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| | number = ML060240085 | | | number = ML060240085 |
| | issue date = 02/08/2006 | | | issue date = 02/08/2006 |
| | title = Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 - Relief Request for Underwater Welding of Heated Junction Thermocouple Holders, Calvert Cliffs Nuclear Power Plant, Units 1 and 2 (TAC Nos. MC8572 and MC8573) | | | title = Relief Request for Underwater Welding of Heated Junction Thermocouple Holders, Calvert Cliffs Nuclear Power Plant, Units 1 and 2 (TAC Nos. MC8572 and MC8573) |
| | author name = Laufer R J | | | author name = Laufer R |
| | author affiliation = NRC/NRR/ADRO/DORL | | | author affiliation = NRC/NRR/ADRO/DORL |
| | addressee name = Spina J A | | | addressee name = Spina J |
| | addressee affiliation = Calvert Cliffs Nuclear Power Plant, Inc | | | addressee affiliation = Calvert Cliffs Nuclear Power Plant, Inc |
| | docket = 05000317, 05000318 | | | docket = 05000317, 05000318 |
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| | page count = 9 | | | page count = 9 |
| | project = TAC:MC8572, TAC:MC8573 | | | project = TAC:MC8572, TAC:MC8573 |
| | stage = Approval | | | stage = Other |
| }} | | }} |
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| =Text= | | =Text= |
| {{#Wiki_filter:February 8, 2006Mr. James A. Spina, Vice PresidentCalvert Cliffs Nuclear Power Plant, Inc. | | {{#Wiki_filter:February 8, 2006 Mr. James A. Spina, Vice President Calvert Cliffs Nuclear Power Plant, Inc. |
| Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs ParkwayLusby, MD 20657-4702 | | Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657-4702 |
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| ==SUBJECT:== | | ==SUBJECT:== |
| CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NOS. 1 AND 2 - RELIEFREQUEST FOR UNDERWATER WELDING OF HEATED JUNCTION THERMOCOUPLE PROBE HOLDERS (TAC NOS. MC8572 AND MC8573) | | CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NOS. 1 AND 2 - RELIEF REQUEST FOR UNDERWATER WELDING OF HEATED JUNCTION THERMOCOUPLE PROBE HOLDERS (TAC NOS. MC8572 AND MC8573) |
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| ==Dear Mr. Spina:== | | ==Dear Mr. Spina:== |
| By letter dated September 30, 2005 (Agencywide Documents Access and Management System(ADAMS) Accession No. ML052770094), Calvert Cliffs Nuclear Power Plant, Inc. (the licensee)submitted a relief request for authorization to use American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section XI, Code Case N-516-2, "Underwater Welding, Section XI, Division 1," to relocate two (per Unit) heated junction thermocouple (HJTC) probe holder assemblies to the existing upper guide structure (UGS) at the Calvert Cliffs NuclearPower Plant, Unit Nos. 1 and 2. As stated in the conditions on use of Code Case N-516-2 in Regulatory Guide 1.147, Revision 13, licensees must obtain Nuclear Regulatory Commission(NRC) approval in accordance with Section 50.55a(a)(3) of Part 50 of Title 10 of the Code ofFederal Regulations (10 CFR) regarding the method to be used in the weld repair orreplacement of irradiated material underwater.The NRC staff has reviewed and evaluated the information regarding the relief request. The results are provided in the enclosed safety evaluation.The NRC staff concludes that the use of the proposed ASME Code Case N-516-2 to relocatethe HJTC probe holder assemblies to the UGSs will provide an acceptable level of quality andsafety. Pursuant to 10 CFR 50.55a(a)(3)(i), the NRC staff authorizes the use of the proposed J. Spina- 2 -code case for the subject welds. All other ASME Code, Section XI requirements for which reliefwas not specifically requested and approved in this request remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.Sincerely,/RA/Richard J. Laufer, ChiefPlant Licensing Branch I-1 Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket Nos. 50-317 and 50-318 | | |
| | By letter dated September 30, 2005 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML052770094), Calvert Cliffs Nuclear Power Plant, Inc. (the licensee) submitted a relief request for authorization to use American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section XI, Code Case N-516-2, Underwater Welding, Section XI, Division 1, to relocate two (per Unit) heated junction thermocouple (HJTC) probe holder assemblies to the existing upper guide structure (UGS) at the Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2. As stated in the conditions on use of Code Case N-516-2 in Regulatory Guide 1.147, Revision 13, licensees must obtain Nuclear Regulatory Commission (NRC) approval in accordance with Section 50.55a(a)(3) of Part 50 of Title 10 of the Code of Federal Regulations (10 CFR) regarding the method to be used in the weld repair or replacement of irradiated material underwater. |
| | The NRC staff has reviewed and evaluated the information regarding the relief request. |
| | The results are provided in the enclosed safety evaluation. |
| | The NRC staff concludes that the use of the proposed ASME Code Case N-516-2 to relocate the HJTC probe holder assemblies to the UGSs will provide an acceptable level of quality and safety. Pursuant to 10 CFR 50.55a(a)(3)(i), the NRC staff authorizes the use of the proposed |
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| | J. Spina code case for the subject welds. All other ASME Code, Section XI requirements for which relief was not specifically requested and approved in this request remain applicable, including third party review by the Authorized Nuclear Inservice Inspector. |
| | Sincerely, |
| | /RA/ |
| | Richard J. Laufer, Chief Plant Licensing Branch I-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-317 and 50-318 |
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| ==Enclosure:== | | ==Enclosure:== |
| As statedcc w/encl: See next page
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| ML060240085OFFICELPLI-1/PMLPLI-1/LACFEB/BCOGCLPLI-1/BCNAMEPMilanoSLittleKGrussRLaufer DATE01/26/0602/02/0601/20/0602/06/0602/08/06 Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 cc:
| | As stated cc w/encl: See next page |
| PresidentCalvert County Board of Commissioners 175 Main Street Prince Frederick, MD 20678Mr. Carey Fleming, EsquireSr. Counsel - Nuclear Generation Constellation Generation Group, LLC 750 East Pratt Street, 17 th floorBaltimore, MD 21202Mr. Louis LarragoiteCalvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs ParkwayLusby, MD 20657-4702Resident InspectorU.S. Nuclear Regulatory Commission
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| P.O. Box 287 St. Leonard, MD 20685Mr. R. I. McLean, ManagerNuclear Programs Power Plant Research Program Maryland Department of Natural Resources 580 Taylor Avenue (B wing, 3rd floor) | | ML060240085 OFFICE LPLI-1/PM LPLI-1/LA CFEB/BC OGC LPLI-1/BC NAME PMilano SLittle KGruss RLaufer DATE 01/26/06 02/02/06 01/20/06 02/06/06 02/08/06 Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 cc: |
| Tawes State Office Building Annapolis, MD 21401Regional Administrator, Region IU.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406Ms. Kristen A. Burger, EsquireMaryland People's Counsel 6 St. Paul Centre Suite 2102 Baltimore, MD 21202-1631Ms. Patricia T. Birnie, EsquireCo-Director Maryland Safe Energy Coalition P.O. Box 33111 Baltimore, MD 21218Mr. Loren F. DonatellNRC Technical Training Center 5700 Brainerd Road Chattanooga, TN 37411-4017 Enclosure SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REGARDING UNDERWATER WELDING OF HEATED JUNCTIONTHERMOCOUPLE PROBE HOLDER WELDSCALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NOS. 1 AND 2CALVERT CLIFFS NUCLEAR POWER PLANT, INC.DOCKET NOS. 50-317 AND 50-31 | | President Ms. Patricia T. Birnie, Esquire Calvert County Board of Co-Director Commissioners Maryland Safe Energy Coalition 175 Main Street P.O. Box 33111 Prince Frederick, MD 20678 Baltimore, MD 21218 Mr. Carey Fleming, Esquire Mr. Loren F. Donatell Sr. Counsel - Nuclear Generation NRC Technical Training Center Constellation Generation Group, LLC 5700 Brainerd Road 750 East Pratt Street, 17th floor Chattanooga, TN 37411-4017 Baltimore, MD 21202 Mr. Louis Larragoite Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657-4702 Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 287 St. Leonard, MD 20685 Mr. R. I. McLean, Manager Nuclear Programs Power Plant Research Program Maryland Department of Natural Resources 580 Taylor Avenue (B wing, 3rd floor) |
| | Tawes State Office Building Annapolis, MD 21401 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Ms. Kristen A. Burger, Esquire Maryland People's Counsel 6 St. Paul Centre Suite 2102 Baltimore, MD 21202-1631 |
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| ==81.0 INTRODUCTION==
| | SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REGARDING UNDERWATER WELDING OF HEATED JUNCTION THERMOCOUPLE PROBE HOLDER WELDS CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NOS. 1 AND 2 CALVERT CLIFFS NUCLEAR POWER PLANT, INC. |
| By letter dated September 30, 2005, Calvert Cliffs Nuclear Power Plant, Inc. (the licensee)submitted a relief request pertaining to the approval, pursuant to the provisions of Section 50.55a(a)(3)(i) of Part 50 of Title10 of the Code of Federal Regulations (10 CFR), to useAmerican Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),
| | DOCKET NOS. 50-317 AND 50-318 |
| Section XI, Code Case N-516-2, "Underwater Welding," to relocate two (per Unit) heated junction thermocouple (HJTC) probe holder assemblies to the existing upper guide structure (UGS) at the Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 (CCNPP). ASME CodeCase N-516-2 has been conditionally accepted by the Nuclear Regulatory Commission (NRC)in Regulatory Guide (RG) 1.147, Revision 13. As stated in RG 1.147, the NRC placed acondition that licensees must obtain NRC approval in accordance with 10 CFR 50.55a(a)(3)regarding the technique to be used in the weld repair or replacement of irradiated material underwater. The components listed above have been irradiated as a result of their location in the reactor vessel and meet the definition of an irradiated component. Therefore, the licenseemust obtain the approval to use the above code case, and the September 30, 2005, letterincludes this request.
