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| {{#Wiki_filter:Michael P. Gallaghe r Vice President. | | {{#Wiki_filter:Michael P. Gallagher Vice President. License Renewal Exelon Generation Exelon Nuclear 200 Exelon Way Kennett Square. PA 19348 610 765 5958 Office 610 765 5956 Fax www.exeloncorp.com michaelp.gallagher@exeloncorp.com 10 CFR 50 10 CFR 51 10 CFR 54 RS-16-052 February 25, 2016 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001 LaSalle County Station, Units 1 and 2 Facility Operating License Nos. NPF-11 and NPF-18 NRC Docket Nos. 50-373 and 50-374 |
| License Renewal Exelon Generation Exelon Nuclear 200 Exelon Way RS-16-052 Kennett Square. PA 19348 610 765 5958 Office 610 765 5956 Fax www.exeloncorp.com michaelp.gallagher@exeloncorp.com 10 CFR 50 10 CFR 51 10 CFR 54 February 25, 2016 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington , DC 20555-0001 | |
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| ==Subject:== | | ==Subject:== |
| References
| | Response to NRC Requests for Additional Information, Set 15, dated February 16, 2016 related to the LaSalle County Station, Units 1 and 2, License Renewal Application (TAC Nos. MF5347 and MF5346) |
| : LaSalle County Station, Units 1 and 2 Facility Operat i ng License Nos. NPF-11 and NPF-18 NRC Docket Nos. 50-373 and 50-37 4 Response to NRC Requests for Additional Information , Set 15, dated February 16, 2016 related to the LaSalle County Station , Units 1 and 2, License Renewal Application (TAC Nos. MF5347 and MF5346) 1. Letter from Michael P. Gallagher, Exelon Generation Company LLC (Exelon), to NRC Document Control Desk, dated December 9 , 2014, " Application for Renewed Operating Licenses" 2. Letter from Jeffrey S. Mitchell , US NRC to Michael P. Gallagher , Exelon, dated February 16, 2016, "Requests for Additional Information for the Review of the LaSalle County Station, Units 1 and 2 License Renewal Application
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| -Set 15 (TAC Nos. MF5347 and MF5346)" In Reference 1, Exelon Generation Company, LLC (Exelon) submitted the License Renewal Application (LRA) for the LaSalle County Station (LSCS), Units 1 and 2. In Reference 2 , the NRC requested additional information to support staff review of the LRA. The Enclosure contains the response to these requests for additional information. There are no new or revised regulatory commitments contained in this letter. If you have any questions , please contact Mr. John Hufnagel , Licensing Lead, LaSalle License Renewal Project, at 610-765-5829. | | ==References:== |
| February 25, 2016 U.S. Nuclear Regulatory Commission Page 2 I declare under penalty of perjury that the foregoing is true and correct. Executed on O) *JS'-20/b Respectfully, Vice President | | : 1. Letter from Michael P. Gallagher, Exelon Generation Company LLC (Exelon), |
| -License Renewal Projects Exelon Generation Company, LLC | | to NRC Document Control Desk, dated December 9, 2014, "Application for Renewed Operating Licenses" |
| | : 2. Letter from Jeffrey S. Mitchell, US NRC to Michael P. Gallagher, Exelon, dated February 16, 2016, "Requests for Additional Information for the Review of the LaSalle County Station, Units 1 and 2 License Renewal Application - Set 15 (TAC Nos. MF5347 and MF5346)" |
| | In Reference 1, Exelon Generation Company, LLC (Exelon) submitted the License Renewal Application (LRA) for the LaSalle County Station (LSCS), Units 1 and 2. In Reference 2, the NRC requested additional information to support staff review of the LRA. |
| | The Enclosure contains the response to these requests for additional information. |
| | There are no new or revised regulatory commitments contained in this letter. |
| | If you have any questions, please contact Mr. John Hufnagel, Licensing Lead, LaSalle License Renewal Project, at 610-765-5829. |
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| | February 25, 2016 U.S. Nuclear Regulatory Commission Page 2 I declare under penalty of perjury that the foregoing is true and correct. |
| | Executed on O) *JS'- 20/b Respectfully, M~e~ |
| | Vice President - License Renewal Projects Exelon Generation Company, LLC |
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| ==Enclosure:== | | ==Enclosure:== |
| Response to Set 15 Requests for Additional Information cc: Regional Administrator | | Response to Set 15 Requests for Additional Information cc: Regional Administrator - NRC Region Ill NRC Project Manager (Safety Review), NRR-DLR NRC Project Manager (Environmental Review), NRR-DLR NRC Project Manager, NRR-DORL- LaSalle County Station NRC Senior Resident Inspector, LaSalle County Station Illinois Emergency Management Agency - Division of Nuclear Safety |
| -NRC Region Ill NRC Project Manager (Safety Review), NRR-DLR NRC Project Manager (Environmental Review), NRR-DLR NRC Project Manager, NRR-DORL-LaSalle County Station NRC Senior Resident Inspector, LaSalle County Station Illinois Emergency Management Agency -Division of Nuclear Safety RS-16-052 Enclosure Page 1 of 11 Enclosure Response to Set 15 Requests for Additional Information related to the LaSalle County Station (LSCS) License Renewal Application (LRA) | | |
| | RS-16-052 Enclosure Page 1 of 11 Enclosure Response to Set 15 Requests for Additional Information related to the LaSalle County Station (LSCS) License Renewal Application (LRA) |
| RAI B.2.1.4-1 RAI B.2.1.7-3b | | RAI B.2.1.4-1 RAI B.2.1.7-3b |
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| RS-16-052 Enclosure Page 2 of 11 RAI B.2.1.4-1 | | RS-16-052 Enclosure Page 2 of 11 RAI B.2.1.4-1 |
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| ==Background:== | | ==Background:== |
| During the IP-71002, "License Renewal Inspection," at LaSalle County Station, Units 1 and 2 (LSCS), NRC inspectors reviewed Exelon Proc edure ER-AB-331, Revision 14, "BWR Internals Program Management." This procedure addresses changes to the enhanced visual examination (EVT-1) requirements in boiling water reactor vessel and internals project (BWRVIP)-03, "Reactor Pressure Vessel and Internals Examination Requirements." of Exelon Procedure ER-AB-331, "Exelon Position on EVT-1 Implementation,"
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| states that changes relating to limitations on the allowable viewing angle have reduced the effective weld coverage to zero percent in some cases. It also states that "EVT-1 inspections of required welds and components that yield an effective coverage of zero percent meet the BWRVIP inspection requirements," because "the BWRVIP guidelines impose no minimum required effective inspection coverage" for EVT-1 examinations. As noted in the Aging Management Program (AMP) Audit report, dated September 22, 2015, ER-AB-331 is used by the BWR Vessel ID Attachment Welds and BWR Vessel Internals AMPs. The examination requirements for American Society of Mechanical Engineers (ASME) Section XI, for Category B-N-2 only refers to "accessible welds," and does not reference a specific figure for examination surface or volume, which could be interpreted as not being a "defined surface or volume" and therefore, not being subject to the ASME Code requirement for "essentially 100 percent coverage." However, the staff's Final License Renewal Safety Evaluation Report for BWRVIP-48 (included with BWRVIP-48-A, under BWRVIP Inspection Guidelines) states "The examination volumes are limited to the attachment weld and the adjacent heat-affected regions of the vessel clad." Based on the statement in the staff's safety evaluation, the accessible welds and the adjacent heat-affected regions of the vessel clad associated with BWR Vessel ID Attachment Welds program are considered a "defined surface or volume." Therefore, it is the staff's expectation that examinations performed on the accessible welds will yield essentially 100 percent coverage, which the staff considers to be 90 percent or greater coverage. BWRVIP is one of the issue programs (IPs) included in NEI 03-08, Rev. 2, "Guideline for Management of Materials Issues." As stated in NEI 03-08, "All utilities shall adopt applicable IP work products in accordance with the expected level of implementation, or provide an appropriate justification for any deviations." Issue: Although not addressed in BWRVIP guidelines, the staff's expectation is that the examination coverage of inspections performed for AMPs based on BWRVIP guidance (i.e., Generic Aging Lessons Learned (GALL) Report AMP XI.M4 "BWR Vessel ID Attachment Welds,") would be in accordance with the ASME Code. Because some BWRVIP guidelines do not address minimum required effective examination coverage, it is unclear to the staff whether limited coverage (i.e., less than 90 percent) is considered a deviation from the BWRVIP's expected level of implementation. In that regard, it is also unclear to the staff whether examination coverage of zero percent meets the BWRVIP's expected level of implementation. Based on this, crediting weld inspections that do not meet essentially 100 percent coverage (i.e., at least 90 percent of RS-16-052 Enclosure Page 3 of 11 the accessible weld), without disposition or justification, is inconsistent with the staff's expectation for implementation of the BWRVIP-based programs during the period of extended operation.
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| Request: 1. For the vessel ID attachment welds that include guidelines associated with the BWRVIP and rely on EVT-1 examinations, provide a summary of the locations where EVT-1 examinations are performed, indicate whether Alloy 182 welds are included, and the percent coverage for these examinations that can be qualified in accordance with the latest revision of BWRVIP-03. 2. For vessel ID attachment weld locations, where examination coverage is expected to be less than 90 percent during the period of extended operation, provide the technical basis regarding the limited inspection coverage, and its adequacy to detect aging degradation prior to loss of intended function(s). 3. For vessel ID attachment welds, provide a summary of the operating experience related to detected flaws, and the results of any flaw analyses, or other evaluations that may offer insights into flaw sizes that can be tolerated. 4. Describe how inspection results that credit EVT-1 examinations (for vessel ID attachment welds) with minimal coverage (i.e., essentially zero percent coverage) will be documented and justified during the period of extended operation. 5. State whether deviation reports will be submitted for inspection results for vessel attachment welds that credit examinations with limited coverage (e.g., less than 90 percent of accessible welds). If deviation reports will not be submitted, justify how the BWRVIP will provide adequate oversight of the effectiveness of the BWR Vessel ID Attachment Welds.
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| Exelon Response 1. The following tables provide a summary of the locations where EVT-1 examinations were performed for the LaSalle Unit 1 and Unit 2 vessel ID attachment welds in accordance with BWRVIP-48-A. Table 1 provides a summary of EVT-1 examination coverage of vessel ID attachment welds for Unit 1. Table 2 provides a summary of EVT-1 examination coverage of vessel ID attachment welds for Unit 2. All examinations were performed in accordance with the latest revision of BWRVIP-03 at the time of the examination. BWRVIP-03, Revision 10 implemented a requirement that the angle of inspection must not exceed 30 degrees from perpendicular to the examination surface to meet the qualification requirements of EVT-1.
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| Prior to the implementation of BWRVIP-03, Revision 10, the angle of inspection could be as much as 60 degrees from perpendicular to the surface, the same as required for ASME Code Section XI VT-1 examinations. This change was made to enhance the EVT-1 examination method to better identify tight cracks that are characteristic of intergranular stress corrosion cracking (IGSCC). For a visual examination to be qualified as EVT-1, requirements for surface cleanliness and limitations on camera scanning speed must also be met. EVT-1 invokes the same requirement as VT-1, as defined in current ASME Code Section XI, for demonstration of character resolution.
