|
|
Line 18: |
Line 18: |
|
| |
|
| =Text= | | =Text= |
| {{#Wiki_filter:January 16, 2007Mr. Christopher M. Crane President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 | | {{#Wiki_filter:January 16, 2007 Mr. Christopher M. Crane President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 |
|
| |
|
| ==SUBJECT:== | | ==SUBJECT:== |
| BYRON STATION, UNIT NOS. 1 AND 2, AND BRAIDWOOD STATION, UNITNOS. 1 AND 2 EVALUATION OF INSERVICE INSPECTION PROGRAM RELIEF REQUESTS I3R-07 AND I2R-46 PERTAINING TO ESSENTIAL SERVICE WATER BURIED PIPING (TAC NOS. MD1757, MD1758, MD1759 AND MD1760) | | BYRON STATION, UNIT NOS. 1 AND 2, AND BRAIDWOOD STATION, UNIT NOS. 1 AND 2 EVALUATION OF INSERVICE INSPECTION PROGRAM RELIEF REQUESTS I3R-07 AND I2R-46 PERTAINING TO ESSENTIAL SERVICE WATER BURIED PIPING (TAC NOS. MD1757, MD1758, MD1759 AND MD1760) |
|
| |
|
| ==Dear Mr. Crane:== | | ==Dear Mr. Crane:== |
|
| |
|
| By letter dated April 20, 2006, Exelon Generation Company, LLC (the licensee) submitted arequest for relief from the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code) Section XI, ?Rules for Inservice Inspection [ISI] of Nuclear PowerPlant Component," 2001 Edition through 2003 Addenda, for Byron Station, Unit Nos. 1 and 2 (Byron) for the third 10-year interval, and the 1989 Edition for Braidwood Station, Unit Nos. 1 and 2 (Braidwood) for the second 10-year interval. The licensee requested relief from the pressure testing requirements for the buried piping portions of the essential service water system.The Nuclear Regulatory Commission staff concludes that the licensee's proposed alternative totest the buried portion of service water piping in conjunction with quarterly testing of service water pumps would detect significant through-wall leakage if present in the subject line and would provide reasonable assurance of structural integrity. Therefore, pursuant to Title 10 ofthe Code of Federal Regulations (CFR) Section 50.55a(a)(3)(ii) (10 CFR 50.55a(a)(3)(ii)), reliefrequests I3R-07 for Byron, and I2R-46 for Braidwood, are authorized on the basis that compliance with the ISI code of record would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. The relief request is authorized for thethird 10-year interval for Byron, and the second 10-year interval for Braidwood.Sincerely,/RA/Michael L. Marshall, Jr., Chief Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket Nos. STN 50-454, STN 50-455, STN 50-456 and STN 50-457 | | By letter dated April 20, 2006, Exelon Generation Company, LLC (the licensee) submitted a request for relief from the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code) Section XI, ?Rules for Inservice Inspection [ISI] of Nuclear Power Plant Component, 2001 Edition through 2003 Addenda, for Byron Station, Unit Nos. 1 and 2 (Byron) for the third 10-year interval, and the 1989 Edition for Braidwood Station, Unit Nos. 1 and 2 (Braidwood) for the second 10-year interval. The licensee requested relief from the pressure testing requirements for the buried piping portions of the essential service water system. |
| | The Nuclear Regulatory Commission staff concludes that the licensees proposed alternative to test the buried portion of service water piping in conjunction with quarterly testing of service water pumps would detect significant through-wall leakage if present in the subject line and would provide reasonable assurance of structural integrity. Therefore, pursuant to Title 10 of the Code of Federal Regulations (CFR) Section 50.55a(a)(3)(ii) (10 CFR 50.55a(a)(3)(ii)), relief requests I3R-07 for Byron, and I2R-46 for Braidwood, are authorized on the basis that compliance with the ISI code of record would result in hardship or unusual difficulty without a |
| | |
| | compensating increase in the level of quality and safety. The relief request is authorized for the third 10-year interval for Byron, and the second 10-year interval for Braidwood. |
| | Sincerely, |
| | /RA/ |
| | Michael L. Marshall, Jr., Chief Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. STN 50-454, STN 50-455, STN 50-456 and STN 50-457 |
|
| |
|
| ==Enclosure:== | | ==Enclosure:== |
| Safety Evaluationcc w/encl: See next page compensating increase in the level of quality and safety. The relief request is authorized for thethird 10-year interval for Byron, and the second 10-year interval for Braidwood.Sincerely,/RA/Michael L. Marshall, Jr., ChiefPlant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket Nos. STN 50-454, STN 50-455, STN 50-456 and STN 50-457 | | |
| | Safety Evaluation cc w/encl: See next page |
| | |
| | compensating increase in the level of quality and safety. The relief request is authorized for the third 10-year interval for Byron, and the second 10-year interval for Braidwood. |
| | Sincerely, |
| | /RA/ |
| | Michael L. Marshall, Jr., Chief Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. STN 50-454, STN 50-455, STN 50-456 and STN 50-457 |
|
| |
|
| ==Enclosure:== | | ==Enclosure:== |
| Safety Evaluationcc w/encl: See next page DISTRIBUTION
| |
| :PUBLICLPL3-2 R/FRidsOgcRpRidsNrrPMCGratton RidsNrrDorlLpl3-2RidsAcrsAcnwMailCenterRidsNrrPMRKuntzTBloomer, OGC RidsNrrLAEWhittRidsRgn3MailCenterRidsNrrDorlDpr Accession Number:ML063260074 *See SE**NLO w/editsNRR-028OFFICELPL3-2/PMLPL3-2/PMLPL3-2/LACFEB/BC*OGC**LPL3-2/BC NAMERKuntz:mwCGrattonEWhittKGrussPMouldingMMarshallDATE1/11/20071/12/2007 1/11/20078/29/200601/11/2007 1/16/2007OFFICIAL RECORD COPY Byron/Braidwood Stations cc:
| |
| Dwain W. Alexander, Project ManagerWestinghouse Electric Corporation Energy Systems Business Unit Post Office Box 355 Pittsburgh, PA 15230-0355Howard A. LearnerEnvironmental Law and Policy Center of the Midwest 35 East Wacker Dr., Suite 1300 Chicago, IL 60601-2110U.S. Nuclear Regulatory CommissionByron Resident Inspectors Office 4448 N. German Church Road Byron, IL 61010-9750Regional Administrator, Region IIIU.S. Nuclear Regulatory Commission Suite 210 2443 Warrenville Road Lisle, IL 60532-4351Ms. Lorraine CreekRR 1, Box 182 Manteno, IL 60950Chairman, Ogle County BoardPost Office Box 357 Oregon, IL 61061Mrs. Phillip B. Johnson1907 Stratford Lane Rockford, IL 61107Attorney General500 S. Second Street Springfield, IL 62701Illinois Emergency Management Agency Division of Disaster Assistance &
| |
| Preparedness 110 East Adams Street Springfield, IL 62701-1109Plant Manager - Byron StationExelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794Site Vice President - ByronExelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794U.S. Nuclear Regulatory CommissionBraidwood Resident Inspectors Office 35100 S. Rt. 53, Suite 79 Braceville, IL 60407County Executive Will County Office Building 302 N. Chicago Street Joliet, IL 60432Plant Manager - Braidwood Station Exelon Generation Company, LLC 35100 S. Rt. 53, Suite 84 Braceville, IL 60407-9619Ms. Bridget Little RoremAppleseed Coordinator 117 N. Linden Street Essex, IL 60935Document Control Desk - LicensingExelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555Site Vice President - BraidwoodExelon Generation Company, LLC 35100 S. Rt. 53, Suite 84 Braceville, IL 60407-9619Senior Vice President - Operations SupportExelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Byron/Braidwood Stations Director - Licensing and Regulatory Affairs Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555Manager Regulatory Assurance - BraidwoodExelon Generation Company, LLC 35100 S. Rt. 53, Suite 84 Braceville, IL 60407-9619Manager Regulatory Assurance - ByronExelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794Assistant General CounselExelon Generation Company, LLC 200 Exelon Way Kennett Square, PA 19348Vice President - Regulatory & Legal AffairsExelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555Manager Licensing - Braidwood/ByronExelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555Senior Vice President - Midwest OperationsExelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATIONRELATED RELIEF TO REQUEST I3R-07 AND I2R-46PERTAINING TO ESSENTIAL SERVICE WATEREXELON GENERATION COMPANY, LLCBYRON STATION, UNIT NOS. 1 AND 2 BRAIDWOOD STATION, UNIT NOS. 1 AND 2DOCKET NOS. STN 50-454, STN 50-455, STN 50-456, AND STN 50-45
| |
|
| |
|
| ==71.0INTRODUCTION== | | Safety Evaluation cc w/encl: See next page DISTRIBUTION: |
| By letter dated April 20, 2006, Exelon Generation Company, LLC (Exelon, the licensee),submitted relief request I3R-07 and I2R-46, related to the inservice inspection (ISI) program pertaining to system leakage tests during the third 10-year interval for the Byron Station, Unit Nos. 1 and 2 (Byron) and the second 10-year interval for the Braidwood Station, Unit Nos. 1 and 2 (Braidwood), respectively. In relief requests I3R-07 and I2R-46, the licensee requested relief from performing the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code) required pressure test of the buried portion of the essential service water (ESW) piping by measuring the rate of pressure loss or change in flow between the ends of the buried components. As an alternative, the licensee proposed a test that would confirm that flow during operation is not impaired. The integrity of the buried piping will be verified during quarterly pump testing under the inservice testing program for pumps and valves. | | PUBLIC LPL3-2 R/F RidsOgcRp RidsNrrPMCGratton RidsNrrDorlLpl3-2 RidsAcrsAcnwMailCenter RidsNrrPMRKuntz TBloomer, OGC RidsNrrLAEWhitt RidsRgn3MailCenter RidsNrrDorlDpr Accession Number:ML063260074 *See SE **NLO w/edits NRR-028 OFFICE LPL3-2/PM LPL3-2/PM LPL3-2/LA CFEB/BC* OGC** LPL3-2/BC NAME RKuntz:mw CGratton EWhitt KGruss PMoulding MMarshall DATE 1/11/2007 1/12/2007 1/11/2007 8/29/2006 01/11/2007 1/16/2007 OFFICIAL RECORD COPY |
| | |
| | Byron/Braidwood Stations cc: |
