RS-07-060, Supplemental Response to NRC Bulletin 2004-01, Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors.
| ML071340060 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 05/11/2007 |
| From: | Gullott D Exelon Nuclear |
| To: | Document Control Desk, NRC/NRR/ADRO |
| References | |
| BL-04-001, RS-07-060 | |
| Download: ML071340060 (4) | |
Text
Exel(5n,.
Nuclear Exelor= Generation www.exeloncorp .corn 4300 Wlnfield Road Warrenville, J 60555 10 CFR 50 .54 (f)
RS-07-060 May 11, 2007 U . S . Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Braidwood Station, Units 1 and 2 Facility Operating License Nos. NPF-72 and NPF-77 NRC Docket Nos. STN 50-456 and STN 50-457 Byron Station, Units 1 and 2 Facility Operating License Nos. NPF-37 and NPF-66 NRC Docket Nos. 50-454 and 50-455
Subject:
Supplemental Response to NRC Bulletin 2004-01, "Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors" References : (1) Letter from K. R. Jury (Exelon Generation Company, LLC) to U. S. Nuclear Regulatory Commission, "Initial response to NRC Bulletin 2004-01,
`Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors,"' dated July 27, 2004 (2) Letter from R. F. Kuntz (U. S. Nuclear Regulatory Commission), to C. M . Crane (Exelon Generation Company, LLC), "Request for Additional Information Related to NRC Bulletin 2004-01, `Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors,' (TAC Nos.
MC3461, MC3462, MC3463, and MC3464)," dated April 4, 2007 In Reference 1, Exelon Generation Company, LLC (EGC) responded to NRC Bulletin 2004-01, "Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors ." In Reference 2, the NRC requested additional information related to the scope of additional examinations to be performed at Braidwood Station and Byron Station if reactor coolant pressure boundary leakage is discovered by visual examination during the inspection of Alloy 82/182 locations. The additional information is provided in the attachment to this letter .
U . S. Nuclear Regulatory Commission Page 2 May 11, 2007 As described in the attachment, Byron Station Units 1 and 2 have completed full structural weld overlays, using primary water stress corrosion cracking resistant material, on all pressurizer Alloy 82/182 connections. With this mitigative action, Byron Station has satisfied the concerns identified in Bulletin 2004-01 and all required actions and committed inspections are complete .
Braidwood Station Units 1 and 2 will complete Bulletin 2004-01 actions with the installation of full structural weld overlays on pressurizer steam space connections during the upcoming refueling outages. EGC will notify the NRC when these actions are complete.
Should you have any questions concerning this letter, please contact Mr. David J . Chrzanowski at (630) 657-2816 .
This submittal does not contain any regulatory commitments.
I declare under penalty of perjury that the foregoing is true and correct. Executed on the 11 th day of May 2007 .
Respectfully, David Gullott Manager - Licensing Attachment : Supplemental Information Regarding the Braidwood Station and Byron Station Response to NRC Bulletin 2004-01
Attachment Supplemental Information Regarding the Braidwood Station and Byron Station Response to NRC Bulletin 2004-01 NRC Request:
Item 1(c) in Bulletin 2004-01 states in part, `7f leaking pressurizer penetrations or steam space piping connections are found, indicate what followup NDE [nondestructive examination] will be performed to characterize flaws in the leaking penetrations . Provide your plans for expansion of the scope of NDE to be performed if circumferential flaws are found in any portion of the leaking pressurizer penetrations or steam space piping connections." Provide a response that addresses whether NDE that is capable of determining crack orientation will be performed in order to accurately characterize the flaw, its orientation and its extent where evidence of apparent reactor coolant pressure boundary leakage is discovered by visual examination. The response should also provide your plans for expansion of the scope of NDE to other components in the pressurizer to be performed if circumferential flaws are found in any portion of the leaking pressurizer penetrations or steam space piping connections. Alternatively, if you will not supplement your original response to address the comments above, please provide a technical justification for not doing so.
Exelon Generation Company, LLC (EGC) Response:
As stated in the Reference 1 response to question (1)(c), Braidwood Station will perform a bare metal visual examination of all affected pressurizer penetrations and steam space piping connections during the next refueling outages for each unit. If, during a given unit's inspection, any of the five low alloy steel nozzle to stainless steel, Alloy 82/182, welded safe-end connections are found to have through-wall leakage, the NRC Project Manager will be contacted and a teleconference or meeting will be scheduled .
The discussion with the NRC will address plans for evaluating the nature of the through-wall leakage, including the NDE techniques to be used to characterize the flaw(s) as axial or circumferential. EGC would discuss with the NRC the nature and scope of repair plans as well as the plans for evaluating the extent of condition.
