SVPLTR 09-0053, Revised License Renewal Commitment for Thermal Aging and Neutron Irradiation Embrittlement of Cast Austenitic Stainless Steel Reactor Internal Components

Revised License Renewal Commitment for Thermal Aging and Neutron Irradiation Embrittlement of Cast Austenitic Stainless Steel Reactor Internal Components

ML093270061
Person / Time
Site:	Dresden
Issue date:	11/12/2009
From:	Hanley T Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
SVPLTR: #09-0053
Download: ML093270061 (3)

Text

Exelon.

Exelon Generation Company, LLC www.exeloncorp.com NuClear Dresden Nuclear Power Station 6500 North Dresden Road Morris, IL 60450-9765 SVPLTR: #09-0053 10CFR.54 November 12, 2009 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington D.C. 20555-0001 Dresden Nuclear Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DPR-19 and DPR-25 NRC Docket Nos. 50-237 and 50-249

Subject:

Revised License Renewal Commitment for Thermal Aging and Neutron Irradiation Embrittlement of Cast Austenitic Stainless Steel (CASS) Reactor Internal Components

References:

(1) Letter (RS-03-181) from Mr. Patrick R. Simpson (Exelon Generation Company, LLC), to the NRC, "Additional Information for the Review of the License Renewal Applications for Quad Cities Nuclear Power Station, Units 1 and 2 and Dresden Nuclear Power Station, Units 2 and 3," dated October 3, 2003 (2) NUREG 1796, "Safety Evaluation Report Related to the License Renewal of the Dresden Nuclear Power Station, Units 2 and 3 and Quad Cities Nuclear Power Station, Units 1 and 2" The purpose of this letter is to inform the NRC that Exelon Generation Company, LLC (EGC) is revising a commitment identified in References (1) and (2) for Dresden Nuclear Power Station (DNPS).

In Reference (1), as a part of EGC's license renewal application for DNPS, and as documented in reference 2, Appendix A, EGC made the following commitment:

An aging management program will be implemented for thermal aging and neutron irradiation embrittlement of Cast Austenitic Stainless Steel (CASS) reactor internal components within the scope of license renewal. A component specific evaluation for the loss of fracture toughness will be included. For those components where the loss of fracture toughness may affect the function of the component, an inspection will be performed as part of the ISI Program.

The commitment included an evaluation that requires the material composition be obtained from certified material test reports (CMTRs). The CMTRs could not be located for the components in question. The purpose of the commitment is to determine the CASS components where a loss of fracture toughness may affect the function of the component and to establish an inspection program for those susceptible components.

The inability to determine material composition from CMTRs affects the ability for EGC to evaluate CASS components for a loss of fracture toughness. Therefore, EGC conservatively assumed that

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November 12, 2009 U.S. Nuclear Regulatory Commission Page 2 of 2 all the components were susceptible and established an inspection program for these components, the same as would be required by the original commitment if an evaluation had concluded there was a loss of fracture toughness that may affect the function of the component.

As a result of the above, EGC is revising Commitment number 10 as documented in Appendix A to Reference 2. The revised commitment is included as Attachment 1 to this letter.

Should you have any questions concerning this letter, please contact Ms. Marri Marchionda at 815-416-2800.

Respectfully, Tim Hanley Site Vice President Dresden Nuclear Power Station

Attachment:

Summary of Regulatory Commitments cc: Regional Administrator - NRC Region III NRC Senior Resident Inspector - Dresden Nuclear Power Station

Attachment 1

SUMMARY

OF REGULATORY COMMITMENTS The following table identifies commitments made in this document. (Any other actions discussed in the document represent intended or planned actions. They are described to the NRC for the NRC's information and are not regulatory commitments.)

COMMIu-ED _________ COMMITMENT TYPE ___

COMMITMENT DATE OR ONE-TIME ACTION PROGRAMMATIC (Yes/No)

(Yes/No)

An aging management program will be 12/20/2009 No Yes implemented for thermal aging and neutron irradiation embrittlement of Cast Austenitic Stainless Steel (CASS) reactor internal components within the scope of license renewal.

A component specific evaluation for the loss of fracture toughness will be included. If material composition cannot be determined, a loss of fracture toughness may be assumed as an alternative to a specific evaluation. For those components where it is assumed or the evaluation has determined a loss of fracture toughness may affect the function of the component, an inspection will be performed as part of the ISI Program