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| ==2.0REGULATORY EVALUATION== | | ==1.0 INTRODUCTION== |
| Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1, 2, and 3 components (includingsupports) must meet the requirements set forth in the ASME Code, Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components," to the extent practical within the limitations of design, geometry, and materials of construction of the components. Paragraph IWA-4221(b) of ASME Code, Section XI requires that an item for repair/replacement activities shall meet the original Construction Code. Paragraph IWA-4221(c) of ASME Code, Section XI allows licensees to use, as an alternative, later editions and addenda of the Construction Code or of ASME Code, Section III, either in their entirety or portions thereof, and code cases. The current CCNPP Code of Record, ASME Code, Section XI, 1998 Edition, no Addenda, doesnot allow underwater welding of irradiated components. Therefore, the licensee is requesting permission to use ASME Code Case N-516-2. As required by RG 1.147, Revision 13, the licensee is requesting NRC approval of the technique (i.e., shielded metal arc welding process)to be used in the weld repair or replacement of irradiated material underwater.
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| ==3.0TECHNICAL EVALUATION==
| | By letter dated September 30, 2005, Calvert Cliffs Nuclear Power Plant, Inc. (the licensee) submitted a relief request pertaining to the approval, pursuant to the provisions of Section 50.55a(a)(3)(i) of Part 50 of Title10 of the Code of Federal Regulations (10 CFR), to use American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code), |
| | Section XI, Code Case N-516-2, "Underwater Welding," to relocate two (per Unit) heated junction thermocouple (HJTC) probe holder assemblies to the existing upper guide structure (UGS) at the Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 (CCNPP). ASME Code Case N-516-2 has been conditionally accepted by the Nuclear Regulatory Commission (NRC) in Regulatory Guide (RG) 1.147, Revision 13. As stated in RG 1.147, the NRC placed a condition that licensees must obtain NRC approval in accordance with 10 CFR 50.55a(a)(3) regarding the technique to be used in the weld repair or replacement of irradiated material underwater. The components listed above have been irradiated as a result of their location in the reactor vessel and meet the definition of an irradiated component. Therefore, the licensee must obtain the approval to use the above code case, and the September 30, 2005, letter includes this request. |
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| ===3.1 Components=== | | ==2.0 REGULATORY EVALUATION== |
| for which Relief is Requested | | |
| : Relief is requested, as required in RG 1.147, Revision 13, to allow the use of Code Case N-516-2 for underwater welding on the CCNPP Unit Nos. 1 and 2 UGSs at locations where theHJTC probe holder will be installed. These components have been irradiated as a result oftheir location in the reactor vessel and can be considered to be an irradiated component. The CCNPP UGSs were formed from austenitic stainless steel. The HJTC probe holder brackets are ASME Code, Section II, Material Classification SA-479 Type 304 austenitic stainless steel.
| | Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1, 2, and 3 components (including supports) must meet the requirements set forth in the ASME Code, Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, to the extent practical within the limitations of design, geometry, and materials of construction of the components. Paragraph IWA-4221(b) of ASME Code, Section XI requires that an item for repair/replacement activities shall meet the original Construction Code. Paragraph IWA-4221(c) of ASME Code, Section XI allows licensees to use, as an alternative, later editions and addenda of the Construction Code or of ASME Code, Section III, either in their entirety or portions thereof, and code cases. |
| | Enclosure |
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| | The current CCNPP Code of Record, ASME Code, Section XI, 1998 Edition, no Addenda, does not allow underwater welding of irradiated components. Therefore, the licensee is requesting permission to use ASME Code Case N-516-2. As required by RG 1.147, Revision 13, the licensee is requesting NRC approval of the technique (i.e., shielded metal arc welding process) to be used in the weld repair or replacement of irradiated material underwater. |
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| | ==3.0 TECHNICAL EVALUATION== |
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| | 3.1 Components for which Relief is Requested: |
| | Relief is requested, as required in RG 1.147, Revision 13, to allow the use of Code Case N-516-2 for underwater welding on the CCNPP Unit Nos. 1 and 2 UGSs at locations where the HJTC probe holder will be installed. These components have been irradiated as a result of their location in the reactor vessel and can be considered to be an irradiated component. The CCNPP UGSs were formed from austenitic stainless steel. The HJTC probe holder brackets are ASME Code, Section II, Material Classification SA-479 Type 304 austenitic stainless steel. |
| The funnels are SA-479 austenitic stainless steel or SA-240 Type 304 austenitic stainless steel. | | The funnels are SA-479 austenitic stainless steel or SA-240 Type 304 austenitic stainless steel. |
| The filler metal is austenitic stainless steel meeting the requirements of ASME, Section IIC,"Specification for Stainless Steel Electrodes for Shielded Metal Arc Welding," SFA 5.4. The production filler metal will meet all the applicable filler metal certification requirements ofparagraph 4.0 of Code Case N-516-2, with the results of the chemical, ferrite, and tensile tests provided to the NRC, if desired. The minimum ferrite number for the production filler metal isFN 5.Code Requirements for which Relief is Requested | | The filler metal is austenitic stainless steel meeting the requirements of ASME, Section IIC, Specification for Stainless Steel Electrodes for Shielded Metal Arc Welding, SFA 5.4. The production filler metal will meet all the applicable filler metal certification requirements of paragraph 4.0 of Code Case N-516-2, with the results of the chemical, ferrite, and tensile tests provided to the NRC, if desired. The minimum ferrite number for the production filler metal is FN 5. |
| :The current Code of Record, ASME Code, Section XI, 1998 Edition, no Addenda, does notallow underwater welding of irradiated components. Therefore, permission must be requested to use Code Case N-516-2. As required by RG 1.147, Revision 13, the licencee is requesting
| | Code Requirements for which Relief is Requested: |
| | The current Code of Record, ASME Code, Section XI, 1998 Edition, no Addenda, does not allow underwater welding of irradiated components. Therefore, permission must be requested to use Code Case N-516-2. As required by RG 1.147, Revision 13, the licencee is requesting NRC approval of the technique (i.e., shielded metal arc welding process) to be used in the weld repair or replacement of irradiated material underwater. |
| | Proposed Alternative: |
| | The NRC documented its conditional acceptance of Code Case N-516-2 in RG 1.147, Revision 13, dated January 2004. The specific condition noted in RG 1.147, Revision 13, requires licensees to obtain NRC approval in accordance with 10 CFR 50.55a(a)(3) regarding the technique to be used in the weld repair or replacement of irradiated material underwater. |
| | The licensee requested NRC approval of ASME Code, Section XI, Code Case N-516-2 for use at CCNPP on the basis that it provides an acceptable level of quality and safety. |
| | The licensee requested approval for the use of Code Case N-516-2 in order to relocate two (per Unit) HJTC probe holder assemblies to the UGSs. The specific application request is for wet underwater welding. |
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| | Licensees Basis for Relief: |
| | The proposed welds will be performed using a weld procedure specification qualified in accordance with Code Case N-516-2 and the welds will be visually examined. The licensees weld procedure specification has been qualified with tensile and bend tests in accordance with ASME Code, Section IX, and the additional requirements of Code Case N-516-2. The filler material will be qualified using chemical, ferrite, and tensile tests performed in accordance with Code Case N-516-2. To support the new probe holder, intermittent fillet welds will be made underwater with the shielded metal arc welding (SMAW) process joining new funnels and support brackets for the probe holders (two per Unit) to the existing UGSs. Mockup testing for welders will be used. The mockup testing will be performed using similar materials and conditions as the production welds. These welds will be subjected to the same inspection requirements as the production welds. The subject fillet welds will only be used to relocate the HJTC probe holders to the UGSs. They will not become structural welds performing a core support structure function, nor will they become pressure boundary welds. The mockup tests and inspections on the welds are licensee requirements that will ensure the performance of the welds is conservative with respect to their safety function. If required, the control element assembly shrouds and UGS plate will be prepared for welding by removal of the non-tightly adherent oxide layer. |