As discussed in the Reference 1 submittal, the Braidwood Station pressurizer upper head penetrations to steam space piping Alloy 82/182 weld connections are configured such that a fully qualified performance demonstration initiative (PDI) ultrasonic examination is not possible . Therefore, the examination techniques, extent of qualification, and potential limitations will be discussed with the NRC.
Braidwood Station will perform visual and dye penetrant examinations of all Alloy 82/182 pressurizer connections in the next Unit 1 and Unit 2 refuel outages as a prerequisite to installing full structural weld overlays on these connections. The present schedules and associated regulatory commitments regarding the Braidwood Station pressurizer weld overlay plans are contained in the Reference 2 transmittal and acknowledged in the Reference 3 Confirmatory Action Letter .
Attachment Supplemental Information Regarding the Braidwood Station and Byron Station Response to NRC Bulletin 2004-01 The issue of follow-up NDE to further characterize visual indications of pressure boundary leakage at the Byron Station Unit 1 and Unit 2 pressurizer steam space connections is no longer applicable. Byron Station Unit 1 and Unit 2 performed visual and dye penetrant examinations of the pressurizer steam space connections in the Fall 2006 refueling outage, for Unit 1, and in the Spring 2007 refueling outage, for Unit 2, prior to the installation of full structural overlays. There were no indications of pressurizer pressure boundary leakage at any of the pressurizer connections.
With the installation of the pressurizer connection weld overlays, Byron Station Units 1 and 2 have completed the required actions and committed inspections associated with Bulletin 2004-01, "Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors ."
The Byron Station Unit 1 and Unit 2 pressurizer Alloy 82/182 connections were overlayed, in the refueling outages listed above, with primary water stress corrosion cracking resistant material . Future examinations of these overlays will be performed in accordance with the requirements of ASME Section XI, Appendix Q, Q-4300 or alternate schedules if mandated in future NRC regulations .
References:
(1) Letter from K. R. Jury (Exelon Generation Company, LLC) to U . S . Nuclear Regulatory Commission, "Initial response to NRC Bulletin 2004-01, `Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors,"' dated July 27, 2004 (2) Letter from T. S. O'Neill (Exelon Generation Company, LLC and AmerGen Energy Company, LLC) to U . S . NRC, "Supplemental Response Regarding Inspection and Mitigation of Alloy 600/82/182 Pressurizer Butt Welds," dated February 21, 2007 (3) Letter from J . E . Dyer (U . S. NRC) to C. M . Crane (Exelon Generation Company, LLC), "Confirmatory Action Letter - Braidwood Station, Units 1 and 2 (TAC NOs.
MD4134 and MD4135)," dated March 22, 2007
Text
Exel(5n,.
Nuclear Exelor= Generation www.exeloncorp .corn 4300 Wlnfield Road Warrenville, J 60555 10 CFR 50 .54 (f)
RS-07-060 May 11, 2007 U . S . Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Braidwood Station, Units 1 and 2 Facility Operating License Nos. NPF-72 and NPF-77 NRC Docket Nos. STN 50-456 and STN 50-457 Byron Station, Units 1 and 2 Facility Operating License Nos. NPF-37 and NPF-66 NRC Docket Nos. 50-454 and 50-455
Subject:
Supplemental Response to NRC Bulletin 2004-01, "Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors" References : (1) Letter from K. R. Jury (Exelon Generation Company, LLC) to U. S. Nuclear Regulatory Commission, "Initial response to NRC Bulletin 2004-01,
`Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors,"' dated July 27, 2004 (2) Letter from R. F. Kuntz (U. S. Nuclear Regulatory Commission), to C. M . Crane (Exelon Generation Company, LLC), "Request for Additional Information Related to NRC Bulletin 2004-01, `Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors,' (TAC Nos.
MC3461, MC3462, MC3463, and MC3464)," dated April 4, 2007 In Reference 1, Exelon Generation Company, LLC (EGC) responded to NRC Bulletin 2004-01, "Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors ." In Reference 2, the NRC requested additional information related to the scope of additional examinations to be performed at Braidwood Station and Byron Station if reactor coolant pressure boundary leakage is discovered by visual examination during the inspection of Alloy 82/182 locations. The additional information is provided in the attachment to this letter .
U . S. Nuclear Regulatory Commission Page 2 May 11, 2007 As described in the attachment, Byron Station Units 1 and 2 have completed full structural weld overlays, using primary water stress corrosion cracking resistant material, on all pressurizer Alloy 82/182 connections. With this mitigative action, Byron Station has satisfied the concerns identified in Bulletin 2004-01 and all required actions and committed inspections are complete .
Braidwood Station Units 1 and 2 will complete Bulletin 2004-01 actions with the installation of full structural weld overlays on pressurizer steam space connections during the upcoming refueling outages. EGC will notify the NRC when these actions are complete.
Should you have any questions concerning this letter, please contact Mr. David J . Chrzanowski at (630) 657-2816 .
This submittal does not contain any regulatory commitments.
