28028 May 1987 Safety Evaluation Re Util 870112 Proposed Plans to Inspect Two Overlay Repaired Core Spray safe-ends in Lieu of Replacement During Upcoming 1987 Refueling Outage.Plans Acceptable,Providing That Insp Results Satisfactory ML20207S7801987-03-12012 March 1987 Safety Evaluation Granting Relief from Tech Spec 4.7.A.3 on one-time Basis to Perform RHR Pump Wear Ring Replacement ML20214T4921986-11-24024 November 1986 Safety Evaluation Accepting Licensee 830511 & 860117 Responses to Generic Ltr 83-08 Re Mod of Vaccum Breakers on Mark I Containments ML20215M5871986-10-24024 October 1986 Preliminary Evaluation of Containment Study Transmitted w/860902 Ltr.Licensee Estimates Appear Optimistic Considering Uncertainties Inherent in Failure Rate Data ML20206F3651986-06-16016 June 1986 Safety Evaluation Re Proposed Repair of Core Spray safe- Ends,During Current Refueling Outage.Plant Can Be Safely Returned to Power Operation After Satisfactory Completion of Core Spray safe-end Repairs ML20206F0681986-06-13013 June 1986 Safety Evaluation Supporting 850514,0710,860327,0411 & 0513 Requests for Approval to Use Pvrc Damping Values (ASME Code Case N-411) for Piping Sys Reanalysis ML20202J4211986-03-31031 March 1986 Safety Evaluation Accepting Util Design Mods & Tech Spec Changes Re Degraded Grid Voltage Protection for Class 1E Sys.Lll Technical Evaluation Rept Encl ML20155B8351986-03-31031 March 1986 Safety Evaluation Supporting Revised Procedure OP-3140, Providing Technically Acceptable Actions During Degraded Grid Voltage Conditions W/O LOCA to Assure Protection of Class 1E Electrical Sys & Equipment ML20140H9881986-03-25025 March 1986 Safety Evaluation Re Util 851008 Request to Install Carpet Over Vinyl Asbestos Tiled Control Room Floor Covering. Installation of Carpet Will Not Decrease Level of Fire Safety in Control Room & Deviation Acceptable ML20138E4201985-12-0202 December 1985 Safety Evaluation Supporting Util 831107 & 840320 Responses to Generic Ltr 83-28,Items 3.1.1,3.1.2,3.2.1,3.2.2 & 4.5.1 Re post-maint Testing & Reactor Trip Sys Reliability ML20136F1241985-11-18018 November 1985 Safety Evaluation Re IE Bulletin 80-11, Masonry Wall Design. Issues Re Arching Action Theory Resolved ML20137S7331985-09-27027 September 1985 Safety Evaluation Approving Use of Fuel Thermal Performance Code,Frosstey,For Analysis of LOCA Conditions at Low & Moderate Burnups ML20135C8921985-09-10010 September 1985 Safety Evaluation Supporting 840824 Commitment to Convert Air Containment Atmosphere Dilution Sys to Nitrogen Sys,In Response to Generic Ltr 84-09 ML20135C9121985-09-10010 September 1985 Safety Evaluation Supporting Conclusion That Diversification of Scram Discharge Vol Level Instrumentation Not Necessary & Tech Specs,As Modified in Amend 76,resolve Staff Concerns Re Need for Instrumentation Diversity ML20134K7351985-08-19019 August 1985 Safety Evaluation Accepting 831107 Response to Generic Ltr 83-28,Items 3.1.3 & 3.2.3 Re post-maint Testing ML20136G3611985-08-12012 August 1985 Safety Evaluation Accepting Seismic Design Criteria Utilized for Evaluation of Modified Recirculation Sys ML20132D8971985-07-22022 July 1985 Safety Evaluation Supporting Use of Pvrc Damping Values (ASME Code Case N-411) for Response Spectrum Seismic Piping Analyses ML20127D8991985-05-0606 May 1985 Safety Evaluation Re 840925 & 1002 Responses to Generic Ltr 83-28,Item 1.1 Concerning post-trip Review Program & Procedures.Program & Procedures Acceptable 1999-09-17
