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Category:SAFETY EVALUATION REPORT--LICENSING & RELATED ISSUES
MONTHYEARML20205L0401999-04-0909 April 1999 SER Accepting Util Relief Requests for Inservice Insp Second 10-year Interval for Beaver Valley Power Station, Unit 2 ML20203E1181999-02-10010 February 1999 SER Accepting Proposed Revs to Plant,Units 1 & 2 Quality Assurance Program Description ML20199F5341998-12-29029 December 1998 Safety Evaluation Granting Relief Requests 1-TYP-3-B3.140-1, 1-TYP-3-B5.70-1,1-TYP-3-RH-E-1-1,1-TYP-3-B-G-1, 1-TYP-3-APP-I-1,1-TYP-3-UT-1,1-TYP-3-N-509,1-TYP-3-N-521, 1-TYP-3-N-524,1-TYP-3-B3.120-1 & 1-TYP-3-C6.10-1 ML20198K8551998-12-21021 December 1998 SER Granting Relief Request PRR-5 for Third 10-year Inservice Testing for Beaver Valley Power Station,Unit 1 ML20198A1631998-12-0909 December 1998 SER Approving Implementation Program to Resolve USI A-46 at Facility That Has Adequately Addressed Purpose of 10CFR50.54(f) Request ML20195J3131998-11-12012 November 1998 Safety Evaluation Granting First & Second 10-yr Interval Inservice Insp Request for Relief ML20154R9121998-10-20020 October 1998 Safety Evaluation Accepting Proposed Changes to QA Program Description in Chapter 17.2 of BVPS-2 Ufsar.Proposed Changes Would Modify QA Organization to Allow Warehouse QC Inspectors to Report to Manager of Nuclear Procurement Dept ML20154P7491998-10-19019 October 1998 SE Accepting Second ten-year Interval Inservice Insp Request for Relief RR-1-TYP-2-B5.40-1,Rev 0,for Plant, Unit 1 ML20154C6711998-10-0101 October 1998 Safety Evaluation Concluding That Revised Model Identified in Dl Submittal Was Appropriate for Analysis of Installed Conduit Ampacity Limits.Determined That There Are No Outstanding Safety Concerns with Respect to Ampacity ML20202B8571997-11-18018 November 1997 SE Approving Relief Requests for Second 10-Yr Interval for Pumps & Valves Inservice Testing Program for Beaver Valley Power Station,Unit 2 ML20199F4641997-11-13013 November 1997 SER Related to Reactor Pressure Vessel,Pressurized Thermal Shock Assessment for Beaver Valley Power Station,Unit 2 ML20212G4961997-10-28028 October 1997 SER Accepting Pressurized Thermal Shock Assessment for Beaver Valley Unit 2 Reactor Vessel ML20217J5311997-10-0808 October 1997 Safety Evaluation Re First,Second & Third 10-year Interval Inservice Inspection Program Plan Requests for Relief for Plant,Units 1 & 2 ML20217J5891997-10-0707 October 1997 Safety Evaluation Related to Reactor Pressure Vessel Pressurized Thermal Shock for Beaver Valley Power Station, Unit 1 ML20211D8441997-09-17017 September 1997 SER Approving SG 90-day Rept Submitted by Duquesne Light Co for Beaver Valley Power Station,Unit 1,per GL 95-05 ML20216J5861997-09-0404 September 1997 Safety Evaluation Re Third 10-year IST Program.Approves Valve Relief Requests 1,3 & 4.Valve Relief Request 2 Not Required.Authorizes Pump Relief Requests 1,2,3 & 4 ML20148E1051997-05-28028 May 1997 Safety Evaluation Supporting Amend 204 to License DPR-66 ML20137X1441997-04-0909 April 1997 Safety Evaluation Supporting Proposed Rev to RPV Surveillance Capsule Withdrawal Schedule ML20057B0641993-09-13013 September 1993 Safety Evaluation Granting Relief for IST of Reactor Plant Component Cooling Water Pumps of Plant ML20056F3561993-08-12012 August 1993 Safety Evaluation Granting Licensee 930607 Request for Relief from Certain ASME Code Requirements for Temporary Repairs to Svc Water Sys ML20126H7601992-12-30030 December 1992 Safety Evaluation Approving Valve Relief Requests VRR-27, VRR-43 & VRR-44 & Will Provide Reasonable Assurance of Operational Readiness of Valves to Perform Intended Functions.Relief Request PRR-11 Cannot Be Approved ML20127P2081992-11-20020 November 1992 SER Accepting Util Commitment to Entire GIP-2,including Both SQUG