| | Dwain W. Alexander, Project Manager Plant Manager - Byron Station Westinghouse Electric Corporation Exelon Generation Company, LLC Energy Systems Business Unit 4450 N. German Church Road Post Office Box 355 Byron, IL 61010-9794 Pittsburgh, PA 15230-0355 Site Vice President - Byron Howard A. Learner Exelon Generation Company, LLC Environmental Law and Policy 4450 N. German Church Road Center of the Midwest Byron, IL 61010-9794 35 East Wacker Dr., Suite 1300 Chicago, IL 60601-2110 U.S. Nuclear Regulatory Commission Braidwood Resident Inspectors Office U.S. Nuclear Regulatory Commission 35100 S. Rt. 53, Suite 79 Byron Resident Inspectors Office Braceville, IL 60407 4448 N. German Church Road Byron, IL 61010-9750 County Executive Will County Office Building Regional Administrator, Region III 302 N. Chicago Street U.S. Nuclear Regulatory Commission Joliet, IL 60432 Suite 210 2443 Warrenville Road Plant Manager - Braidwood Station Lisle, IL 60532-4351 Exelon Generation Company, LLC 35100 S. Rt. 53, Suite 84 Ms. Lorraine Creek Braceville, IL 60407-9619 RR 1, Box 182 Manteno, IL 60950 Ms. Bridget Little Rorem Appleseed Coordinator Chairman, Ogle County Board 117 N. Linden Street Post Office Box 357 Essex, IL 60935 Oregon, IL 61061 Document Control Desk - Licensing Mrs. Phillip B. Johnson Exelon Generation Company, LLC 1907 Stratford Lane 4300 Winfield Road Rockford, IL 61107 Warrenville, IL 60555 Attorney General Site Vice President - Braidwood 500 S. Second Street Exelon Generation Company, LLC Springfield, IL 62701 35100 S. Rt. 53, Suite 84 Braceville, IL 60407-9619 Illinois Emergency Management Agency Senior Vice President - Operations Support Division of Disaster Assistance & Exelon Generation Company, LLC Preparedness 4300 Winfield Road 110 East Adams Street Warrenville, IL 60555 Springfield, IL 62701-1109 |
| | |
| | Byron/Braidwood Stations Director - Licensing and Regulatory Senior Vice President - Midwest Operations Affairs Exelon Generation Company, LLC Exelon Generation Company, LLC 4300 Winfield Road 4300 Winfield Road Warrenville, IL 60555 Warrenville, IL 60555 Manager Regulatory Assurance - Braidwood Exelon Generation Company, LLC 35100 S. Rt. 53, Suite 84 Braceville, IL 60407-9619 Manager Regulatory Assurance - Byron Exelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794 Assistant General Counsel Exelon Generation Company, LLC 200 Exelon Way Kennett Square, PA 19348 Vice President - Regulatory & Legal Affairs Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Manager Licensing - Braidwood/Byron Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 |
| | |
| | SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED RELIEF TO REQUEST I3R-07 AND I2R-46 PERTAINING TO ESSENTIAL SERVICE WATER EXELON GENERATION COMPANY, LLC BYRON STATION, UNIT NOS. 1 AND 2 BRAIDWOOD STATION, UNIT NOS. 1 AND 2 DOCKET NOS. STN 50-454, STN 50-455, STN 50-456, AND STN 50-457 |
| | |
| | ==1.0 INTRODUCTION== |
| | |
| | By letter dated April 20, 2006, Exelon Generation Company, LLC (Exelon, the licensee), |
| | submitted relief request I3R-07 and I2R-46, related to the inservice inspection (ISI) program pertaining to system leakage tests during the third 10-year interval for the Byron Station, Unit Nos. 1 and 2 (Byron) and the second 10-year interval for the Braidwood Station, Unit Nos. 1 and 2 (Braidwood), respectively. In relief requests I3R-07 and I2R-46, the licensee requested relief from performing the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code) required pressure test of the buried portion of the essential service water (ESW) piping by measuring the rate of pressure loss or change in flow between the ends of the buried components. As an alternative, the licensee proposed a test that would confirm that flow during operation is not impaired. The integrity of the buried piping will be verified during quarterly pump testing under the inservice testing program for pumps and valves. |
| | |
| | ==2.0 REGULATORY EVALUATION== |
| | |
| | Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(g) requires that ISI of ASME Code Class 1, 2, and 3 components be performed in accordance with Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, of the ASME Code and applicable addenda, except where specific written relief has been granted by the Nuclear Regulatory Commission (NRC, the Commission) pursuant to 10 CFR 50.55a(g)(6)(i). According to 10 CFR 50.55a(a)(3), alternatives to the requirements of paragraph 50.55a(g) may be used, when authorized by the NRC, if an applicant demonstrates that: (i) the proposed alternatives would provide an acceptable level of quality and safety or (ii) the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. |
| | Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1, 2, and 3 components (including supports) shall meet the requirements, except the design and access provisions and the preservice examination requirements, set forth in the ASME Code, Section XI to the extent practical within the limitations of design, geometry, and materials of construction of the components. |
| | |
| | 10 CFR 50.55a(a)(g)(4) requires that ISI of components and system pressure tests conducted during the first 10-year interval and subsequent intervals comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a(b) 12 months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The ASME Code of record for the third 10-year interval at Byron is the 2001 Edition through the 2003 Addenda. The ASME Code of record for the second 10-year inspection interval at Braidwood is the 1989 Edition. |
| | |
| | ==3.0 TECHNICAL EVALUATION== |
| | |
| | 3.1 System/Component(s) for Which Relief is Requested Buried Class 3 components in the ESW supply and return lines. |
| | 3.2 ASME Code Requirements The 2001 Edition through the 2003 Addenda of ASME Code, the code of record for Byron, Section XI, Table IWD-2500-1, Examination Category D-B, Item No. D2.10 requires a system leakage test and a VT-2 visual examination. For buried components where a VT-2 visual examination cannot be performed, the examination requirement of item D2.10 is satisfied by the following: |
| | The system pressure test for buried components that are isolable by means of valves shall consist of a test that determines the rate of pressure loss. Alternatively, the test may determine the change in flow between the ends of the buried components. |
| | The acceptable rate of pressure loss or flow shall be established by the Owner. |
| | The 1989 Edition of ASME Code, the code of record for Braidwood, Section XI, Table IWD-2500-1, Examination Category D-B, Item No. D2.10 requires a system pressure test and a VT-2 visual examination. Subsection IWA-5244(a) requires that nonredundant/isolable buried components that are isolable by means of valves be tested to determine the rate of pressure loss. Alternatively, the test may determine the change in flow between the ends of the buried components. However, the 1989 edition of the ASME Code has no provision for the pressure testing of redundant/isolable buried components such as those used at Braidwood. Therefore, the test requirement of Subsection IWA-5244(a) was applied. |
| | 3.3 Licensees Request for Relief Relief is requested from performing the system pressure test or the system leakage test for buried portions of the ESW piping that are isolable by means of valves. The proposed alternative would determine the rate of pressure loss or the change in flow between the ends of buried components. |
| | 3.3.1 Licensees Basis for Requesting Relief The ESW buried piping at Braidwood consists of six 30 inch (") diameter common supply headers that feed into two 48" diameter supply headers, including the suction piping that runs between the lake screen house and the turbine building. The buried return lines are two 48" |
|
| |
|
| ==2.0REGULATORY EVALUATION==
| | diameter return headers and piping that runs between the turbine building and the ESW cooling pond. At Byron, the ESW buried piping consists of two 48" common supply headers and two 48" return headers located between the ESW cooling towers and the auxiliary building. The remaining buried piping consists of two 36" pump supply lines in each unit and four 24" risers and two 24" hot water bypass lines that branch out from each 48" return header. There is no access to the buried sections of piping without excavation. Further, no annuluses were provided during original construction, which would allow for examination of these buried sections of piping. |
| Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(g) requires that ISI of ASME CodeClass 1, 2, and 3 components be performed in accordance with Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components," of the ASME Code and applicable addenda, except where specific written relief has been granted by the Nuclear Regulatory Commission (NRC, the Commission) pursuant to 10 CFR 50.55a(g)(6)(i). According to 10 CFR 50.55a(a)(3), alternatives to the requirements of paragraph 50.55a(g) may be used, when authorized by the NRC, if an applicant demonstrates that: (i) the proposed alternatives would provide an acceptable level of quality and safety or (ii) the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1, 2, and 3 components (includingsupports) shall meet the requirements, except the design and access provisions and the preservice examination requirements, set forth in the ASME Code, Section XI to the extent practical within the limitations of design, geometry, and materials of construction of the components. 10 CFR 50.55a(a)(g)(4) requires that ISI of components and system pressure tests conductedduring the first 10-year interval and subsequent intervals comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a(b) 12 months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The ASME Code of record for the third 10-year interval at Byron is the 2001 Edition through the 2003 Addenda. The ASME Code of record for the second 10-year inspection interval at Braidwood is the 1989 Edition.