| | Welding will be performed after 23 effective full-power years of operation, corresponding to a calculated thermal neutron fluence of less than 5 x 1016 neutrons per square centimeter (5E16 n/cm2) at 42 inches above the fuel alignment plate (FAP). The water depth of the lowest weld, which is located at 42 inches above the FAP, will be approximately 25 feet. The qualification depth rules of Code Case N-516-2 will be met. The mockup tests and inspections on the welds, combined with the alternative requirements of Code Case N-516-2, provide an acceptable level of quality and safety for underwater welding. Non-destructive examination will be performed by visual examination only, per Code Case N-516-2, by a certified examiner. |
| | Ongoing examinations of the welds will fall under the normal In-service Inspection intervals, per ASME Code, Section XI. |
| | This relief request will be implemented during the next refueling outages for each unit and will remain in place for the life of the plant. |
| | 3.3 Staff Evaluation ASME Code Case N-516-2 has been conditionally accepted by the NRC in RG 1.147, Revision 13. As stated in RG 1.147, the NRC staff placed a condition that [l]icensees must obtain NRC approval in accordance with 10 CFR 50.55a(a)(3) regarding the technique to be used in the weld repair or replacement of irradiated material underwater. The components listed above have been irradiated to a calculated thermal neutron fluence of less than 5E16 n/cm2, as a result of their location in the reactor vessel and can be considered to be an irradiated component. Therefore, the licensee must obtain NRC approval to use the above code case. |
| | Welded repairs in stainless steel components that are located in high thermal neutron fluence regions in the reactor pressure vessel have been complicated by cracking and the resultant decrease in mechanical properties in the welded joint. This material degradation is caused by transmutation of various elements contained in the materials to be welded, such as boron and |
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| | nickel, and the formation of helium. Helium tends to have a low solubility in metals and forms small clusters with diameters on the order of a few tenths of a nanometer. These clusters form at preferred nucleation sites which are lattice inhomogeneities such as radiation-induced defects, precipitate interfaces, dislocations and most importantly, grain boundaries. At elevated temperatures, these clusters and bubbles can grow very rapidly and under applied stress can severely weaken grain boundaries. Because conventional, deep penetration, fusion welding processes produce high stress (above yield strength) as well as high temperatures (above the melting point), entrapped helium can severely affect the weldability and postweld properties of irradiated materials. The severity of the observed effects is dominated by the helium content and the extent and magnitude of the temperature and stress fields that prevail near the fusion line during welding. However, welded repairs of components can be performed using various welding techniques which minimize the extent and magnitude of the temperature and stress fields. These techniques for welding stainless steel components located in high thermal neutron fluence regions are available from various sources; however, the techniques are held as proprietary. |
| | Although industrys research on the phenomenon of the cracking of weld repairs in highly irradiated material due to helium formation is ongoing and much of the data is proprietary, there are certain threshold values below which this phenomenon does not occur. The licensees calculated maximum thermal neutron fluence of 5E16 n/cm2 for these components is well below these values. Therefore, it is unlikely that cracking and the resultant decrease in mechanical properties will occur in the welded joint of the HJTC probe holder assembly to the UGSs. As an added safety margin, the weld procedure specification has been qualified with tensile and bend tests in accordance with ASME Code, Section IX, and the additional requirements of ASME Code Case N-516-2. The filler material will be qualified with chemical, ferrite, and tensile tests performed in accordance with Code Case N-516-2. Also, mockup testing for welders will be used. The mockup testing will be performed using similar materials and conditions as the production welds. The proposed welds will be subjected to the same inspection requirements as the production welds. The welds described above assist in the relocation of the HJTC probe holder assemblies and provide support to the HJTC probe holder assemblies, which will be positioned against the existing UGSs. The proposed welds will only be used to join a guide for inserting the HJTC probes into the probe holder to the UGSs. The welds do not perform an ASME core support structure function and are not ASME pressure boundary welds. |
| | Non-destructive examination will be performed by visual examination, per Code Case N-516-2, by a certified examiner. |
| | The requirements imposed on the welds are conservative with respect to the safety function of the welds. The qualification depth rules of Code Case N-516-2 for performing the test welds underwater will be met. The conditions stated above relative to the thermal neutron fluence, combined with the licensees proposed testing and examination requirements of the ASME Code, Section IX, and Code Case N-516-2, provide an acceptable level of quality and safety for underwater welding of the subject components. |
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| | ==4.0 CONCLUSION== |
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| NRC approval of the technique (i.e., shielded metal arc welding process) to be used in the weldrepair or replacement of irradiated material underwater.Proposed Alternative:The NRC documented its conditional acceptance of Code Case N-516-2 in RG 1.147,Revision 13, dated January 2004. The specific condition noted in RG 1.147, Revision 13, requires licensees to obtain NRC approval in accordance with 10 CFR 50.55a(a)(3) regardingthe technique to be used in the weld repair or replacement of irradiated material underwater. | | The NRC staff has reviewed the licensees relief request and determined that the use of the proposed ASME Code Case N-516-2 to relocate two (per Unit) HJTC probe holder assemblies to the UGSs will provide an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the NRC staff authorizes the use of the proposed code case for the |
| The licensee requested NRC approval of ASME Code, Section XI, Code Case N-516-2 for useat CCNPP on the basis that it provides an acceptable level of quality and safety.The licensee requested approval for the use of Code Case N-516-2 in order to relocate two (perUnit) HJTC probe holder assemblies to the UGSs. The specific application request is for wet underwater welding. Licensee's Basis for Relief
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| : The proposed welds will be performed using a weld procedure specification qualified inaccordance with Code Case N-516-2 and the welds will be visually examined. The licensee'sweld procedure specification has been qualified with tensile and bend tests in accordance with ASME Code, Section IX, and the additional requirements of Code Case N-516-2. The fillermaterial will be qualified using chemical, ferrite, and tensile tests performed in accordance withCode Case N-516-2. To support the new probe holder, intermittent fillet welds will be madeunderwater with the shielded metal arc welding (SMAW) process joining new funnels and support brackets for the probe holders (two per Unit) to the existing UGSs. Mockup testing for welders will be used. The mockup testing will be performed using similar materials and conditions as the production welds. These welds will be subjected to the same inspectionrequirements as the production welds. The subject fillet welds will only be used to relocate theHJTC probe holders to the UGSs. They will not become structural welds performing a coresupport structure function, nor will they become pressure boundary welds. The mockup testsand inspections on the welds are licensee requirements that will ensure the performance of thewelds is conservative with respect to their safety function. If required, the control element assembly shrouds and UGS plate will be prepared for welding by removal of the non-tightlyadherent oxide layer.Welding will be performed after 23 effective full-power years of operation, corresponding to acalculated thermal neutron fluence of less than 5 x 10 16 neutrons per square centimeter(5E16 n/cm
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| : 2) at 42 inches above the fuel alignment plate (FAP). The water depth of the lowestweld, which is located at 42 inches above the FAP, will be approximately 25 feet. Thequalification depth rules of Code Case N-516-2 will be met. The mockup tests and inspectionson the welds, combined with the alternative requirements of Code Case N-516-2, provide an acceptable level of quality and safety for underwater welding. Non-destructive examination willbe performed by visual examination only, per Code Case N-516-2, by a certified examiner.