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| RS-16-052 Enclosure Page 4 of 11 BWRVIP-03, Revision 10 was implemented for the first time at LaSalle for the Unit 2 refueling outage in 2009 and for the Unit 1 refueling outage in 2010. The following
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| tables provide EVT-1 examination coverage for examinations performed prior to 2009, and also from 2009 through 2015, showing the decrease in EVT-1 coverage that resulted from the more restrictive angle of inspection that was implemented in 2009. Visual examinations are performed on the entire (100 percent) accessible surface of the vessel ID attachment weld, however only the percentage of the entire (accessible + | | During the IP-71002, License Renewal Inspection, at LaSalle County Station, Units 1 and 2 (LSCS), NRC inspectors reviewed Exelon Procedure ER-AB-331, Revision 14, BWR Internals Program Management. This procedure addresses changes to the enhanced visual examination (EVT-1) requirements in boiling water reactor vessel and internals project (BWRVIP)-03, Reactor Pressure Vessel and Internals Examination Requirements. of Exelon Procedure ER-AB-331, Exelon Position on EVT-1 Implementation, states that changes relating to limitations on the allowable viewing angle have reduced the effective weld coverage to zero percent in some cases. It also states that EVT-1 inspections of required welds and components that yield an effective coverage of zero percent meet the BWRVIP inspection requirements, because the BWRVIP guidelines impose no minimum required effective inspection coverage for EVT-1 examinations. As noted in the Aging Management Program (AMP) Audit report, dated September 22, 2015, ER-AB-331 is used by the BWR Vessel ID Attachment Welds and BWR Vessel Internals AMPs. |
| | The examination requirements for American Society of Mechanical Engineers (ASME) |
| | Section XI, for Category B-N-2 only refers to accessible welds, and does not reference a specific figure for examination surface or volume, which could be interpreted as not being a defined surface or volume and therefore, not being subject to the ASME Code requirement for essentially 100 percent coverage. However, the staffs Final License Renewal Safety Evaluation Report for BWRVIP-48 (included with BWRVIP-48-A, under BWRVIP Inspection Guidelines) states The examination volumes are limited to the attachment weld and the adjacent heat-affected regions of the vessel clad. Based on the statement in the staffs safety evaluation, the accessible welds and the adjacent heat-affected regions of the vessel clad associated with BWR Vessel ID Attachment Welds program are considered a defined surface or volume. Therefore, it is the staffs expectation that examinations performed on the accessible welds will yield essentially 100 percent coverage, which the staff considers to be 90 percent or greater coverage. |
| | BWRVIP is one of the issue programs (IPs) included in NEI 03-08, Rev. 2, Guideline for Management of Materials Issues. As stated in NEI 03-08, All utilities shall adopt applicable IP work products in accordance with the expected level of implementation, or provide an appropriate justification for any deviations. |
| | Issue: |
| | Although not addressed in BWRVIP guidelines, the staffs expectation is that the examination coverage of inspections performed for AMPs based on BWRVIP guidance (i.e., Generic Aging Lessons Learned (GALL) Report AMP XI.M4 BWR Vessel ID Attachment Welds,) would be in accordance with the ASME Code. Because some BWRVIP guidelines do not address minimum required effective examination coverage, it is unclear to the staff whether limited coverage (i.e., |
| | less than 90 percent) is considered a deviation from the BWRVIPs expected level of implementation. In that regard, it is also unclear to the staff whether examination coverage of zero percent meets the BWRVIPs expected level of implementation. Based on this, crediting weld inspections that do not meet essentially 100 percent coverage (i.e., at least 90 percent of |
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| | RS-16-052 Enclosure Page 3 of 11 the accessible weld), without disposition or justification, is inconsistent with the staffs expectation for implementation of the BWRVIP-based programs during the period of extended operation. |
| | Request: |
| | : 1. For the vessel ID attachment welds that include guidelines associated with the BWRVIP and rely on EVT-1 examinations, provide a summary of the locations where EVT-1 examinations are performed, indicate whether Alloy 182 welds are included, and the percent coverage for these examinations that can be qualified in accordance with the latest revision of BWRVIP-03. |
| | : 2. For vessel ID attachment weld locations, where examination coverage is expected to be less than 90 percent during the period of extended operation, provide the technical basis regarding the limited inspection coverage, and its adequacy to detect aging degradation prior to loss of intended function(s). |
| | : 3. For vessel ID attachment welds, provide a summary of the operating experience related to detected flaws, and the results of any flaw analyses, or other evaluations that may offer insights into flaw sizes that can be tolerated. |
| | : 4. Describe how inspection results that credit EVT-1 examinations (for vessel ID attachment welds) with minimal coverage (i.e., essentially zero percent coverage) will be documented and justified during the period of extended operation. |
| | : 5. State whether deviation reports will be submitted for inspection results for vessel attachment welds that credit examinations with limited coverage (e.g., less than 90 percent of accessible welds). If deviation reports will not be submitted, justify how the BWRVIP will provide adequate oversight of the effectiveness of the BWR Vessel ID Attachment Welds. |
| | Exelon Response |
| | : 1. The following tables provide a summary of the locations where EVT-1 examinations were performed for the LaSalle Unit 1 and Unit 2 vessel ID attachment welds in accordance with BWRVIP-48-A. Table 1 provides a summary of EVT-1 examination coverage of vessel ID attachment welds for Unit 1. Table 2 provides a summary of EVT-1 examination coverage of vessel ID attachment welds for Unit 2. All examinations were performed in accordance with the latest revision of BWRVIP-03 at the time of the examination. BWRVIP-03, Revision 10 implemented a requirement that the angle of inspection must not exceed 30 degrees from perpendicular to the examination surface to meet the qualification requirements of EVT-1. Prior to the implementation of BWRVIP-03, Revision 10, the angle of inspection could be as much as 60 degrees from perpendicular to the surface, the same as required for ASME Code Section XI VT-1 examinations. This change was made to enhance the EVT-1 examination method to better identify tight cracks that are characteristic of intergranular stress corrosion cracking (IGSCC). For a visual examination to be qualified as EVT-1, requirements for surface cleanliness and limitations on camera scanning speed must also be met. EVT-1 invokes the same requirement as VT-1, as defined in current ASME Code Section XI, for demonstration of character resolution. |
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| | RS-16-052 Enclosure Page 4 of 11 BWRVIP-03, Revision 10 was implemented for the first time at LaSalle for the Unit 2 refueling outage in 2009 and for the Unit 1 refueling outage in 2010. The following tables provide EVT-1 examination coverage for examinations performed prior to 2009, and also from 2009 through 2015, showing the decrease in EVT-1 coverage that resulted from the more restrictive angle of inspection that was implemented in 2009. |
| | Visual examinations are performed on the entire (100 percent) accessible surface of the vessel ID attachment weld, however only the percentage of the entire (accessible + |
| inaccessible) weld surface and adjacent base metal, where the examination requirements for EVT-1 can be met, is reported as the percentage of examination coverage. The accessible surface of the weld where not all of the EVT-1 examination requirements can be met is visually examined by a qualified NDE (Non-Destructive Examination) specialist, in accordance with site procedures and the guidance within BWRVIP-48-A and BWRVIP-03. For example, if a weld is 10 inches long and 9 inches of the weld is accessible for visual examination, and the examination requirements for EVT-1 can only be met for 7 inches of the weld, then 70 percent is reported as the EVT-1 examination coverage. The remaining accessible 2 inches is visually examined, but not to EVT-1 requirements. | | inaccessible) weld surface and adjacent base metal, where the examination requirements for EVT-1 can be met, is reported as the percentage of examination coverage. The accessible surface of the weld where not all of the EVT-1 examination requirements can be met is visually examined by a qualified NDE (Non-Destructive Examination) specialist, in accordance with site procedures and the guidance within BWRVIP-48-A and BWRVIP-03. For example, if a weld is 10 inches long and 9 inches of the weld is accessible for visual examination, and the examination requirements for EVT-1 can only be met for 7 inches of the weld, then 70 percent is reported as the EVT-1 examination coverage. The remaining accessible 2 inches is visually examined, but not to EVT-1 requirements. |
| TABLE 1 Unit 1 BWR Vessel ID Atta chment Weld Examinations Vessel ID Attachment Weld Location Exams 2004 through 2008 Exams 2009 through 2015 Number of EVT-1 weld exams Average EVT-1 Coverage Number of EVT-1 weld exams Average EVT-1 Coverage Minimum EVT-1 Coverage Core Spray Piping Brackets 8 88% 4 65% 65% Jet Pump Riser Braces 30 99% 18 74% 70% Steam Dryer Support Brackets 8 100% None performed; Next examinations are scheduled in 2016 Feedwater Sparger Brackets 14 69% None performed; Next examinations are scheduled in 2016 Total / Overall Average 60 91% 22 72% NA | | TABLE 1 Unit 1 BWR Vessel ID Attachment Weld Examinations Exams 2004 through Exams 2009 through 2015 Vessel ID Attachment 2008 Weld Location Number Average Number Average Minimum of EVT-1 EVT-1 of EVT-1 EVT-1 EVT-1 weld Coverage weld Coverage Coverage exams exams Core Spray Piping 8 88% 4 65% 65% |
| | Brackets Jet Pump Riser Braces 30 99% 18 74% 70% |
| | Steam Dryer Support 8 100% None performed; Next examinations Brackets are scheduled in 2016 Feedwater Sparger 14 69% None performed; Next examinations Brackets are scheduled in 2016 Total / Overall Average 60 91% 22 72% NA |
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| RS-16-052 Enclosure Page 5 of 11 TABLE 2 Unit 2 BWR Vessel ID Atta chment Weld Examinations Vessel ID Attachment Weld Location Exams 2004 through 2008 Exams 2009 through 2015 Number of EVT-1 weld exams Average EVT-1 Coverage Number of EVT-1 weld exams Average EVT-1 Coverage Minimum EVT-1 Coverage Core Spray Piping Brackets 10 86% 8 64% 60% Jet Pump Riser Braces 22 92% 10 70% 70% Steam Dryer Support Brackets 4 100% 4 96% 90% Feedwater Sparger Brackets 12 73% 12 53% 30% Total / Overall Average 48 87% 34 66% NA EVT-1 examination coverages of less than 100 percent are caused by physical interferences or component geometry such that the camera used for visual examination cannot be positioned close enough or within the required angle of inspection to the examination surface. The data shows that prior to 2009, qualified EVT-1 examination coverage averaged approximately 89 percent of the entire weld surface for the vessel ID attachment welds; whereas from 2009 to 2015, EVT-1 qualified examination coverage averaged approximately 68 percent. This reduc tion was caused by the EVT-1 required angle of inspection being reduced from 60 degrees to 30 degrees. In all cases the entire accessible weld surface was visually examined. Review of available records indicates that most of the LaSalle vessel ID attachment welds that are examined using the EVT-1 examination method are at least partially fabricated with Alloy 182 material that is susceptible to IGSCC. The EVT-1 examination method was developed to provide more effective visual examination that can detect tight cracks that are characteristic of IGSCC in reactor internal welds. | | RS-16-052 Enclosure Page 5 of 11 TABLE 2 Unit 2 BWR Vessel ID Attachment Weld Examinations Exams 2004 through Exams 2009 through 2015 Vessel ID Attachment 2008 Weld Location Number Average Number Average Minimum of EVT-1 EVT-1 of EVT-1 EVT-1 EVT-1 weld Coverage weld Coverage Coverage exams exams Core Spray Piping 10 86% 8 64% 60% |
| | Brackets Jet Pump Riser Braces 22 92% 10 70% 70% |
| | Steam Dryer Support 4 100% 4 96% 90% |
| | Brackets Feedwater Sparger 12 73% 12 53% 30% |
| | Brackets Total / Overall Average 48 87% 34 66% NA EVT-1 examination coverages of less than 100 percent are caused by physical interferences or component geometry such that the camera used for visual examination cannot be positioned close enough or within the required angle of inspection to the examination surface. The data shows that prior to 2009, qualified EVT-1 examination coverage averaged approximately 89 percent of the entire weld surface for the vessel ID attachment welds; whereas from 2009 to 2015, EVT-1 qualified examination coverage averaged approximately 68 percent. This reduction was caused by the EVT-1 required angle of inspection being reduced from 60 degrees to 30 degrees. In all cases the entire accessible weld surface was visually examined. |
| | Review of available records indicates that most of the LaSalle vessel ID attachment welds that are examined using the EVT-1 examination method are at least partially fabricated with Alloy 182 material that is susceptible to IGSCC. The EVT-1 examination method was developed to provide more effective visual examination that can detect tight cracks that are characteristic of IGSCC in reactor internal welds. |
| : 2. If the qualification requirements for the EVT-1 examination method remain unchanged during the period of extended operation, then the EVT-1 examination coverages for vessel ID attachment welds are expected to be consistent with those reported for the period of 2009 through 2015, as shown in Tables 1 and 2. The technical bases for limited EVT-1 examination coverage (less than 90 percent of the entire weld surface) being adequate to detect aging degradation prior to loss of intended function are as follows: | | : 2. If the qualification requirements for the EVT-1 examination method remain unchanged during the period of extended operation, then the EVT-1 examination coverages for vessel ID attachment welds are expected to be consistent with those reported for the period of 2009 through 2015, as shown in Tables 1 and 2. The technical bases for limited EVT-1 examination coverage (less than 90 percent of the entire weld surface) being adequate to detect aging degradation prior to loss of intended function are as follows: |
| RS-16-052 Enclosure Page 6 of 11 GALL Report AMP XI.M4, Element 4, Detection of Aging Effects, recommends examination in accordance with ASME Section XI, Subsection IWB, Examination Category B-N-2, supplemented with the inspection guidelines within BWRVIP-48-A and BWRVIP-03. ASME Section XI, Table IWB-2500-1, Examination Category B-N-2 requires examination of the accessible reactor vessel interior attachment welds. VT-1 is to be performed on attachment welds within the beltline and VT-3 is to be performed on welds outside the beltline. Section XI, IWA-2200(c) states that when performing "... examination on a component with a defined surface or volume, essentially 100% of the defined volume shall be examined. Essentially 100% coverage is achieved when the applicable examination coverage is greater than 90%; however ..." This 90 percent coverage requirement does not apply to ASME Code inspection of the vessel ID attachment welds since the "Examination Requirements/Figure No."
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| column in Table IWB-2500-1, Exam Category B-N-2 for vessel ID attachment welds, does not refer to a figure that defines the surface or volume; and instead it states that the "accessible welds" are required to be examined. Therefore, ASME Code requires 100 percent examination coverage of the surface of the vessel ID attachment welds that is accessible when using the specified visual examination method (i.e., VT-1 only or VT-3 only). LaSalle is committed to implement the examination requirements for vessel ID attachment welds in accordance with BWRVIP-48-A and BWRVIP-03. Since the examination methods directed for use in BWRVIP-48-A and BWRVIP-03 for some of the vessel ID attachment welds are different than those specified within ASME Code Section XI (i.e., EVT-1 instead of VT-1 or VT-3), Exelon applied for, and on April 30, 2008 was granted relief in accordance with 10 CFR 50.55(a), from certain ASME Code requirements. LaSalle is currently authorized to perform these examinations in accordance with BWRVIP-48-A and BWRVIP-03 as an alternate to certain ASME Code requirements. BWRVIP-48-A requires a different examination method for certain vessel ID attachment welds, but does not address required examination coverage for the welds. For EVT-1 examinations, the current revision (Revision 18) of BWRVIP-03, Section 2.5, "Generic Standards for Visual Inspection of Reactor Pressure Vessel Internals, Components, and Associated Repairs," subsection 6.4.1, which applies to visual examination of reactor internal components and welds, states "The area of interest for components shall consist of all accessible surfaces of the component." Subsection 6.4.1 continues to clarify that for welds the area of interest includes adjacent base metal. Since the BWRVIP examination coverage requirement is "The area of interest for components shall consist of all accessible surfaces of the component,"
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| and the ASME Code examination coverage requirement is "accessible welds," the examination coverage requirement is the same; that is, accessible surfaces. Therefore, BWRVIP-48-A and BWRVIP-03 do not change the examination coverage requirement from ASME Code Section XI requirements that are discussed above. However, as noted above, the examination methods directed for use in BWRVIP-48-A and BWRVIP-03 for certain vessel ID attachment welds are different, that is EVT-1, than those specified within ASME Code Section XI, which is VT-1 or VT-3. The EVT-1 examination method was developed to provide a more effective visual RS-16-052 Enclosure Page 7 of 11 examination to detect tight cracks that are characteristic of IGSCC in reactor internal welds. BWRVIP-03 and the procedure used to perform EVT-1 at LaSalle require examination of the entire (100 percent) accessible examination surface; however only the percentage of the entire (accessible + inaccessible) weld surface where the examination requirements for EVT-1 can be met is reported as the percentage of examination coverage. The accessible weld surface where not all the EVT-1 examination can be met is visually examined by a qualified NDE specialist. Since EVT-1 has been demonstrated to be more effective at detecting tight cracks that are characteristic of IGSCC, it is specified within BWRVIP-48-A as the examination method for vessel ID attachment welds that are most susceptible to IGSCC. The examination is performed by a NDE specialist qualified to at least Level II, independently reviewed by a qualified Level II or III NDE specialist, and oversight is provided by an Exelon representative. The training and qualification standards required for the examiner and independent reviewer provide assurance that the proper EVT-1 examination coverage is documented in accordance with procedure requirements. In summary, although limited EVT-1 examination coverage (less than 90 percent of the entire weld surface) may be reported for some vessel ID attachment welds; those examinations are adequate to detect aging degradation prior to loss of intended function.