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARML20217L8831999-10-21021 October 1999 Safety Evaluation Supporting Proposed Alternatives to Code Requirements Described in RR-V17 & RR-V18 ML20217G2041999-10-13013 October 1999 Safety Evaluation Supporting Amend 179 to License DPR-28 BVY-99-127, Monthly Operating Rept for Sept 1999 for Vermont Yankee Nuclear Power Station.With1999-09-30030 September 1999 Monthly Operating Rept for Sept 1999 for Vermont Yankee Nuclear Power Station.With ML20212C2551999-09-17017 September 1999 Safety Evaluation Supporting Amend 175 to License DPR-28 BVY-99-112, Monthly Operating Rept for Aug 1999 for Vermont Yankee.With1999-08-31031 August 1999 Monthly Operating Rept for Aug 1999 for Vermont Yankee.With BVY-99-109, Ro:On 990812,stack Ng Effluent Instrumentation for PAM Was Declared Oos.Caused by Instrument Drift Due to Electronic Components Based on Insps by Instrumentation & Controls Dept.Detector & Preamplifier Will Be Replaced on 9908311999-08-19019 August 1999 Ro:On 990812,stack Ng Effluent Instrumentation for PAM Was Declared Oos.Caused by Instrument Drift Due to Electronic Components Based on Insps by Instrumentation & Controls Dept.Detector & Preamplifier Will Be Replaced on 990831 BVY-99-102, Monthly Operating Rept for July 1999 for Vermont Yankee. with1999-07-31031 July 1999 Monthly Operating Rept for July 1999 for Vermont Yankee. with ML20209J0081999-07-14014 July 1999 Special Rept:On 990615,diesel Driven Fire Pump Failed to Achieve Rated Flow of 2500 Gallons Per Minute.Pump Was Inoperable for Greater than 7 Days.Corrective Maint Was Performed to Reset Pump Lift Setting BVY-99-090, Monthly Operating Rept for June 1999 for Vermont Yankee Nuclear Power Station.With1999-06-30030 June 1999 Monthly Operating Rept for June 1999 for Vermont Yankee Nuclear Power Station.With ML20196G5071999-06-23023 June 1999 Vynp Assessment of On-Site Disposal of Contaminated Soil by Land Spreading BVY-99-077, Monthly Operating Rept for May 1999 for Vermont Yankee Nuclear Power Station.With1999-05-31031 May 1999 Monthly Operating Rept for May 1999 for Vermont Yankee Nuclear Power Station.With BVY-99-068, Monthly Operating Rept for Apr 1999 for Vynp.With1999-04-30030 April 1999 Monthly Operating Rept for Apr 1999 for Vynp.With ML20206E8741999-04-29029 April 1999 SER Determined That Flaw Evaluation Meets Rules of ASME Code & Assumed Crack Growth Rate Adequate for Application ML20206D9301999-04-27027 April 1999 1999 Emergency Preparedness Exercise 990427 Exercise Manual (Plume Portion) ML20205S4211999-04-16016 April 1999 Non-proprietary Version of Revised Page 4-3 of HI-981932 Technical Rept for Vermont Yankee Spent Fuel Pool Storage Expansion ML20205K7581999-04-0707 April 1999 Safety Evaluation Supporting Alternative Proposal for Reexamination of Circumferential Welds with Detected Flaw Indications in Plant RPV BVY-99-046, Monthly Operating Rept for Mar 1999 for Vermont Yankee Nuclear Power Station.With1999-03-31031 March 1999 Monthly Operating Rept for Mar 1999 for Vermont Yankee Nuclear Power Station.With ML20205F6631999-03-0404 March 1999 Jet Pump Riser Weld Leakage Evaluation BVY-99-035, Monthly Operating Rept for Feb 1999 for Vermont Yankee Nuclear Station.With1999-02-28028 February 1999 Monthly Operating Rept for Feb 1999 for Vermont Yankee Nuclear Station.With ML20205P8241999-02-28028 February 1999 Rev 2 to Vermont Yankee Cycle 20 Colr ML20203H9881999-02-18018 February 1999 SER Accepting Alternative to 10CFR50.55a(g)(6)(ii)(A) Augmented Reactor Vessel Exam at Vermont Yankee Nuclear Power Station.Technical Ltr Rept Encl ML20203A6951999-02-0404 