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In GALL Report, Revision 1 Volume 2, this aging is addressed in Item IV. 02-4, applicable only to once-through SGs, but not to recirculating SGs. The staff notes that ASME Code Section XI does not require any inspection of the tubesheet welds. In addition, no NRC Orders or bulletins require examination of this weld. However, the staff's concern is that, if the tubesheet clad is Alloy 600, the tube-to-tubesheet weld region may not have sufficient chromium content to prevent initiation of PWSCC, even when the SG tubes are made from Alloy 690n. Consequently, such a PWSCC crack initiated in this region, close to a tube, could propagate into/through the weld, causing a failure of the weld and of the reactor coolant pressure boundary, for both recirculating and once-through SGs. In license renewal application (LRA) Table 3.1.1, the applicant stated that item number 3.1.1-35 is not applicable because they do not have once-through SGs and therefore, do not have the components associated with this model of SGs. In UFSAR Section 5.5.2.2.2, the applicant described that the Unit 1 Model-F steam generator tubes are fabricated from Alloy 600TT and are welded to the Inconel cladding on the primary face of the tube plate. In UFSAR Section 5.5.2.2.1, the applicant stated that the Unit 2 replacement steam generator tubes are fabricated from Alloy 690TT, and that the primary side of the tubesheet is weld clad with Alloy 600. Therefore, despite the fact that it is not an aging effect identified in GALL Revision 1, the staff is concerned that there may exist a similar aging effect for the SGs at Salem, given the similar material and environment of the SGs. Issue: Unless the NRC has approved a redefinition of the pressure boundary in which the autogenous tube-to-tubesheet weld is no longer included, or the tubesheet cladding and welds are not susceptible to PWSCC, the staff considers that the effectiveness of the primary water chemistry program should be verified to ensure PWSCC cracking is not occurring.
In GALL Report, Revision 1 Volume 2, this aging is addressed in Item IV. 02-4, applicable only to once-through SGs, but not to recirculating SGs. The staff notes that ASME Code Section XI does not require any inspection of the tubesheet welds. In addition, no NRC Orders or bulletins require examination of this weld. However, the staff's concern is that, if the tubesheet clad is Alloy 600, the tube-to-tubesheet weld region may not have sufficient chromium content to prevent initiation of PWSCC, even when the SG tubes are made from Alloy 690n. Consequently, such a PWSCC crack initiated in this region, close to a tube, could propagate into/through the weld, causing a failure of the weld and of the reactor coolant pressure boundary, for both recirculating and once-through SGs. In license renewal application (LRA) Table 3.1.1, the applicant stated that item number 3.1.1-35 is not applicable because they do not have once-through SGs and therefore, do not have the components associated with this model of SGs. In UFSAR Section 5.5.2.2.2, the applicant described that the Unit 1 Model-F steam generator tubes are fabricated from Alloy 600TT and are welded to the Inconel cladding on the primary face of the tube plate. In UFSAR Section 5.5.2.2.1, the applicant stated that the Unit 2 replacement steam generator tubes are fabricated from Alloy 690TT, and that the primary side of the tubesheet is weld clad with Alloy 600. Therefore, despite the fact that it is not an aging effect identified in GALL Revision 1, the staff is concerned that there may exist a similar aging effect for the SGs at Salem, given the similar material and environment of the SGs. Issue: Unless the NRC has approved a redefinition of the pressure boundary in which the autogenous tube-to-tubesheet weld is no longer included, or the tubesheet cladding and welds are not susceptible to PWSCC, the staff considers that the effectiveness of the primary water chemistry program should be verified to ensure PWSCC cracking is not occurring.
ENCLOSURE   
ENCLOSURE   
-2 Request: (1a) For Unit 1 SGs, clarify whether the tube-to-tubesheet welds are included in the reactor coolant pressure boundary or alternate repair criteria have been permanently approved.  
-2 Request: (1a) For Unit 1 SGs, clarify whether the tube-to-tubesheet welds are included in the reactor coolant pressure boundary or alternate repair criteria have been permanently approved.
(1 b) If the SGs do not have permanently approved alternate repair criteria, provide a specific aging management program (AMP) that will complement the primary water chemistry program, in order to verify the effectiveness of the primary water chemistry program and ensure that cracking due to PWSCC is not occurring in tube-to-tubesheet welds. (2) For Unit 2 SGs tube-to-tubesheet welds, provide either a plant-specific AMP that will complement the primary water chemistry program, in order to verify the effectiveness of the primary water chemistry program and ensure that cracking due to PWSCC is not occurring in tube-to-tubesheet welds, or a rationale for why such a program is not needed.
(1 b) If the SGs do not have permanently approved alternate repair criteria, provide a specific aging management program (AMP) that will complement the primary water chemistry program, in order to verify the effectiveness of the primary water chemistry program and ensure that cracking due to PWSCC is not occurring in tube-to-tubesheet welds. (2) For Unit 2 SGs tube-to-tubesheet welds, provide either a plant-specific AMP that will complement the primary water chemistry program, in order to verify the effectiveness of the primary water chemistry program and ensure that cracking due to PWSCC is not occurring in tube-to-tubesheet welds, or a rationale for why such a program is not needed.
November 4,2010 Mr. Thomas Joyce President and Chief Nuclear Officer PSEG Nuclear LLC P.O. Box 236 Hancocks Bridge, NJ 08038 REQUEST FOR ADDITIONAL INFORMATION FOR SALEM NUCLEAR GENERATING STATION, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION ON PRIMARY WATER STRESS CORROSION CRACKING IN STEAM GENERATOR TUBE-TO-TUBESHEET WELDS INSPECTION PROGRAM (TAC NOS. ME1834 AND ME1836)  
November 4,2010 Mr. Thomas Joyce President and Chief Nuclear Officer PSEG Nuclear LLC P.O. Box 236 Hancocks Bridge, NJ 08038 REQUEST FOR ADDITIONAL INFORMATION FOR SALEM NUCLEAR GENERATING STATION, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION ON PRIMARY WATER STRESS CORROSION CRACKING IN STEAM GENERATOR TUBE-TO-TUBESHEET WELDS INSPECTION PROGRAM (TAC NOS. ME1834 AND ME1836)  