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| The EVT-1 method is the nuclear industry standard for visual examination to detect IGSCC cracks. The implementing procedures for EVT-1 examination require visual examination of the entire accessible weld surface and qualifying the EVT-1 examination to the maximum extent practical coverage. Although LaSalle implements a NRC-approved ASME Code alternative for the current 10-year inservice inspection interval to perform examinations of vessel ID attachment welds in accordance with BWRVIP-48-A in lieu of ASME Code requirements, the alternative involves implementing a more effective visual examination method for certain welds and the ASME Code Section XI requirement to inspect the accessible welds is met. 3. Cracking indications have not been detected in any LaSalle Unit 1 or Unit 2 vessel ID attachment welds during their operating history. Therefore, there have not been any flaw analyses or other evaluations performed to determine the maximum flaw sizes that can be tolerated. There also has not been any operating experience of cracking caused by IGSCC in vessel ID attachment welds within the domestic BWR fleet. As discussed within BWRVIP-48-A, there was one domestic BWR that detected cracking in a steam dryer support bracket that was caused by fatigue. The causes of that event did not have generic implications for other BWRs. The following guidance for evaluating flaws detected in vessel ID attachment welds is provided in BWRVIP-48-A. If cracking is detected in a vessel ID attachment weld, the flaw would be evaluated using the acceptance criteria within ASME Section XI, IWB-3140 and the examination standards within ASME Section XI, IWB-3520. If the acceptance criteria for the flaw are not met, then the flaw would be evaluated in accordance with ASME Section XI, IWB-3600 for acceptability, which includes RS-16-052 Enclosure Page 8 of 11 determining the maximum allowable flaw size at the flaw location and comparing that to the existing flaw, including flaw growth. 4. LaSalle operating experience, as summarized in Tables 1 and 2, indicates that EVT-1 examinations of vessel ID attachment welds with essentially zero percent coverage have not been credited in the past, and are not expected to occur or be credited during the period of extended operation. Exelon has revised the referenced procedure ER-AB-331 to delete discussion of the possibility of zero percent EVT-1 examination coverage being acceptable. The procedure has been revised to require that when EVT-1 or VT-1 method is specified, the entire accessible surface of the weld or components is to be visually examined and the specified method (EVT-1 or VT-1) is to be performed to the maximum extent practical given the qualifications requirements for the specified visual examination method. This is consistent with the current revision of BWRVIP-03 (Revision 18) and the implementing procedure us ed at LaSalle for EVT-1 examination of vessel internals. The procedure has been revised to clarify that if a visual examination of a reactor internal component results in zero percent EVT-1 examination coverage, the condition would be entered into the corrective action program and evaluated for whether a BWRVIP deviation report would be required. As shown in Tables 1 and 2 above, the minimum historical EVT-1 coverage is 30 percent for a Unit 2 feedwater sparger
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| attachment weld and the average EVT-1 examination coverages are approximately 68 percent for vessel ID attachment welds. Therefore, it is not expected that any EVT-1 examinations of vessel ID attachment welds would approach essentially zero percent examination coverage during the period of extended operation. 5. As discussed in NEI 03-08, Revision 2, BWRVIP deviation reports are required to be submitted if "mandatory" or "needed" work product elements are not being implemented consistent with the intent of the BWRVIP guidance. Exelon implementing procedures require submittal of deviation reports consistent with this guidance. It is expected that during the period of extended operation, the EVT-1 examination coverages will be typical of those reported in Table 1 and 2 above. The LaSalle implementing procedures for | | RS-16-052 Enclosure Page 6 of 11 GALL Report AMP XI.M4, Element 4, Detection of Aging Effects, recommends examination in accordance with ASME Section XI, Subsection IWB, Examination Category B-N-2, supplemented with the inspection guidelines within BWRVIP-48-A and BWRVIP-03. ASME Section XI, Table IWB-2500-1, Examination Category B-N-2 requires examination of the accessible reactor vessel interior attachment welds. VT-1 is to be performed on attachment welds within the beltline and VT-3 is to be performed on welds outside the beltline. |
| | Section XI, IWA-2200(c) states that when performing ... examination on a component with a defined surface or volume, essentially 100% of the defined volume shall be examined. Essentially 100% coverage is achieved when the applicable examination coverage is greater than 90%; however ... This 90 percent coverage requirement does not apply to ASME Code inspection of the vessel ID attachment welds since the Examination Requirements/Figure No. |
| | column in Table IWB-2500-1, Exam Category B-N-2 for vessel ID attachment welds, does not refer to a figure that defines the surface or volume; and instead it states that the accessible welds are required to be examined. Therefore, ASME Code requires 100 percent examination coverage of the surface of the vessel ID attachment welds that is accessible when using the specified visual examination method (i.e., VT-1 only or VT-3 only). |
| | LaSalle is committed to implement the examination requirements for vessel ID attachment welds in accordance with BWRVIP-48-A and BWRVIP-03. Since the examination methods directed for use in BWRVIP-48-A and BWRVIP-03 for some of the vessel ID attachment welds are different than those specified within ASME Code Section XI (i.e., EVT-1 instead of VT-1 or VT-3), Exelon applied for, and on April 30, 2008 was granted relief in accordance with 10 CFR 50.55(a), |
| | from certain ASME Code requirements. LaSalle is currently authorized to perform these examinations in accordance with BWRVIP-48-A and BWRVIP-03 as an alternate to certain ASME Code requirements. BWRVIP-48-A requires a different examination method for certain vessel ID attachment welds, but does not address required examination coverage for the welds. For EVT-1 examinations, the current revision (Revision 18) of BWRVIP-03, Section 2.5, Generic Standards for Visual Inspection of Reactor Pressure Vessel Internals, Components, and Associated Repairs, subsection 6.4.1, which applies to visual examination of reactor internal components and welds, states The area of interest for components shall consist of all accessible surfaces of the component. Subsection 6.4.1 continues to clarify that for welds the area of interest includes adjacent base metal. Since the BWRVIP examination coverage requirement is The area of interest for components shall consist of all accessible surfaces of the component, and the ASME Code examination coverage requirement is accessible welds, the examination coverage requirement is the same; that is, accessible surfaces. Therefore, BWRVIP-48-A and BWRVIP-03 do not change the examination coverage requirement from ASME Code Section XI requirements that are discussed above. However, as noted above, the examination methods directed for use in BWRVIP-48-A and BWRVIP-03 for certain vessel ID attachment welds are different, that is EVT-1, than those specified within ASME Code Section XI, which is VT-1 or VT-3. The EVT-1 examination method was developed to provide a more effective visual |
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| | RS-16-052 Enclosure Page 7 of 11 examination to detect tight cracks that are characteristic of IGSCC in reactor internal welds. |
| | BWRVIP-03 and the procedure used to perform EVT-1 at LaSalle require examination of the entire (100 percent) accessible examination surface; however only the percentage of the entire (accessible + inaccessible) weld surface where the examination requirements for EVT-1 can be met is reported as the percentage of examination coverage. The accessible weld surface where not all the EVT-1 examination can be met is visually examined by a qualified NDE specialist. Since EVT-1 has been demonstrated to be more effective at detecting tight cracks that are characteristic of IGSCC, it is specified within BWRVIP-48-A as the examination method for vessel ID attachment welds that are most susceptible to IGSCC. |
| | The examination is performed by a NDE specialist qualified to at least Level II, independently reviewed by a qualified Level II or III NDE specialist, and oversight is provided by an Exelon representative. The training and qualification standards required for the examiner and independent reviewer provide assurance that the proper EVT-1 examination coverage is documented in accordance with procedure requirements. |
| | In summary, although limited EVT-1 examination coverage (less than 90 percent of the entire weld surface) may be reported for some vessel ID attachment welds; those examinations are adequate to detect aging degradation prior to loss of intended function. |
| | The EVT-1 method is the nuclear industry standard for visual examination to detect IGSCC cracks. The implementing procedures for EVT-1 examination require visual examination of the entire accessible weld surface and qualifying the EVT-1 examination to the maximum extent practical coverage. Although LaSalle implements a NRC-approved ASME Code alternative for the current 10-year inservice inspection interval to perform examinations of vessel ID attachment welds in accordance with BWRVIP-48-A in lieu of ASME Code requirements, the alternative involves implementing a more effective visual examination method for certain welds and the ASME Code Section XI requirement to inspect the accessible welds is met. |
| | : 3. Cracking indications have not been detected in any LaSalle Unit 1 or Unit 2 vessel ID attachment welds during their operating history. Therefore, there have not been any flaw analyses or other evaluations performed to determine the maximum flaw sizes that can be tolerated. There also has not been any operating experience of cracking caused by IGSCC in vessel ID attachment welds within the domestic BWR fleet. As discussed within BWRVIP-48-A, there was one domestic BWR that detected cracking in a steam dryer support bracket that was caused by fatigue. The causes of that event did not have generic implications for other BWRs. |
| | The following guidance for evaluating flaws detected in vessel ID attachment welds is provided in BWRVIP-48-A. If cracking is detected in a vessel ID attachment weld, the flaw would be evaluated using the acceptance criteria within ASME Section XI, IWB-3140 and the examination standards within ASME Section XI, IWB-3520. If the acceptance criteria for the flaw are not met, then the flaw would be evaluated in accordance with ASME Section XI, IWB-3600 for acceptability, which includes |
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| performing visual examination of reactor vessel internals require that when EVT-1 or VT-1 method is specified, the entire (100 percent) accessible surface of the weld or components is to be visually examined and the specified method (EVT-1 or VT-1) is to be performed to the maximum extent practical given the qualifications requirements for specified visual examination method. This is consistent with BWRVIP-48-A and the current revision of BWRVIP-03 (Revision 18). The BWRVIP provides adequate oversight of the effectiveness of the BWR Vessel ID Attachment Welds aging management program by utilizing INPO to review the implementation of the overall BWRVIP program as discussed in NEI 03-08 Revision 2. | | RS-16-052 Enclosure Page 8 of 11 determining the maximum allowable flaw size at the flaw location and comparing that to the existing flaw, including flaw growth. |
| | : 4. LaSalle operating experience, as summarized in Tables 1 and 2, indicates that EVT-1 examinations of vessel ID attachment welds with essentially zero percent coverage have not been credited in the past, and are not expected to occur or be credited during the period of extended operation. Exelon has revised the referenced procedure ER-AB-331 to delete discussion of the possibility of zero percent EVT-1 examination coverage being acceptable. The procedure has been revised to require that when EVT-1 or VT-1 method is specified, the entire accessible surface of the weld or components is to be visually examined and the specified method (EVT-1 or VT-1) is to be performed to the maximum extent practical given the qualifications requirements for the specified visual examination method. This is consistent with the current revision of BWRVIP-03 (Revision 18) and the implementing procedure used at LaSalle for EVT-1 examination of vessel internals. |
| | The procedure has been revised to clarify that if a visual examination of a reactor internal component results in zero percent EVT-1 examination coverage, the condition would be entered into the corrective action program and evaluated for whether a BWRVIP deviation report would be required. As shown in Tables 1 and 2 above, the minimum historical EVT-1 coverage is 30 percent for a Unit 2 feedwater sparger attachment weld and the average EVT-1 examination coverages are approximately 68 percent for vessel ID attachment welds. Therefore, it is not expected that any EVT-1 examinations of vessel ID attachment welds would approach essentially zero percent examination coverage during the period of extended operation. |
| | : 5. As discussed in NEI 03-08, Revision 2, BWRVIP deviation reports are required to be submitted if mandatory or needed work product elements are not being implemented consistent with the intent of the BWRVIP guidance. Exelon implementing procedures require submittal of deviation reports consistent with this guidance. It is expected that during the period of extended operation, the EVT-1 examination coverages will be typical of those reported in Table 1 and 2 above. The LaSalle implementing procedures for performing visual examination of reactor vessel internals require that when EVT-1 or VT-1 method is specified, the entire (100 percent) accessible surface of the weld or components is to be visually examined and the specified method (EVT-1 or VT-1) is to be performed to the maximum extent practical given the qualifications requirements for specified visual examination method. This is consistent with BWRVIP-48-A and the current revision of BWRVIP-03 (Revision 18). |
| | The BWRVIP provides adequate oversight of the effectiveness of the BWR Vessel ID Attachment Welds aging management program by utilizing INPO to review the implementation of the overall BWRVIP program as discussed in NEI 03-08 Revision 2. |
| The BWRVIP program includes aging management of the vessel ID attachment welds as defined in BWRVIP-48-A and BWRVIP-03. Specific activities include participation in periodic comprehensive on-site assessments of program implementation, monitoring, review and analysis of industry operating experience, and providing industry updates to the industry on trends in performance in implementing the program. Also, the results of reactor in-vessel examinations are provided to the BWRVIP following each refueling outage. | | The BWRVIP program includes aging management of the vessel ID attachment welds as defined in BWRVIP-48-A and BWRVIP-03. Specific activities include participation in periodic comprehensive on-site assessments of program implementation, monitoring, review and analysis of industry operating experience, and providing industry updates to the industry on trends in performance in implementing the program. Also, the results of reactor in-vessel examinations are provided to the BWRVIP following each refueling outage. |
| RS-16-052 Enclosure Page 9 of 11 RAI B.2.1.7-3b | | |
| | RS-16-052 Enclosure Page 9 of 11 RAI B.2.1.7-3b |
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| ==Background:== | | ==Background:== |
| By letters dated June 25, 2015, and September 15, 2015, Exelon responded to requests for additional information (RAIs) B.2.1.7-3 and B.2.1.7-3a regarding limited examination coverage for inspections of welds associated with the BWR Stress Corrosion Cracking AMP and NRC Generic Letter (GL) 88-01. Exelon's responses indicate that additional inspections to compensate for limited examination coverage are not necessary to manage cracking due to intergranular stress corrosion cracking during the period of extended operation. As discussed in the initial RAI, GL 88-01 states, "Examinations performed under the Scope of this letter should comply with the applicable Edition and Addenda of the ASME Code, Section XI, as specified in paragraph (g), 'Inservice Inspection (ISI) Requirements' of 10 CFR 50.55a, Codes and Standards, or as otherwise approved by the NRC." In addition, the required volume for ASME Code examinations is defined as more than 90 percent of the specified volume. Based on information from LSCS's docketed ISI reports, the examination coverage for a number of GL 88-01 welds is only 50 percent. Although the staff-approved BWRVIP-75-A, "Technical Basis for Revisions to Generic Letter 88-01 Inspection Schedules," allows for modifications to the inspection extent and schedule described in GL 88-01, the modification to the inspection extent only applies to the number of welds being inspected, not the extent of examination coverage. BWRVIP-75-A does not specifically address the minimum required effective examination coverage. Issue: Although not explicitly addressed in BWRVIP-75-A, the staff's expectation has been that the examination coverage of inspections performed for AMPs consistent with GALL Report AMP XI.M7 "BWR Stress Corrosion Cracking," would be the same as that required by the ASME Code (i.e., greater than 90 percent). BWRVIP-75-A includes a discussion about the sampling percentages from ASME Section XI Inspection requirements and notes that ASME Section XI has been the ISI mechanism for assuring a robust reactor coolant system boundary and an adequate level of plant safety. Crediting weld inspections that do not meet the required ASME Code examination coverage without specific documented justification is inconsistent with the staff's expectation for implementation of the BWR Stress Corrosion Cracking program, during the period of extended operation. Since a minimum extent of effective examination coverage is not specified in BWRVIP-75-A, it is unclear to the staff what percentage of examination volume coverage Exelon considers as "inspected" for a weld examination that will be credited under the BWR Stress Corrosion Cracking program. Although Exelon has not considered additional weld inspections as being necessary to compensate for limited examination coverage, it is unclear to the staff that sufficient bases will be documented and independently reviewed to justify the limited examination coverage, where less than 90 percent of a weld has been examined. The staff considers sufficient bases, as information comparable to that which would be included in a relief request, had the inspection been an ASME Code examination.
