ML17047A708
| ML17047A708 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 02/16/2017 |
| From: | Bono S Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BWRVIP-48-A | |
| Download: ML17047A708 (2) | |
Text
Tennessee Valley Authority, Post Office Box 2000, Decatur, Alabama 35609-2000 February 16, 2017 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Browns Ferry Nuclear Plant, Unit 1 Renewed Facility Operating License No. DPR-33 NRC Docket No. 50-259 10 CFR 50.4
Subject:
Boiling Water Reactor Vessel Internals Project (BWRVIP) -
Notification of Deviation from BWRVIP-48-A, Vessel ID Attachment Weld Inspection and Flaw Evaluation Guidelines
Reference:
Letter from Boiling Water Reactor Vessel and Internals Project (BWRVIP) to the Nuclear Regulatory Commission, "BWRVIP Utility Commitments to the BWRVIP," dated October 30, 1997 The Tennessee Valley Authority (TVA) is providing notification that the Browns Ferry Nuclear Plant (BFN), Unit 1, will not fully implement the subject guidance of BWRVIP-48-A, "Vessel ID Attachment Weld Inspection and Flaw Evaluation Guidelines." In accordance with the referenced BWRVIP letter dated October 30, 1997, Boiling Water Reactor (BWR) licensees that are part of the Boiling Water Reactor Vessel and Internals Project (BWRVIP) are required to provide timely notification to the NRC of a decision, by a licensee, to not fully implement the applicable BWRVIP product.
A deviation disposition (DD) has been prepared, reviewed, and approved in accordance with BWRVIP-94NP, Revision 2, "BWR Vessel and Internals Project Program Implementation Guide," and TVA internal procedures. This DD provides assurance that there are no safety implications or reliability concerns with the deviation.
The BFN, Unit 1, deviation concerns one item. BFN, Unit 1, is not meeting the requirement for an Extended VT-1 (EVT-1) visual examination of the Steam Dryer Support Bracket to Reactor Pressure Vessel (RPV) Weld at 184 degrees stipulated by Section 3.2.1 of BWRVIP-48-A.
Section 3.2.1 of BWRVIP-48-A states that the Steam Dryer Support Bracket Attachments should be visually examined using the EVT-1 inspection method based on their relatively higher susceptibility due to:
U.S. Nuclear Regulatory Commission Page 2 February 16, 2017 (1) Location in regions of the downcomer annulus where the environmental factors produce increased susceptibility to lntergranular Stress Corrosion Cracking (IGSCC).
(2) Significant loading during normal operating conditions.
During the In-Vessel Visual Inspection of the Steam Dryer Support Bracket to RPV Welds performed during Unit 1 Refueling Outage 11 in October 2016, heavy crud buildup was noted on the bracket located at 184 degrees which made it impossible to perform the required EVT-1 visual examination. A VT-3 visual examination was performed in lieu of the required examination, and no relevant indications were noted.
The Steam Dryer Support Bracket to RPV Weld at 184 Degrees was examined during Unit 1 Recovery (EVT-1) and no IGSCC indications were present. Additionally, no IGSCC indications have been observed on any of the Steam Dryer Support Bracket to RPV welds for all three units at BFN. For that reason, it is believed that a VT-3 visual examination is adequate for one cycle.
The inspection vendor (GE-Hitachi) will bring the proper cleaning tools to remove the heavy crud buildup for the Steam Dryer Support Bracket to RPV Weld at 184 degrees during the next scheduled refueling outage (Unit 1 Refueling Outage 12 in Fall 2018), which will make it possible to obtain the BWRVIP-mandated EVT-1 visual examination and more thoroughly monitor the weld for signs of IGSCC.
This deviation will remain in place for the next BFN, Unit 1, two-year fuel cycle only (Cycle 12 - Fall 2016 to Fall 2018). This notification is being transmitted for information only.
TVA is not requesting any specific action from the NRC.
There are no new regulatory commitments in this letter. If you have any questions, please contact M. W. Oliver, Nuclear Site Licensing Manager, at (256) 729-2636.
cc:
NRC Regional Administrator - Region II NRC Senior Resident Inspector - Browns Ferry Nuclear Plant