Revision as of 21:36, 30 April 2019

Request for Additional Information for Salem Nuclear Generating Station, Units 1 and 2, LRA on Primary Water Stress Corrosion Cracking in Steam Generator Tube-to-Tube Sheet Welds (TAC Nos. ME1834 and ME1836)
ML102930049
Person / Time
Site: Salem  PSEG icon.png
Issue date: 11/04/2010
From: Brady B M
License Renewal Projects Branch 1
To: Joyce T P
Public Service Enterprise Group
BRADY B, NRR/DLR/RPB1, 415-2981
References
TAC ME1834, TAC ME1836
Download: ML102930049 (5)
v • d • e


Text

UNITED NUCLEAR REGULATORY WASHINGTON, D.C. 20555-0001 November 4, 2010 Mr. Thomas Joyce President and Chief Nuclear Officer PSEG Nuclear LLC P.O. Box 236 Hancocks Bridge, NJ 08038 REQUEST FOR ADDITIONAL INFORMATION FOR SALEM NUCLEAR GENERATING STATION, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION ON PRIMARY WATER STRESS CORROSION CRACKING IN STEAM GENERATOR TUBE-TO-TUBESHEET WELDS INSPECTION PROGRAM (TAC NOS. ME1834 AND ME1836)

Dear Mr. Joyce:

By letter dated August 18, 2009, Public Service Enterprise Group Nuclear, LLC, submitted an application pursuant to Title 10 of the Code of Federal Regulations Part 54 for renewal of Operating License Nos. DPR-70 and DPR-75 for Salem Nuclear Generating Station, Units 1 and 2, respectively.

The staff of the U.S. Nuclear Regulatory Commission (NRC or the staff) is reviewing this application in accordance with the guidance in NUREG-1800, "Standard Review Plan for Review of License Renewal Applications for Nuclear Power Plants." During its review, the staff has identified areas where additional information is needed to complete the review. The staff's request for additional information is included in the Enclosure.

Further requests for additional information may be issued in the future. Items in the enclosure were provided to John Hufnagel and other members of your staff, and a mutually agreeable date for the response is within 30 days from the date of this letter. If you have any questions, please contact me by telephone at 301-415-2981 or bye-mail at bennett.brady@nrc.gov. Sincerely, Bennett M. Brady, Project Manager Projects Branch 1 Division of License Renewal Office of Nuclear Reactor Regulation Docket Nos. 50-272 and 50-311

Enclosure:

As stated cc w/encl: Distribution via Listserv REQUEST FOR ADDITIONAL INFORMATION SALEM NUCLEAR GENERATING STATION, UNITS 1 AND LICENSE RENEWAL APPLICATION FOR PRIMARY WATER STRESS CRACKING IN STEAM GENERATOR TUBE-TO-TUBESHEET WELDS (TAC NOS. ME1834 AND RAI3.1.1-03

Background:

Standard Review Plan License Renewal (SRP-LR) Section 3.1.2.2.16 states that cracking due to primary water stress corrosion cracking (PWSCC) could occur on the primary coolant side of pressurized water reactor steel steam generator (SG) tube-to-tubesheet welds made or cladded with nickel alloy. The Generic Aging Lessons Learned (GALL) Report recommends American Society of Mechanical Engineers (ASME) Code Section XI inservice inspection and control of water chemistry to manage this aging and recommends no further aging management review for PWSCC of nickel alloy if the applicant complies with applicable U.S. Nuclear Regulatory Commission (NRC or the staff) Orders and provides a commitment in the Updated Final Safety Analysis Report (UFSAR) supplement to implement applicable (1) Bulletins and Generic Letters and (2) staff-accepted industry guidelines.