| | The supply and return lines use butterfly valves for isolation. These valves are not suitable for performing a pressure isolation function since they were not designed to be leak tight. |
| | Extensive maintenance or system modification would be necessary to conduct a rate-of-pressure-loss test. The alternative test would be to determine the change in flow between the ends of buried components. However, the buried ESW supply and return headers were not designed with plant instrumentation and flow orifices on both sides of the buried sections of piping to determine the rates. Further, sufficient length of accessible straight pipe is not available to use an ultrasonic flow measuring device. Therefore, the configuration of the buried ESW system does not permit a determination of the change in flow between the ends of the buried components. |
| | 3.3.2 Licensees Proposed Alternative In lieu of performing a system pressure test in accordance with the requirements of the IWA-5244(b)(1) for Byron, and of the IWA-5244(a) for Braidwood, Exelon proposed as an alternative to use the provisions of IWA-5244(c) and IWA-5244(b)(2) of the 1989 Edition and the 2001 Edition through the 2003 Addenda of the ASME Section XI Code, respectively, to confirm that flow during operation is not impaired in non-isolable buried piping. The unimpaired flow in the buried piping will be verified during quarterly ESW pump testing. Byron and Braidwood will use the Owner-established minimum flow rate specified in the site inservice testing (IST) surveillance, 23,520 and 24,000 gallons per minute, respectively, for all ESW pumps as the acceptance criteria for IWA-5244 pressure testing of ESW buried piping. If, during an IST surveillance, the minimum flow could not be achieved and the cause of the deviation is not attributed to the test instruments being used, the pump would be declared inoperable and an issue report would be generated in accordance with the Exelon corrective action program as required by the existing IST surveillance. Further corrective actions (e.g., |
| | maintenance on the pump and system walk-downs) would be initiated as necessary to restore the pump and/or the system to an operable status. In addition, Exelon would monitor pressure drop across each pump at the reference flow rate to assess any leakage through the buried piping, assuming no degradation of the pump. |
| | 3.4 NRC Staff Evaluation The ASME Code of record requires a system pressure test for the buried portion of ESW piping to determine either a rate of pressure loss or a change in flow at the ends of the buried piping. |
| | The buried service water piping at Byron and Braidwood uses butterfly valves at the ends that were not designed for pressure isolation, and therefore, are unsuitable for determining a meaningful rate of pressure loss. Similarly, change in flow cannot be determined both because of the limitations of the current system configuration and because one end of the buried piping |
|
| |
|
| ==3.0TECHNICAL EVALUATION==
| | is not instrumented for flow measurement. Consequently, the ASME Code-required tests cannot be performed without significant system modification, including excavation. For nonisolable buried components ASME Code compliance can be accomplished by confirming that flow during operation is not impaired. The NRC staff finds the licensees approach, by which unimpaired flow in the buried piping can be qualitatively assessed during quarterly IST surveillance of the ESW pumps, to be acceptable. By using the flow instrument downstream from the pump discharge, a reference flow rate can be established that would correspond to a target pump head. A decrease in pump head may indicate increase in flow due to any through-wall leakage in the buried piping. An assessment can be made of the integrity of the buried piping, from the trending of head loss (pressure drop) during a pump test at the reference flow. However, pump head loss may also be caused by the deterioration of the pump rather than the leakage in the buried pipe. As the pump deteriorates, the developed head decreases at the reference flow. Therefore, the licensee has stated that if during an IST surveillance, the minimum flow could not be achieved and the cause of the deviation could not be attributed to the test instruments being used, the pump would be declared inoperable and an Issue Report would be generated in accordance with the Exelon corrective action program as required by the existing IST surveillance. Further corrective actions (e.g., maintenance on the pump and system walk-downs) would be initiated as necessary to restore the pump and/or the system to an operable status. |
| | Based on its independent review, the NRC staff has determined that the licensees proposed alternative to test the buried portion of service water piping in conjunction with quarterly testing of service water pumps would detect significant through-wall leakage if present in the subject line and would provide reasonable assurance of structural integrity. In light of this proposed alternative, and because performance of the ASME Code-required tests would require installation of an additional flow measuring device at the inlet end of the buried piping, compliance with the ASME Code requirement would result in hardship without a compensating increase in the level of quality and safety. |
|
| |
|
| 3.1System/Component(s) for Which Relief is RequestedBuried Class 3 components in the ESW supply and return lines.
| | ==4.0 CONCLUSION== |
| 3.2ASME Code RequirementsThe 2001 Edition through the 2003 Addenda of ASME Code, the code of record for Byron,Section XI, Table IWD-2500-1, Examination Category D-B, Item No. D2.10 requires a system leakage test and a VT-2 visual examination. For buried components where a VT-2 visual examination cannot be performed, the examination requirement of item D2.10 is satisfied by the following:The system pressure test for buried components that are isolable by means of valvesshall consist of a test that determines the rate of pressure loss. Alternatively, the test may determine the change in flow between the ends of the buried components.
| |
| The acceptable rate of pressure loss or flow shall be established by the Owner. The 1989 Edition of ASME Code, the code of record for Braidwood, Section XI, Table IWD-2500-1, Examination Category D-B, Item No. D2.10 requires a system pressure test and a VT-2 visual examination. Subsection IWA-5244(a) requires that nonredundant/isolable buried components that are isolable by means of valves be tested to determine the rate of pressure loss. Alternatively, the test may determine the change in flow between the ends of the buried components. However, the 1989 edition of the ASME Code has no provision for the pressure testing of redundant/isolable buried components such as those used at Braidwood. Therefore, the test requirement of Subsection IWA-5244(a) was applied.3.3Licensee's Request for ReliefRelief is requested from performing the system pressure test or the system leakage test forburied portions of the ESW piping that are isolable by means of valves. The proposed alternative would determine the rate of pressure loss or the change in flow between the ends of buried components. 3.3.1Licensee's Basis for Requesting Relief The ESW buried piping at Braidwood consists of six 30 inch (") diameter common supplyheaders that feed into two 48" diameter supply headers, including the suction piping that runsbetween the lake screen house and the turbine building. The buried return lines are two 48" diameter return headers and piping that runs between the turbine building and the ESW coolingpond. At Byron, the ESW buried piping consists of two 48" common supply headers and two 48" return headers located between the ESW cooling towers and the auxiliary building. The remaining buried piping consists of two 36" pump supply lines in each unit and four 24" risers and two 24" hot water bypass lines that branch out from each 48" return header. There is no access to the buried sections of piping without excavation. Further, no annuluses were provided during original construction, which would allow for examination of these buried sections of piping.The supply and return lines use butterfly valves for isolation. These valves are not suitable forperforming a pressure isolation function since they were not designed to be leak tight.
| |
| Extensive maintenance or system modification would be necessary to conduct a rate-of-pressure-loss test. The alternative test would be to determine the change in flow between the ends of buried components. However, the buried ESW supply and return headers were not designed with plant instrumentation and flow orifices on both sides of the buried sections of piping to determine the rates. Further, sufficient length of accessible straight pipe is not available to use an ultrasonic flow measuring device. Therefore, the configuration of the buried ESW system does not permit a determination of the change in flow between the ends of the buried components.3.3.2Licensee's Proposed Alternative In lieu of performing a system pressure test in accordance with the requirements of theIWA-5244(b)(1) for Byron, and of the IWA-5244(a) for Braidwood, Exelon proposed as analternative to use the provisions of IWA-5244(c) and IWA-5244(b)(2) of the 1989 Edition andthe 2001 Edition through the 2003 Addenda of the ASME Section XI Code, respectively , toconfirm that flow during operation is not impaired in non-isolable buried piping. The unimpairedflow in the buried piping will be verified during quarterly ESW pump testing. Byron and Braidwood will use the Owner-established minimum flow rate specified in the site inservice testing (IST) surveillance, 23,520 and 24,000 gallons per minute, respectively, for all ESW pumps as the acceptance criteria for IWA-5244 pressure testing of ESW buried piping. If, during an IST surveillance, the minimum flow could not be achieved and the cause of the deviation is not attributed to the test instruments being used, the pump would be declared inoperable and an issue report would be generated in accordance with the Exelon corrective action program as required by the existing IST surveillance. Further corrective actions (e.g.,
| |
| maintenance on the pump and system walk-downs) would be initiated as necessary to restore the pump and/or the system to an operable status. In addition, Exelon would monitor pressure drop across each pump at the reference flow rate to assess any leakage through the buried piping, assuming no degradation of the pump. 3.4NRC Staff EvaluationThe ASME Code of record requires a system pressure test for the buried portion of ESW pipingto determine either a rate of pressure loss or a change in flow at the ends of the buried piping.