I declare under penalty of perjury that the foregoing is true and correct. Executed on the 11 th day of May 2007 .
Respectfully, David Gullott Manager - Licensing Attachment : Supplemental Information Regarding the Braidwood Station and Byron Station Response to NRC Bulletin 2004-01
Attachment Supplemental Information Regarding the Braidwood Station and Byron Station Response to NRC Bulletin 2004-01 NRC Request:
Item 1(c) in Bulletin 2004-01 states in part, `7f leaking pressurizer penetrations or steam space piping connections are found, indicate what followup NDE [nondestructive examination] will be performed to characterize flaws in the leaking penetrations . Provide your plans for expansion of the scope of NDE to be performed if circumferential flaws are found in any portion of the leaking pressurizer penetrations or steam space piping connections." Provide a response that addresses whether NDE that is capable of determining crack orientation will be performed in order to accurately characterize the flaw, its orientation and its extent where evidence of apparent reactor coolant pressure boundary leakage is discovered by visual examination. The response should also provide your plans for expansion of the scope of NDE to other components in the pressurizer to be performed if circumferential flaws are found in any portion of the leaking pressurizer penetrations or steam space piping connections. Alternatively, if you will not supplement your original response to address the comments above, please provide a technical justification for not doing so.
Exelon Generation Company, LLC (EGC) Response:
As stated in the Reference 1 response to question (1)(c), Braidwood Station will perform a bare metal visual examination of all affected pressurizer penetrations and steam space piping connections during the next refueling outages for each unit. If, during a given unit's inspection, any of the five low alloy steel nozzle to stainless steel, Alloy 82/182, welded safe-end connections are found to have through-wall leakage, the NRC Project Manager will be contacted and a teleconference or meeting will be scheduled .
The discussion with the NRC will address plans for evaluating the nature of the through-wall leakage, including the NDE techniques to be used to characterize the flaw(s) as axial or circumferential. EGC would discuss with the NRC the nature and scope of repair plans as well as the plans for evaluating the extent of condition.
As discussed in the Reference 1 submittal, the Braidwood Station pressurizer upper head penetrations to steam space piping Alloy 82/182 weld connections are configured such that a fully qualified performance demonstration initiative (PDI) ultrasonic examination is not possible . Therefore, the examination techniques, extent of qualification, and potential limitations will be discussed with the NRC.
Braidwood Station will perform visual and dye penetrant examinations of all Alloy 82/182 pressurizer connections in the next Unit 1 and Unit 2 refuel outages as a prerequisite to installing full structural weld overlays on these connections. The present schedules and associated regulatory commitments regarding the Braidwood Station pressurizer weld overlay plans are contained in the Reference 2 transmittal and acknowledged in the Reference 3 Confirmatory Action Letter .
Attachment Supplemental Information Regarding the Braidwood Station and Byron Station Response to NRC Bulletin 2004-01 The issue of follow-up NDE to further characterize visual indications of pressure boundary leakage at the Byron Station Unit 1 and Unit 2 pressurizer steam space connections is no longer applicable. Byron Station Unit 1 and Unit 2 performed visual and dye penetrant examinations of the pressurizer steam space connections in the Fall 2006 refueling outage, for Unit 1, and in the Spring 2007 refueling outage, for Unit 2, prior to the installation of full structural overlays. There were no indications of pressurizer pressure boundary leakage at any of the pressurizer connections.
With the installation of the pressurizer connection weld overlays, Byron Station Units 1 and 2 have completed the required actions and committed inspections associated with Bulletin 2004-01, "Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors ."
The Byron Station Unit 1 and Unit 2 pressurizer Alloy 82/182 connections were overlayed, in the refueling outages listed above, with primary water stress corrosion cracking resistant material . Future examinations of these overlays will be performed in accordance with the requirements of ASME Section XI, Appendix Q, Q-4300 or alternate schedules if mandated in future NRC regulations .
References:
(1) Letter from K. R. Jury (Exelon Generation Company, LLC) to U . S . Nuclear Regulatory Commission, "Initial response to NRC Bulletin 2004-01, `Inspection of Alloy 82/182/600 Materials Used in the Fabrication of Pressurizer Penetrations and Steam Space Piping Connections at Pressurized-Water Reactors,"' dated July 27, 2004 (2) Letter from T. S. O'Neill (Exelon Generation Company, LLC and AmerGen Energy Company, LLC) to U . S . NRC, "Supplemental Response Regarding Inspection and Mitigation of Alloy 600/82/182 Pressurizer Butt Welds," dated February 21, 2007 (3) Letter from J . E . Dyer (U . S. NRC) to C. M . Crane (Exelon Generation Company, LLC), "Confirmatory Action Letter - Braidwood Station, Units 1 and 2 (TAC NOs.
MD4134 and MD4135)," dated March 22, 2007