In GALL Report, Revision 1 Volume 2, this aging is addressed in Item IV. 02-4, applicable only to once-through SGs, but not to recirculating SGs. The staff notes that ASME Code Section XI does not require any inspection of the tubesheet welds. In addition, no NRC Orders or bulletins require examination of this weld. However, the staff's concern is that, if the tubesheet clad is Alloy 600, the tube-to-tubesheet weld region may not have sufficient chromium content to prevent initiation of PWSCC, even when the SG tubes are made from Alloy 690n. Consequently, such a PWSCC crack initiated in this region, close to a tube, could propagate into/through the weld, causing a failure of the weld and of the reactor coolant pressure boundary, for both recirculating and once-through SGs. In license renewal application (LRA) Table 3.1.1, the applicant stated that item number 3.1.1-35 is not applicable because they do not have once-through SGs and therefore, do not have the components associated with this model of SGs. In UFSAR Section 5.5.2.2.2, the applicant described that the Unit 1 Model-F steam generator tubes are fabricated from Alloy 600TT and are welded to the Inconel cladding on the primary face of the tube plate. In UFSAR Section 5.5.2.2.1, the applicant stated that the Unit 2 replacement steam generator tubes are fabricated from Alloy 690TT, and that the primary side of the tubesheet is weld clad with Alloy 600. Therefore, despite the fact that it is not an aging effect identified in GALL Revision 1, the staff is concerned that there may exist a similar aging effect for the SGs at Salem, given the similar material and environment of the SGs. Issue: Unless the NRC has approved a redefinition of the pressure boundary in which the autogenous tube-to-tubesheet weld is no longer included, or the tubesheet cladding and welds are not susceptible to PWSCC, the staff considers that the effectiveness of the primary water chemistry program should be verified to ensure PWSCC cracking is not occurring.

ENCLOSURE

-2 Request: (1a) For Unit 1 SGs, clarify whether the tube-to-tubesheet welds are included in the reactor coolant pressure boundary or alternate repair criteria have been permanently approved.

(1 b) If the SGs do not have permanently approved alternate repair criteria, provide a specific aging management program (AMP) that will complement the primary water chemistry program, in order to verify the effectiveness of the primary water chemistry program and ensure that cracking due to PWSCC is not occurring in tube-to-tubesheet welds. (2) For Unit 2 SGs tube-to-tubesheet welds, provide either a plant-specific AMP that will complement the primary water chemistry program, in order to verify the effectiveness of the primary water chemistry program and ensure that cracking due to PWSCC is not occurring in tube-to-tubesheet welds, or a rationale for why such a program is not needed.

November 4,2010 Mr. Thomas Joyce President and Chief Nuclear Officer PSEG Nuclear LLC P.O. Box 236 Hancocks Bridge, NJ 08038 REQUEST FOR ADDITIONAL INFORMATION FOR SALEM NUCLEAR GENERATING STATION, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION ON PRIMARY WATER STRESS CORROSION CRACKING IN STEAM GENERATOR TUBE-TO-TUBESHEET WELDS INSPECTION PROGRAM (TAC NOS. ME1834 AND ME1836)

Dear Mr. Joyce:

By letter dated August 18, 2009, Public Service Enterprise Group Nuclear, LLC, submitted an application pursuant to Title 10 of the Code of Federal Regulations Part 54 for renewal of Operating License Nos. DPR-70 and DPR-75 for Salem Nuclear Generating Station, Units 1 and 2, respectively.

The staff of the U.S. Nuclear Regulatory Commission (NRC or the staff) is reviewing this application in accordance with the guidance in NUREG-1800, "Standard Review Plan for Review of License Renewal Applications for Nuclear Power Plants." During its review, the staff has identified areas where additional information is needed to complete the review. The staffs request for additional information is included in the Enclosure.

Further requests for additional information may be issued in the future. Items in the enclosure were provided to John Hufnagel and other members of your staff, and a mutually agreeable date for the response is within 30 days from the date of this letter. If you have any questions, please contact me by telephone at 301-415-2981 or bye-mail at bennett. brady@nrc.gov.

Sincerely, IRAI Bennett M. Brady, Project Manager Projects Branch 1 Division of License Renewal Office of Nuclear Reactor Regulation Docket Nos. 50-272 and 50-311

Enclosure:

As stated cc w/encl: Distribution via Listserv DISTRIBUTION:

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