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| Ongoing examinations of the welds will fall under the normal In-service Inspection intervals, perASME Code, Section XI.This relief request will be implemented during the next refueling outages for each unit and willremain in place for the life of the plant.3.3Staff EvaluationASME Code Case N-516-2 has been conditionally accepted by the NRC in RG 1.
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| 147,Revision 13. As stated in RG 1.147, the NRC staff placed a condition that "[l]icensees mustobtain NRC approval in accordance with 10 CFR 50.55a(a)(3) regarding the technique to beused in the weld repair or replacement of irradiated material underwater." The components listed above have been irradiated to a calculated thermal neutron fluence of less than5E16 n/cm 2, as a result of their location in the reactor vessel and can be considered to be anirradiated component. Therefore, the licensee must obtain NRC approval to use the abovecode case. Welded repairs in stainless steel components that are located in high thermal neutron fluenceregions in the reactor pressure vessel have been complicated by cracking and the resultant decrease in mechanical properties in the welded joint. This material degradation is caused by transmutation of various elements contained in the materials to be welded, such as boron and nickel, and the formation of helium. Helium tends to have a low solubility in metals and formssmall clusters with diameters on the order of a few tenths of a nanometer. These clusters form at preferred nucleation sites which are lattice inhomogeneities such as radiation-induced defects, precipitate interfaces, dislocations and most importantly, grain boundaries. At elevated temperatures, these clusters and bubbles can grow very rapidly and under applied stress can severely weaken grain boundaries. Because conventional, deep penetration, fusion welding processes produce high stress (above yield strength) as well as high temperatures (above the melting point), entrapped helium can severely affect the weldability and postweld properties ofirradiated materials. The severity of the observed effects is dominated by the helium content and the extent and magnitude of the temperature and stress fields that prevail near the fusionline during welding. However, welded repairs of components can be performed using various welding techniques which minimize the extent and magnitude of the temperature and stressfields. These techniques for welding stainless steel components located in high thermal neutron fluence regions are available from various sources; however, the techniques are held as proprietary.Although industry's research on the phenomenon of the cracking of weld repairs in highlyirradiated material due to helium formation is ongoing and much of the data is proprietary, there are certain threshold values below which this phenomenon does not occur. The licensee's calculated maximum thermal neutron fluence of 5E16 n/cm 2 for these components is well belowthese values. Therefore, it is unlikely that cracking and the resultant decrease in mechanical properties will occur in the welded joint of the HJTC probe holder assembly to the UGSs. As anadded safety margin, the weld procedure specification has been qualified with tensile and bend tests in accordance with ASME Code, Section IX, and the additional requirements of ASME Code Case N-516-2. The filler material will be qualified with chemical, ferrite, and tensile testsperformed in accordance with Code Case N-516-2. Also, mockup testing for welders will beused. The mockup testing will be performed using similar materials and conditions as theproduction welds. The proposed welds will be subjected to the same inspection requirementsas the production welds. The welds described above assist in the relocation of the HJTC probe holder assemblies and provide support to the HJTC probe holder assemblies, which will bepositioned against the existing UGSs. The proposed welds will only be used to join a guide forinserting the HJTC probes into the probe holder to the UGSs. The welds do not perform an ASME core support structure function and are not ASME pressure boundary welds.
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| Non-destructive examination will be performed by visual examination, per Code Case N-516-2,by a certified examiner. The requirements imposed on the welds are conservative with respect to the safety function ofthe welds. The qualification depth rules of Code Case N-516-2 for performing the test welds underwater will be met. The conditions stated above relative to the thermal neutron fluence,combined with the licensee's proposed testing and examination requirements of the ASME Code, Section IX, and Code Case N-516-2, provide an acceptable level of quality and safety for underwater welding of the subject components.
| |
|
| |
|
| ==4.0CONCLUSION==
| | subject welds at CCNPP for the remainder of the third 10-year inservice inspection interval. All other ASME Code, Section XI requirements for which relief was not specifically requested and approved in this request remain applicable, including third party review by the Authorized Nuclear Inservice Inspector. |
| The NRC staff has reviewed the licensee's relief request and determined that the use of theproposed ASME Code Case N-516-2 to relocate two (per Unit) HJTC probe holder assemblies to the UGSs will provide an acceptable level of quality and safety. Therefore, pursuant to10 CFR 50.55a(a)(3)(i), the NRC staff authorizes the use of the proposed code case for the subject welds at CCNPP for the remainder of the third 10-year inservice inspection interval. Allother ASME Code, Section XI requirements for which relief was not specifically requested and approved in this request remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.Principal Contributor: E. Andruszkiewicz Date: February 8, 2006}}
| | Principal Contributor: E. Andruszkiewicz Date: February 8, 2006}} |
Letter Sequence Other |
|---|
|
|
MONTHYEARML0527700942005-09-30030 September 2005
Request for Approval of ASME Section XI Code Case N-516-2 for Underwater Welding of Heated Junction Thermocouple Probe Holders
Project stage: Request
ML0602400852006-02-0808 February 2006
Relief Request for Underwater Welding of Heated Junction Thermocouple Holders, Calvert Cliffs Nuclear Power Plant, Units 1 and 2 (TAC Nos. MC8572 and MC8573)
Project stage: Other
2005-09-30
[Table View] |
|
|---|
Category:Code Relief or Alternative
MONTHYEARML23156A6752023-06-20020 June 2023
Request for Withholding Information from Public Disclosure for Proposed Alternative to the Requirements for Repair/Replacement of Saltwater System Buried Piping
ML22195A0252023-01-0303 January 2023
Authorization and Safety Evaluation for Alternative Request No. ISI-05-016
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.
