TMI-10-053, Request to Extend the Inservice Inspection Interval for Reactor Vessel Weld and Internal Examinations - Relief Requests RR-09-01 and RR-09-02

Request to Extend the Inservice Inspection Interval for Reactor Vessel Weld and Internal Examinations - Relief Requests RR-09-01 and RR-09-02

ML101450005
Person / Time
Site:	Three Mile Island
Issue date:	05/24/2010
From:	Cowan P Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RR-09-01, RR-09-02, TMI-10-053
Download: ML101450005 (2)

Text

Exelon Nuclear www.exeloncorp.com Exelon.

200 Exelon Way Nuclear Kennett Square, PA 19348 10 CFR 50.55a TMI-10-053 May 24,2010 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Three Mile Island, Unit 1 Renewed Facility Operating License No. DPR-50 NRC Docket No. 50-289

Subject:

Request to Extend the Inservice Inspection Interval for Reactor Vessel Weld and Internal Examinations - Relief Requests RR-09-01 and RR-09-02

Reference:

Letter from P. B. Cowan (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission, "Request to Extend the Inservice Inspection Interval for Reactor Vessel Weld and Internal Examinations - Relief Requests RR-09-01 and RR-09-02, dated October 29, 2009 II In the referenced letter, Exelon Generation Company, LLC (EGC) submitted RR-09-01 to request an alternative from the ASME Code requirements; this alternative would extend the inspection of the reactor vessel shell welds to 20 years. Further, EGC requested approval to defer visual examinations under Table IWB-2500-1, Examination Categories B-N-2 and B-N-3, Item Nos. B13.50 and B13.70 for the extended inspection interval from 10 to 20 years as described in RR-09-02.

As noted in Table 3 (" Details of TWCF Calculation for 60 EFPY of Operation") of RR-09-01, the output of the fluence calculation for the Lower Shell Plate (row beginnin~ with "Plate - PL" in the Outputs section of the table) was identified as 2.273 x 1019 neutrons/cm ,E>1MeV. This value should be 2.274 x 1019 neutrons/cm 2 , E>1 MeV, as provided in the inputs. No other values in this table are changed. The correct value of 2.274 x 1019 neutrons/cm 2 , E>1 MeV, was used in the actual computations. This issue has been entered into the EGC corrective action process.

U.S. Nuclear Regulatory Commission May 24,2010 Page 2 There are no regulatory commitments in this letter.

If you have any questions concerning this letter, please contact Tom Loomis at (610) 765-5510.

Respectfully,

~~j f1vr!N1WI Pamela B. Cowan Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC cc: S. J. Collins, Regional Administrator, Region I, USNRC D. M. Kern, USNRC Senior Resident Inspector, TMI P. J. Bamford, Project Manager [TMI] USNRC