February 1999 Revised Rev 2,App B to Vermont Yankee Operational QA Manual (Voqam) ML20199K7151999-01-21021 January 1999 Corrected Safety Evaluation Supporting Amend 163 Issued to FOL DPR-28.Pages 2 & 3 Required Correction & Clarification ML20199K6991999-01-20020 January 1999 Safety Evaluation Concluding That Request to Use YAEC-1339, Yankee Atomic Electric Co Application of FIBWR2 Core Hydraulics Code to BWR Reload Analysis, at Vermont Yankee Acceptable ML20199L5951999-01-14014 January 1999 Safety Evaluation Accepting Licensee Proposed Alternative to Code Requirement,Described in Rev 2 to Pump Relief Request RR-P10 Pursuant to 10CFR50.55a(a)(3)(i) BVY-99-071, Corp 1998 Annual Rept. with1998-12-31031 December 1998 Corp 1998 Annual Rept. with BVY-99-001, Monthly Operating Rept for Dec 1998 for Vermont Yankee Nuclear Power Station1998-12-31031 December 1998 Monthly Operating Rept for Dec 1998 for Vermont Yankee Nuclear Power Station ML20198H5481998-12-23023 December 1998 Rev 2 to Vermont Operational QA Manual,Voqam ML20196H8641998-12-0101 December 1998 Cycle 19 Operating Rept BVY-98-163, Monthly Operating Rept for Nov 1998 for Vermont Yankee Nuclear Power Station.With1998-11-30030 November 1998 Monthly Operating Rept for Nov 1998 for Vermont Yankee Nuclear Power Station.With ML20195C4161998-11-0909 November 1998 SER Accepting Request That NRC Approve ASME Code Case N-560, Alternative Exam Requirement for Class 1,Category B-J Piping Welds BVY-98-154, Monthly Operating Rept for Oct 1998 for Vermont Yankee Nuclear Power Station.With1998-10-31031 October 1998 Monthly Operating Rept for Oct 1998 for Vermont Yankee Nuclear Power Station.With ML20155B6471998-10-26026 October 1998 Safety Evaluation Accepting Jet Pump Riser Insp Results & Flaw Evaluation,Conducted During 1998 Refueling Outage ML20154N0891998-10-16016 October 1998 Rev 1 to Vermont Operational QA Program Manual (Voqam) ML20154B6951998-10-0101 October 1998 SER Re Licensee Response to GL 95-07, Pressure Locking & Thermal Binding of Safety-Related Power-Operated Gate Valves, for Vermont Yankee Nuclear Power Station BVY-98-149, Monthly Operating Rept for Sept 1998 for Vermont Yankee Nuclear Power Station.With1998-09-30030 September 1998 Monthly Operating Rept for Sept 1998 for Vermont Yankee Nuclear Power Station.With ML20239A1361998-09-0202 September 1998 SER Re License Request for NRC Review & Concurrence W/Changes to NRC-approved Fire Protection Program BVY-98-135, Monthly Operating Rept for Aug 1998 for Vermont Yankee Nuclear Power Station.With1998-08-31031 August 1998 Monthly Operating Rept for Aug 1998 for Vermont Yankee Nuclear Power Station.With ML20151U0361998-08-28028 August 1998 Non-proprietary Rev 1 to Holtec Rept HI-981932, Vermont Yankee Nuclear Power Station Spent Storage Expansion Project ML20237E9221998-08-20020 August 1998 Vynp 1998 Form NIS-1 Owners Summary Rept for ISI, 961103-980603 BVY-98-122, Monthly Operating Rept for July 1998 for Vermont Yankee Nuclear Power Station1998-07-31031 July 1998 Monthly Operating Rept for July 1998 for Vermont Yankee Nuclear Power Station ML20205F6491998-07-31031 July 1998 Rev 1 to GE-NE-B13-01935-02, Jet Pump Assembly Welds Flaw Evaluation Handbook for Vermont Yankee ML20236G0011998-06-30030 June 1998 Individual Plant Exam External Events BVY-98-098, Monthly Operating Rept for June 1998 for Vermont Yankee Nuclear Power Station1998-06-30030 June 1998 Monthly Operating Rept for June 1998 for Vermont Yankee Nuclear Power Station ML20248C5081998-05-31031 May 1998 Rev 2 to 24A5416, Supplemental Reload