| |
| The buried service water piping at Byron and Braidwood uses butterfly valves at the ends that were not designed for pressure isolation, and therefore, are unsuitable for determining a meaningful rate of pressure loss. Similarly, change in flow cannot be determined both because of the limitations of the current system configuration and because one end of the buried piping is not instrumented for flow measurement. Consequently, the ASME Code-required testscannot be performed without significant system modification, including excavation. For nonisolable buried components ASME Code compliance can be accomplished by confirming that flow during operation is not impaired. The NRC staff finds the licensee's approach, by which unimpaired flow in the buried piping can be qualitatively assessed during quarterly IST surveillance of the ESW pumps, to be acceptable. By using the flow instrument downstream from the pump discharge, a reference flow rate can be established that would correspond to a target pump head. A decrease in pump head may indicate increase in flow due to any through-wall leakage in the buried piping. An assessment can be made of the integrity of the buried piping, from the trending of head loss (pressure drop) during a pump test at the reference flow. However, pump head loss may also be caused by the deterioration of the pump rather than the leakage in the buried pipe. As the pump deteriorates, the developed head decreases at the reference flow. Therefore, the licensee has stated that if during an IST surveillance, the minimum flow could not be achieved and the cause of the deviation could not be attributed to the test instruments being used, the pump would be declared inoperable and an Issue Report would be generated in accordance with the Exelon corrective action program as required by the existing IST surveillance. Further corrective actions (e.g., maintenance on the pump and system walk-downs) would be initiated as necessary to restore the pump and/or the system to an operable status. Based on its independent review, the NRC staff has determined that the licensee's proposedalternative to test the buried portion of service water piping in conjunction with quarterly testing of service water pumps would detect significant through-wall leakage if present in the subject line and would provide reasonable assurance of structural integrity. In light of this proposed alternative, and because performance of the ASME Code-required tests would require installation of an additional flow measuring device at the inlet end of the buried piping, compliance with the ASME Code requirement would result in hardship without a compensating increase in the level of quality and safety.
| |
|
| |
|
| ==4.0CONCLUSION==
| | The NRC staff concludes that for the buried portion of service water piping, compliance with the ASME Code requirement to perform a test that determines the rate of pressure loss or the change in flow would result in hardship to the licensee without a compensating increase in the level of quality and safety. By providing for detection of any degradation in the buried portion of service water piping, the licensees proposed alternative provides reasonable assurance of structural integrity. Therefore, pursuant to 10 CFR 50.55a(a)(3)(ii), the licensees proposed alternative in relief requests I3R-07 and I2R-46 is authorized for the third 10-year ISI interval for Byron and the second 10-year ISI interval for Braidwood. All other requirements of the ASME Code, Section XI for which relief has not been specifically requested remain applicable, including a third party review by the Authorized Nuclear Inservice Inspector. |
| The NRC staff concludes that for the buried portion of service water piping, compliance with theASME Code requirement to perform a test that determines the rate of pressure loss or the change in flow would result in hardship to the licensee without a compensating increase in the level of quality and safety. By providing for detection of any degradation in the buried portion of service water piping, the licensee's proposed alternative provides reasonable assurance of structural integrity. Therefore, pursuant to 10 CFR 50.55a(a)(3)(ii), the licensee's proposed alternative in relief requests I3R-07 and I2R-46 is authorized for the third 10-year ISI interval for Byron and the second 10-year ISI interval for Braidwood. All other requirements of the ASME Code, Section XI for which relief has not been specifically requested remain applicable, including a third party review by the Authorized Nuclear Inservice Inspector. Principal Contributor: P. Patnaik Date: January 16, 2007}} | | Principal Contributor: P. Patnaik Date: January 16, 2007}} |
Letter Sequence Other |
---|
|
|
MONTHYEARML0632600742007-01-16016 January 2007 Evaluation of Inservice Inspection Program Relief Requests 13R-07 and 12R-46 Pertaining to Essential Service Water Buried Piping Project stage: Other 2007-01-16
[Table View] |
|
---|
Category:Code Relief or Alternative
MONTHYEARML22307A2462022-11-10010 November 2022 Proposed Alternative to the Requirements of the American Society of Mechanical Engineers Boiler & Pressure Vessel Code (EPIDs L-2021-LLR-0035 and L-2021-LLR-0036) RS-22-110, Supplemental Information - Proposed Alternatives Related to the Steam Generators and Request.2022-09-20020 September 2022 Supplemental Information - Proposed Alternatives Related to the Steam Generators and Request. RS-22-036, Supplemental Information - Proposed Alternative for Examination of Pressurizer Circumferential and Longitudinal Shell-to-Head Welds and Nozzle-to-Vessel Welds2022-03-10010 March 2022 Supplemental Information - Proposed Alternative for Examination of Pressurizer Circumferential and Longitudinal Shell-to-Head Welds and Nozzle-to-Vessel Welds ML21280A0782021-10-27027 October 2021 Proposed Alternative to Use of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code Case N-893 (Epids L-2020-LLR-0147 and L-2020-LLR-0148) ML21230A2062021-09-0303 September 2021 Proposed Alternative to Use ASME OM Code Case OMN-28 ML21216A2202021-08-0505 August 2021 Proposed Alternative to Eliminate Certain Documentation Requirements for Pressure Retaining Bolting ML21134A0062021-08-0303 August 2021 Proposed Alternatives to the Requirements of the American Society of Mechanical Engineers Boiler & Pressure Vessel Code (Epids L-2020-LLR-0099 and L-2020-LLR-0100) RS-21-008, Request for Alternative: One-Time Deferral of Follow-Up Inspection for Reactor Pressure Vessel Head Penetration Nozzles with Mitigated Alloy 600/82/182 Peened Surfaces in Accordance with 10 CFR 50.55a(z)(2)2021-01-25025 January 2021 Request for Alternative: One-Time Deferral of Follow-Up Inspection for Reactor Pressure Vessel Head Penetration Nozzles with Mitigated Alloy 600/82/182 Peened Surfaces in Accordance with 10 CFR 50.55a(z)(2) ML20269A2002020-09-30030 September 2020 Request to Use a Provision of Later Edition of the ASME Boiler and Pressure Vessel Code, Section XI (EPID L2020-LLR-0117 ML20245E5062020-09-0909 September 2020 Relief from the Requirements of the ASME Code (COVID-19) ML20188A2642020-07-0606 July 2020 Clinton Power Station, R.E. Ginna Station, Limerick Station, Nine Mile Point Station & Peach Bottom Station - Proposed Alternative to Utilize Code Case OMN-26 - Response to Request for Additional Information ML20113F0412020-04-30030 April 2020 Proposed Alternative to the Submittal Schedule for Certain Reports (COVID-19) ML20099D9552020-04-17017 April 2020 Request to Use Provisions in the 2013 Edition of the ASME Boiler and Pressure Vessel Code for Performing Non-Destructive Examinations RS-20-020, Relief Request for Alternative Frequency to Supplemental Indication Requirements of 10 CFR 50.55a(b)(3)(xi)2020-02-28028 February 2020 Relief Request for Alternative Frequency to Supplemental Indication Requirements of 10 CFR 50.55a(b)(3)(xi) ML19269C5342019-09-27027 September 2019 Proposed Alternative to Use Encoded Phased Array Ultrasonic Examination Techniques ML19136A3862019-06-0505 June 2019 Relief from the Requirements of the American Society of Mechanical Engineers Code ML19141A0202019-06-0505 June 2019 Relief from the Requirements of the American Society of Mechanical Engineers Code ML19155A0602019-06-0505 June 2019 Relief from the Requirements of the American Society of Mechanical Engineers Code ML19161A2572019-06-0404 June 2019 BWR Fleet Msv/Srv - Testing Frequency Relief Request NRC Pre-Application Meeting June 4, 2019 ML19035A2942019-02-25025 February 2019 Relief from the Requirements of the ASME Code JAFP-19-0023, Relief Request Associated with the Use of Encoded Phased Array Ultrasonic Examination Techniques in Lieu of Radiography for Ferritic and Austenitic Piping Welds2019-02-15015 February 2019 Relief Request Associated with the Use of Encoded Phased Array Ultrasonic Examination Techniques in Lieu of Radiography for Ferritic and Austenitic Piping Welds RS-19-015, Relief Request 14-RS-1 to Implement Code Case OMN-132019-01-31031 January 2019 Relief Request 14-RS-1 to Implement Code Case OMN-13 ML18318A3342019-01-17017 January 2019 Relief from the Requirements of the American Society of Mechanical Engineers Code ML18331A0372019-01-17017 