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| RS-16-052 Enclosure Page 10 of 11 Request: 1. State the minimum percentage of weld volume examination coverage for a single weld to be considered "inspected" under the BWR Stress Corrosion Cracking program, during the period of extended operation. If the minimum examination volume coverage percentage for crediting a weld as "inspected" is less than 90 percent, provide the technical basis to show that "adequate levels of piping integrity and reliability" will be achieved, as discussed in GL 88-01. 2. For each inspection performed under the BWR Stress Corrosion Cracking program, which will credit weld examinations with less than 90 percent coverage (during the period of extended operation), a. state whether documentation will be available onsite that provides the justification for the limitation, and whether the documentation will be independently reviewed
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| to validate the justification, b. if documentation discussed in a) above will not be available, identify the controls that will be established to justify the limited weld examinations. | | By letters dated June 25, 2015, and September 15, 2015, Exelon responded to requests for additional information (RAIs) B.2.1.7-3 and B.2.1.7-3a regarding limited examination coverage for inspections of welds associated with the BWR Stress Corrosion Cracking AMP and NRC Generic Letter (GL) 88-01. Exelons responses indicate that additional inspections to compensate for limited examination coverage are not necessary to manage cracking due to intergranular stress corrosion cracking during the period of extended operation. |
| | As discussed in the initial RAI, GL 88-01 states, Examinations performed under the Scope of this letter should comply with the applicable Edition and Addenda of the ASME Code, Section XI, as specified in paragraph (g), Inservice Inspection (ISI) Requirements of 10 CFR 50.55a, Codes and Standards, or as otherwise approved by the NRC. In addition, the required volume for ASME Code examinations is defined as more than 90 percent of the specified volume. |
| | Based on information from LSCSs docketed ISI reports, the examination coverage for a number of GL 88-01 welds is only 50 percent. Although the staff-approved BWRVIP-75-A, Technical Basis for Revisions to Generic Letter 88-01 Inspection Schedules, allows for modifications to the inspection extent and schedule described in GL 88-01, the modification to the inspection extent only applies to the number of welds being inspected, not the extent of examination coverage. BWRVIP-75-A does not specifically address the minimum required effective examination coverage. |
| | Issue: |
| | Although not explicitly addressed in BWRVIP-75-A, the staffs expectation has been that the examination coverage of inspections performed for AMPs consistent with GALL Report AMP XI.M7 BWR Stress Corrosion Cracking, would be the same as that required by the ASME Code (i.e., greater than 90 percent). BWRVIP-75-A includes a discussion about the sampling percentages from ASME Section XI Inspection requirements and notes that ASME Section XI has been the ISI mechanism for assuring a robust reactor coolant system boundary and an adequate level of plant safety. Crediting weld inspections that do not meet the required ASME Code examination coverage without specific documented justification is inconsistent with the staffs expectation for implementation of the BWR Stress Corrosion Cracking program, during the period of extended operation. |
| | Since a minimum extent of effective examination coverage is not specified in BWRVIP-75-A, it is unclear to the staff what percentage of examination volume coverage Exelon considers as inspected for a weld examination that will be credited under the BWR Stress Corrosion Cracking program. Although Exelon has not considered additional weld inspections as being necessary to compensate for limited examination coverage, it is unclear to the staff that sufficient bases will be documented and independently reviewed to justify the limited examination coverage, where less than 90 percent of a weld has been examined. The staff considers sufficient bases, as information comparable to that which would be included in a relief request, had the inspection been an ASME Code examination. |
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| | RS-16-052 Enclosure Page 10 of 11 Request: |
| | : 1. State the minimum percentage of weld volume examination coverage for a single weld to be considered inspected under the BWR Stress Corrosion Cracking program, during the period of extended operation. If the minimum examination volume coverage percentage for crediting a weld as inspected is less than 90 percent, provide the technical basis to show that adequate levels of piping integrity and reliability will be achieved, as discussed in GL 88-01. |
| | : 2. For each inspection performed under the BWR Stress Corrosion Cracking program, which will credit weld examinations with less than 90 percent coverage (during the period of extended operation), |
| | : a. state whether documentation will be available onsite that provides the justification for the limitation, and whether the documentation will be independently reviewed to validate the justification, |
| | : b. if documentation discussed in a) above will not be available, identify the controls that will be established to justify the limited weld examinations. |
| Exelon Response | | Exelon Response |
| : 1. The minimum percentage of weld volume examination coverage for a single weld to be considered "inspected" under the current GL 88-01 program and BWR Stress Corrosion Cracking program during the period of extended operation is greater than 90 percent, unless the bases for accepting the limited coverage is evaluated and documented. As discussed in the response to RAI B.2.1.7-3a, all volumetric examinations under the BWR Stress Corrosion Cracking program are performed using current Performance Demonstration Initiative (PDI) methods and procedures. For certain weld configurations, due to the specific contour of the weld or other interferences to the equipment used to perform the examination, the PDI method can only provide qualified and reliable examination results for a limited examination volume of the weld that may be less than or equal to 90 percent. For welds with less than or equal to 90 percent examination coverage to be considered "inspected" during the period of extended operation under the BWR Stress Corrosion Cracking program, the condition will be evaluated as discussed below. The current Exelon implementing procedure for inservice inspection of welds requires generation of a corrective action issue report with related documentation and disposition for weld examinations that have limited examination coverage (i.e., less than or equal to 90 percent). If the examination is credited to meet ASME Section XI Inservice Inspection requirements, then the procedure also requires justifying the adequacy of the limited examination coverage in a relief request from ASME Code Section XI inservice inspection requirements. The procedure also specifies actions to ensure that the examination coverage is maximized to the extent practical. The procedure will be revised to improve clarity for the extent of evaluation required when examination coverage is less than or equal to 90 percent for weld examinations that are only credited under the BWR Stress Corrosion Cracking program (i.e., not credited to meet ASME Code Section XI requirements). This guidance will require performing an Engineering Technical Evaluation that includes content comparable with that which would be RS-16-052 Enclosure Page 11 of 11 included in a relief request, had the inspection been an ASME Code examination. Welds with less than or equal to 90 percent coverage, that are examined to the maximum examination coverage attainable using the PDI methods and procedures, may be considered "inspected" under the BWR Stress Corrosion Cracking program if the Engineering Technical Evaluation provides a documented bases that is comparable with the content of a relief request, had the inspection been an ASME Code examination. 2. a. For each weld examination performed during the period of extended operation under the BWR Stress Corrosion Cracking program, which will credit examinations with less than or equal to 90 percent coverage, documentation will be available onsite that provides the justification for the limitation. As discussed in the response to request 1 above, if the weld examination is also credited to meet ASME Code Section XI inservice inspection requirements, a relief request from ASME Code requirements that provides the justification for the limitation will be submitted for NRC approval. For weld examinations that are only credited under the BWR Stress Corrosion Cracking program, an Engineering Technical Evaluation will provide the justification for the limited examination coverage as adequate to credit the weld examination. Procedural guidance for Engineering Technical Evaluations requires safety-related Engineering Technical Evaluations to be independently reviewed and maintained as permanent plant records. Since | | : 1. The minimum percentage of weld volume examination coverage for a single weld to be considered inspected under the current GL 88-01 program and BWR Stress Corrosion Cracking program during the period of extended operation is greater than 90 percent, unless the bases for accepting the limited coverage is evaluated and documented. As discussed in the response to RAI B.2.1.7-3a, all volumetric examinations under the BWR Stress Corrosion Cracking program are performed using current Performance Demonstration Initiative (PDI) methods and procedures. For certain weld configurations, due to the specific contour of the weld or other interferences to the equipment used to perform the examination, the PDI method can only provide qualified and reliable examination results for a limited examination volume of the weld that may be less than or equal to 90 percent. |
| | For welds with less than or equal to 90 percent examination coverage to be considered inspected during the period of extended operation under the BWR Stress Corrosion Cracking program, the condition will be evaluated as discussed below. The current Exelon implementing procedure for inservice inspection of welds requires generation of a corrective action issue report with related documentation and disposition for weld examinations that have limited examination coverage (i.e., less than or equal to 90 percent). If the examination is credited to meet ASME Section XI Inservice Inspection requirements, then the procedure also requires justifying the adequacy of the limited examination coverage in a relief request from ASME Code Section XI inservice inspection requirements. The procedure also specifies actions to ensure that the examination coverage is maximized to the extent practical. The procedure will be revised to improve clarity for the extent of evaluation required when examination coverage is less than or equal to 90 percent for weld examinations that are only credited under the BWR Stress Corrosion Cracking program (i.e., not credited to meet ASME Code Section XI requirements). This guidance will require performing an Engineering Technical Evaluation that includes content comparable with that which would be |
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| all welds examined under the BWR Stress Corrosion Cracking program are safety-related, the Engineering Technical Evaluations that provide the justification for the limited examination coverage will be independently reviewed, retained, and available for onsite review. b. As discussed in the response to request 2a, the documentation that provides the justification for the limited examination coverage being adequate to credit the weld examination during the period of extended operation will be available as a permanent plant record.}} | | RS-16-052 Enclosure Page 11 of 11 included in a relief request, had the inspection been an ASME Code examination. |
| | Welds with less than or equal to 90 percent coverage, that are examined to the maximum examination coverage attainable using the PDI methods and procedures, may be considered inspected under the BWR Stress Corrosion Cracking program if the Engineering Technical Evaluation provides a documented bases that is comparable with the content of a relief request, had the inspection been an ASME Code examination. |
| | : 2. a. For each weld examination performed during the period of extended operation under the BWR Stress Corrosion Cracking program, which will credit examinations with less than or equal to 90 percent coverage, documentation will be available onsite that provides the justification for the limitation. As discussed in the response to request 1 above, if the weld examination is also credited to meet ASME Code Section XI inservice inspection requirements, a relief request from ASME Code requirements that provides the justification for the limitation will be submitted for NRC approval. For weld examinations that are only credited under the BWR Stress Corrosion Cracking program, an Engineering Technical Evaluation will provide the justification for the limited examination coverage as adequate to credit the weld examination. Procedural guidance for Engineering Technical Evaluations requires safety-related Engineering Technical Evaluations to be independently reviewed and maintained as permanent plant records. Since all welds examined under the BWR Stress Corrosion Cracking program are safety-related, the Engineering Technical Evaluations that provide the justification for the limited examination coverage will be independently reviewed, retained, and available for onsite review. |
| | : b. As discussed in the response to request 2a, the documentation that provides the justification for the limited examination coverage being adequate to credit the weld examination during the period of extended operation will be available as a permanent plant record.}} |
Letter Sequence Response to RAI |
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TAC:MF5346, Control Room Habitability (Approved, Closed) TAC:MF5347, Control Room Habitability (Approved, Closed) |
Results
Other: ML15104A782, ML15196A045, ML15196A115, ML16202A033, RS-15-193, Responds to NRC Requests for Additional Information, Set 5, Dated July 7, 2015 Related to the License Renewal Application, RS-15-194, Responds to NRC Requests for Additional Information, Set 6, Dated July 7, 2015 Related to the License Renewal Application, RS-15-305, Corrections to the License Renewal Application Dated December 9, 2014, RS-15-306, Submittal of 10 CFR 54.21(b) Annual Amendment to the License Renewal Application, RS-16-033, Update to Commitment 47 Related to the License Renewal Application, RS-16-068, Comments on the Safety Evaluation Report with Open Items, Related to the License Renewal Application, RS-16-128, Second 10 CFR 54.21(b) Annual Amendment to the License Renewal Application
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MONTHYEARML15104A7822015-05-0808 May 2015 Scoping and Screening Methodology Audit Report Regarding LaSalle County Station, Units 1 and 2 Project stage: Other ML15111A1372015-05-14014 May 2015 Requests for Additional Information for the Review of the LaSalle County Station, Units 1 and 2 License Renewal Application - Set 1 (TAC Nos. MF5347 and MF5346) Project stage: RAI ML15125A1982015-05-29029 May 2015 Requests for Additional Information for the Review of the LaSalle County Station, Units 1 and 2 License Renewal Application - Set 2 (TAC Nos. MF5347 and MF5346) Project stage: RAI ML15131A4132015-06-0808 June 2015 Requests for Additional Information for the Review of the LaSalle County Station, Units 1 and 2 License Renewal Application - Set 3 (TAC Nos. MF5347 and MF5346) Project stage: RAI ML15140A1922015-06-0808 June 2015 Summary of Telephone Conference Call Held on May 13, 2015, Between the U.S. Nuclear Regulatory Commission and Exelon Generation Co., LLC, Concerning Requests for Additional Information, Set 2 Pertaining to the Lasalle County Station License Project stage: RAI ML15146A2622015-06-19019 June 2015 Requests for Additional Information for the Review of the LaSalle County Station, Units 1 and 2 License Renewal Application-Set 4 (TAC Nos. MF5347 and MF5346) Project stage: RAI RS-15-165, Response to NRC Requests for Additional Information, Set 2, Dated May 29, 2015 Related to the License Renewal Application2015-06-25025 June 2015 Response to NRC Requests for Additional Information, Set 2, Dated May 29, 2015 Related to the License Renewal Application Project stage: Response to RAI RS-15-171, Response to NRC Requests for Additional Information, Set 3, Dated June 8, 2015, Related to the License Renewal Application2015-07-0101 July 2015 Response to NRC Requests for Additional Information, Set 3, Dated June 8, 2015, Related to the License Renewal Application Project stage: Response to RAI ML15159A9002015-07-0606 July 2015 Telephone Conference Call Held on May 20, 2015, Between the U.S. Nuclear Regulatory Commission and Exelon Generation Co., LLC, Requests for Additional Information, Set 3 Pertaining to the LaSalle County Station License Renewal Application ( Project stage: RAI ML15163A0712015-07-0707 July 2015 Requests for Additional Information for the Review of the LaSalle County Station, Units 1 and 2 License Renewal Application - Set 6 (TAC Nos. MF5347 and MF5346) Project stage: RAI ML15159A2082015-07-0707 July 2015 Requests for Additional Information for the Review of the LaSalle County Station, Units 1 and 2 License Renewal Application - Set 5 (TAC Nos. MF5347 and MF5346) Project stage: RAI RS-15-180, Response to NRC Requests for Additional Information, Set 4, Dated June 19, 2015 Related to the