Licensing Rept for Vermont Yankee Nuclear Power Station Reload 19 Cycle 20 ML20248C4951998-05-31031 May 1998 Rev 1 to Vermont Yankee Nuclear Power Station Cycle 20 Colr BVY-98-081, Monthly Operating Rept for May 1998 for Vermont Yankee Nuclear Power Station1998-05-31031 May 1998 Monthly Operating Rept for May 1998 for Vermont Yankee Nuclear Power Station ML20247J8341998-05-31031 May 1998 Peak Suppression Pool Temp Analyses for Large Break LOCA Scenarios, for May 1998 ML20247G4001998-05-12012 May 1998 Interview Rept of Ej Massey ML20247E6351998-04-30030 April 1998 Rev 1 to GE-NE-B13-01935-LTR, Jet Pump Riser Welds Allowable Flaw Sizes Ltr Rept for Vermont Yankee 1999-09-30
[Table view] |
Text
U pa " Ecog ye yi UNITED STATES i S NUCLEAR REGULATORY COMMISSION (21f WASHINGTON. c.c- 20555 4 001
%4 8 4
.....,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION )
i VERMONT YANKEE NUCLEAR POWER STATION j VERMONT YANKEE NUCLEAR POWER CORPORATION p_OCKET NUMBER 50-271 l'
1.0 INTRODUCTION
On January 28,1999, the Vermont Yankee Nuclear Power Corporation (the licensee) submitted a request seeking approval of an alternative examination to replace that specified in the American Society of Mechanical Engineers (ASME) Code regarding successive reexamination of the area containing flaw indications in circumferential welds of the reactor pressure vessel (RPV) for Vermont Yankee Nuclear Power Station. IWB-2420(b) of Section XI requires three ,
successive reexaminations of the areas containing flaws or relevant conditions that have been i approved for continued service. The licensee is seeking approval under the provisions of I Section 50.55a(a)(3)(i) to Title 10 of the Code of Federal Regulations [10 CFR 50.55a(a)(3)(i))
for an alternative inspection schedule that would eliminate the successive reexaminations for the current inspection interval. Section 10 CFR 50.55a(a)(3)(i) allows licensees to propose i alternatives to the inservice inspection (ISI) requirements when the proposed alternatives would i provide an acceptable level of quality and safety in lieu of implementing the requirements.
2.0 BACKGROUND
I "BWR Vessel and Internals Projects, BWR Reactor Vessel Shell Weld Inspection !
Recommendations (Technical Report BWRVIP-05)
By letter dated September 28,1995,' the Boiling Water Reactor Vessel and Internals Project (BWRVIP), a technical committee of the BWR Owners Group (BWROG), submitted the proprietary report, "BWR Vessel and Internals Project, BWR Reactor Vessel Shell Weld ;
Inspection Recommendations (BWRVIP-05)." This report proposed to reduce the scope of inspection of the BWR RPV welds and to eliminate the successive reexamination requirements j in the ASME Code regarding welds with detected indications. The three conditions for the elimination of the successive reexamination r3quirements are:
1 As supplemented by letters dated June 24,1996; October 29,1996; May 16,1997; June 4,1997; June 13, 1997; and December 18,1997.
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9904140008 990407 PDR P ADOCK 05000271 PDR Enclosure
f t . l 2
(1) The flaw is characterized as subsurface in accordance with Figure 9-1 (of the BWRVIP-05 l Report).
(2) The NDE technique and evaluation that detected and characterized the flaw as originating from material manufacture or vessel fabrication shall be documented in a flavt evaluation report.
(3) The vessel containing the flaw is acceptable for continued service in accordance with IWB-3600 and the flaw is demonstrated acceptable for the intended senrice life of the vessel.