January 2019 Relief from the Requirements of the American Society of Mechanical Engineers Code ML18347B4192019-01-17017 January 2019 Relief Request I4R-03, Relief from ASME Requirements for the Fourth 10-Year Inservice Inspection Interval Related to Degraded Canopy Seal Welds Associated with Control Rod Drive Mechanism ML18305A3602018-12-0606 December 2018 Relief from the Requirements of the American Society of Mechanical Engineers Code RS-18-125, Proposed Alternative Requirements for the Repair and Examination of Reactor Pressure Vessel Head Penetration Nozzles for the Fourth Lnservice Inspection Interval in Accordance with 10 CFR 50.55a(z)(1)2018-10-11011 October 2018 Proposed Alternative Requirements for the Repair and Examination of Reactor Pressure Vessel Head Penetration Nozzles for the Fourth Lnservice Inspection Interval in Accordance with 10 CFR 50.55a(z)(1) RS-18-123, Request for Alternative Follow-up Inspection for Reactor Pressure Vessel Head Penetration Nozzles with Mitigated Alloy 600/82/182 Peened Surfaces in Accordance with 10 CFR 50.55a(z)(2)2018-09-24024 September 2018 Request for Alternative Follow-up Inspection for Reactor Pressure Vessel Head Penetration Nozzles with Mitigated Alloy 600/82/182 Peened Surfaces in Accordance with 10 CFR 50.55a(z)(2) JAFP-18-0052, Proposed Alternative to Utilize Code Case N-8792018-05-30030 May 2018 Proposed Alternative to Utilize Code Case N-879 JAFP-18-0053, Proposed Alternative to Utilize Code Cases N-878 and N-8802018-05-30030 May 2018 Proposed Alternative to Utilize Code Cases N-878 and N-880 ML17325B5712018-01-10010 January 2018 Non-Proprietary, Request for Relief for Extension of Examination Interval for Reactor Pressure Vessel Head Penetration Nozzles with Mitigated Alloy 600/82/182 Peened Services (CAC No. MF9854; EPID L-2017-LLR-0042) RS-17-168, Request for Relief for Extension of Examination Interval for Reactor Pressure Vessel Head Penetration Nozzles with Mitigated Alloy 600/82/182 Peened Surfaces in Accordance with 10 CFR 50.55a(z)(1)2017-12-20020 December 2017 Request for Relief for Extension of Examination Interval for Reactor Pressure Vessel Head Penetration Nozzles with Mitigated Alloy 600/82/182 Peened Surfaces in Accordance with 10 CFR 50.55a(z)(1) RS-17-168, Braidwood Station, Unit 2, Request for Relief for Extension of Examination Interval for Reactor Pressure Vessel Head Penetration Nozzles with Mitigated Alloy 600/82/182 Peened Surfaces in Accordance with 10 CFR 50.55a(z)(1)2017-12-20020 December 2017 Braidwood Station, Unit 2, Request for Relief for Extension of Examination Interval for Reactor Pressure Vessel Head Penetration Nozzles with Mitigated Alloy 600/82/182 Peened Surfaces in Accordance with 10 CFR 50.55a(z)(1) ML17249A2982017-11-13013 November 2017 Relief from the Requirements of the ASME Code (CAC No. MF9597; EPID L-2017-LLR-0021) ML17249A2412017-09-19019 September 2017 Relief from the Requirements of the ASME Code RS-17-083, Inservice Inspection Program Third Interval Relief Requests 13R-12 and 13R-152017-06-29029 June 2017 Inservice Inspection Program Third Interval Relief Requests 13R-12 and 13R-15 ML17170A0132017-06-26026 June 2017 Proposed Alternative to Eliminate Examination of Threads in Reactor Pressure Vessel Flange (CAC Nos. MF8712-MF8729 and MF9548) ML17095A2682017-03-31031 March 2017 Submittal of Request for Relief for Extension of Examination Interval for Reactor Pressure Vessel Head Penetration Nozzles with Mitigated Alloy 600/82/182 Peened Surfaces: Attachment 1, Relief Request ML17054C2552017-03-15015 March 2017 Request for Relief from Requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) ML17062A4282017-03-0606 March 2017 Request for Relief from the Requirements of the ASME Code ML17047A0382017-02-24024 February 2017 Request I4R-11 Relief from the Requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) ML16327A3182016-12-20020 December 2016 Request I4R-06, Relief from the Requirements of the ASME Code ML16327A3962016-12-20020 December 2016 Request I4R-01, Relief from the Requirements of the ASME Code ML16327A4212016-12-19019 December 2016 Requested Relief from the Requirements of the Asme Code (CAC Nos. MF7641 and MF7642) ML16306A3662016-11-0808 November 2016 Request I4R-08, Relief from the Requirements of the ASME Code ML16230A2372016-09-0606 September 2016 Fleet Request for Proposed Alternative to Use ASME Code Case N-513-4 (CAC Nos. MF7301-MF7322) ML16162A2112016-06-29029 June 2016 Request for Use of Alternative ML16109A3372016-04-27027 April 2016 Relief from the Requirements of the ASME Code (CAC Nos. MF6715, MF6716, MF6717, and MF6718) ML15173A4362015-06-30030 June 2015 Relief from the Requirements of the ASME Code RS-15-170, Submittal of Relief Requests Associated with the Fourth Inservice Testing Interval2015-06-22022 June 2015 Submittal of Relief Requests Associated with the Fourth Inservice Testing Interval 2022-09-20
[Table view] Category:Letter
MONTHYEARIR 05000456/20230042024-02-0202 February 2024 Integrated Inspection Report 05000456/2023004 and 05000457/2023004 IR 05000454/20230042024-02-0202 February 2024 Integrated Inspection Report 05000454/2023004 and 05000455/2023004 ML24025C7242024-01-29029 January 2024 Notification of NRC Baseline Inspection and Request for Information; Inspection Report 05000456/2024002; 05000457/2024002 IR 05000457/20230112024-01-25025 January 2024 2B Auxiliary Feedwater Pump Diesel Fuel Oil Dilution Report 05000457/2023011 and Preliminary Greater than Green Finding and Apparent Violation ML24022A2722024-01-23023 January 2024 Request for Information for an NRC Post-Approval Site Inspection for License Renewal Inspection Report 05000454/2024011 ML24018A0362024-01-17017 January 2024 Paragon Energy Solutions, Defect with Detroit Diesel/Mtu Fuel Injectors P/N R5229660 Cat Id 0001390618 RS-24-004, Proposed Alternative to the Distribution Requirements of ASME Code Table IWC-2411-1 for the Steam Generators2024-01-11011 January 2024 Proposed Alternative to the Distribution Requirements of ASME Code Table IWC-2411-1 for the Steam Generators ML23348A2162023-12-15015 December 2023 Exemption from Select Requirements of 10 CFR Part 73 (EPID L-2023-LLE-0030 (Security Notifications, Reports, and Recordkeeping and Suspicious Activity Reporting)) IR 05000456/20200232023-12-15015 December 2023 Baseline Security Inspection Document; 05000456/2023/402; 05000457/2023/402 ML23320A1762023-12-13013 December 2023 Exemption from Select Requirements of 10 CFR Part 73 (EPID L-2023-LLE-0027 (Security Notifications, Reports, and Recordkeeping and Suspicious Activity Reporting)) ML23277A0032023-12-11011 December 2023 Issuance of Amendments Regarding Adoption of TSTF-370 ML23339A0452023-12-0505 December 2023 Request for Information for an NRC Post-Approval Site Inspection for License Renewal Inspection Report 05000546/2024010 ML23313A1552023-12-0101 December 2023 Review of the Fall 2022 Steam Generator Tube Inspection Report ML23318A5102023-12-0101 December 2023 Relief from the Requirements of the ASME Code IR 05000454/20233012023-11-27027 November 2023 NRC Initial License Examination Report 05000454/2023301 and 05000455/2023301 ML23331A8922023-11-22022 November 2023 Supplement - Braidwood Security Rule Exemption Request ISFSI Docket No. Reference 05000457/LER-2023-001, Submittal of LER 2023-001-00 for Braidwood Station, Unit 2, Train B Auxiliary Feedwater Pump Was Inoperable Due to Degraded Oil in the Crank Case2023-11-17017 November 2023 Submittal of LER 2023-001-00 for Braidwood Station, Unit 2, Train B Auxiliary Feedwater Pump Was Inoperable Due to Degraded Oil in the Crank Case ML23321A0442023-11-17017 November 2023 Notification of Deviation from Electric Power Research Institute (EPRI) Topical Report MRP-227, Revision 1-A, Materials Reliability Program: Pressurized Water Reactor Internals Inspection and Evaluation Guideline BYRON 2023-0065, Unit 2 - Notification of Deviation from Electric Power Research Institute (EPRI) Topical Report MRP-227, Revision 1-A, Materials Reliability Program: Pressurized Water Reactor Internals Inspection and Evaluation Guideline2023-11-17017 November 2023 Unit 2 - Notification of Deviation from Electric Power Research Institute (EPRI) Topical Report MRP-227, Revision 1-A, Materials Reliability Program: Pressurized Water Reactor Internals Inspection and Evaluation Guideline BYRON 2023-0063, Day Inservice Inspection Report for Interval 4, Period 3, (B2R24)2023-11-16016 November 2023 Day Inservice Inspection Report for Interval 4, Period 3, (B2R24) IR 05000454/20230032023-11-13013 November 2023 Integrated Inspection Report 05000454/2023003 and 05000455/2023003 and Exercise of Enforcement Discretion RS-23-117, Supplemental Information Letter for Part 73 Exemption Request - Responses to Request for Confirmatory Information2023-11-10010 November 2023 Supplemental Information Letter for Part 73 Exemption Request - Responses to Request for Confirmatory Information ML23317A1192023-11-10010 November 2023 Constellation Energy Generation, LLC - 2023 Annual Report - Guarantees of Payment of Deferred Premiums RS-23-118, Supplemental Information Letter for Part 73 Exemption Request - Responses to Request for Confirmatory Information2023-11-10010 