License Renewal Application2015-07-15015 July 2015 Response to NRC Requests for Additional Information, Set 4, Dated June 19, 2015 Related to the License Renewal Application Project stage: Response to RAI RS-15-198, Request for Schedule Change Related to Advisory Committee on Reactor Safeguards (ACRS) Subcommittee Review of License Renewal Application (TAC Nos. MF5347 and MF5346)2015-07-16016 July 2015 Request for Schedule Change Related to Advisory Committee on Reactor Safeguards (ACRS) Subcommittee Review of License Renewal Application (TAC Nos. MF5347 and MF5346) Project stage: Request ML15196A5292015-07-27027 July 2015 Requests for Additional Information for the Review of the Lasalle County Station, Units 1 and 2 License Renewal Application - Set 7 (Tac Nos. MF5347 and MF5346) Project stage: RAI RS-15-194, Responds to NRC Requests for Additional Information, Set 6, Dated July 7, 2015 Related to the License Renewal Application2015-08-0606 August 2015 Responds to NRC Requests for Additional Information, Set 6, Dated July 7, 2015 Related to the License Renewal Application Project stage: Other RS-15-193, Responds to NRC Requests for Additional Information, Set 5, Dated July 7, 2015 Related to the License Renewal Application2015-08-0606 August 2015 Responds to NRC Requests for Additional Information, Set 5, Dated July 7, 2015 Related to the License Renewal Application Project stage: Other ML15204A6302015-08-18018 August 2015 Requests for Additional Information for the Review of the LaSalle County Station Units 1 & 2 License Renewal Application - Set 9 (TAC Nos. MF5347 and MF5346) Project stage: RAI RS-15-223, Response to NRC Requests for Additional Information, Set 7, Dated July 27, 2015; and a Correction to Information Associated with the Set 2 Response to RAI 8.2.1.20-2, Related to the Renewal Application2015-08-26026 August 2015 Response to NRC Requests for Additional Information, Set 7, Dated July 27, 2015; and a Correction to Information Associated with the Set 2 Response to RAI 8.2.1.20-2, Related to the Renewal Application Project stage: Response to RAI ML15229A0192015-08-27027 August 2015 Requests for Additional Information for the Review of the LaSalle County Station, Units 1 and 2 License Renewal Application - Set 10 (TAC Nos. MF5347 and MF5346) Project stage: RAI ML15217A5412015-08-28028 August 2015 June 9, 2015, Summary of Telecon Held Between the NRC and Exelon Generation Co., LLC, Concerning Request for Additional Information Set 5 Pertaining to the LaSalle County Station License Renewal Application (TAC Nos. MF5347 and MF5346) Project stage: RAI ML15217A5642015-08-28028 August 2015 June 3, 2015, Summary of Telecon Held Between the NRC and Exelon Generation Co., LLC, Concerning Request for Additional Information Set 4 Pertaining to the LaSalle County Station License Renewal Application (Tac Nos. MF5347 and MF5346) Project stage: RAI ML15217A5752015-08-28028 August 2015 June 10, 2015, Summary of Telecon Held Between the NRC and Exelon Generation Co., LLC, Concerning Request for Additional Information Set 4 Pertaining to the LaSalle County Station License Renewal Application (TAC Nos. MF5347 and MF5346) Project stage: RAI ML15219A2772015-08-28028 August 2015 June 23, 2015, Summary of Telecon Held Between the NRC and Exelon Generation Co., LLC, Concerning Request for Additional Information Set 6 Pertaining to the LaSalle County Station License Renewal Application (TAC Nos. MF5347 and MF5346) Project stage: RAI ML15222A0062015-08-28028 August 2015 August 5, 2015, Summary of Telecon Held Between the NRC and Exelon Generation Co., LLC, Concerning Request for Additional Information Set 9 Pertaining to the LaSalle County Station License Renewal Application (TAC Nos. MF5347 and MF5346) Project stage: RAI ML15195A3382015-08-28028 August 2015 Requests for Additional Information for the Review of the LaSalle County Station, Units 1 and 2 License Renewal Application-Set 8 (TAC Nos. MF5347 and MF5346) Project stage: RAI ML15222A0082015-08-28028 August 2015 July 22, 2015, Summary of Telecon Held Between the NRC and Exelon Generation Co., LLC, Concerning Request for Additional Information Set 8 Pertaining to the LaSalle County Station License Renewal Application (TAC Nos. MF5347 and MF5346) Project stage: RAI ML15222A0152015-08-28028 August 2015 July 8, 2015, Summary of Telecon Held Between the NRC and Exelon Generation Co., LLC, Concerning Request for Additional Information Set 7 Pertaining to the LaSalle County Station License Renewal Application (TAC Nos. MF5347 and MF5346) Project stage: RAI ML15224A9352015-08-28028 August 2015 August 11, 2015, Summary of Telecon Held Between the NRC and Exelon Generation Co., LLC, Concerning Request for Additional Information Set 9 Pertaining to the LaSalle County Station License Renewal Application (TAC Nos. MF5347 and MF5346) Project stage: RAI ML15244B3532015-09-14014 September 2015 RAI for the Review of the LaSalle County Station, Units 1 and 2 License Renewal Application - Set 11 (TAC Nos. MF5347 and MF5346) Project stage: RAI RS-15-232, Response to NRC Requests for Additional Information, Set 9, Dated August 18, 2015 Related to the License Renewal Application2015-09-15015 September 2015 Response to NRC Requests for Additional Information, Set 9, Dated August 18, 2015 Related to the License Renewal Application Project stage: Response to RAI RS-15-238, Response to NRC Requests for Additional Information, Set 10, Dated August 27, 2015 Related to License Renewal Application2015-09-17017 September 2015 Response to NRC Requests for Additional Information, Set 10, Dated August 27, 2015 Related to License Renewal Application Project stage: Response to RAI ML15196A1152015-09-22022 September 2015 Aging Management Programs Audit Report Regarding Lasalle County Station, Units 1 and 2, Project stage: Other ML15196A0452015-09-22022 September 2015 Aging Management Programs Audit Report Regarding Lasalle County Station, Units 1 and 2, (TAC Nos. MF5347 and MF5346). Cover Letter Project stage: Other RS-15-239, Response to NRC Requests for Additional Information, Set 8, Dated August 28, 2015 Related to the License Renewal Application2015-09-28028 September 2015 Response to NRC Requests for Additional Information, Set 8, Dated August 28, 2015 Related to the License Renewal Application Project stage: Response to RAI RS-15-256, Response to NRC Request for Additional Information, Set 11, Dated September 14, 2015 Related to the License Renewal Application2015-10-0808 October 2015 Response to NRC Request for Additional Information, Set 11, Dated September 14, 2015 Related to the License Renewal Application Project stage: Response to RAI ML15208A0522015-10-22022 October 2015 Schedule Revision for the Review of the Lasalle County Station License Renewal Application (TAC Nos. MF5347 & MF5346) Project stage: Approval ML15271A0212015-10-23023 October 2015 Requests for Additional Information for the Review of the Lasalle County Station, Units 1 and 2 License Renewal Application-Set 12 (TAC Nos. MF5347 and MF5346) Project stage: RAI RS-15-281, Response to NRC Requests for Additional Information, Set 12, Dated October 23, 2015 Related to the License Renewal Application2015-10-29029 October 2015 Response to NRC Requests for Additional Information, Set 12, Dated October 23, 2015 Related to the License Renewal Application Project stage: Response to RAI ML15300A3662015-11-0303 November 2015 Requests for Additional Information for the Review of the LaSalle County Station, Units 1 and 2 License Renewal Application - Set 13 (TAC Nos. MF5347 and MF5346) Project stage: RAI RS-15-305, Corrections to the License Renewal Application Dated December 9, 20142015-12-0202 December 2015 Corrections to the License Renewal Application Dated December 9, 2014 Project stage: Other RS-15-306, Submittal of 10 CFR 54.21(b) Annual Amendment to the License Renewal Application2015-12-0202 December 2015 Submittal of 10 CFR 54.21(b) Annual Amendment to the License Renewal Application Project stage: Other RS-15-292, Response to NRC Requests for Additional Information, Set 13, Dated November 3, 2015 Related to the License Renewal Application2015-12-10010 December 2015 Response to NRC Requests for Additional Information, Set 13, Dated November 3, 2015 Related to the License Renewal Application Project stage: Response to RAI ML15272A4002015-12-11011 December 2015 Summary of Teleconference Held on September 24, 2015, Between the NRC and Exelon Generation Co., LLC, Concerning RAI Set 10 Response Pertaining to the LaSalle County Station License Renewal Application (TAC Nos. MF5347 and MF5346) Project stage: RAI ML15301A1892015-12-14014 December 2015 Request for Additional Information for the Review of the LaSalle County Station, Units 1 & 2 License Renewal Application - Set 14 (TAC Nos. MF5347 and MF5346) Project stage: RAI RS-16-003, Responses to NRC Requests for Additional Information, Set 14, Dated December 14, 2015, and Two Additional Commitment Implementation Schedule Clarifications, Related to the License Renewal Application2016-01-0707 January 2016 Responses to NRC Requests for Additional Information, Set 14, Dated December 14, 2015, and Two Additional Commitment Implementation Schedule Clarifications, Related to the License Renewal Application Project stage: Response to RAI ML15357A2812016-01-0707 January 2016 Summary of Teleconference Held on December 22, 2015, Between the NRC and Exelon Generation Co., LLC, Concerning the LaSalle County Station License Renewal Application (Tac Nos. MF5347 and MF5346) Project stage: Meeting RS-16-007, Supplemental Information Associated with Implementation of BWRVIP-25, Core Plate Inspection and Flaw Evaluation Guidelines, Related to the License Renewal Application2016-01-14014 January 2016 Supplemental Information Associated with Implementation of BWRVIP-25, Core Plate Inspection and Flaw Evaluation Guidelines, Related to the License Renewal Application Project stage: Supplement ML16021A3252016-01-29029 January 2016 Summary of Teleconference Held on January 21, 2016, Between the NRC and Exelon Generation Co., LLC, Concerning RAI 4.2.10-1 Response Project stage: RAI RS-16-033, Update to Commitment 47 Related to the License Renewal Application2016-02-0101 February 2016 Update to Commitment 47 Related to the License Renewal Application Project stage: Other ML15344A3542016-02-16016 February 2016 Requests for Additional Information for the Review of the Lasalle County, Units 1 and 2 License Renewal Application Set 15 (TAC Nos. MF5347 and MF5346) Project stage: RAI 2015-07-16
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Category:Letter type:RS
MONTHYEARRS-23-120, 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 RS-23-103, 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-23-080, Constellation Energy Generation, LLC, Application to Revise Technical Specifications to Adopt TSTF-264-A, Revision 0, 3.3.9 and 3.3.10 - Delete Flux Monitors Specific Overlap Requirement SRs2023-08-30030 August 2023 Constellation Energy Generation, LLC, Application to Revise Technical Specifications to Adopt TSTF-264-A, Revision 0, 3.3.9 and 3.3.10 - Delete Flux Monitors Specific Overlap Requirement SRs RS-23-087, Revision to Approved Alternatives Associated with the Use of the BWRVIP Guidelines in Lieu of Specific ASME Code Requirements on Reactor2023-08-0404 August 2023 Revision to Approved Alternatives Associated with the Use of the BWRVIP Guidelines in Lieu of Specific ASME Code Requirements on Reactor RS-23-084, Response to Request for Additional Information Regarding the Application to Revise Design Basis to Allow Use of Plastic Section Properties in Lower Downcomer Braces Analysis2023-07-24024 July 2023 Response to Request for Additional Information Regarding the Application to Revise Design Basis to Allow Use of Plastic Section Properties in Lower Downcomer Braces Analysis RS-23-077, Response to NRC Regulatory Issue Summary 2023-01, Preparation and Scheduling of Operator Licensing Examinations2023-06-16016 June 2023 Response to NRC Regulatory Issue Summary 2023-01, Preparation and Scheduling of Operator Licensing Examinations RS-23-042, Application to Revise Technical Specifications to Adopt TSTF-580, Provide Exception from Entering Mode 4 with No Operable RHR Shutdown Cooling2023-05-25025 May 2023 Application to Revise Technical Specifications to Adopt TSTF-580, Provide Exception from Entering Mode 4 with No Operable RHR Shutdown Cooling RS-23-049, Constellation Energy Generation, LLC, Report on Status of Decommissioning Funding for Reactors and Independent Spent Fuel Storage Installations2023-03-23023 March 2023 Constellation Energy Generation, LLC, Report on Status of Decommissioning Funding for Reactors and Independent Spent Fuel Storage Installations RS-23-048, Exigent Amendment Request to Revise Design Basis Related to Seismic Requirements2023-03-0707 March 2023 Exigent Amendment Request to Revise Design Basis Related to Seismic Requirements RS-23-045, Constellation Energy Generation, LLC Submittal of Fitness for Duty Performance Data Reports for 2022 Per 10 CFR 26.717(c) & 10 CFR 26.2032023-02-28028 February 2023 Constellation Energy Generation, LLC Submittal of Fitness for Duty Performance Data Reports for 2022 Per 10 CFR 26.717(c) & 10 CFR 26.203 RS-23-037, Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors for LaSalle County Station2023-02-22022 February 2023 Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors for LaSalle County Station RS-23-003, Constellation Energy Generation, LLC, Summary of Changes to Quality Assurance Topical Report, NO-AA-10, and Decommissioning Quality Assurance Program, NO-DC-102023-01-31031 January 2023 Constellation Energy Generation, LLC, Summary of Changes to Quality Assurance Topical Report, NO-AA-10, and Decommissioning Quality Assurance Program, NO-DC-10 RS-22-085, Application to Revise Design Basis to Allow Use of Plastic Section Properties in Lower Downcomer Braces Analysis2023-01-12012 January 2023 Application to Revise Design Basis to Allow Use of Plastic Section Properties in Lower Downcomer Braces Analysis RS-23-006, Supplemental Information Regarding License Amendment Request Relocation of Pressure and Temperature Limit Curves to the Pressure and Temperature Limits Report2023-01-10010 January 2023 Supplemental Information Regarding License Amendment Request Relocation of Pressure and Temperature Limit Curves to the Pressure and Temperature Limits Report RS-22-126, Constellation Energy Generation, LLC - Request to Use Provisions of a Later Edition of the ASME Boiler and Pressure Vessel Code, Section XI2022-11-30030 November 2022 Constellation Energy Generation, LLC - Request to Use Provisions of a Later Edition of the ASME Boiler and Pressure Vessel Code, Section XI RS-22-109, Response to Request for Additional Information License Amendments Related to Fuel Storage2022-10-12012 October 2022 Response to Request for Additional Information License Amendments Related to Fuel Storage RS-22-092, Nine and Quad Cities - Application to Revise Primary Containment Isolation Instrumentation Technical Specifications in Accordance with TSTF-306, Revision 2, Add Action to LCO 3.3.6.1 to Give Option to Isolate the Penetration2022-10-0303 October 2022 Nine and Quad Cities - Application to Revise Primary Containment Isolation Instrumentation Technical Specifications in Accordance with TSTF-306, Revision 2, Add Action to LCO 3.3.6.1 to Give Option to Isolate the Penetration RS-22-093, Advisement of Leadership Changes for Constellation Energy Generation, LLC and Submittal of Updated Standard Practice Procedures Plans2022-08-18018 August 2022 Advisement of Leadership Changes for Constellation Energy Generation, LLC and Submittal of Updated Standard Practice Procedures Plans RS-22-083, Response to Request for Additional Information Related to the License Amendment Request to Change New Fuel Storage Vault and Spent Fuel Storage Pool Criticality Methodologies, with Proposed Changes to Technical2022-06-17017 June 2022 Response to Request for Additional Information Related to the License Amendment Request to Change New Fuel Storage Vault and Spent Fuel Storage Pool Criticality Methodologies, with Proposed Changes to Technical RS-22-051, Constellation Energy Generation, LLC - Update to Correspondence Addressees and Service Lists2022-04-12012 April 2022 Constellation Energy Generation, LLC - Update to Correspondence Addressees and Service Lists RS-22-049, Constellation Energy Generation, LLC, Supplemental Information to Correct Typographical Errors in Constellation'S Application to Revise Technical Specifications to Adopt TSTF-541 Revision 2, Add Exceptions to Surveillance Requirements for2022-04-0404 April 2022 Constellation Energy Generation, LLC, Supplemental Information to Correct Typographical Errors in Constellation'S Application to Revise Technical Specifications to Adopt TSTF-541 Revision 2, Add Exceptions to Surveillance Requirements for V RS-22-045, Constellation Energy Generation, LLC, Response to NRC Regulatory Issue Summary 2022-01, Preparation and Scheduling of Operator Licensing Examinations2022-03-25025 March 2022 Constellation Energy Generation, LLC, Response to NRC Regulatory Issue Summary 2022-01, Preparation and Scheduling of Operator Licensing Examinations RS-22-035, Supplemental Information Regarding Relief Request I4R-13 Relief from Code Examinations for 1B33-F060A and 1B33-F060B Repairs2022-03-0404 March 2022 Supplemental Information Regarding Relief Request I4R-13 Relief from Code Examinations for 1B33-F060A and 1B33-F060B Repairs RS-22-033, Response to Request for Additional Information Regarding Relief Request I4R-13 Relief from Code Examinations for 1B33-F060A and 1B33-F060B Repairs2022-03-0303 March 2022 Response to Request for Additional Information Regarding Relief Request I4R-13 Relief from Code Examinations for 1B33-F060A and 1B33-F060B Repairs RS-22-032, Relief Request I4R-13 Relief from