The staff accepted the proposal regarding successive reexaminations in the final safety evaluation (SE) dated July 28,1998, for the BWRVIP-05 report. l 3.0 EVALUATION Proposed Alternative to the Successive Reexamination Requirements for Circumferential Welds in the Vermont Yankee RPV 3.1 Reauest for Relief The licensee is requesting relief from performing successive reexaminations of the area containing flaw indications in circumferential welds of the Vermont Yankee RPV for the current inspection interval.
3.2 A_poticable Reauirement Pursuant to the requirements of 10 CFR 50.55a(g)(4), ASME Code Class 1,2, and 3 components mue>t meet the requirements, except the decign and access provisions and the preservice examination requirements, set forth in Section XI, " Rules for Inservice Inspection of Nuclear Power Plant Components," of ASME Code (Section XI) to the extent practical within the limitations of design, geometry and materials of construction of the components.2 The regulations require that all inservice examinations and system pressure tests conducted during the first 10-year interval and subsequent intervals on ASME Code Class 1,2, and 3 components must comply with the requirements in the latest edition and addenda of Section XI incorporated by reference in 10 CFR 50.55a(b) on the date 12 months prior to the start of the 10-year interval.
If components with detected flaw indications from the ISI are accepted for continued service in accordance with the ASME Code, Paragraph IWB-2420 requires that the areas containing flaws or relevant conditions shall be reexamined during the next three inspection periods listed in the schedule of the inspection program of IWB-2400.
3.3 Basis for Relief Section 10 CFR 50.55a(a)(3)(i) allows licensees to propose alternatives to the IS! requirements when the proposed alternatives would provide an acceptable level of quality and safety in lieu of 2 Except for design and access provisions and preservice inspection requirements.
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3 complying with the requirements. The licensee demonstrated that the proposed alternative has I an acceptable level of quality and safety by employing the approved criteria (reproduced in Section 2.0 of this SE) in the BWRVIP-05 report for eliminating successive reexaminations of subsurface flaws in RPV circumferential welds.
3.4 Proposed Alternatives The licensee proposes to eliminate the successive reexaminations of subsurface flaws in RPV circumferential welds fo. the current inspection interval.
3.5 Evaluation i
It was stated in the relief request that the detected flaws in the RPV circumferential welds, I which were approved for continued service, meet all three criteria of BWRVIP-05 for the elimination of the successive reexamination requirement of the ASME Code. As mentioned, these proposed criteria for the circumferential welds were accepted by the staff. This I determination was based on the low failure probability of 8.2 X 104 /yr from the staff's
. independent calculation for the limiting plant-specific analyses (32 EFPY) using a low l temperature transient with an event frequency of 1 X 10 /yr. In the current evaluation, the staff l confirmed that (1) the detected flaw is characterized as a subsurface flaw, which was accepted by the staff in another SE dated October 11,1996, (2) the NDE technique and evaluation that detected and characterized the flaw are documented in the flaw evaluation report previously i submitted, and (3) the vessel containing the flaw was approved (the same SE dated October 11,1996) for continued service without repair through end-of-license for Vermont Yankee. Hence, all three criteria in the BWRVIP-05 report for eliminating successive l reexaminations of detected flaws have been satisfied.
It should be noted that the bounding failure probability of 8.2 X 104/yr from the staff's independent evaluation of the BWRVIP-05 report is for the limiting Babcock and Wilcox vessel. t The corresponding value for the limiting Chicago Bridge and Iron (CB&l) vessel (Vermont i Yankee's RPV was manufactured by CB&l) is an order of magnitude lower as indicated in the final SE for the BWRVIP-05 report. This provides additional assurance that an acceptable level of quality and safety will be maintained for the alternative inspection requested by the licensee.
4.0 CONCLUSION
S The staff has reviewed the licensee's alternative proposal for the reexamination of the ,
circumferential welds with detected flaw indications in the Vermont Yankee RPV. The staff has determined that the licensee's alternative proposal for the circumferential welds meets the conditions in the BWRVIP-05 report approved by the staff for the elimination of the successive reexaminations for the circumferential welds with detected flaw indications. Hence, the staff has determined, pursuant to 10 CFR 50.55a(a)(3)(i), that the alternative inspection provides an acceptable level of quality and safety relative to assuring the structural integrity of the subject circumferential weld.
Principal Contributor: S. Sheng Date: April 7,1999 l