Commitments & Implementation Guidance ML20248D7681989-09-29029 September 1989 Supplemental Safety Evaluation Supporting Util Actions in Response to Open Items in 890510 Safety Evaluation Re Plant Safety Monitoring Sys ML20247N3561989-05-30030 May 1989 SER Supporting Util Actions to Comply W/Item 4.5.3 of Generic Ltr 83-28, Reactor Trip Sys Functional Testing ML20246M1791989-05-10010 May 1989 Safety Evaluation Re Verification & Validation Plan for Plant Safety Monitoring Sys.Hardware Design of Sys Found Acceptable.Verification & Validation Plan Found Incomplete & Unacceptable.Software Design Process Inadequate ML20246D5501989-04-26026 April 1989 Safety Evaluation Accepting Util Submittals on Natural Circulation Cooldown for Unit ML20206G0431988-11-17017 November 1988 Safety Evaluation Concluding That All Issues Raised Under Item Resolved & Item 4.3 Closed ML20153C0911988-08-17017 August 1988 Safety Evaluation Re Licensee 870731 Comments on Sser 5, Section 9.5.1.Fire Protection in Cable Rooms & Containment Constitutes Acceptable Deviations from Branch Technical Position Cmeb 9.5-1 ML20205T0021988-08-10010 August 1988 SER Accepting Util 831104,840330 & 870504 Responses to Item 2.2.1 of Generic Ltr 83-28 Re Equipment Classification Programs for All safety-related Components ML20154R4451988-05-31031 May 1988 Safety Evaluation Re Compliance W/Atws Rule 10CFR50.62.Util Proposed Design Acceptable Subj to Final Resolution of Tech Spec Issue ML20154P4341988-05-24024 May 1988 Safety Evaluation Concluding That Proposed Tech Spec Change Acceptable.No Amend Issued Since Conditions Resulting in Need for Amend to License NPF-73 No Longer Exist ML20154F9841988-05-12012 May 1988 Supplemental Safety Evaluation Concluding That Licensee 851114 Response to Open Issues Noted in 851017 Draft Technical Evaluation Rept of 831104 Submittal Re Salem ATWS Event Action Item 1.2, Post-Trip Review Satisfactory ML20154F9901988-05-12012 May 1988 Supplemental Safety Evaluation Concluding That Licensee 880322 Response to Open Issues Identified in 860722 Draft Technical Evaluation Rept of 840330 Submittal Re Salem ATWS Event Action Item 1.2, Post-Trip Review Satisfactory ML20153B6291988-04-25025 April 1988 Safety Evaluation Granting Util 870616 & 871110 Requests for Inservice Insp Relief for Welds on Nonregenerative Hxs,Per 10CFR50.55a(g)(6)(i) ML20148K5231988-03-18018 March 1988 Safety Evaluation Supporting Util Inservice Testing Program & Requests for Relief ML20234E0531987-12-0808 December 1987 Safety Evaluation Accepting Design Changes to Be Implemented During Unit 1 Cycle 7 Fuel Reload.Tech Spec Change Unnecessary ML20236X4941987-11-0909 November 1987 Safety Evaluation Granting Util 860617 Relief Request from Performing Volumetric & Visual Exam Requirements of ASME Section XI for Reactor Coolant Pumps Casing Welds & Internal Surfaces ML20237B1651987-10-21021 October 1987 Safety Evaluation Supporting Elimination of Primary Component Support Snubbers from Primary Coolant Loops ML20204H7181987-03-18018 March 1987 Interim Safety Evaluation Re Pump & Valve Operability Assurance (SER Confirmatory Issue 13).Pages from Pvort Audit Encl ML20206G2231987-03-12012 March 1987 SER Accepting Licensee Request to Use Damping Values from ASME Code Case N-411 Per Conditions Outlined in Util ML20207P6551987-01-0202 January 1987 SER Accepting Licensee Compliance W/Generic Ltr 83-28,Item 2.1,Part 2 Re Vendor Interface Program for Reactor Trip Sys (RTS) Components & Item 4.5.2 Concerning RTS Online Reliability Testing ML20212B0111986-11-30030 November 1986 Safety Evaluation Granting Util Request for Exemptions from App R Requirements Re Separation of Cables & Equipment & Associated Circuits ML20205G4491986-08-31031 August 1986 Safety Evaluation Accepting Projected Values of Matl Properties for Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock Events ML20204G9281986-07-31031 July 1986 Safety Evaluation Supporting Util 860502 Submittal of Westinghouse Reload Safety Evaluation,Beaver Valley Nuclear Plant,Unit 1 Cycle 6 ML20203G2371986-07-28028 July 1986 Interim SER Re Dcrdr Summary Rept & Preimplementation Audit on 860211 & 12.Requirements of Suppl 1 to NUREG-0737 Generally Satisfied.Several Items Remain to Be Completed ML20206H4931986-06-19019 June 1986 Safety Evaluation on Generic Ltr 83-28,Item 4.2.3 & 4.2.4, Preventive Maint Program for Reactor Trip Breakers/Life Testing. Licensee Position Unacceptable ML20205N1151986-04-22022 April 1986 Interim Rept Re Review of Util Response to Generic Ltr 85-12 on Reactor Coolant Pump Trip Criteria.Addl Info Required ML20202C5721986-04-0303 April 1986 Sser Accepting Util 860304 Response to Generic Ltr 83-28, Item 4.3, Seismic Qualification of Shunt Trip Components ML20214E3631986-03-17017 March 1986 Safety Evaluation Supporting Amend 2 to CPPR-105 ML20154N7451986-03-10010 March 1986 Safety Evaluation Supporting Util 850819 Request to Withdraw Original Commitment to Provide Steam Leakage Collection Sys Around Certain Steam Valves 1999-04-09
[Table view] Category:TEXT-SAFETY REPORT
MONTHYEARL-99-154, Monthly Operating Repts for Sept 199 for Bvps,Units 1 & 2. with1999-09-30030 September 1999 Monthly Operating Repts for Sept 199 for Bvps,Units 1 & 2. with L-99-139, LER 99-S01-00:on 990813,uncompensated Loss of Ability to Detect within Single Intrusion Security Detection Zone Occurred.Caused by Procedure non-compliance.Involved Personnel Received Counseling Re Event.With1999-09-0202 September 1999 LER 99-S01-00:on 990813,uncompensated Loss of Ability to Detect within Single Intrusion Security Detection Zone Occurred.Caused by Procedure non-compliance.Involved Personnel Received Counseling Re Event.With L-99-140, Monthly Operating Repts for Aug 1999 for Bvps,Units 1 & 2. with1999-08-31031 August 1999 Monthly Operating Repts for Aug 1999 for Bvps,Units 1 & 2. with L-99-126, Monthly Operating Repts for Jul 1999 for Beaver Valley Power Station,Units 1 & 2.With1999-07-31031 July 1999 Monthly Operating Repts for Jul 1999 for Beaver Valley Power Station,Units 1 & 2.With L-99-107, Monthly Operating Repts for June 1999 for Bvps,Units 1 & 2. with1999-06-30030 June 1999 Monthly Operating Repts for June 1999 for Bvps,Units 1 & 2. with ML20209D9531999-06-27027 June 1999 Inservice Insp Ninety-Day Rept Bvps,Unit 2 Outage 7,Year 1999 L-99-096, Monthly Operating Repts for May 1999 for BVPS Units 1 & 2. with1999-05-31031 May 1999 Monthly Operating Repts for May 1999 for BVPS Units 1 & 2. with L-99-078, Special Rept:On 990326,seismic Monitoring Instruments Were Declared Inoperable.Caused by Resolution of Potential TS Compliance Issue & Work Scheduling Issue.Instrumentation Was Returned to Svc Following Calibr & Declared Operable1999-05-0303 May 1999 Special Rept:On 990326,seismic Monitoring Instruments Were Declared Inoperable.Caused by Resolution of Potential TS Compliance Issue & Work Scheduling Issue.Instrumentation Was Returned to Svc Following Calibr & Declared Operable L-99-079, Monthly Operating Repts for Apr 1999 for Beaver Valley Power Station,Units 1 & 2.With1999-04-30030 April 1999 Monthly Operating Repts for Apr 1999 for Beaver Valley Power Station,Units 1 & 2.With ML20205L0401999-04-0909 April 1999 SER Accepting Util Relief Requests for Inservice Insp Second 10-year Interval for Beaver Valley Power Station, Unit 2 L-99-054, Special Rept:On 990320,meteorological Tower Wind Speed Sensors Were Declared Inoperable.Caused by Calibration Completed by Vendor Did Not Adequately Cover Full Operating Range of Sensors.Removed Sensors & Sent Offsite1999-04-0505 April 1999 Special Rept:On 990320,meteorological Tower Wind Speed Sensors Were