Code Examinations for 1B33-F060A and 1B33-F060B Repairs2022-03-0202 March 2022 Relief Request I4R-13 Relief from Code Examinations for 1B33-F060A and 1B33-F060B Repairs RS-22-023, Constellation Energy Generation, LLC, Executed Trust Fund Agreement Amendment and Subordinate Trust Agreement2022-02-23023 February 2022 Constellation Energy Generation, LLC, Executed Trust Fund Agreement Amendment and Subordinate Trust Agreement RS-22-027, Constellation, Response to Request for Additional Information Regarding Application to Revise Technical Specifications to Adopt TSTF-541 Revision 2, Add Exceptions to Surveillance Requirements for Valves and Dampers Locked in the Actuated2022-02-23023 February 2022 Constellation, Response to Request for Additional Information Regarding Application to Revise Technical Specifications to Adopt TSTF-541 Revision 2, Add Exceptions to Surveillance Requirements for Valves and Dampers Locked in the Actuated P RS-22-018, Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors for LaSalle County Station2022-02-22022 February 2022 Annual 10 CFR 50.46 Report of Emergency Core Cooling System Evaluation Model Changes and Errors for LaSalle County Station RS-22-019, Constellation Energy Generation, LLC - Update to Correspondence Addressees and Service Lists2022-02-16016 February 2022 Constellation Energy Generation, LLC - Update to Correspondence Addressees and Service Lists RS-22-015, Notification of Completion of License Transfer and Request to Continue Processing Pending NRC Actions Previously Requested by Exelon Generation Company, LLC2022-02-0101 February 2022 Notification of Completion of License Transfer and Request to Continue Processing Pending NRC Actions Previously Requested by Exelon Generation Company, LLC RS-22-004, Supplement to Application to Adopt TSTF-554, Revision 1, Revise Reactor Coolant Leakage Requirements2022-01-0404 January 2022 Supplement to Application to Adopt TSTF-554, Revision 1, Revise Reactor Coolant Leakage Requirements RS-21-121, Proposed Changes to Decommissioning Trust Agreements and Master Terms2021-12-15015 December 2021 Proposed Changes to Decommissioning Trust Agreements and Master Terms RS-21-115, Supplemental Information for License Amendment Request Regarding New Fuel Storage Vault and Spent Fuel Storage Pool Criticality Methodologies, with Proposed Changes to Technical Specifications 4.3.1 and 5.6.52021-11-0404 November 2021 Supplemental Information for License Amendment Request Regarding New Fuel Storage Vault and Spent Fuel Storage Pool Criticality Methodologies, with Proposed Changes to Technical Specifications 4.3.1 and 5.6.5 RS-21-109, Request to Withhold Meeting Materials for the Non-Public Meeting Held on September 2, 20212021-10-14014 October 2021 Request to Withhold Meeting Materials for the Non-Public Meeting Held on September 2, 2021 RS-21-091, Implementation of Insider Threat Program Requirements Associated with the Voluntary Security Clearance Program and Advisement of Leadership Changes2021-09-13013 September 2021 Implementation of Insider Threat Program Requirements Associated with the Voluntary Security Clearance Program and Advisement of Leadership Changes RS-21-078, Response to Request for Additional Information for Application to Revise Technical Specification to Adopt TSTF-582, Reactor Pressure Vessel Water Inventory Control (RPV WIC) Enhancements, and TSTF-583-T, TSTF-582 Diesel2021-08-19019 August 2021 Response to Request for Additional Information for Application to Revise Technical Specification to Adopt TSTF-582, Reactor Pressure Vessel Water Inventory Control (RPV WIC) Enhancements, and TSTF-583-T, TSTF-582 Diesel RS-21-085, Response to Request for Additional Information Regarding License Amendment Request to Incorporate Licensing Topical Report NEDE-33885PA, Revision 1, GNF CRDA Application Methodology (EPID-L-2021-LLA-0016)2021-08-17017 August 2021 Response to Request for Additional Information Regarding License Amendment Request to Incorporate Licensing Topical Report NEDE-33885PA, Revision 1, GNF CRDA Application Methodology (EPID-L-2021-LLA-0016) RS-21-063, Application to Adopt TSTF-554, Revision 1, Revise Reactor Coolant Leakage Requirements2021-06-30030 June 2021 Application to Adopt TSTF-554, Revision 1, Revise Reactor Coolant Leakage Requirements RS-21-064, License Amendment Request Re New Fuel Storage Vault and Spent Fuel Storage Pool Criticality Methodologies - Cover Letter2021-06-30030 June 2021 License Amendment Request Re New Fuel Storage Vault and Spent Fuel Storage Pool Criticality Methodologies - Cover Letter RS-21-070, Proposed Alternative to Utilize Code Case N-8932021-06-30030 June 2021 Proposed Alternative to Utilize Code Case N-893 RS-21-055, Response to Third Round Request for Additional Information (Rals) for LaSalle License Amendment Request to Adopt Risk Informed Completion Times TSTF- 505, Revision 2, Provide Risk-Informed Extended.2021-05-10010 May 2021 Response to Third Round Request for Additional Information (Rals) for LaSalle License Amendment Request to Adopt Risk Informed Completion Times TSTF- 505, Revision 2, Provide Risk-Informed Extended. RS-21-054, Response to NRC Regulatory Issue Summary 2021-01, Preparation and Scheduling of Operator Licensing Examinations2021-04-29029 April 2021 Response to NRC Regulatory Issue Summary 2021-01, Preparation and Scheduling of Operator Licensing Examinations RS-21-050, Response to Request for Additional Information (RAI) Regarding Request for License Amendment Regarding Ultimate Heat Sink (EPID-L-2020-LLA-0165)2021-04-16016 April 2021 Response to Request for Additional Information (RAI) Regarding Request for License Amendment Regarding Ultimate Heat Sink (EPID-L-2020-LLA-0165) RS-21-045, Response to Request for Additional Information (RAI) Regarding Request for License Amendment Regarding Ultimate Heat Sink (EPID-L-2020-LLA-0165)2021-04-0707 April 2021 Response to Request for Additional Information (RAI) Regarding Request for License Amendment Regarding Ultimate Heat Sink (EPID-L-2020-LLA-0165) RS-21-040, Response to Second Round Request for Additional Information (Rais) for License Amendment Request to Adopt Risk Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b2021-03-31031 March 2021 Response to Second Round Request for Additional Information (Rais) for License Amendment Request to Adopt Risk Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b RS-21-043, Supplemental Information Regarding Relief Request I4R-12 Relief from Code Examinations for 2B33-F060A and 2B33-F060B Repairs, Revision 22021-03-26026 March 2021 Supplemental Information Regarding Relief Request I4R-12 Relief from Code Examinations for 2B33-F060A and 2B33-F060B Repairs, Revision 2 RS-21-042, Relief Request I4R-12 Relief from Code Examinations for 2B33-F060A and 2B33-F060B Repairs, Revision 22021-03-26026 March 2021 Relief Request I4R-12 Relief from Code Examinations for 2B33-F060A and 2B33-F060B Repairs, Revision 2 RS-21-039, Supplemental Information Regarding Application for Order Approving Transfers and Proposed Conforming License Amendments2021-03-25025 March 2021 Supplemental Information Regarding Application for Order Approving Transfers and Proposed Conforming License Amendments RS-21-035, Relief Request I4R-12 Relief from Code Examinations for 2B33-F060A and 2B33-F060B Repairs2021-03-0909 March 2021 Relief Request I4R-12 Relief from Code Examinations for 2B33-F060A and 2B33-F060B Repairs 2023-08-04
[Table view] Category:Response to Request for Additional Information (RAI)
MONTHYEARRS-23-120, 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 RS-23-084, Response to Request for Additional Information Regarding the Application to Revise Design Basis to Allow Use of Plastic Section Properties in Lower Downcomer Braces Analysis2023-07-24024 July 2023 Response to Request for Additional Information Regarding the Application to Revise Design Basis to Allow Use of Plastic Section Properties in Lower Downcomer Braces Analysis RS-22-109, Response to Request for Additional Information License Amendments Related to Fuel Storage2022-10-12012 October 2022 Response to Request for Additional Information License Amendments Related to Fuel Storage RS-22-083, Response to Request for Additional Information Related to the License Amendment Request to Change New Fuel Storage Vault and Spent Fuel Storage Pool Criticality Methodologies, with Proposed Changes to Technical2022-06-17017 June 2022 Response to Request for Additional Information Related to the License Amendment Request to Change New Fuel Storage Vault and Spent Fuel Storage Pool Criticality Methodologies, with Proposed Changes to Technical RS-22-033, Response to Request for Additional Information Regarding Relief Request I4R-13 Relief from Code Examinations for 1B33-F060A and 1B33-F060B Repairs2022-03-0303 March 2022 Response to Request for Additional Information Regarding Relief Request I4R-13 Relief from Code Examinations for 1B33-F060A and 1B33-F060B Repairs RS-22-027, Constellation, Response to Request for Additional Information Regarding Application to Revise Technical Specifications to Adopt TSTF-541 Revision 2, Add Exceptions to Surveillance Requirements for Valves and Dampers Locked in the Actuated2022-02-23023 February 2022 Constellation, Response to Request for Additional Information Regarding Application to Revise Technical Specifications to Adopt TSTF-541 Revision 2, Add Exceptions to Surveillance Requirements for Valves and Dampers Locked in the Actuated P NMP1L3447, Constellation Energy Generation, LLC - Response to Request for Additional Information - Proposed Relief Request Associated with Reactor Pressure Vessel Water Level Instrumentation Partial Penetration Nozzle Repairs2022-02-0202 February 2022 Constellation Energy Generation, LLC - Response to Request for Additional Information - Proposed Relief Request Associated with Reactor Pressure Vessel Water Level Instrumentation Partial Penetration Nozzle Repairs JAFP-21-0087, Response to Request for Additional Information Regarding Request for Approval of Transfer of Licenses and Conforming Amendments2021-09-16016 September 2021 Response to Request for Additional Information Regarding Request for Approval of Transfer of Licenses and Conforming Amendments RS-21-078, Response to Request for Additional Information for Application to Revise Technical Specification to Adopt TSTF-582, Reactor Pressure Vessel Water Inventory Control (RPV WIC) Enhancements, and TSTF-583-T, TSTF-582 Diesel2021-08-19019 August 2021 Response to Request for Additional Information for Application to Revise Technical Specification to Adopt TSTF-582, Reactor Pressure Vessel Water Inventory Control (RPV WIC) Enhancements, and TSTF-583-T, TSTF-582 Diesel RS-21-085, Response to Request for Additional Information Regarding License Amendment Request to Incorporate Licensing Topical Report NEDE-33885PA, Revision 1, GNF CRDA Application Methodology (EPID-L-2021-LLA-0016)2021-08-17017 August 2021 Response to Request for Additional Information Regarding License Amendment Request to Incorporate Licensing Topical Report NEDE-33885PA, Revision 1, GNF CRDA Application Methodology (EPID-L-2021-LLA-0016) NMP2L2773, Company - Response to Request for Additional Information2021-06-30030 June 2021 Company - Response to Request for Additional Information JAFP-21-0044, Response to Request for Additional Information Regarding Request for Approval of Transfer of Licenses and Conforming Amendments2021-06-11011 June 2021 Response to Request for Additional Information Regarding Request for Approval of Transfer of Licenses and Conforming Amendments RS-21-055, Response to Third Round Request for Additional Information (Rals) for LaSalle License Amendment Request to Adopt Risk Informed Completion Times TSTF- 505, Revision 2, Provide Risk-Informed Extended.2021-05-10010 May 2021 Response to Third Round Request for Additional Information (Rals) for LaSalle License Amendment Request to Adopt Risk Informed Completion Times TSTF- 505, Revision 2, Provide Risk-Informed Extended. JAFP-21-0032, Response to Request for Additional Information - Proposed Alternative Concerning ASME Section XI Repair/Replacement Documentation for Replacement of Pressure Retaining Bolting2021-04-20020 April 2021 Response to Request for Additional Information - Proposed Alternative Concerning ASME Section XI Repair/Replacement Documentation for Replacement of Pressure Retaining Bolting RS-21-050, Response to Request for Additional Information (RAI) Regarding Request for License Amendment Regarding Ultimate Heat Sink (EPID-L-2020-LLA-0165)2021-04-16016 April 2021 Response to Request for Additional Information (RAI) Regarding Request for License Amendment Regarding Ultimate Heat Sink (EPID-L-2020-LLA-0165) RS-21-045, Response to Request for Additional Information (RAI) Regarding Request for License Amendment Regarding Ultimate Heat Sink (EPID-L-2020-LLA-0165)2021-04-0707 April 2021 Response to Request for Additional Information (RAI) Regarding Request for License Amendment Regarding Ultimate Heat Sink (EPID-L-2020-LLA-0165) RS-21-040, Response to Second Round Request for Additional Information (Rais) for License Amendment Request to Adopt Risk Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b2021-03-31031 March 2021 Response to Second Round Request for Additional Information (Rais) for License Amendment Request to Adopt Risk Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b RS-21-027, Response to Request for Additional Information Regarding Request for Exemption from Pre-Access Drug and Alcohol Testing Requirements in 10 CFR 26.652021-02-21021 February 2021 Response to Request for Additional Information Regarding Request for Exemption from Pre-Access Drug and Alcohol Testing Requirements in 10 CFR 26.65 ML21022A1302021-01-22022 January 2021 Response to Request for Additional Information Regarding the License Amendment Request to Adopt 10 CFR 50.69 RS-20-136, Response to Request for Additional Information Re License Amendment Requests for Amendments to Renewed Facility OL to Adopt 10CFR50.69 & to Adopt TSTF-505, Rev. 2 (EPID L-2020-LLA-0017 and EPID-L-2020-LLA-0018)2020-10-29029 October 2020 Response to Request for Additional Information Re License Amendment Requests for Amendments to Renewed Facility OL to Adopt 10CFR50.69 & to Adopt TSTF-505, Rev. 2 (EPID L-2020-LLA-0017 and EPID-L-2020-LLA-0018) RS-20-133, Response to Request for Additional Information Re License Amendment Request to Renewed Facility Operating Licenses to Adopt 10 CFR 50.692020-10-16016 October 2020 Response to Request for Additional Information Re License Amendment Request to Renewed Facility Operating Licenses to Adopt 10 CFR 50.69 RS-20-104, Supplement to the Request for a License Amendment Technical Specification 3.7.3, Ultimate Heat Sink2020-09-11011 September 2020 Supplement to the Request for a License Amendment Technical Specification 3.7.3, Ultimate Heat Sink RS-20-112, Response to Request for Additional Information Related to License Amendment Request to Adopt TSTF-5682020-09-0303 September 2020 Response to Request for Additional Information Related to License Amendment Request to Adopt TSTF-568 NMP2L2711, Byron Station; Calvert Cliffs; Clinton Power Station; LaSalle County Station; Limerick Generating Station; and Nine Mile Point Nuclear Station - Proposed Alternative to Utilize Code Case N-8792019-10-16016 October 2019 Byron Station; Calvert Cliffs; Clinton Power Station; LaSalle County Station; Limerick Generating Station; and Nine Mile Point Nuclear Station - Proposed Alternative to Utilize Code Case N-879 JAFP-19-0057, Response to Request for Additional Information - Proposed Alternative to Utilize Code Cases N-878 and N-8802019-06-0404 June 2019 Response to Request for Additional Information - Proposed Alternative to Utilize Code Cases N-878 and N-880 NMP1L3279, Response to Request for Additional Information - Proposed Alternatives to Utilize Code Cases N-878 and N-880 for Plants2019-05-0101 May 2019 Response to Request for Additional Information - Proposed Alternatives to Utilize Code Cases N-878 and N-880 for Plants RS-19-052, Supplement to the Response to Request for Additional Information Regarding License Amendment Request to Remove Operating Mode Restrictions for Performing Surveillance Testing of the Division 3 Battery and High ..2019-04-24024 April 2019 Supplement to the Response to Request for Additional Information Regarding License Amendment Request to Remove Operating Mode Restrictions for Performing Surveillance Testing of the Division 3 Battery and High .. RS-19-019, Response to Request for Additional Information Regarding Relief Request 13R-152019-04-0202 April 2019 Response to Request for Additional Information Regarding Relief Request 13R-15 JAFP-19-0006, Response to Request for Additional Information - Proposed Alternative to Utilize Code Cases N-878 and N-8802019-01-0808 January 2019 Response to Request for Additional Information - Proposed Alternative to Utilize Code Cases N-878 and N-880 RS-18-143, Supplemental Information Supporting License Amendment Requests for Approval of Changes to Emergency Plan Staffing Requirements2018-11-29029 November 2018 Supplemental Information Supporting License Amendment Requests for Approval of Changes to Emergency Plan Staffing Requirements RS-18-097, Response to Request for Additional Information and Supplemental Information-License Amendment.2018-07-27027 July 2018 Response to Request for Additional Information and Supplemental Information-License Amendment. RS-18-086, Response to Request for Additional Information Regarding License Amendment Request for Temporary Extensions to Technical Specifications Supporting Maintenance on Portions of the Core Standby Cooling System2018-07-16016 July 2018 Response to Request for Additional Information Regarding License Amendment Request for Temporary Extensions to Technical Specifications Supporting Maintenance on Portions