November 2023 Supplemental Information Letter for Part 73 Exemption Request - Responses to Request for Confirmatory Information ML23313A0852023-11-0909 November 2023 Submittal of 2023-301 Byron Initial License Examination Post-Examination Comments RS-23-114, Proposed Alternative for Examination of Pressurizer Circumferential and Longitudinal Shell-to-Head Welds and Nozzle-to-Vessel Welds2023-11-0101 November 2023 Proposed Alternative for Examination of Pressurizer Circumferential and Longitudinal Shell-to-Head Welds and Nozzle-to-Vessel Welds ML23297A2352023-10-26026 October 2023 Information Request for the Cyber Security Baseline Inspection, Notification to Perform Inspection IR 05000456/20234012023-10-18018 October 2023 Security Baseline Inspection Report 05000456/2023401 and 05000457/2023401 IR 05000456/20230102023-10-18018 October 2023 Functional Engineering Inspection Commercial Grade Dedication Report 05000456/2023010 and 05000457/2023010 RS-23-100, Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation2023-10-13013 October 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation RS-23-097, Constellation Energy Generation, LLC, Advisement of Leadership Changes and Submittal of Updated Standard Practice Procedures Plans2023-10-12012 October 2023 Constellation Energy Generation, LLC, Advisement of Leadership Changes and Submittal of Updated Standard Practice Procedures Plans RS-23-108, Proposed Alternative for Examinations of Examination Categories B-B, B-D, and C-A Steam Generator Pressure Retaining Welds and Full Penetration Welded Nozzles2023-10-11011 October 2023 Proposed Alternative for Examinations of Examination Categories B-B, B-D, and C-A Steam Generator Pressure Retaining Welds and Full Penetration Welded Nozzles RS-23-105, Proposed Alternative for Examinations of Examination Category C-B Steam Generator Nozzle-to-Shell Welds and Nozzle Inside Radius Sections2023-10-10010 October 2023 Proposed Alternative for Examinations of Examination Category C-B Steam Generator Nozzle-to-Shell Welds and Nozzle Inside Radius Sections ML23278A0272023-10-0505 October 2023 Operator Licensing Examination Approval - Byron Station, October 2023 RS-23-094, Relief Request I4R-24, Alternative for Post-Peening Reexamination Frequency for Reactor Pressure Vessel Head Penetration Nozzle Number 752023-09-29029 September 2023 Relief Request I4R-24, Alternative for Post-Peening Reexamination Frequency for Reactor Pressure Vessel Head Penetration Nozzle Number 75 RS-23-093, License Amendment to Braidwood Station, Units 1 and 2, and Byron Station, Units 1 and 2, Technical Specifications 3.7.15, Spent Fuel Pool Boron Concentration, 3.7.16, Spent Fuel.2023-09-29029 September 2023 License Amendment to Braidwood Station, Units 1 and 2, and Byron Station, Units 1 and 2, Technical Specifications 3.7.15, Spent Fuel Pool Boron Concentration, 3.7.16, Spent Fuel. ML23251A1622023-09-29029 September 2023 Steam Generator Tube Inspection Reports to Reflect TSTF-577 Reporting Requirements RS-23-091, Relief Request I4R-25, Alternative Requirements for Reactor Pressure Vessel Inservice Inspection Intervals2023-09-26026 September 2023 Relief Request I4R-25, Alternative Requirements for Reactor Pressure Vessel Inservice Inspection Intervals ML23226A0062023-09-19019 September 2023 Review of License Renewal Commitment Number 10 Submittal ML23180A1692023-09-11011 September 2023 Calvert Cliff Units 1 & 2, and R.E. Ginna Plant - Withdrawal of Proposed Alternatives to American Society of Mechanical Engineers (ASME) Requirements (Epids L-2022-LRR-0074, 0076, 0079, 0091, 0092, 0093 and 0094) ML23242A3282023-09-0101 September 2023 Amendment No. 233 Correction IR 05000454/20235012023-08-31031 August 2023 Emergency Preparedness Biennial Exercise Inspection Report 05000454/2023501 and 05000455/2023501 IR 05000454/20230052023-08-30030 August 2023 Updated Inspection Plan for Byron Station (Report 05000454/2023005 and 05000455/2023005) IR 05000456/20230052023-08-30030 August 2023 Updated Inspection Plan for Braidwood Station Report 05000456/2023005 and 05000457/2023005 ML23234A2462023-08-25025 August 2023 Confirmation of Initial License Examination IR 05000456/20230022023-08-0303 August 2023 Integrated Inspection Report 05000456/2023002 and 05000457/2023002 IR 05000454/20230022023-08-0303 August 2023 Integrated Inspection Report 05000454/2023002 and 05000455/2023002 2024-02-02
[Table view] Category:Safety Evaluation
MONTHYEARML23277A0032023-12-11011 December 2023 Issuance of Amendments Regarding Adoption of TSTF-370 ML23318A5102023-12-0101 December 2023 Relief from the Requirements of the ASME Code ML23241A9092023-09-19019 September 2023 Enclosure 2 - Non-Proprietary - Review of License Renewal Commitment Number 10 Safety Evaluation ML23188A1292023-07-26026 July 2023 Issuance of Amendment Nos. 233 and 233 Adoption of TSTF-577, Revised Frequencies for Steam Generator Tube Inspections, Revision 1 ML23122A3022023-07-20020 July 2023 Issuance of Amendments Technical Specifications 2.1.1 and 4.2.1 to Allow a Previously Irradiated Accident Tolerant Fuel Lead Test Assembly to Be Further Irradiated in Unit No. 2 ML23087A0762023-07-13013 July 2023 Issuance of Amendment Nos. 232 and 232 Revision of Technical Specifications for the Ultimate Heat Sink ML23114A2522023-04-28028 April 2023 Request to Use a Provision of a Later Edition of the ASME Boiler & Pressure Vessel Code, Section XI ML22364A0242023-03-0101 March 2023 R. E. Ginna Nuclear Power Plant Issuance of Amendments Nos. 231, 231, 232, 232, and 154 Regarding Adoption of TSTF-246 ML22305A6992022-12-28028 December 2022 Issuance of Amendment Nos. 231 and 231 Adoption of TSTF-577, Revised Frequencies for Steam Generator Tube Inspections, Revision 1 ML22293B8052022-11-30030 November 2022 Constellation Energy Generation, Llc_Fleet - Request to Authorize Use Honeywell Mururoa V4F1 R Supplied Air Suits ML22307A2462022-11-10010 November 2022 Proposed Alternative to the Requirements of the American Society of Mechanical Engineers Boiler & Pressure Vessel Code (EPIDs L-2021-LLR-0035 and L-2021-LLR-0036) ML22210A0312022-08-30030 August 2022 Issuance of Amendments Nos. 230, 230, 230, and 230, Respectively, Regarding Adoption of Technical Specifications Task Force Traveler (TSTF) 501, Revision 1, Relocate Stored Fuel Oil and Lube Oil Volume Values to Licensee Control ML22173A1812022-08-11011 August 2022 Issuance of Amendment No. 229 to Remove License Condition ML22173A2142022-08-10010 August 2022 Issuance of Amendments Nos. 228 and 228 Revision of Technical Specifications for the Ultimate Heat Sink ML22095A2702022-05-12012 May 2022 Issuance of Amendment Nos. 227, 227, 229, 229, and 245, Respectively, Regarding Adoption of TSTF 273, Safety Function Determination Program Clarifications ML22090A0862022-04-29029 April 2022 Amendments to Adopt TSTF-541,Rev.2,Add Exceptions to Surveillance Requirements for Valves,Dampers Locked in Actuated Position ML22026A4892022-03-22022 March 2022 Issuance of Amendment Nos. 225, 225, 227, 227, and 148, Respectively, Regarding Issues Identified in Westinghouse Documents (EPID L-2021-LLA-0066) Nonproprietary ML21347A0382022-01-13013 January 2022 Issuance of Amendments to Revise Reactor Coolant Leakage Requirements ML21277A2482021-11-16016 November 2021 Letter with Enclosure 4, Safety Evaluation for Transfer of Licenses and Draft Conforming License Amendments (Public Version) ML21280A0782021-10-27027 October 2021 Proposed Alternative to Use of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code Case N-893 (Epids L-2020-LLR-0147 and L-2020-LLR-0148) ML21230A2062021-09-0303 September 2021 Proposed Alternative to Use ASME OM Code Case OMN-28 ML21076A3712021-08-17017 August 2021 Approval of Certified Fuel Handler Training and Retraining Program ML21216A2202021-08-0505 August 2021 Proposed Alternative to Eliminate Certain Documentation Requirements for Pressure Retaining Bolting ML21134A0062021-08-0303 August 2021 Proposed Alternatives to the Requirements of the American Society of Mechanical Engineers Boiler & Pressure Vessel Code (Epids L-2020-LLR-0099 and L-2020-LLR-0100) ML21154A0462021-07-13013 July 2021 Issuance of Amendments Nos. 222 and 222 Revision of Technical Specifications for the Ultimate Heat Sink ML21166A1682021-06-25025 June 2021 ML21060B2812021-04-0202 April 2021 Issuance of Amendments Nos. 221, 221, 224, and 224 Regarding Technical Specifications 3.8.1, AC Sources-Operating ML21054A0082021-03-10010 March 2021 Issuance of Amendment Nos. 220 and 220 One-Time Deferral of Steam Generator Tube Inspections ML21063A0162021-03-0808 March 2021 Relief from the Requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Alternative to 10 CFR 50.55a(z)(2) ML21039A6362021-02-17017 February 2021 R. E. Ginna - Proposed Alternative to Use the American Society of Mechanical Engineers Boiler and Pressure Vessel Code Case N-885 ML21013A0052021-02-0404 February 2021 Issuance of Amendments to Adopt Technical Specifications Task Traveler TSTF-568, Revise Applicability of BWR/4 TS 3.6.2.5 and TS 3.6.3.2 ML21028A6732021-02-0303 February 2021 Request to Use a Provision of Later Edition of the ASME Boiler and Pressure Vessel Code, Section XI (EPID L-2020-LLR-011 ML20317A0012020-12-28028 