Declared Inoperable.Caused by Calibration Completed by Vendor Did Not Adequately Cover Full Operating Range of Sensors.Removed Sensors & Sent Offsite L-99-058, Monthly Operating Repts for Mar 1999 for Bvps,Units 1 & 2. with1999-03-31031 March 1999 Monthly Operating Repts for Mar 1999 for Bvps,Units 1 & 2. with ML20196K7981999-03-25025 March 1999 Rev 4 to COLR, for Cycle 8 L-99-038, Monthly Operating Repts for Feb 1999 for Bvps,Units 1 & 2. with1999-02-28028 February 1999 Monthly Operating Repts for Feb 1999 for Bvps,Units 1 & 2. with ML20203E1181999-02-10010 February 1999 SER Accepting Proposed Revs to Plant,Units 1 & 2 Quality Assurance Program Description L-99-019, Special Rept:On 990120,meteorological Tower Wind Speed Sensors Declared Inoperable.Caused by Processor Card for Sensor Locked Up & Needed to Be Reset.Heater That Fit Around Shaft of Sensor Replaced1999-02-0505 February 1999 Special Rept:On 990120,meteorological Tower Wind Speed Sensors Declared Inoperable.Caused by Processor Card for Sensor Locked Up & Needed to Be Reset.Heater That Fit Around Shaft of Sensor Replaced ML20196F7011999-01-31031 January 1999 BVPS Unit 2 Heatup & Cooldown Limit Curves During Normal Operation at 15 EFPY Using Code Case N-626 ML20203D4811999-01-31031 January 1999 Monthly Operating Repts for Jan 1999 for Bvps,Units 1 & 2, in Accordance with NRC GL 97-02.With ML20207E6631999-01-28028 January 1999 Rev 0 to EMECH-0713-1, Operational Assessment of SG Tubing at Beaver Valley Unit 1,Cycle 13 ML20210G7041999-01-22022 January 1999 BVPS Unit 1 Facility Changes,Tests & Experiments for 980123-990122 ML20207E5861998-12-31031 December 1998 Annual Rept 1998 for Toledo Edison ML20207E5601998-12-31031 December 1998 Annual Rept 1998 for Pennpower ML20198B9021998-12-31031 December 1998 BVPS Unit 1 Simulator Four Yr Certification Rept for 1995-1998 ML20207E5901998-12-31031 December 1998 Dqe 1998 Annual Rept to Shareholders ML20199C9971998-12-31031 December 1998 Monthly Operating Repts for Dec 1998 for Bvps,Units 1 & 2. with ML20207E5521998-12-31031 December 1998 Annual Rept 1998 for Ohio Edison ML20207E5761998-12-31031 December 1998 Annual Rept 1998 for Illuminating Co ML20204J6751998-12-31031 December 1998 1998 Annual Rept for Dbnps,Unit 1,PNPP,Unit 1 & BVPS Units 1 & 2 ML20199F5341998-12-29029 December 1998 Safety Evaluation Granting Relief Requests 1-TYP-3-B3.140-1, 1-TYP-3-B5.70-1,1-TYP-3-RH-E-1-1,1-TYP-3-B-G-1, 1-TYP-3-APP-I-1,1-TYP-3-UT-1,1-TYP-3-N-509,1-TYP-3-N-521, 1-TYP-3-N-524,1-TYP-3-B3.120-1 & 1-TYP-3-C6.10-1 ML20198K8551998-12-21021 December 1998 SER Granting Relief Request PRR-5 for Third 10-year Inservice Testing for Beaver Valley Power Station,Unit 1 ML20198A1631998-12-0909 December 1998 SER Approving Implementation Program to Resolve USI A-46 at Facility That Has Adequately Addressed Purpose of 10CFR50.54(f) Request L-98-229, Monthly Operating Repts for Nov 1998 for Bvps,Units 1 & 2. with1998-11-30030 November 1998 Monthly Operating Repts for Nov 1998 for Bvps,Units 1 & 2. with ML20195J3131998-11-12012 November 1998 Safety Evaluation Granting First & Second 10-yr Interval Inservice Insp Request for Relief L-98-210, Monthly Operating Repts for Oct 1998 for Bvps,Units 1 & 2. with1998-10-31031 October 1998 Monthly Operating Repts for Oct 1998 for Bvps,Units 1 & 2. with ML20206G0291998-10-31031 October 1998 BVPS Unit 2 Facility Changes,Tests & Experiments for Period 971101-981031 ML20154R9121998-10-20020 October 1998 Safety Evaluation Accepting Proposed Changes to QA Program Description in Chapter 17.2 of BVPS-2 Ufsar.Proposed Changes Would Modify QA Organization to Allow Warehouse QC Inspectors to Report to Manager of Nuclear Procurement Dept ML20154P7491998-10-19019 October 1998 SE Accepting Second ten-year Interval Inservice Insp Request for Relief RR-1-TYP-2-B5.40-1,Rev 