ML22105A4052022-05-0202 May 2022
Authorization and Safety Evaluation for Proposed Alternative No. ISI-05-019
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
ML21190A0042021-09-0202 September 2021
Proposed Alternative to the Requirements of the ASME Section XI, Subsection Iwl Concerning Unbound Post-Tensioning Systems
ML21216A2202021-08-0505 August 2021
Proposed Alternative to Eliminate Certain Documentation Requirements for Pressure Retaining Bolting
ML21130A0382021-05-21021 May 2021
Memo to File - Draft Request for Additional Information Relief Request CISI-03-01 Concerning Containment Unbonded Post-Tensioning System Inservice Inspection Requirements
ML20275A1022020-11-0404 November 2020
Proposed Alternative I4r-07 to the Requirements of the American Society of Mechanical Engineers Code
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
ML20196L7242020-07-14014 July 2020
Acceptance of Relief Requests Associated with Inservice Inspection Impracticality
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
ML19168A1172019-07-29029 July 2019
Issuance of Relief Request 15R-03 Use of ASME Code N-513-4
ML19196A1232019-07-19019 July 2019
Issuance of Relief Request 15R-04 Use of Encoded Phased Array Ultrasonic Examination Techniques
ML19161A2572019-06-0404 June 2019
BWR Fleet Msv/Srv - Testing Frequency Relief Request NRC Pre-Application Meeting June 4, 2019
ML19136A2162019-05-30030 May 2019
Use of a Provision in a Later Edition of the ASME Code
ML19106A0032019-04-15015 April 2019
Submittal of Relief Requests Associated with the Fifth Inservice Inspection (ISI) Interval
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
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
JAFP-18-0052, Proposed Alternative to Utilize Code Case N-8792018-05-30030 May 2018
Proposed Alternative to Utilize Code Case N-879
ML17297A5242017-11-0606 November 2017
R. E. Ginna - Request for Use of a Portion of a Later Edition and Addenda of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (CAC Nos. MG0079-MG0083; EPID L-2017-LLR-0061)
ML17228A7082017-08-21021 August 2017
Acceptance of Requested Licensing Action Relief Requests GV-RR-01, RC-RR-01, and SI-RR-01
ML17170A0132017-06-26026 June 2017
Proposed Alternative to Eliminate Examination of Threads in Reactor Pressure Vessel Flange (CAC Nos. MF8712-MF8729 and MF9548)
ML16337A1902016-12-19019 December 2016
Relief Request RR-ISI-4-11 for Dissimilar Metal Butt Weld Examinations
ML16230A2372016-09-0606 September 2016
Fleet Request for Proposed Alternative to Use ASME Code Case N-513-4 (CAC Nos. MF7301-MF7322)
ML16138A0212016-05-19019 May 2016
Proposed Alternative to Use Code Case N-789 (CAC Nos. MF7018-MF7022)
ML16033A4082016-02-11011 February 2016
Relief Request for Dissimilar Metal Butt Weld Examinations
ML15327A3672015-12-0707 December 2015
Relief Request for Extension of Volumteric Examination Interval for Reactor Vessel Heads with Alloy 690 Nozzles
ML15201A0672015-07-13013 July 2015
Relief Request for Extension of Volumetric Examination Interval for Reactor Vessel Heads with Alloy 690 Nozzles
ML14246A0692014-12-19019 December 2014
Relief Request RR-ISI-04-08, Revision 1, Request for Relief Using Alternative Repair for Buried Saltwater Piping (Tac Nos. MF3413 and MF3414)
ML14279A5652014-11-0606 November 2014
Relief Request RR-ISI-04-09 Regarding Saltwater System Piping Repair
ML14247A5552014-09-24024 September 2014
Relief Request IST-RR-01 Regarding the Frequency of Inservice Testing Requirements of the Pumps and Valves
ML13297A2932013-11-13013 November 2013
Relief Request RR-ISI-04-08 Regarding Mitigating of Buried Saltwater Piping Degradation
ML13051A7402013-02-18018 February 2013
Response to Request for Additional Information - Relief Request RR-ISI-04-07A, Dissimilar Metal Butt Welds Baseline Examinations
ML12164A3722012-06-0707 June 2012
Relief Request Dissimilar Metal Butt Welds Baseline Examinations (RR-ISI-04-07A)
ML12009A0732011-12-29029 December 2011
Relief Requests for Dissimilar Metal Butt Welds Baseline Inspections (RR-ISI-04-06 & ISI-04-07)
ML1109104462011-04-26026 April 2011
Third 10-Year Interval Inservice Inspection (ISI) Program Plan Requests for Relief ISI-24, ISI-25, ISI-26, and ISI-27, for Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2
ML1014100602010-05-18018 May 2010
Request for Approval of Alternate (Relief Request) for Dissimilar Metal Weld Repairs (ISI-04-05)
ML0930300522009-11-0909 November 2009
Relief Request ISI-022 & ISI-023 to Extend Reactor Vessel and Reactor Vessel Internal Weld Examinations-Calvert Cliffs Nuclear Power Plant, Unit 1
ML0905401222009-02-24024 February 2009
Acceptance Review of Relief Requests ISI-04-01 Through ISI-04-04-Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2
ML0905400622009-02-18018 February 2009
Request to Extend the Inservice Inspection Interval for Reactor Vessel Weld Examinations - Relief Requests (ISI-022 and ISI-023)
ML0712300902007-04-27027 April 2007
Part 21 Interim Report, Dresser Investigation File No. 2007-02, Interim Reporting of a Potential Defect Involving Power Actuated Pressure Relief Valves Supplied to Calvert Cliffs, Fort Calhoun and Oconee Plants
NOC-AE-06002031, Request for Relief from ASME Boiler and Pressure Vessel Code, Section XI Requirements for Use of Penetrameters in Radiographic Examinations2006-06-14014 June 2006
Request for Relief from ASME Boiler and Pressure Vessel Code, Section XI Requirements for Use of Penetrameters in Radiographic Examinations
ML0611102322006-05-11011 May 2006
Relief Request, Use Alternative Techniques for Repair of Welded Nozzles
ML0602400852006-02-0808 February 2006
Relief Request for Underwater Welding of Heated Junction Thermocouple Holders, Calvert Cliffs Nuclear Power Plant, Units 1 and 2 (TAC Nos. MC8572 and MC8573)
2023-06-20
[Table view]
Category:Letter
MONTHYEARIR 05000317/20230042024-02-0101 February 2024
Integrated Inspection Report 05000317/2023004 and 05000318/2023004
ML24029A0102024-01-29029 January 2024
Request for Information and Notification of Conduct of IP 71111.21.N.04, Age-Related Degradation, Reference Inspection Report 05000317/2024010 and 05000318/2024010
ML24003A8872024-01-19019 January 2024
Exemption from Select Requirements of 10 CFR Part 73 (EPID L-2023-LLE-0033 (Security Notifications, Reports, and Recordkeeping and Suspicious Activity Reporting))
05000318/LER-2023-004, Submittal of LER 2023-004-00 for Calvert Cliffs Nuclear Power Plant, Unit 2, Submittal of Automatic Reactor Trip from Reactor Protection System Actuation Due to Loss of Unit Service Transformer2024-01-16016 January 2024
Submittal of LER 2023-004-00 for Calvert Cliffs Nuclear Power Plant, Unit 2, Submittal of Automatic Reactor Trip from Reactor Protection System Actuation Due to Loss of Unit Service Transformer
ML24011A0732024-01-11011 January 2024
Proposed Alternative to the Requirements for Repair/Replacement of Saltwater (SW) System Buried Piping
05000318/LER-2023-002, Forward LER 2023-002-00 for Calvert Cliffs Nuclear Power Plant, Unit 2, Automatic Reactor Trip from Reactor Protection System Actuation Due to Loss of Unit Service Transformer2024-01-0808 January 2024
Forward LER 2023-002-00 for Calvert Cliffs Nuclear Power Plant, Unit 2, Automatic Reactor Trip from Reactor Protection System Actuation Due to Loss of Unit Service Transformer
05000318/LER-2023-003, Forward LER 2023-003-00 for Calvert Cliffs Nuclear Power Plant, Unit 2, Manual Actuation of Auxiliary Feedwater System Due to 22 Steam Generator Feedwater Pump Trip2024-01-0808 January 2024
Forward LER 2023-003-00 for Calvert Cliffs Nuclear Power Plant, Unit 2, Manual Actuation of Auxiliary Feedwater System Due to 22 Steam Generator Feedwater Pump Trip
ML24005A0222024-01-0505 January 2024
Revised Steam Generator Tube Inspection Reports
ML23304A0642024-01-0202 January 2024
Issuance of Amendment No. 349 to Modify the Long-Term Coupon Surveillance Program
RS-23-125, Request for Exemption from 10 CFR 2.109(b)2023-12-0707 December 2023
Request for Exemption from 10 CFR 2.109(b)
ML23331A2992023-11-27027 November 2023