of the Core Standby Cooling System RS-18-078, Supplemental Information Related to Application to Revise Technical Specifications to Adopt TSTF-542, Reactor Pressure Vessel Water Inventory Control2018-06-18018 June 2018 Supplemental Information Related to Application to Revise Technical Specifications to Adopt TSTF-542, Reactor Pressure Vessel Water Inventory Control RS-18-061, Response to Request for Additional Information Regarding Decommissioning Funding Plans for Independent Spent Fuel Storage Installations (Isfsis)2018-05-0202 May 2018 Response to Request for Additional Information Regarding Decommissioning Funding Plans for Independent Spent Fuel Storage Installations (Isfsis) RS-18-014, Supplement to Request to Revise Technical Specifications 2.1.1 for Minimum Critical Power Ratio Safety Limits2018-01-25025 January 2018 Supplement to Request to Revise Technical Specifications 2.1.1 for Minimum Critical Power Ratio Safety Limits RS-17-147, Response to Request for Additional Information Regarding LaSalle County Station Fourth Inservice Inspection Interval Relief Request 14R-012017-11-10010 November 2017 Response to Request for Additional Information Regarding LaSalle County Station Fourth Inservice Inspection Interval Relief Request 14R-01 RS-17-146, Additional Information Regarding License Amendment Request to Revise Suppression Pool Swell Design Analysis2017-10-19019 October 2017 Additional Information Regarding License Amendment Request to Revise Suppression Pool Swell Design Analysis RS-17-099, Response to Request for Additional Information Regarding LaSalle County Station License Amendment Request for Extension of Type a and Type C Containment Leak Rate Test Intervals (PRA Branch)2017-08-0808 August 2017 Response to Request for Additional Information Regarding LaSalle County Station License Amendment Request for Extension of Type a and Type C Containment Leak Rate Test Intervals (PRA Branch) RS-17-101, Response to Request for Additional Information Regarding License Amendment Request to Revise Suppression Pool Swell Design Analysis2017-07-28028 July 2017 Response to Request for Additional Information Regarding License Amendment Request to Revise Suppression Pool Swell Design Analysis RS-17-102, Response to Request for Supplemental Information Regarding Fourth Inservice Inspection Interval Relief Request 14R-012017-07-20020 July 2017 Response to Request for Supplemental Information Regarding Fourth Inservice Inspection Interval Relief Request 14R-01 RS-17-098, Response to Request for Additional Information Regarding License Amendment Request for Extension of Type a and Type C Containment Leak Rate Test Intervals (Sbpb Branch)2017-07-17017 July 2017 Response to Request for Additional Information Regarding License Amendment Request for Extension of Type a and Type C Containment Leak Rate Test Intervals (Sbpb Branch) RS-17-044, Response to Request for Additional Information Regarding Proposed Alternative for the Use of Encoded Phased Array Ultrasonic Examination Techniques in Lieu of Radiography2017-03-13013 March 2017 Response to Request for Additional Information Regarding Proposed Alternative for the Use of Encoded Phased Array Ultrasonic Examination Techniques in Lieu of Radiography RS-17-010, Response to Request for Additional Information Regarding LaSalle County Station Alternative Request RV-01 for the Lnservice Testing Program Fourth 10-Year Interval2017-02-0909 February 2017 Response to Request for Additional Information Regarding LaSalle County Station Alternative Request RV-01 for the Lnservice Testing Program Fourth 10-Year Interval RS-16-244, Additional Information Regarding Request for License Amendment to Address Secondary Containment Access Openings2016-12-12012 December 2016 Additional Information Regarding Request for License Amendment to Address Secondary Containment Access Openings RS-16-176, County, High Frequency Supplement to Seismic Hazard Screening Report, Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ic2016-12-0101 December 2016 County, High Frequency Supplement to Seismic Hazard Screening Report, Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ich RS-16-125, Spent Fuel Pool Evaluation Supplemental Report, Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident2016-08-31031 August 2016 Spent Fuel Pool Evaluation Supplemental Report, Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident RS-16-159, County, and Quad Cities - Response to Request for Additional Information Regarding License Amendment to Address Secondary Containment Access Openings2016-07-28028 July 2016 County, and Quad Cities - Response to Request for Additional Information Regarding License Amendment to Address Secondary Containment Access Openings RS-16-144, Response to Request for Additional Information on Severe Accident Mitigation Alternatives for License Renewal Environmental Review Dated July 6, 20162016-07-11011 July 2016 Response to Request for Additional Information on Severe Accident Mitigation Alternatives for License Renewal Environmental Review Dated July 6, 2016 RA-16-049, Response to Request for Additional Information Regarding Requests to Withhold Emergency Preparedness Documents from Public Disclosure2016-05-26026 May 2016 Response to Request for Additional Information Regarding Requests to Withhold Emergency Preparedness Documents from Public Disclosure RS-16-076, Response to Request for Additional Information Regarding License Amendment Request to Reduce the Reactor Steam Dome Pressure Specified in the Technical Specification 2.1.1, Reactor Core Sls.2016-04-11011 April 2016 Response to Request for Additional Information Regarding License Amendment Request to Reduce the Reactor Steam Dome Pressure Specified in the Technical Specification 2.1.1, Reactor Core Sls. 2023-07-24
[Table view] |
Text
Michael P. Gallagher Vice President. License Renewal Exelon Generation Exelon Nuclear 200 Exelon Way Kennett Square. PA 19348 610 765 5958 Office 610 765 5956 Fax www.exeloncorp.com michaelp.gallagher@exeloncorp.com 10 CFR 50 10 CFR 51 10 CFR 54 RS-16-052 February 25, 2016 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001 LaSalle County Station, Units 1 and 2 Facility Operating License Nos. NPF-11 and NPF-18 NRC Docket Nos. 50-373 and 50-374
Subject:
Response to NRC Requests for Additional Information, Set 15, dated February 16, 2016 related to the LaSalle County Station, Units 1 and 2, License Renewal Application (TAC Nos. MF5347 and MF5346)
References:
- 1. Letter from Michael P. Gallagher, Exelon Generation Company LLC (Exelon),
to NRC Document Control Desk, dated December 9, 2014, "Application for Renewed Operating Licenses"
- 2. Letter from Jeffrey S. Mitchell, US NRC to Michael P. Gallagher, Exelon, dated February 16, 2016, "Requests for Additional Information for the Review of the LaSalle County Station, Units 1 and 2 License Renewal Application - Set 15 (TAC Nos. MF5347 and MF5346)"
In Reference 1, Exelon Generation Company, LLC (Exelon) submitted the License Renewal Application (LRA) for the LaSalle County Station (LSCS), Units 1 and 2. In Reference 2, the NRC requested additional information to support staff review of the LRA.
The Enclosure contains the response to these requests for additional information.
There are no new or revised regulatory commitments contained in this letter.
If you have any questions, please contact Mr. John Hufnagel, Licensing Lead, LaSalle License Renewal Project, at 610-765-5829.
February 25, 2016 U.S. Nuclear Regulatory Commission Page 2 I declare under penalty of perjury that the foregoing is true and correct.
Executed on O) *JS'- 20/b Respectfully, M~e~
Vice President - License Renewal Projects Exelon Generation Company, LLC
Enclosure:
Response to Set 15 Requests for Additional Information cc: Regional Administrator - NRC Region Ill NRC Project Manager (Safety Review), NRR-DLR NRC Project Manager (Environmental Review), NRR-DLR NRC Project Manager, NRR-DORL- LaSalle County Station NRC Senior Resident Inspector, LaSalle County Station Illinois Emergency Management Agency - Division of Nuclear Safety
RS-16-052 Enclosure Page 1 of 11 Enclosure Response to Set 15 Requests for Additional Information related to the LaSalle County Station (LSCS) License Renewal Application (LRA)
RAI B.2.1.4-1 RAI B.2.1.7-3b
RS-16-052 Enclosure Page 2 of 11 RAI B.2.1.4-1
Background:
During the IP-71002, License Renewal Inspection, at LaSalle County Station, Units 1 and 2 (LSCS), NRC inspectors reviewed Exelon Procedure ER-AB-331, Revision 14, BWR Internals Program Management. This procedure addresses changes to the enhanced visual examination (EVT-1) requirements in boiling water reactor vessel and internals project (BWRVIP)-03, Reactor Pressure Vessel and Internals Examination Requirements. of Exelon Procedure ER-AB-331, Exelon Position on EVT-1 Implementation, states that changes relating to limitations on the allowable viewing angle have reduced the effective weld coverage to zero percent in some cases. It also states that EVT-1 inspections of required welds and components that yield an effective coverage of zero percent meet the BWRVIP inspection requirements, because the BWRVIP guidelines impose no minimum required effective inspection coverage for EVT-1 examinations. As noted in the Aging Management Program (AMP) Audit report, dated September 22, 2015, ER-AB-331 is used by the BWR Vessel ID Attachment Welds and BWR Vessel Internals AMPs.
The examination requirements for American Society of Mechanical Engineers (ASME)
Section XI, for Category B-N-2 only refers to accessible welds, and does not reference a specific figure for examination surface or volume, which could be interpreted as not being a defined surface or volume and therefore, not being subject to the ASME Code requirement for essentially 100 percent coverage. However, the staffs Final License Renewal Safety Evaluation Report for BWRVIP-48 (included with BWRVIP-48-A, under BWRVIP Inspection Guidelines) states The examination volumes are limited to the attachment weld and the adjacent heat-affected regions of the vessel clad. Based on the statement in the staffs safety evaluation, the accessible welds and the adjacent heat-affected regions of the vessel clad associated with BWR Vessel ID Attachment Welds program are considered a defined surface or volume. Therefore, it is the staffs expectation that examinations performed on the accessible welds will yield essentially 100 percent coverage, which the staff considers to be 90 percent or greater coverage.
BWRVIP is one of the issue programs (IPs) included in NEI 03-08, Rev. 2, Guideline for Management of Materials Issues. As stated in NEI 03-08, All utilities shall adopt applicable IP work products in accordance with the expected level of implementation, or provide an appropriate justification for any deviations.
Issue:
Although not addressed in BWRVIP guidelines, the staffs expectation is that the examination coverage of inspections performed for AMPs based on BWRVIP guidance (i.e., Generic Aging Lessons Learned (GALL) Report AMP XI.M4 BWR Vessel ID Attachment Welds,) would be in accordance with the ASME Code. Because some BWRVIP guidelines do not address minimum required effective examination coverage, it is unclear to the staff whether limited coverage (i.e.,
less than 90 percent) is considered a deviation from the BWRVIPs expected level of implementation. In that regard, it is also unclear to the staff whether examination coverage of zero percent meets the BWRVIPs expected level of implementation. Based on this, crediting weld inspections that do not meet essentially 100 percent coverage (i.e., at least 90 percent of
RS-16-052 Enclosure Page 3 of 11 the accessible weld), without disposition or justification, is inconsistent with the staffs expectation for implementation of the BWRVIP-based programs during the period of extended operation.
Request:
- 1. For the vessel ID attachment welds that include guidelines associated with the BWRVIP and rely on EVT-1 examinations, provide a summary of the locations where EVT-1 examinations are performed, indicate whether Alloy 182 welds are included, and the percent coverage for these examinations that can be qualified in accordance with the latest revision of BWRVIP-03.
- 2. For vessel ID attachment weld locations, where examination coverage is expected to be less than 90 percent during the period of extended operation, provide the technical basis regarding the limited inspection coverage, and its adequacy to detect aging degradation prior to loss of intended function(s).
- 3. For vessel ID attachment welds, provide a summary of the operating experience related to detected flaws, and the results of any flaw analyses, or other evaluations that may offer insights into flaw sizes that can be tolerated.
- 4. Describe how inspection results that credit EVT-1 examinations (for vessel ID attachment welds) with minimal coverage (i.e., essentially zero percent coverage) will be documented and justified during the period of extended operation.
- 5. State whether deviation reports will be submitted for inspection results for vessel attachment welds that credit examinations with limited coverage (e.g., less than 90 percent of accessible welds). If deviation reports will not be submitted, justify how the BWRVIP will provide adequate oversight of the effectiveness of the BWR Vessel ID Attachment Welds.
Exelon Response
- 1. The following tables provide a summary of the locations where EVT-1 examinations were performed for the LaSalle Unit 1 and Unit 2 vessel ID attachment welds in accordance with BWRVIP-48-A. Table 1 provides a summary of EVT-1 examination coverage of vessel ID attachment welds for Unit 1. Table 2 provides a summary of EVT-1 examination coverage of vessel ID attachment welds for Unit 2. All examinations were performed in accordance with the latest revision of BWRVIP-03 at the time of the examination. BWRVIP-03, Revision 10 implemented a requirement that the angle of inspection must not exceed 30 degrees from perpendicular to the examination surface to meet the qualification requirements of EVT-1. Prior to the implementation of BWRVIP-03, Revision 10, the angle of inspection could be as much as 60 degrees from perpendicular to the surface, the same as required for ASME Code Section XI VT-1 examinations. This change was made to enhance the EVT-1 examination method to better identify tight cracks that are characteristic of intergranular stress corrosion cracking (IGSCC). For a visual examination to be qualified as EVT-1, requirements for surface cleanliness and limitations on camera scanning speed must also be met. EVT-1 invokes the same requirement as VT-1, as defined in current ASME Code Section XI, for demonstration of character resolution.
RS-16-052 Enclosure Page 4 of 11 BWRVIP-03, Revision 10 was implemented for the first time at LaSalle for the Unit 2 refueling outage in 2009 and for the Unit 1 refueling outage in 2010. The following tables provide EVT-1 examination coverage for examinations performed prior to 2009, and also from 2009 through 2015, showing the decrease in EVT-1 coverage that resulted from the more restrictive angle of inspection that was implemented in 2009.
Visual examinations are performed on the entire (100 percent) accessible surface of the vessel ID attachment weld, however only the percentage of the entire (accessible +
inaccessible) weld surface and adjacent base metal, where the examination requirements for EVT-1 can be met, is reported as the percentage of examination coverage. The accessible surface of the weld where not all of the EVT-1 examination requirements can be met is visually examined by a qualified NDE (Non-Destructive Examination) specialist, in accordance with site procedures and the guidance within BWRVIP-48-A and BWRVIP-03. For example, if a weld is 10 inches long and 9 inches of the weld is accessible for visual examination, and the examination requirements for EVT-1 can only be met for 7 inches of the weld, then 70 percent is reported as the EVT-1 examination coverage. The remaining accessible 2 inches is visually examined, but not to EVT-1 requirements.
TABLE 1 Unit 1 BWR Vessel ID Attachment Weld Examinations Exams 2004 through Exams 2009 through 2015 Vessel ID Attachment 2008 Weld Location Number Average Number Average Minimum of EVT-1 EVT-1 of EVT-1 EVT-1 EVT-1 weld Coverage weld Coverage Coverage exams exams Core Spray Piping 8 88% 4 65% 65%
Brackets Jet Pump Riser Braces 30 99% 18 74% 70%
Steam Dryer Support 8 100% None performed; Next examinations Brackets are scheduled in 2016 Feedwater Sparger 14 69% None performed; Next examinations Brackets are scheduled in 2016 Total / Overall Average 60 91% 22 72% NA
RS-16-052 Enclosure Page 5 of 11 TABLE 2 Unit 2 BWR Vessel ID Attachment Weld Examinations Exams 2004 through Exams 2009 through 2015 Vessel ID Attachment 2008 Weld Location Number Average Number Average Minimum of EVT-1 EVT-1 of EVT-1 EVT-1 EVT-1 weld Coverage weld Coverage Coverage exams exams Core Spray Piping 10 86% 8 64% 60%
Brackets Jet Pump Riser Braces 22 92% 10 70% 70%
Steam Dryer Support 4 100% 4 96% 90%
Brackets Feedwater Sparger 12 73% 12 53% 30%
Brackets Total / Overall Average 48 87% 34 66% NA EVT-1 examination coverages of less than 100 percent are caused by physical interferences or component geometry such that the camera used for visual examination cannot be positioned close enough or within the required angle of inspection to the examination surface. The data shows that prior to 2009, qualified EVT-1 examination coverage averaged approximately 89 percent of the entire weld surface for the vessel ID attachment welds; whereas from 2009 to 2015, EVT-1 qualified examination coverage averaged approximately 68 percent. This reduction was caused by the EVT-1 required angle of inspection being reduced from 60 degrees to 30 degrees. In all cases the entire accessible weld surface was visually examined.