0,for Plant, Unit 1 ML20198F7611998-10-0606 October 1998 Duquesne Light Co,Beaver Valley Power Station 1998 Emergency Preparedness Ingestion Zone Exercise, Conducted on 981006 ML20154C6711998-10-0101 October 1998 Safety Evaluation Concluding That Revised Model Identified in Dl Submittal Was Appropriate for Analysis of Installed Conduit Ampacity Limits.Determined That There Are No Outstanding Safety Concerns with Respect to Ampacity ML20154D5001998-09-30030 September 1998 Special Rept on Overview of BVPS-1 & BVPS-2 TS Compliance Issues & Corrective Action Taken L-98-197, Monthly Operating Repts for Sept 1998 for Beaver Valley Power Station,Units 1 & 2.With1998-09-30030 September 1998 Monthly Operating Repts for Sept 1998 for Beaver Valley Power Station,Units 1 & 2.With ML20154E2171998-09-28028 September 1998 Follow-up Part 21 Rept Re Defect with 1200AC & 1200BC Recorders Built Under Westronics 10CFR50 App B Program. Westronics Has Notified Bvps,Ano & RBS & Is Currently Making Arrangements to Implement Design Mods L-98-188, Special Rept:During 1998,Unit 2 SG Eddy Current exam,26 Tubes Were Improperly Encoded in SG 2RCS-SG21C During Previous Outage.Use of Independent Databases to Track New Indications Being Implemented as Preventive Measure1998-09-21021 September 1998 Special Rept:During 1998,Unit 2 SG Eddy Current exam,26 Tubes Were Improperly Encoded in SG 2RCS-SG21C During Previous Outage.Use of Independent Databases to Track New Indications Being Implemented as Preventive Measure L-98-178, Monthly Operating Repts for Aug 1998 for Bvps,Units 1 & 2. with1998-08-31031 August 1998 Monthly Operating Repts for Aug 1998 for Bvps,Units 1 & 2. with ML20155B5871998-08-28028 August 1998 Non-proprietary Rev 1 to 51-5001925-01, Risk Assessment for Installation of Electrosleeves at BVPS & Callaway Plant ML20236X2351998-08-0505 August 1998 Part 21 Rept Re Defect Associated W/Westronics 1200AC & 1200BC Recorders Built Under Westronics 10CFR50,App B Program.Beaver Valley,Arkansas Nuclear One & River Bend Station Notified.Design Mod Is Being Developed L-98-168, Monthly Operating Repts for July 1998 for Bvps,Units 1 & 21998-07-31031 July 1998 Monthly Operating Repts for July 1998 for Bvps,Units 1 & 2 L-98-157, Special Rept:On 980423,inoperability of Seismic Monitoring Instrument Noted.Caused by Obsolescence of Instrument & Inability to Obtain Necessary Spare Parts.Design Change Is Being Pursued to Obtain Replacement Product1998-07-29029 July 1998 Special Rept:On 980423,inoperability of Seismic Monitoring Instrument Noted.Caused by Obsolescence of Instrument & Inability to Obtain Necessary Spare Parts.Design Change Is Being Pursued to Obtain Replacement Product L-98-139, Monthly Operating Repts for June 1998 for Bvps,Units 1 & 21998-06-30030 June 1998 Monthly Operating Repts for June 1998 for Bvps,Units 1 & 2 L-98-119, Monthly Operating Repts for Bvps,Units 1 & 21998-05-31031 May 1998 Monthly Operating Repts for Bvps,Units 1 & 2 1999-09-30
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ENCLOSURE
[ o g UNITED STATES ,
n NUCLEAR REGULATORY COMMISSION g E WASHINGTON, D. C. 20555
%.....) SAFETY EVALUATION BY THE OFFICE OF NVCLEAR REACTOR REGULATION REdVESTFORRELIEFFROMASMECODEREPAIRRE0VIREMENTS FOR SERVICE WATER EXPANSION JOINTS DUOVESNE LIGHT COMPANY BEAVER VALLEY POWER STATION. UNIT NO. 2 DOCKET NO. 50-412
1.0 INTRODUCTION
By letter dated June 7, 1993, Duquesne Light Company, the licensee, requested relief from the ASME Code Section XI repair requirements .for two leaks in a moderate energy class 3 service water system (SW) at Beaver Valley Power Station, Unit No. 2. The leaks were detected in two 30-inch diameter metal expansion joints (MEJ). There is one affected joint in each of the two independent SW system supply trains. The licensee proposes to apply a temporary, reversible, non-Code repair to each joint until a Code repair can be performed later this year.