Submittal of Condition Prohibited by Technical Specifications Due to Failure to Sample Diesel Generator Fuel Oil Storage Tank
IR 05000317/20230102023-11-20020 November 2023
Biennial Problem Identification and Resolution Inspection Report 05000317/2023010 and 05000318/2023010
ML23318A4722023-11-14014 November 2023
Supplement to License Amendment Request to Adopt TSTF-59-A
ML23317A1032023-11-10010 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
ML23310A0442023-11-0707 November 2023
Project Manager Assignment
IR 05000317/20230402023-11-0202 November 2023
95001 Supplemental Inspection Report 05000317/2023040 and Follow-Up Assessment Letter
IR 05000317/20230032023-11-0101 November 2023
Integrated Inspection Report 05000317/2023003 and 05000318/2023003
IR 05000317/20230902023-10-26026 October 2023
Final Significance Determination of a White Finding with Assessment Follow-Up and Notice of Violation; Inspection Report 05000317/2023090
ML23289A1202023-10-16016 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
ML23279A1202023-10-0606 October 2023
Response to NRC Inspection Report and Preliminary White Finding
IR 05000317/20230502023-09-29029 September 2023
Special Inspection Report 05000317/2023050 and Preliminary White Finding and Apparent Violation
ML23272A1032023-09-29029 September 2023
Condition Prohibited by Technical Specifications Due to Inoperable Nuclear Instrumentation at Very Low Power
IR 05000317/20234012023-09-18018 September 2023
Cyber Security Inspection Report 05000317/2023401 and 05000318/2023401
ML23254A0012023-09-0505 September 2023
Registration of Use of Casks to Store Spent Fuel
IR 05000317/20230052023-08-31031 August 2023
Updated Inspection Plan for Calvert Cliffs Nuclear Power Plant, Units 1 and 2 (Report 05000317/2023005 and 05000318/2023005)
ML23158A1952023-08-30030 August 2023
R. E. Ginna - Issuance of Amendments to Adopt TSTF-273-A, Revision 2, Safety Function Determination Program Clarifications
ML23241A8412023-08-29029 August 2023
Response to Request for Additional Information - Proposed Alternative to the Requirements for Repair/Replacement of Saltwater (SW) System Buried Piping
ML23240A3872023-08-28028 August 2023
Senior Reactor and Reactor Operator Initial License Examinations
ML23151A3472023-08-21021 August 2023
Issuance of Amendments to Adopt TSTF-295-A, Modify Note 2 to Actions of PAM Table to Allow Separate Condition Entry for Each Penetration
ML23219A1662023-08-16016 August 2023
Request for Additional Information Regarding Proposed Alternative to the Requirements for Repair/Replacement of Saltwater (SW) System Buried Piping (EPID: L-2023-LLR-0006) - Non-proprietary
ML23228A1002023-08-15015 August 2023
Notification of Readiness for NRC 95001 Inspection
ML23188A0402023-08-0808 August 2023
Issuance of Amendment Nos. 346 and 324 Adoption of TSTF-577, Revised Frequencies for Steam Generator Tube Inspections, Revision 1
ML23214A1572023-08-0707 August 2023
Correction to the Renewed Facility Operating License Page 3 in Amendment No 345
IR 05000317/20230022023-08-0303 August 2023
Integrated Inspection Report 05000317/2023002
ML23188A0512023-07-13013 July 2023
Correction to the Renewed Facility Operating License Pages in Amendment Nos. 336 and 314
ML23186A0372023-07-13013 July 2023
Correction to the Renewed Facility Operating License Pages in Amendment Nos. 340 and 318
IR 05000317/20233012023-07-12012 July 2023
Initial Operator Licensing Examination Report 05000317/2023301 and 05000318/2023301
IR 05000317/20230122023-07-10010 July 2023
Commercial Grade Dedication Report 05000317/2023012 and 05000318/2023012
ML23180A2362023-06-29029 June 2023
Correction of Errors on Technical Specification Pages
RS-23-083, Withdrawal - Proposed Alternatives Related to the Steam Generators2023-06-27027 June 2023
Withdrawal - Proposed Alternatives Related to the Steam Generators
ML23156A6752023-06-20020 June 2023
Request for Withholding Information from Public Disclosure for Proposed Alternative to the Requirements for Repair/Replacement of Saltwater System Buried Piping
2024-02-01
[Table view]
Category:Safety Evaluation
MONTHYEARML23304A0642024-01-0202 January 2024
Issuance of Amendment No. 349 to Modify the Long-Term Coupon Surveillance Program
ML23158A1952023-08-30030 August 2023
R. E. Ginna - Issuance of Amendments to Adopt TSTF-273-A, Revision 2, Safety Function Determination Program Clarifications
ML23151A3472023-08-21021 August 2023
Issuance of Amendments to Adopt TSTF-295-A, Modify Note 2 to Actions of PAM Table to Allow Separate Condition Entry for Each Penetration
ML23188A0402023-08-0808 August 2023
Issuance of Amendment Nos. 346 and 324 Adoption of TSTF-577, Revised Frequencies for Steam Generator Tube Inspections, Revision 1
ML23114A2522023-04-28028 April 2023
Request to Use a Provision of a Later Edition of the ASME Boiler & Pressure Vessel Code, Section XI
ML23086C0672023-04-24024 April 2023
Issuance of Amendment Nos. 345 and 323 Deletion of License Conditions Related to Decommissioning Trust
ML22195A0252023-01-0303 January 2023
Authorization and Safety Evaluation for Alternative Request No. ISI-05-016
ML22293B8052022-11-30030 November 2022
Constellation Energy Generation, Llc_Fleet - Request to Authorize Use Honeywell Mururoa V4F1 R Supplied Air Suits
ML22202A5142022-07-28028 July 2022
Authorization of Relief Request No. RR-ISI-05-20 Regarding Mitigation of Buried Saltwater System Piping Degradation
ML22105A4052022-05-0202 May 2022
Authorization and Safety Evaluation for Proposed Alternative No. ISI-05-019
ML22090A0862022-04-29029 April 2022
Amendments to Adopt TSTF-541,Rev.2,Add Exceptions to Surveillance Requirements for Valves,Dampers Locked in Actuated Position
ML21347A0382022-01-13013 January 2022
Issuance of Amendments to Revise Reactor Coolant Leakage Requirements
ML21347A8642022-01-13013 January 2022
Issuance of Amendment Nos. 342 and 320 Modifying the Licensing Basis to Allow for Full Core Offload with No Shutdown Cooling Loop Available During Certain Refueling Outages
ML21299A0052021-12-14014 December 2021
Issuance of Amendments No. 340 and 318 Adoption of Technical Specifications Task Force Traveler TSTF-567, Revision 1, Add Containment Sump TS to Address GSI-191 Issues
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
ML21190A0042021-09-0202 September 2021
Proposed Alternative to the Requirements of the ASME Section XI, Subsection Iwl Concerning Unbound Post-Tensioning Systems
ML21216A2202021-08-0505 August 2021
Proposed Alternative to Eliminate Certain Documentation Requirements for Pressure Retaining Bolting
ML21166A1682021-06-25025 June 2021
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
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
ML20363A2422021-01-26026 January 2021
Issuance of Amendment Nos. 339 and 317 Regarding Accident Tolerant Fuel Lead Test Assemblies (EPID L-2019-LLA-0282) - (Non-Proprietary)
ML20356A1212021-01-15015 January 2021
Relief from the Requirements of the ASME Code
ML20273A0882020-11-0909 November 2020
Issuance of Amendment Nos. 338 and 316 Revise Emergency Diesel Generator Surveillance Requirements for Frequency and Voltage Tolerances
ML20287A1302020-11-0505 November 2020
Review of Quality Assurance Program Changes
ML20275A1022020-11-0404 November 2020
Proposed Alternative I4r-07 to the Requirements of the American Society of Mechanical Engineers Code
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
ML20232A1712020-09-0101 September 2020
Request to Use Alternative Code Case OMN-26
ML20182A1942020-08-13013 August 2020
Issuance of Amendment Nos. 336 and 314 Concerning Reactor Coolant Pump Flywheel Inspection Program
ML20134H9402020-07-0808 July 2020
Issuance of Amendments Revising the High Radiation Area Administrative Controls
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
ML19330D9092020-02-28028 February 2020
Issuance of Amendment Nos. 332 and 310 Risk-Informed Categorization and Treatment of Systems, Structures, and Components
ML19337D0352020-02-28028 February 2020
Issuance of Amendment Nos. 333 and 311 Deletion of E-Bar Definition and Revision to Reactor Coolant System Specific Activity Technical Specifications
