L-08-104, Steam Generator Tube Circumferential Cracking Report for the Fifteenth Refueling Outage
| ML081070433 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 04/10/2008 |
| From: | Allen B FirstEnergy Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-08-104 | |
| Download: ML081070433 (2) | |
Text
FENOC 5501 North State Route 2 FirstEnergy Nuclear Operating Company Oak Harbor, Ohio 43449 Barry S. Allen 419-321-7676 Vice President - Nuclear Fax: 419-321-7582 April 10, 2008 L-08-104 ATTN: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001
SUBJECT:
Davis-Besse Nuclear Power Station, Unit 1 Docket No. 50-346, License No. NPF-3 Davis-Besse Nuclear Power Station Unit 1 Steam Generator Tube Circumferential Cracking Report for the Fifteenth Refuelinq Outage In accordance with License Condition 2.C(7) of the Davis-Besse Nuclear Power Station Unit 1 (DBNPS) Operating License, the FirstEnergy Nuclear Operating Company (FENOC) hereby provides required information regarding the January 2008 eddy current inspection of the DBNPS steam generator tubes performed during the Fifteenth Refueling Outage (15RFO).
The information specified by the license condition is provided below.
- a. No circumferential cracking was found inboard of any installed repair roll.
- b. There was one tube in Steam Generator (SG) 2A that had a new circumferential Primary Water Stress Corrosion Cracking (PWSCC) crack indication in the tube-to-tubesheet seal weld heat affected zone.
This tube was plugged in accordance with Technical Specification 3.4.5.b requirements. The indication met the reporting requirements of License Condition 2.C(7). This indication was reported to the NRC by teleconference on January 12, 2008. No tubes in SG 1B had similar indications.
- c. The large-break loss-of-coolant accident (LBLOCA) Leakage Integrity Evaluation was performed and was included in the DBNPS 15RFO Steam Generator Condition Monitoring and Operational Assessment Evaluation. The projected best-estimate LBLOCA leakage for degradation observed during 15RFO is 0.0 gpm from SG 1B and 0.16 gpm from SG 2A.
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Davis-Besse Nuclear Power Station L-08-104 Page 2 The estimated combined steam generator leak rate is less than the leak rate assumed in the LBLOCA accident analysis in the Davis-Besse Updated Safety Analysis Report.
Accordingly, the off-site dose consequences from a LBLOCA would be below the 10 CFR Part 100 limits.
There are no regulatory commitments contained in this letter. If there are any questions or if additional information is required, please contact Mr. Thomas A. Lentz, Manager -
Fleet Licensing, at (330) 761-6071.
Sincerely, cc:
NRC Region III Administrator NRR Project Manager - Davis-Besse Nuclear Power Station NRC Resident Inspector - Davis-Besse Nuclear Power Station Executive Director, Ohio Emergency Management Agency, State of Ohio (NRC Liaison)
Utility Radiological Safety Board