Each joint is located in its own independent SW train valve pit which is outside the plant, between the screen house and the plant building. The SW ,
system conveys ambient temperature Ohio river water at a design pressure of 150 psig. Each MEJ is constructed of type 304 stainless steel corrugated bellows with 150 psi rated carbon steel flanges. The bellows are !
unreinforced; there is no external wire braid. The rest of the SW system is I unlined carbon steel.
The leak on the "B" train MEJ was discovered first. The maximum leakage rate observed since discovery is estimated to be less than 1 gallon per hour.
During the subsequent augmented inspection of the SW system, the leak on the "A" train MEJ was discovered. This joint is the sister joint to the first.
The weep rate for the "A" joint has been observed at one drop per 5 minutes.
The leakage is suspected to be caused by erosion and/or corrosion / pitting in the region of the dissimilar metal weld joining the stainless steel bellows to the carbon steel flange. Type 309 stainless steel weld metal was used. The bellows material fits into the flange in a socket joint like configuration.
However, unlike a socket fitting, the weld was executed from inside the pipe, presumably to preclude creating a wetted crevice in the annulus-between the bellows and the carbon steel flange. The observed leakage on both MEJs is from this crevice. Only one weld on each MEJ is leaking. In both cases,-it is on the discharge end of the joint.
Due to this weld configuration, the flaw cannot be observed visually. The licensee has been una~ o le to detect any flaws by ultrasonic testing (UT).
Thus, the flaws cannot be characterized as to location, type, size, or cause.
Flaw evaluation, using analytical methods such as found in Generic Letter 90-05 is consequently impossible. However, because of the very low leakage rates, the licens,ee has assumed that the flaws are..small.
9308270024 930812 .
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Because of the MEJ locations in the SW trains, the leaks cannot be isolated a for repair without removing their respective SW trains from service. The j licensee has estimated that repair / replacement would require longer than the Limiting Conditions for Operation period (72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />) for one SW train. Thus, a I unit shutdown is required to effect Code repairs.
As a compensatory measure, the licensee proposed application of a reversible mechanical restraint on each joint. The restraint is a segmented ring (six dogs) which fits between two convolutions of the bellows. The six dogs are i bolted to the flange studs. With this arrangement, the dogs prevent relative movement between the end of the bellows and the attached flange. This restraint would prevent separation of the bellows from the flange in the event i '
of a postulated guillotine break of the bellows to flange weld. This restraint would not significantly affect the functioning of the bellows.
, In addition to the structural reinforcement provided by the six dogs, the 4
licensee proposed application of a glass-epoxy circumferential patch at the bellows-flange junction. This would effectively create an encapsulating fiberglass pipe at the leak location to provide added strength and prevent gross leakage. There would be no effect on the function of the bellows.
These temporary repairs are proposed to be employed until the next refueling 1
outage which is scheduled to begin in September 1993. At that time a Code repair / replacement would be performed along with a root cause analysis. If a planned outage of 30 days or more occurred before then, the joints would be repaired during that outage.