ML20028E3992020-02-0404 February 2020
Proposed Alternative to Use ASME Code Case N-879
ML19298C9722019-10-31031 October 2019
50.69 Apla SE Input L-2018-LLA-0482
ML19269C5342019-09-27027 September 2019
Proposed Alternative to Use Encoded Phased Array Ultrasonic Examination Techniques
ML19165A2472019-08-26026 August 2019
Issuance of Amendment Nos 330 and 308 Relocation and Consolidation the Emergency Operations Facility and Joint Information Center for the Calvert Cliffs Nuclear Power Plant
ML19168A1172019-07-29029 July 2019
Issuance of Relief Request 15R-03 Use of ASME Code N-513-4
ML19196A1232019-07-19019 July 2019
Issuance of Relief Request 15R-04 Use of Encoded Phased Array Ultrasonic Examination Techniques
ML19192A2442019-07-18018 July 2019
Proposed Alternative to Use ASME Code Cases N-878 and N-880
ML19134A3732019-05-30030 May 2019
Issuance of Relief Request I5R-05 Relief from the Requirements of the ASME Code
ML19136A2162019-05-30030 May 2019
Use of a Provision in a Later Edition of the ASME Code
ML19053A5882019-04-19019 April 2019
Plants, Units 1 and 2 - Issuance of Amendment Nos. 329 and 307 Removal of an Exception to the Minimum Education Requirements for Shift Technical Advisors
ML19046A0432019-02-25025 February 2019
Plants, Units 1 and 2 - Revision to the Reactor Pressure Vessel Surveillance Capsule Withdrawal Schedule
ML18365A3732019-01-22022 January 2019
Issuance of Amendment Nos. 328 and 306 to Extend Completion Time of Required Action D.3 of Technical Specification 3.8.1 to 14 Days
ML18318A0142018-11-30030 November 2018
Correction to Amendment Nos. 326 and 304 Add Risk-Informed Completion Time Program
ML18309A3012018-11-15015 November 2018
R. E. Ginna - Issuance of Amendment Nos. 327, 305, 232, 173, and 133, Respectively, Eliminating the Nuclear Advisory Committee Requirements
ML18270A1302018-10-30030 October 2018
Issuance of Amendment Nos. 326 and 304 to Add Risk-Informed Completion Time Program
2024-01-02
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February 8, 2006 Mr. James A. Spina, Vice President Calvert Cliffs Nuclear Power Plant, Inc.
Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657-4702
SUBJECT:
CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NOS. 1 AND 2 - RELIEF REQUEST FOR UNDERWATER WELDING OF HEATED JUNCTION THERMOCOUPLE PROBE HOLDERS (TAC NOS. MC8572 AND MC8573)
Dear Mr. Spina:
By letter dated September 30, 2005 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML052770094), Calvert Cliffs Nuclear Power Plant, Inc. (the licensee) submitted a relief request for authorization to use American Society of Mechanical Engineers Boiler and Pressure Vessel Code,Section XI, Code Case N-516-2, Underwater Welding,Section XI, Division 1, to relocate two (per Unit) heated junction thermocouple (HJTC) probe holder assemblies to the existing upper guide structure (UGS) at the Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2. As stated in the conditions on use of Code Case N-516-2 in Regulatory Guide 1.147, Revision 13, licensees must obtain Nuclear Regulatory Commission (NRC) approval in accordance with Section 50.55a(a)(3) of Part 50 of Title 10 of the Code of Federal Regulations (10 CFR) regarding the method to be used in the weld repair or replacement of irradiated material underwater.
The NRC staff has reviewed and evaluated the information regarding the relief request.
The results are provided in the enclosed safety evaluation.
The NRC staff concludes that the use of the proposed ASME Code Case N-516-2 to relocate the HJTC probe holder assemblies to the UGSs will provide an acceptable level of quality and safety. Pursuant to 10 CFR 50.55a(a)(3)(i), the NRC staff authorizes the use of the proposed
J. Spina code case for the subject welds. All other ASME Code,Section XI requirements for which relief was not specifically requested and approved in this request remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.
Sincerely,
/RA/
Richard J. Laufer, Chief Plant Licensing Branch I-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-317 and 50-318
Enclosure:
As stated cc w/encl: See next page
ML060240085 OFFICE LPLI-1/PM LPLI-1/LA CFEB/BC OGC LPLI-1/BC NAME PMilano SLittle KGruss RLaufer DATE 01/26/06 02/02/06 01/20/06 02/06/06 02/08/06 Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 cc:
President Ms. Patricia T. Birnie, Esquire Calvert County Board of Co-Director Commissioners Maryland Safe Energy Coalition 175 Main Street P.O. Box 33111 Prince Frederick, MD 20678 Baltimore, MD 21218 Mr. Carey Fleming, Esquire Mr. Loren F. Donatell Sr. Counsel - Nuclear Generation NRC Technical Training Center Constellation Generation Group, LLC 5700 Brainerd Road 750 East Pratt Street, 17th floor Chattanooga, TN 37411-4017 Baltimore, MD 21202 Mr. Louis Larragoite Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657-4702 Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 287 St. Leonard, MD 20685 Mr. R. I. McLean, Manager Nuclear Programs Power Plant Research Program Maryland Department of Natural Resources 580 Taylor Avenue (B wing, 3rd floor)
Tawes State Office Building Annapolis, MD 21401 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Ms. Kristen A. Burger, Esquire Maryland People's Counsel 6 St. Paul Centre Suite 2102 Baltimore, MD 21202-1631
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REGARDING UNDERWATER WELDING OF HEATED JUNCTION THERMOCOUPLE PROBE HOLDER WELDS CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NOS. 1 AND 2 CALVERT CLIFFS NUCLEAR POWER PLANT, INC.
DOCKET NOS. 50-317 AND 50-318
1.0 INTRODUCTION
By letter dated September 30, 2005, Calvert Cliffs Nuclear Power Plant, Inc. (the licensee) submitted a relief request pertaining to the approval, pursuant to the provisions of Section 50.55a(a)(3)(i) of Part 50 of Title10 of the Code of Federal Regulations (10 CFR), to use American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),
Section XI, Code Case N-516-2, "Underwater Welding," to relocate two (per Unit) heated junction thermocouple (HJTC) probe holder assemblies to the existing upper guide structure (UGS) at the Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 (CCNPP). ASME Code Case N-516-2 has been conditionally accepted by the Nuclear Regulatory Commission (NRC) in Regulatory Guide (RG) 1.147, Revision 13. As stated in RG 1.147, the NRC placed a condition that licensees must obtain NRC approval in accordance with 10 CFR 50.55a(a)(3) regarding the technique to be used in the weld repair or replacement of irradiated material underwater. The components listed above have been irradiated as a result of their location in the reactor vessel and meet the definition of an irradiated component. Therefore, the licensee must obtain the approval to use the above code case, and the September 30, 2005, letter includes this request.
2.0 REGULATORY EVALUATION
Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1, 2, and 3 components (including supports) must meet the requirements set forth in the ASME Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, to the extent practical within the limitations of design, geometry, and materials of construction of the components. Paragraph IWA-4221(b) of ASME Code,Section XI requires that an item for repair/replacement activities shall meet the original Construction Code. Paragraph IWA-4221(c) of ASME Code,Section XI allows licensees to use, as an alternative, later editions and addenda of the Construction Code or of ASME Code,Section III, either in their entirety or portions thereof, and code cases.
Enclosure
The current CCNPP Code of Record, ASME Code,Section XI, 1998 Edition, no Addenda, does not allow underwater welding of irradiated components. Therefore, the licensee is requesting permission to use ASME Code Case N-516-2. As required by RG 1.147, Revision 13, the licensee is requesting NRC approval of the technique (i.e., shielded metal arc welding process) to be used in the weld repair or replacement of irradiated material underwater.