December 2020 Non-Proprietary, Issuance of Amendment Nos. 219, 219, 223, and 223, Revise Loss-of-Coolant Accident Methodology in TS 5.6.5, Core Operating Limits Report (COLR) ML20287A1302020-11-0505 November 2020 Review of Quality Assurance Program Changes ML20269A2002020-09-30030 September 2020 Request to Use a Provision of Later Edition of the ASME Boiler and Pressure Vessel Code, Section XI (EPID L2020-LLR-0117 ML20245E4192020-09-24024 September 2020 Issuance of Amendments Nos. 218 and 218 Revision of Technical Specifications for the Ultimate Heat Sink ML20246G8652020-09-21021 September 2020 Issuance of Amendment Nos. 222 and 222 One-Time Extension of Unit No. 2 Steam Generator Inspections (COVID-19) ML20163A0462020-09-18018 September 2020 Issuance of Amendments Nos. 217, 217, 221, and 221, Revise Technical Specification 5.6.6 to Allow Use of Areva Np Topical Report BAW-2308 ML20167A0072020-09-11011 September 2020 R. E. Ginna - Issuance of Amendment Nos. 216, 216, 220, 220, and 143 - Adoption of TSTF-567, Rev. 1, Add Containment Sump Technical Specifications to Address GSI-191 Issues ML20149K6982020-09-10010 September 2020 Issuance of Amendment Nos. 215, 215, 219, and 219 Permanent Extension of Type a and Type C Leak Rate Test Frequencies ML20232A1712020-09-0101 September 2020 Request to Use Alternative Code Case OMN-26 ML20153A8042020-07-31031 July 2020 Co. - Issuance of Amendments Revising Emergency Action RA3 ML20141L6362020-07-10010 July 2020 Issuance of Amendments Based on TSTF-427,Allowance for Nontechnical Specification Barrier Degradation on Supported System Operability,Rev 2 ML20134H9402020-07-0808 July 2020 Issuance of Amendments Revising the High Radiation Area Administrative Controls ML20118C4292020-06-0909 June 2020 Issuance of Amendments Revision of Technical Specifications for the Ultimate Heat Sink ML20133K0932020-05-14014 May 2020 Relief from the Requirements of the ASME Code ML20111A0002020-05-0101 May 2020 Issuance of Amendment No. 209, Revision Technical Specification 5.5.9, Steam Generator (SG) Program, for One-Time Revision to Frequency of SG Tube Inspections (Exigent Circumstances) ML20113F0412020-04-30030 April 2020 Proposed Alternative to the Submittal Schedule for Certain Reports (COVID-19) ML20021A0702020-04-0606 April 2020 Issuance of Amendments to Delete License Conditions for Decommissioning Trusts ML19331A7252020-02-14014 February 2020 Issuance of Amendments Revising Emergency Action Levels 2023-09-19
[Table view] |
Text
January 16, 2007 Mr. Christopher M. Crane President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
BYRON STATION, UNIT NOS. 1 AND 2, AND BRAIDWOOD STATION, UNIT NOS. 1 AND 2 EVALUATION OF INSERVICE INSPECTION PROGRAM RELIEF REQUESTS I3R-07 AND I2R-46 PERTAINING TO ESSENTIAL SERVICE WATER BURIED PIPING (TAC NOS. MD1757, MD1758, MD1759 AND MD1760)
Dear Mr. Crane:
By letter dated April 20, 2006, Exelon Generation Company, LLC (the licensee) submitted a request for relief from the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code)Section XI, ?Rules for Inservice Inspection [ISI] of Nuclear Power Plant Component, 2001 Edition through 2003 Addenda, for Byron Station, Unit Nos. 1 and 2 (Byron) for the third 10-year interval, and the 1989 Edition for Braidwood Station, Unit Nos. 1 and 2 (Braidwood) for the second 10-year interval. The licensee requested relief from the pressure testing requirements for the buried piping portions of the essential service water system.
The Nuclear Regulatory Commission staff concludes that the licensees proposed alternative to test the buried portion of service water piping in conjunction with quarterly testing of service water pumps would detect significant through-wall leakage if present in the subject line and would provide reasonable assurance of structural integrity. Therefore, pursuant to Title 10 of the Code of Federal Regulations (CFR) Section 50.55a(a)(3)(ii) (10 CFR 50.55a(a)(3)(ii)), relief requests I3R-07 for Byron, and I2R-46 for Braidwood, are authorized on the basis that compliance with the ISI code of record would result in hardship or unusual difficulty without a
compensating increase in the level of quality and safety. The relief request is authorized for the third 10-year interval for Byron, and the second 10-year interval for Braidwood.
Sincerely,
/RA/
Michael L. Marshall, Jr., Chief Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. STN 50-454, STN 50-455, STN 50-456 and STN 50-457
Enclosure:
Safety Evaluation cc w/encl: See next page
compensating increase in the level of quality and safety. The relief request is authorized for the third 10-year interval for Byron, and the second 10-year interval for Braidwood.
Sincerely,
/RA/
Michael L. Marshall, Jr., Chief Plant Licensing Branch III-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. STN 50-454, STN 50-455, STN 50-456 and STN 50-457
Enclosure:
Safety Evaluation cc w/encl: See next page DISTRIBUTION:
PUBLIC LPL3-2 R/F RidsOgcRp RidsNrrPMCGratton RidsNrrDorlLpl3-2 RidsAcrsAcnwMailCenter RidsNrrPMRKuntz TBloomer, OGC RidsNrrLAEWhitt RidsRgn3MailCenter RidsNrrDorlDpr Accession Number:ML063260074 *See SE **NLO w/edits NRR-028 OFFICE LPL3-2/PM LPL3-2/PM LPL3-2/LA CFEB/BC* OGC** LPL3-2/BC NAME RKuntz:mw CGratton EWhitt KGruss PMoulding MMarshall DATE 1/11/2007 1/12/2007 1/11/2007 8/29/2006 01/11/2007 1/16/2007 OFFICIAL RECORD COPY
Byron/Braidwood Stations cc:
Dwain W. Alexander, Project Manager Plant Manager - Byron Station Westinghouse Electric Corporation Exelon Generation Company, LLC Energy Systems Business Unit 4450 N. German Church Road Post Office Box 355 Byron, IL 61010-9794 Pittsburgh, PA 15230-0355 Site Vice President - Byron Howard A. Learner Exelon Generation Company, LLC Environmental Law and Policy 4450 N. German Church Road Center of the Midwest Byron, IL 61010-9794 35 East Wacker Dr., Suite 1300 Chicago, IL 60601-2110 U.S. Nuclear Regulatory Commission Braidwood Resident Inspectors Office U.S. Nuclear Regulatory Commission 35100 S. Rt. 53, Suite 79 Byron Resident Inspectors Office Braceville, IL 60407 4448 N. German Church Road Byron, IL 61010-9750 County Executive Will County Office Building Regional Administrator, Region III 302 N. Chicago Street U.S. Nuclear Regulatory Commission Joliet, IL 60432 Suite 210 2443 Warrenville Road Plant Manager - Braidwood Station Lisle, IL 60532-4351 Exelon Generation Company, LLC 35100 S. Rt. 53, Suite 84 Ms. Lorraine Creek Braceville, IL 60407-9619 RR 1, Box 182 Manteno, IL 60950 Ms. Bridget Little Rorem Appleseed Coordinator Chairman, Ogle County Board 117 N. Linden Street Post Office Box 357 Essex, IL 60935 Oregon, IL 61061 Document Control Desk - Licensing Mrs. Phillip B. Johnson Exelon Generation Company, LLC 1907 Stratford Lane 4300 Winfield Road Rockford, IL 61107 Warrenville, IL 60555 Attorney General Site Vice President - Braidwood 500 S. Second Street Exelon Generation Company, LLC Springfield, IL 62701 35100 S. Rt. 53, Suite 84 Braceville, IL 60407-9619 Illinois Emergency Management Agency Senior Vice President - Operations Support Division of Disaster Assistance & Exelon Generation Company, LLC Preparedness 4300 Winfield Road 110 East Adams Street Warrenville, IL 60555 Springfield, IL 62701-1109
Byron/Braidwood Stations Director - Licensing and Regulatory Senior Vice President - Midwest Operations Affairs Exelon Generation Company, LLC Exelon Generation Company, LLC 4300 Winfield Road 4300 Winfield Road Warrenville, IL 60555 Warrenville, IL 60555 Manager Regulatory Assurance - Braidwood Exelon Generation Company, LLC 35100 S. Rt. 53, Suite 84 Braceville, IL 60407-9619 Manager Regulatory Assurance - Byron Exelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794 Assistant General Counsel Exelon Generation Company, LLC 200 Exelon Way Kennett Square, PA 19348 Vice President - Regulatory & Legal Affairs Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Manager Licensing - Braidwood/Byron Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED RELIEF TO REQUEST I3R-07 AND I2R-46 PERTAINING TO ESSENTIAL SERVICE WATER EXELON GENERATION COMPANY, LLC BYRON STATION, UNIT NOS. 1 AND 2 BRAIDWOOD STATION, UNIT NOS. 1 AND 2 DOCKET NOS. STN 50-454, STN 50-455, STN 50-456, AND STN 50-457
1.0 INTRODUCTION
By letter dated April 20, 2006, Exelon Generation Company, LLC (Exelon, the licensee),
submitted relief request I3R-07 and I2R-46, related to the inservice inspection (ISI) program pertaining to system leakage tests during the third 10-year interval for the Byron Station, Unit Nos. 1 and 2 (Byron) and the second 10-year interval for the Braidwood Station, Unit Nos. 1 and 2 (Braidwood), respectively. In relief requests I3R-07 and I2R-46, the licensee requested relief from performing the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code) required pressure test of the buried portion of the essential service water (ESW) piping by measuring the rate of pressure loss or change in flow between the ends of the buried components. As an alternative, the licensee proposed a test that would confirm that flow during operation is not impaired. The integrity of the buried piping will be verified during quarterly pump testing under the inservice testing program for pumps and valves.