Review of available records indicates that most of the LaSalle vessel ID attachment welds that are examined using the EVT-1 examination method are at least partially fabricated with Alloy 182 material that is susceptible to IGSCC. The EVT-1 examination method was developed to provide more effective visual examination that can detect tight cracks that are characteristic of IGSCC in reactor internal welds.
- 2. If the qualification requirements for the EVT-1 examination method remain unchanged during the period of extended operation, then the EVT-1 examination coverages for vessel ID attachment welds are expected to be consistent with those reported for the period of 2009 through 2015, as shown in Tables 1 and 2. The technical bases for limited EVT-1 examination coverage (less than 90 percent of the entire weld surface) being adequate to detect aging degradation prior to loss of intended function are as follows:
RS-16-052 Enclosure Page 6 of 11 GALL Report AMP XI.M4, Element 4, Detection of Aging Effects, recommends examination in accordance with ASME Section XI, Subsection IWB, Examination Category B-N-2, supplemented with the inspection guidelines within BWRVIP-48-A and BWRVIP-03. ASME Section XI, Table IWB-2500-1, Examination Category B-N-2 requires examination of the accessible reactor vessel interior attachment welds. VT-1 is to be performed on attachment welds within the beltline and VT-3 is to be performed on welds outside the beltline.
Section XI, IWA-2200(c) states that when performing ... examination on a component with a defined surface or volume, essentially 100% of the defined volume shall be examined. Essentially 100% coverage is achieved when the applicable examination coverage is greater than 90%; however ... This 90 percent coverage requirement does not apply to ASME Code inspection of the vessel ID attachment welds since the Examination Requirements/Figure No.
column in Table IWB-2500-1, Exam Category B-N-2 for vessel ID attachment welds, does not refer to a figure that defines the surface or volume; and instead it states that the accessible welds are required to be examined. Therefore, ASME Code requires 100 percent examination coverage of the surface of the vessel ID attachment welds that is accessible when using the specified visual examination method (i.e., VT-1 only or VT-3 only).
LaSalle is committed to implement the examination requirements for vessel ID attachment welds in accordance with BWRVIP-48-A and BWRVIP-03. Since the examination methods directed for use in BWRVIP-48-A and BWRVIP-03 for some of the vessel ID attachment welds are different than those specified within ASME Code Section XI (i.e., EVT-1 instead of VT-1 or VT-3), Exelon applied for, and on April 30, 2008 was granted relief in accordance with 10 CFR 50.55(a),
from certain ASME Code requirements. LaSalle is currently authorized to perform these examinations in accordance with BWRVIP-48-A and BWRVIP-03 as an alternate to certain ASME Code requirements. BWRVIP-48-A requires a different examination method for certain vessel ID attachment welds, but does not address required examination coverage for the welds. For EVT-1 examinations, the current revision (Revision 18) of BWRVIP-03, Section 2.5, Generic Standards for Visual Inspection of Reactor Pressure Vessel Internals, Components, and Associated Repairs, subsection 6.4.1, which applies to visual examination of reactor internal components and welds, states The area of interest for components shall consist of all accessible surfaces of the component. Subsection 6.4.1 continues to clarify that for welds the area of interest includes adjacent base metal. Since the BWRVIP examination coverage requirement is The area of interest for components shall consist of all accessible surfaces of the component, and the ASME Code examination coverage requirement is accessible welds, the examination coverage requirement is the same; that is, accessible surfaces. Therefore, BWRVIP-48-A and BWRVIP-03 do not change the examination coverage requirement from ASME Code Section XI requirements that are discussed above. However, as noted above, the examination methods directed for use in BWRVIP-48-A and BWRVIP-03 for certain vessel ID attachment welds are different, that is EVT-1, than those specified within ASME Code Section XI, which is VT-1 or VT-3. The EVT-1 examination method was developed to provide a more effective visual
RS-16-052 Enclosure Page 7 of 11 examination to detect tight cracks that are characteristic of IGSCC in reactor internal welds.
BWRVIP-03 and the procedure used to perform EVT-1 at LaSalle require examination of the entire (100 percent) accessible examination surface; however only the percentage of the entire (accessible + inaccessible) weld surface where the examination requirements for EVT-1 can be met is reported as the percentage of examination coverage. The accessible weld surface where not all the EVT-1 examination can be met is visually examined by a qualified NDE specialist. Since EVT-1 has been demonstrated to be more effective at detecting tight cracks that are characteristic of IGSCC, it is specified within BWRVIP-48-A as the examination method for vessel ID attachment welds that are most susceptible to IGSCC.
The examination is performed by a NDE specialist qualified to at least Level II, independently reviewed by a qualified Level II or III NDE specialist, and oversight is provided by an Exelon representative. The training and qualification standards required for the examiner and independent reviewer provide assurance that the proper EVT-1 examination coverage is documented in accordance with procedure requirements.
In summary, although limited EVT-1 examination coverage (less than 90 percent of the entire weld surface) may be reported for some vessel ID attachment welds; those examinations are adequate to detect aging degradation prior to loss of intended function.
The EVT-1 method is the nuclear industry standard for visual examination to detect IGSCC cracks. The implementing procedures for EVT-1 examination require visual examination of the entire accessible weld surface and qualifying the EVT-1 examination to the maximum extent practical coverage. Although LaSalle implements a NRC-approved ASME Code alternative for the current 10-year inservice inspection interval to perform examinations of vessel ID attachment welds in accordance with BWRVIP-48-A in lieu of ASME Code requirements, the alternative involves implementing a more effective visual examination method for certain welds and the ASME Code Section XI requirement to inspect the accessible welds is met.
- 3. Cracking indications have not been detected in any LaSalle Unit 1 or Unit 2 vessel ID attachment welds during their operating history. Therefore, there have not been any flaw analyses or other evaluations performed to determine the maximum flaw sizes that can be tolerated. There also has not been any operating experience of cracking caused by IGSCC in vessel ID attachment welds within the domestic BWR fleet. As discussed within BWRVIP-48-A, there was one domestic BWR that detected cracking in a steam dryer support bracket that was caused by fatigue. The causes of that event did not have generic implications for other BWRs.
The following guidance for evaluating flaws detected in vessel ID attachment welds is provided in BWRVIP-48-A. If cracking is detected in a vessel ID attachment weld, the flaw would be evaluated using the acceptance criteria within ASME Section XI, IWB-3140 and the examination standards within ASME Section XI, IWB-3520. If the acceptance criteria for the flaw are not met, then the flaw would be evaluated in accordance with ASME Section XI, IWB-3600 for acceptability, which includes
RS-16-052 Enclosure Page 8 of 11 determining the maximum allowable flaw size at the flaw location and comparing that to the existing flaw, including flaw growth.
- 4. LaSalle operating experience, as summarized in Tables 1 and 2, indicates that EVT-1 examinations of vessel ID attachment welds with essentially zero percent coverage have not been credited in the past, and are not expected to occur or be credited during the period of extended operation. Exelon has revised the referenced procedure ER-AB-331 to delete discussion of the possibility of zero percent EVT-1 examination coverage being acceptable. The procedure has been revised to require that when EVT-1 or VT-1 method is specified, the entire accessible surface of the weld or components is to be visually examined and the specified method (EVT-1 or VT-1) is to be performed to the maximum extent practical given the qualifications requirements for the specified visual examination method. This is consistent with the current revision of BWRVIP-03 (Revision 18) and the implementing procedure used at LaSalle for EVT-1 examination of vessel internals.
The procedure has been revised to clarify that if a visual examination of a reactor internal component results in zero percent EVT-1 examination coverage, the condition would be entered into the corrective action program and evaluated for whether a BWRVIP deviation report would be required. As shown in Tables 1 and 2 above, the minimum historical EVT-1 coverage is 30 percent for a Unit 2 feedwater sparger attachment weld and the average EVT-1 examination coverages are approximately 68 percent for vessel ID attachment welds. Therefore, it is not expected that any EVT-1 examinations of vessel ID attachment welds would approach essentially zero percent examination coverage during the period of extended operation.
- 5. As discussed in NEI 03-08, Revision 2, BWRVIP deviation reports are required to be submitted if mandatory or needed work product elements are not being implemented consistent with the intent of the BWRVIP guidance. Exelon implementing procedures require submittal of deviation reports consistent with this guidance. It is expected that during the period of extended operation, the EVT-1 examination coverages will be typical of those reported in Table 1 and 2 above. The LaSalle implementing procedures for performing visual examination of reactor vessel internals require that when EVT-1 or VT-1 method is specified, the entire (100 percent) accessible surface of the weld or components is to be visually examined and the specified method (EVT-1 or VT-1) is to be performed to the maximum extent practical given the qualifications requirements for specified visual examination method. This is consistent with BWRVIP-48-A and the current revision of BWRVIP-03 (Revision 18).
The BWRVIP provides adequate oversight of the effectiveness of the BWR Vessel ID Attachment Welds aging management program by utilizing INPO to review the implementation of the overall BWRVIP program as discussed in NEI 03-08 Revision 2.
The BWRVIP program includes aging management of the vessel ID attachment welds as defined in BWRVIP-48-A and BWRVIP-03. Specific activities include participation in periodic comprehensive on-site assessments of program implementation, monitoring, review and analysis of industry operating experience, and providing industry updates to the industry on trends in performance in implementing the program. Also, the results of reactor in-vessel examinations are provided to the BWRVIP following each refueling outage.
RS-16-052 Enclosure Page 9 of 11 RAI B.2.1.7-3b
Background:
By letters dated June 25, 2015, and September 15, 2015, Exelon responded to requests for additional information (RAIs) B.2.1.7-3 and B.2.1.7-3a regarding limited examination coverage for inspections of welds associated with the BWR Stress Corrosion Cracking AMP and NRC Generic Letter (GL) 88-01. Exelons responses indicate that additional inspections to compensate for limited examination coverage are not necessary to manage cracking due to intergranular stress corrosion cracking during the period of extended operation.
As discussed in the initial RAI, GL 88-01 states, Examinations performed under the Scope of this letter should comply with the applicable Edition and Addenda of the ASME Code,Section XI, as specified in paragraph (g), Inservice Inspection (ISI) Requirements of 10 CFR 50.55a, Codes and Standards, or as otherwise approved by the NRC. In addition, the required volume for ASME Code examinations is defined as more than 90 percent of the specified volume.
Based on information from LSCSs docketed ISI reports, the examination coverage for a number of GL 88-01 welds is only 50 percent. Although the staff-approved BWRVIP-75-A, Technical Basis for Revisions to Generic Letter 88-01 Inspection Schedules, allows for modifications to the inspection extent and schedule described in GL 88-01, the modification to the inspection extent only applies to the number of welds being inspected, not the extent of examination coverage. BWRVIP-75-A does not specifically address the minimum required effective examination coverage.
Issue:
Although not explicitly addressed in BWRVIP-75-A, the staffs expectation has been that the examination coverage of inspections performed for AMPs consistent with GALL Report AMP XI.M7 BWR Stress Corrosion Cracking, would be the same as that required by the ASME Code (i.e., greater than 90 percent). BWRVIP-75-A includes a discussion about the sampling percentages from ASME Section XI Inspection requirements and notes that ASME Section XI has been the ISI mechanism for assuring a robust reactor coolant system boundary and an adequate level of plant safety. Crediting weld inspections that do not meet the required ASME Code examination coverage without specific documented justification is inconsistent with the staffs expectation for implementation of the BWR Stress Corrosion Cracking program, during the period of extended operation.
Since a minimum extent of effective examination coverage is not specified in BWRVIP-75-A, it is unclear to the staff what percentage of examination volume coverage Exelon considers as inspected for a weld examination that will be credited under the BWR Stress Corrosion Cracking program. Although Exelon has not considered additional weld inspections as being necessary to compensate for limited examination coverage, it is unclear to the staff that sufficient bases will be documented and independently reviewed to justify the limited examination coverage, where less than 90 percent of a weld has been examined. The staff considers sufficient bases, as information comparable to that which would be included in a relief request, had the inspection been an ASME Code examination.
RS-16-052 Enclosure Page 10 of 11 Request:
- 1. State the minimum percentage of weld volume examination coverage for a single weld to be considered inspected under the BWR Stress Corrosion Cracking program, during the period of extended operation. If the minimum examination volume coverage percentage for crediting a weld as inspected is less than 90 percent, provide the technical basis to show that adequate levels of piping integrity and reliability will be achieved, as discussed in GL 88-01.
- 2. For each inspection performed under the BWR Stress Corrosion Cracking program, which will credit weld examinations with less than 90 percent coverage (during the period of extended operation),
- a. state whether documentation will be available onsite that provides the justification for the limitation, and whether the documentation will be independently reviewed to validate the justification,
- b. if documentation discussed in a) above will not be available, identify the controls that will be established to justify the limited weld examinations.
Exelon Response
- 1. The minimum percentage of weld volume examination coverage for a single weld to be considered inspected under the current GL 88-01 program and BWR Stress Corrosion Cracking program during the period of extended operation is greater than 90 percent, unless the bases for accepting the limited coverage is evaluated and documented. As discussed in the response to RAI B.2.1.7-3a, all volumetric examinations under the BWR Stress Corrosion Cracking program are performed using current Performance Demonstration Initiative (PDI) methods and procedures. For certain weld configurations, due to the specific contour of the weld or other interferences to the equipment used to perform the examination, the PDI method can only provide qualified and reliable examination results for a limited examination volume of the weld that may be less than or equal to 90 percent.
For welds with less than or equal to 90 percent examination coverage to be considered inspected during the period of extended operation under the BWR Stress Corrosion Cracking program, the condition will be evaluated as discussed below. The current Exelon implementing procedure for inservice inspection of welds requires generation of a corrective action issue report with related documentation and disposition for weld examinations that have limited examination coverage (i.e., less than or equal to 90 percent). If the examination is credited to meet ASME Section XI Inservice Inspection requirements, then the procedure also requires justifying the adequacy of the limited examination coverage in a relief request from ASME Code Section XI inservice inspection requirements. The procedure also specifies actions to ensure that the examination coverage is maximized to the extent practical. The procedure will be revised to improve clarity for the extent of evaluation required when examination coverage is less than or equal to 90 percent for weld examinations that are only credited under the BWR Stress Corrosion Cracking program (i.e., not credited to meet ASME Code Section XI requirements). This guidance will require performing an Engineering Technical Evaluation that includes content comparable with that which would be
RS-16-052 Enclosure Page 11 of 11 included in a relief request, had the inspection been an ASME Code examination.
Welds with less than or equal to 90 percent coverage, that are examined to the maximum examination coverage attainable using the PDI methods and procedures, may be considered inspected under the BWR Stress Corrosion Cracking program if the Engineering Technical Evaluation provides a documented bases that is comparable with the content of a relief request, had the inspection been an ASME Code examination.
- 2. a. For each weld examination performed during the period of extended operation under the BWR Stress Corrosion Cracking program, which will credit examinations with less than or equal to 90 percent coverage, documentation will be available onsite that provides the justification for the limitation. As discussed in the response to request 1 above, if the weld examination is also credited to meet ASME Code Section XI inservice inspection requirements, a relief request from ASME Code requirements that provides the justification for the limitation will be submitted for NRC approval. For weld examinations that are only credited under the BWR Stress Corrosion Cracking program, an Engineering Technical Evaluation will provide the justification for the limited examination coverage as adequate to credit the weld examination. Procedural guidance for Engineering Technical Evaluations requires safety-related Engineering Technical Evaluations to be independently reviewed and maintained as permanent plant records. Since all welds examined under the BWR Stress Corrosion Cracking program are safety-related, the Engineering Technical Evaluations that provide the justification for the limited examination coverage will be independently reviewed, retained, and available for onsite review.
- b. As discussed in the response to request 2a, the documentation that provides the justification for the limited examination coverage being adequate to credit the weld examination during the period of extended operation will be available as a permanent plant record.