3.0 TECHNICAL EVALUATION
3.1 Components for which Relief is Requested:
Relief is requested, as required in RG 1.147, Revision 13, to allow the use of Code Case N-516-2 for underwater welding on the CCNPP Unit Nos. 1 and 2 UGSs at locations where the HJTC probe holder will be installed. These components have been irradiated as a result of their location in the reactor vessel and can be considered to be an irradiated component. The CCNPP UGSs were formed from austenitic stainless steel. The HJTC probe holder brackets are ASME Code,Section II, Material Classification SA-479 Type 304 austenitic stainless steel.
The funnels are SA-479 austenitic stainless steel or SA-240 Type 304 austenitic stainless steel.
The filler metal is austenitic stainless steel meeting the requirements of ASME, Section IIC, Specification for Stainless Steel Electrodes for Shielded Metal Arc Welding, SFA 5.4. The production filler metal will meet all the applicable filler metal certification requirements of paragraph 4.0 of Code Case N-516-2, with the results of the chemical, ferrite, and tensile tests provided to the NRC, if desired. The minimum ferrite number for the production filler metal is FN 5.
Code Requirements for which Relief is Requested:
The current Code of Record, ASME Code,Section XI, 1998 Edition, no Addenda, does not allow underwater welding of irradiated components. Therefore, permission must be requested to use Code Case N-516-2. As required by RG 1.147, Revision 13, the licencee is requesting NRC approval of the technique (i.e., shielded metal arc welding process) to be used in the weld repair or replacement of irradiated material underwater.
Proposed Alternative:
The NRC documented its conditional acceptance of Code Case N-516-2 in RG 1.147, Revision 13, dated January 2004. The specific condition noted in RG 1.147, Revision 13, requires licensees to obtain NRC approval in accordance with 10 CFR 50.55a(a)(3) regarding the technique to be used in the weld repair or replacement of irradiated material underwater.
The licensee requested NRC approval of ASME Code,Section XI, Code Case N-516-2 for use at CCNPP on the basis that it provides an acceptable level of quality and safety.
The licensee requested approval for the use of Code Case N-516-2 in order to relocate two (per Unit) HJTC probe holder assemblies to the UGSs. The specific application request is for wet underwater welding.
Licensees Basis for Relief:
The proposed welds will be performed using a weld procedure specification qualified in accordance with Code Case N-516-2 and the welds will be visually examined. The licensees weld procedure specification has been qualified with tensile and bend tests in accordance with ASME Code,Section IX, and the additional requirements of Code Case N-516-2. The filler material will be qualified using chemical, ferrite, and tensile tests performed in accordance with Code Case N-516-2. To support the new probe holder, intermittent fillet welds will be made underwater with the shielded metal arc welding (SMAW) process joining new funnels and support brackets for the probe holders (two per Unit) to the existing UGSs. Mockup testing for welders will be used. The mockup testing will be performed using similar materials and conditions as the production welds. These welds will be subjected to the same inspection requirements as the production welds. The subject fillet welds will only be used to relocate the HJTC probe holders to the UGSs. They will not become structural welds performing a core support structure function, nor will they become pressure boundary welds. The mockup tests and inspections on the welds are licensee requirements that will ensure the performance of the welds is conservative with respect to their safety function. If required, the control element assembly shrouds and UGS plate will be prepared for welding by removal of the non-tightly adherent oxide layer.
Welding will be performed after 23 effective full-power years of operation, corresponding to a calculated thermal neutron fluence of less than 5 x 1016 neutrons per square centimeter (5E16 n/cm2) at 42 inches above the fuel alignment plate (FAP). The water depth of the lowest weld, which is located at 42 inches above the FAP, will be approximately 25 feet. The qualification depth rules of Code Case N-516-2 will be met. The mockup tests and inspections on the welds, combined with the alternative requirements of Code Case N-516-2, provide an acceptable level of quality and safety for underwater welding. Non-destructive examination will be performed by visual examination only, per Code Case N-516-2, by a certified examiner.
Ongoing examinations of the welds will fall under the normal In-service Inspection intervals, per ASME Code,Section XI.
This relief request will be implemented during the next refueling outages for each unit and will remain in place for the life of the plant.
3.3 Staff Evaluation ASME Code Case N-516-2 has been conditionally accepted by the NRC in RG 1.147, Revision 13. As stated in RG 1.147, the NRC staff placed a condition that [l]icensees must obtain NRC approval in accordance with 10 CFR 50.55a(a)(3) regarding the technique to be used in the weld repair or replacement of irradiated material underwater. The components listed above have been irradiated to a calculated thermal neutron fluence of less than 5E16 n/cm2, as a result of their location in the reactor vessel and can be considered to be an irradiated component. Therefore, the licensee must obtain NRC approval to use the above code case.
Welded repairs in stainless steel components that are located in high thermal neutron fluence regions in the reactor pressure vessel have been complicated by cracking and the resultant decrease in mechanical properties in the welded joint. This material degradation is caused by transmutation of various elements contained in the materials to be welded, such as boron and
nickel, and the formation of helium. Helium tends to have a low solubility in metals and forms small clusters with diameters on the order of a few tenths of a nanometer. These clusters form at preferred nucleation sites which are lattice inhomogeneities such as radiation-induced defects, precipitate interfaces, dislocations and most importantly, grain boundaries. At elevated temperatures, these clusters and bubbles can grow very rapidly and under applied stress can severely weaken grain boundaries. Because conventional, deep penetration, fusion welding processes produce high stress (above yield strength) as well as high temperatures (above the melting point), entrapped helium can severely affect the weldability and postweld properties of irradiated materials. The severity of the observed effects is dominated by the helium content and the extent and magnitude of the temperature and stress fields that prevail near the fusion line during welding. However, welded repairs of components can be performed using various welding techniques which minimize the extent and magnitude of the temperature and stress fields. These techniques for welding stainless steel components located in high thermal neutron fluence regions are available from various sources; however, the techniques are held as proprietary.
Although industrys research on the phenomenon of the cracking of weld repairs in highly irradiated material due to helium formation is ongoing and much of the data is proprietary, there are certain threshold values below which this phenomenon does not occur. The licensees calculated maximum thermal neutron fluence of 5E16 n/cm2 for these components is well below these values. Therefore, it is unlikely that cracking and the resultant decrease in mechanical properties will occur in the welded joint of the HJTC probe holder assembly to the UGSs. As an added safety margin, the weld procedure specification has been qualified with tensile and bend tests in accordance with ASME Code,Section IX, and the additional requirements of ASME Code Case N-516-2. The filler material will be qualified with chemical, ferrite, and tensile tests performed in accordance with Code Case N-516-2. Also, mockup testing for welders will be used. The mockup testing will be performed using similar materials and conditions as the production welds. The proposed welds will be subjected to the same inspection requirements as the production welds. The welds described above assist in the relocation of the HJTC probe holder assemblies and provide support to the HJTC probe holder assemblies, which will be positioned against the existing UGSs. The proposed welds will only be used to join a guide for inserting the HJTC probes into the probe holder to the UGSs. The welds do not perform an ASME core support structure function and are not ASME pressure boundary welds.
Non-destructive examination will be performed by visual examination, per Code Case N-516-2, by a certified examiner.
The requirements imposed on the welds are conservative with respect to the safety function of the welds. The qualification depth rules of Code Case N-516-2 for performing the test welds underwater will be met. The conditions stated above relative to the thermal neutron fluence, combined with the licensees proposed testing and examination requirements of the ASME Code,Section IX, and Code Case N-516-2, provide an acceptable level of quality and safety for underwater welding of the subject components.
4.0 CONCLUSION
The NRC staff has reviewed the licensees relief request and determined that the use of the proposed ASME Code Case N-516-2 to relocate two (per Unit) HJTC probe holder assemblies to the UGSs will provide an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the NRC staff authorizes the use of the proposed code case for the
subject welds at CCNPP for the remainder of the third 10-year inservice inspection interval. All other ASME Code,Section XI requirements for which relief was not specifically requested and approved in this request remain applicable, including third party review by the Authorized Nuclear Inservice Inspector.
Principal Contributor: E. Andruszkiewicz Date: February 8, 2006