An augmented inspection of the SW system was performed. Two other joints of
- the same design and similar operational impact have been identified and were not leaking. Since the cause of the two leaks is uncertain, the licensee i committed to monitoring the other two joints once a week for the duration of
- the proposed temporary repairs.
2.0 DISCUSSION Due to the unknown cause of the two observed leaks, a flaw analysis is impossible. In its place, a consequence analysis was performed to investigate the effects of a postulated guillotine break at the expansion joint weld. The consequence analysis included investigation of the ability of the restraining dogs to withstand a guillotine break, piping system reactions, flooding of '
equipment, and loss of flow.
For the postulated guillotine break, seismic and operational loads at the joints were analyzed. Nearby pipe anchors are capable of withstanding all reaction forces involved in a postulated guillotine break. The loads on the expansion joint are minimal. Its only apparent function is to provide for thermal expansion. There are no pipe reaction forces transmitted across it.
The pipe anchors absorb all reaction forces.
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- l From this analysis, the licensee concluded that the forces acting upon a '
presumed flaw in the bellows to flange weld are small. Thus, flaw growth, and increasingly larger leak rates are not anticipated to occur as a result of a stress driven mechanism. Should the cause be erosion or corrosion, the staff I expects that a slow leak rate increase may be anticipated. The licensee has committed to a twice daily visual inspection of the two leaking joints. l Leakage will be estimated and trended. Any leakage beyond the rate of 1 '
gallon per minute (gpm) for either joint will be reported to the NRC. l The six restraining dogs bolted to the flange joint are designed to retain the end of the bellows inside the flange joint. This compensatory action provides .
mitigation for a structural weakness in two ways. First, the six restraining dogs will act to reinforce the weld joint. This will reduce the stress levels !
at the weld and slow crack growth, assuming a crack-like flaw. Second, should !
degradation of the joint be due to another mechanism, such as erosion, the restraining dogs will still prevent separation of the bellows from the flange.
This would minimize the loss of flow and flooding of other equipment. '
Additionally, this modification will not prevent the bellows from performing its normal function. l i
i With respect to the application of the leak mitigating fiberglass / resin wrap, the staff cannot determine if it would provide any substantive structural l reinforcement. This is due to the unknowns regarding the shear strength of l the resin to stainless steel bond. Thus, no credit for its application would l be warranted. 1 Given a failure of one of the bellcws welds, the installed " dogs" would limit the amount of leakage to about 300 gpm which would allow approximately 20 i minutes to isolate the leak before the isolation valve became inundated. This !
would leave the redund ut train to bring the plant to safe shutdown conditions. Even if the bellows was not isolated, the 300 gpm leak rate would not prevent safe shutdawn because only the equipment in the vault would be affected. The flooding conditions in the vault would not cause any of the valves in the vault to change position and isolate safety related cooling loads. The loss of only 300 gpm would not prevent the affected header from receiving adequate flow to perform its safe shutdown function. If it is assumed that both trains' bellows fail simultaneously which is the worst-case scenario, the plant could still be brought to safe shutdown conditions using one or both trains of the system with or without isolation of the leakage. If both bellows are isolated cooling would be lost to the primary component cooling water (CCW) system and the secondary plant CCW system. At Beaver Valley 2, this would not prevent safe plant shutdown. Without isolation, both trains of the SW system could still be used to supply all cooling water loads; however, one train would have to be isolated to affect repairs. Based on the capability of safe plant shutdown being maintained, and the impracticality of performing the Code repairs without imposing the burden of the plant transients associated with an unnecessary plant shutdown and startup, the request for relief should be granted.
l . 4.
1
3.0 CONCLUSION
The staff concludes that the proposed. temporary non-Code repair provides reasonable assurance.of structural integrity for a postulated guillotine break of the expansion joint weld and that the capability of safe plant shutdown is maintained. Based on these findings, and the impracticality of performing the Code repairs without imposing a burden on the licensee, relief should be granted pursuant to 10 CFR 50.55 a(g)(6)(1).
- An administrative limit of 1 gpm per joint must not be exceeded without
- authorization from the NRC.
l Principal Reviewers:
l G. Hornseth l W. Lefave j G. Edison i
j Date: August 12, 1993 i
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