ML101450039
| ML101450039 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 05/25/2010 |
| From: | Michael Mahoney Plant Licensing Branch III |
| To: | Lentz T FirstEnergy Corp |
| mahoney, m NRR/DORL/LPLIII-2 415-3867 | |
| References | |
| TAC ME3703 | |
| Download: ML101450039 (2) | |
Text
From:
Mahoney, Michael Sent:
Tuesday, May 25, 2010 8:40 AM To:
talentz@firstenergycorp.com
Subject:
Request for Additional Information - ME3703 - 10 CFR 50.55a Relief Requet RR-A34 Alternative Repairs for Reactor Pressure Vessel Head Penetration Nozzles Question:
By letters dated April 1, 2010 and May 17, 2010, the licensee submitted the half nozzle repair relief request for the control rod drive mechanism (CRDM) nozzles at Davis Besse. In response to RAI Question number 2 in Attachment 3 to the May 17, 2010, submittal, the licensee stated that Code Case N-416-3 will be used to satisfy pressure testing requirements subsequent to the CRDM nozzle repair. In the teleconference dated May 24, 2010, the licensee indicated that it will perform a visual (VT-2) examination from outside the service structure of the reactor pressure vessel without any direct view of the surface of the head in the areas that were repaired during the system leakage test. In general, the NRC accepts this type of indirect visual (VT-2) examination. However, it may not be appropriate for Davis-Besse CRDM nozzle repairs based on the following:
- 1) A larger number of repaired CRDM nozzles increases possibility for fabrication defects that may be missed by nondestructive examination.
- 2) Several unsuccessful repairs on CRDM nozzle 4 create the possibility for unforeseen fabrication defects.
- 3) Inability of a visual (VT-2) examination from the outside service structure to detect small leakage from a through-wall fabrication defect in a repaired nozzle.
For these reasons, the staff requests a direct viewing of the bare metal head surface through one or more access hole penetrations during the system leakage test to provide an additional defense in-depth and increase confidence in these nozzle repairs. Alternatively, the licensee needs to justify why the proposed indirect visual (VT-2) examination is acceptable.
Thanks Mike Michael Mahoney Project Manager, Branch III-2 U. S. Nuclear Regulatory Commission Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Phone: (301)415-3867 Email: MXM15@NRC.GOV E-mail Properties The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again.
Mail Envelope Properties (A41C2340DAB39B44AD0B9623285CB3330C3C68C54C)
Subject:
Request for Additional Information - ME3703 - 10 CFR 50.55a Relief Requet RR-A34 Alternative Repairs for Reactor Pressure Vessel Head Penetration Nozzles Sent Date: 5/25/2010 8:40:11 AM Received Date: 5/25/2010 8:40:11 AM From: Mahoney, Michael Created By: Michael.Mahoney@nrc.gov Recipients:
talentz@firstenergycorp.com (talentz@firstenergycorp.com)
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