2.0 REGULATORY EVALUATION
Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(g) requires that ISI of ASME Code Class 1, 2, and 3 components be performed in accordance with Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, of the ASME Code and applicable addenda, except where specific written relief has been granted by the Nuclear Regulatory Commission (NRC, the Commission) pursuant to 10 CFR 50.55a(g)(6)(i). According to 10 CFR 50.55a(a)(3), alternatives to the requirements of paragraph 50.55a(g) may be used, when authorized by the NRC, if an applicant demonstrates that: (i) the proposed alternatives would provide an acceptable level of quality and safety or (ii) the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1, 2, and 3 components (including supports) shall meet the requirements, except the design and access provisions and the preservice examination requirements, set forth in the ASME Code,Section XI to the extent practical within the limitations of design, geometry, and materials of construction of the components.
10 CFR 50.55a(a)(g)(4) requires that ISI of components and system pressure tests conducted during the first 10-year interval and subsequent intervals comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a(b) 12 months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The ASME Code of record for the third 10-year interval at Byron is the 2001 Edition through the 2003 Addenda. The ASME Code of record for the second 10-year inspection interval at Braidwood is the 1989 Edition.
3.0 TECHNICAL EVALUATION
3.1 System/Component(s) for Which Relief is Requested Buried Class 3 components in the ESW supply and return lines.
3.2 ASME Code Requirements The 2001 Edition through the 2003 Addenda of ASME Code, the code of record for Byron,Section XI, Table IWD-2500-1, Examination Category D-B, Item No. D2.10 requires a system leakage test and a VT-2 visual examination. For buried components where a VT-2 visual examination cannot be performed, the examination requirement of item D2.10 is satisfied by the following:
The system pressure test for buried components that are isolable by means of valves shall consist of a test that determines the rate of pressure loss. Alternatively, the test may determine the change in flow between the ends of the buried components.
The acceptable rate of pressure loss or flow shall be established by the Owner.
The 1989 Edition of ASME Code, the code of record for Braidwood,Section XI, Table IWD-2500-1, Examination Category D-B, Item No. D2.10 requires a system pressure test and a VT-2 visual examination. Subsection IWA-5244(a) requires that nonredundant/isolable buried components that are isolable by means of valves be tested to determine the rate of pressure loss. Alternatively, the test may determine the change in flow between the ends of the buried components. However, the 1989 edition of the ASME Code has no provision for the pressure testing of redundant/isolable buried components such as those used at Braidwood. Therefore, the test requirement of Subsection IWA-5244(a) was applied.
3.3 Licensees Request for Relief Relief is requested from performing the system pressure test or the system leakage test for buried portions of the ESW piping that are isolable by means of valves. The proposed alternative would determine the rate of pressure loss or the change in flow between the ends of buried components.
3.3.1 Licensees Basis for Requesting Relief The ESW buried piping at Braidwood consists of six 30 inch (") diameter common supply headers that feed into two 48" diameter supply headers, including the suction piping that runs between the lake screen house and the turbine building. The buried return lines are two 48"
diameter return headers and piping that runs between the turbine building and the ESW cooling pond. At Byron, the ESW buried piping consists of two 48" common supply headers and two 48" return headers located between the ESW cooling towers and the auxiliary building. The remaining buried piping consists of two 36" pump supply lines in each unit and four 24" risers and two 24" hot water bypass lines that branch out from each 48" return header. There is no access to the buried sections of piping without excavation. Further, no annuluses were provided during original construction, which would allow for examination of these buried sections of piping.
The supply and return lines use butterfly valves for isolation. These valves are not suitable for performing a pressure isolation function since they were not designed to be leak tight.
Extensive maintenance or system modification would be necessary to conduct a rate-of-pressure-loss test. The alternative test would be to determine the change in flow between the ends of buried components. However, the buried ESW supply and return headers were not designed with plant instrumentation and flow orifices on both sides of the buried sections of piping to determine the rates. Further, sufficient length of accessible straight pipe is not available to use an ultrasonic flow measuring device. Therefore, the configuration of the buried ESW system does not permit a determination of the change in flow between the ends of the buried components.
3.3.2 Licensees Proposed Alternative In lieu of performing a system pressure test in accordance with the requirements of the IWA-5244(b)(1) for Byron, and of the IWA-5244(a) for Braidwood, Exelon proposed as an alternative to use the provisions of IWA-5244(c) and IWA-5244(b)(2) of the 1989 Edition and the 2001 Edition through the 2003 Addenda of the ASME Section XI Code, respectively, to confirm that flow during operation is not impaired in non-isolable buried piping. The unimpaired flow in the buried piping will be verified during quarterly ESW pump testing. Byron and Braidwood will use the Owner-established minimum flow rate specified in the site inservice testing (IST) surveillance, 23,520 and 24,000 gallons per minute, respectively, for all ESW pumps as the acceptance criteria for IWA-5244 pressure testing of ESW buried piping. If, during an IST surveillance, the minimum flow could not be achieved and the cause of the deviation is not attributed to the test instruments being used, the pump would be declared inoperable and an issue report would be generated in accordance with the Exelon corrective action program as required by the existing IST surveillance. Further corrective actions (e.g.,
maintenance on the pump and system walk-downs) would be initiated as necessary to restore the pump and/or the system to an operable status. In addition, Exelon would monitor pressure drop across each pump at the reference flow rate to assess any leakage through the buried piping, assuming no degradation of the pump.
3.4 NRC Staff Evaluation The ASME Code of record requires a system pressure test for the buried portion of ESW piping to determine either a rate of pressure loss or a change in flow at the ends of the buried piping.
The buried service water piping at Byron and Braidwood uses butterfly valves at the ends that were not designed for pressure isolation, and therefore, are unsuitable for determining a meaningful rate of pressure loss. Similarly, change in flow cannot be determined both because of the limitations of the current system configuration and because one end of the buried piping
is not instrumented for flow measurement. Consequently, the ASME Code-required tests cannot be performed without significant system modification, including excavation. For nonisolable buried components ASME Code compliance can be accomplished by confirming that flow during operation is not impaired. The NRC staff finds the licensees approach, by which unimpaired flow in the buried piping can be qualitatively assessed during quarterly IST surveillance of the ESW pumps, to be acceptable. By using the flow instrument downstream from the pump discharge, a reference flow rate can be established that would correspond to a target pump head. A decrease in pump head may indicate increase in flow due to any through-wall leakage in the buried piping. An assessment can be made of the integrity of the buried piping, from the trending of head loss (pressure drop) during a pump test at the reference flow. However, pump head loss may also be caused by the deterioration of the pump rather than the leakage in the buried pipe. As the pump deteriorates, the developed head decreases at the reference flow. Therefore, the licensee has stated that if during an IST surveillance, the minimum flow could not be achieved and the cause of the deviation could not be attributed to the test instruments being used, the pump would be declared inoperable and an Issue Report would be generated in accordance with the Exelon corrective action program as required by the existing IST surveillance. Further corrective actions (e.g., maintenance on the pump and system walk-downs) would be initiated as necessary to restore the pump and/or the system to an operable status.
Based on its independent review, the NRC staff has determined that the licensees proposed alternative to test the buried portion of service water piping in conjunction with quarterly testing of service water pumps would detect significant through-wall leakage if present in the subject line and would provide reasonable assurance of structural integrity. In light of this proposed alternative, and because performance of the ASME Code-required tests would require installation of an additional flow measuring device at the inlet end of the buried piping, compliance with the ASME Code requirement would result in hardship without a compensating increase in the level of quality and safety.
4.0 CONCLUSION
The NRC staff concludes that for the buried portion of service water piping, compliance with the ASME Code requirement to perform a test that determines the rate of pressure loss or the change in flow would result in hardship to the licensee without a compensating increase in the level of quality and safety. By providing for detection of any degradation in the buried portion of service water piping, the licensees proposed alternative provides reasonable assurance of structural integrity. Therefore, pursuant to 10 CFR 50.55a(a)(3)(ii), the licensees proposed alternative in relief requests I3R-07 and I2R-46 is authorized for the third 10-year ISI interval for Byron and the second 10-year ISI interval for Braidwood. All other requirements of the ASME Code,Section XI for which relief has not been specifically requested remain applicable, including a third party review by the Authorized Nuclear Inservice Inspector.
Principal Contributor: P. Patnaik Date: January 16, 2007