ML19295G582
| ML19295G582 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  (DPR-068) |
| Issue date: | 10/22/2019 |
| From: | Bono S Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML19295G582 (3) | |
Text
Tennessee Valley Authority, Post Office Box 2000, Decatur, Alabama 35609-2000 October 22, 2019 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Browns Ferry Nuclear Plant, Unit 3 Facility Operating License No. DPR-68 NRC Docket No. 50-296 10 CFR 50.4
Subject:
Boiling Water Reactor Vessel and Internals Project (BWRVIP) -
Notification of Deviation from BWRVIP-41, Revision 4-A, BWR Jet Pump Assembly Inspection and Flaw Evaluation Guidelines
Reference:
Letter from Boiling Water Reactor Vessel and Internals Project (BWRVIP) to the Nuclear Regulatory Commission dated October 30, 1997, "BWRVIP Utility Commitments to the BWRVIP" The Tennessee Valley Authority (TVA) is providing notification that the Browns Ferry Nuclear Plant (BFN) Unit 3 will not fully implement the subject guidance of BWRVIP-41, Revision 4-A, "BWR Jet Pump Assembly Inspection and Flaw Evaluation Guidelines." In accordance with a prior agreement with the NRC and BWR utilities that are part of the Boiling Water Reactor Vessel and Internals Project (BWRVIP), participating licensees are required to provide timely notification to the NRC of a decision, by the 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 3, "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 3 deviation concerns one item. BFN Unit 3 is not meeting the requirements for visual examination (EVT-1) of the riser brace to yoke welds (Welds RB-2a, b, c, and d) for Jet Pumps 5 and 6 as stipulated by BWRVIP-41, Revision 4-A.
U.S. Nuclear Regulatory Commission Page 2 October 22, 2019 During the In-Vessel Visual Inspection of Unit 3 performed in 1992 in preparation for unit restart, crack indications were identified at the two attachment welds of the riser brace to the riser pipe (RS-8 and RS-9) adjacent to Jet Pump Number 5 at the reactor vessel 90° azimuth.
A repair clamp was installed between the riser brace yoke and the riser pipe to capture the riser brace and perform the function of the deficient weld attachment. The repair clamp was also designed to allow future inspections of the existing cracks. However, it was discovered during the initial baseline inspection that the repair clamp obstructed inspection of the riser brace to yoke (RB-2) welds. The RB-2 welds are categorized as a medium priority location.
A BWRVIP baseline inspection has been conducted for all three units at BFN, and no indications have been observed at this location. This provides a reasonable level of assurance that the RB-2 welds associated with Jet Pumps 5 and 6 are intact. Therefore, TVA is waiving this examination for the Unit 3 Jet Pumps 5 and 6. The vendor-recommended inspection will continue to be performed every other refueling outage to ensure that the repair clamp is performing its function as designed. This inspection will also provide TVA with information whether any signs of increased flow-induced vibration are present, which would be indicative of failure of the RB-2 welds.
The next scheduled inspection to ensure that the repair clamp is performing its function as designed will be performed during the Unit 3 Refueling Outage 20 (U3R20) in 2022.
Since this inspection will serve in place of the BWRVIP-41 mandated inspection of the RB-2 welds, this deviation disposition will remain in effect until that time. Following the next inspection, the results will be evaluated and another deviation disposition prepared if results are satisfactory. Evaluating this condition every four years will provide greater attention to this location than would be obtained otherwise by performing the BWRVIP-41 mandated inspection.
This deviation is effective for the next two BFN Unit 3 two-year fuel cycles (Cycle 19 -
Spring 2018 to Spring 2020, and Cycle 20 - Spring 2020 to Spring 2022). 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 J. L. Paul, Nuclear Site Licensing Manager, at (256) 729-2636.
cc:
NRC Regional Administrator - Region II NRC Senior Resident Inspector - Browns Ferry Nuclear Plant
U.S. Nuclear Regulatory Commission Page 3 October 22, 2019 JLP:RWC bee:
S. M. Bono C. C. Chandler D. M. Czufin V. L. Dennis R. E. Detwiler S. M. Douglas C. D. Dunn M.R. Henderson D. L. Hughes K. D. Hulvey J. A. Kent R. J. Krigelman E. Q. Leonard E. C. Meisner M. W. Oliver T. J. Orf J. L. Paul J. T. Polickoski T. S. Rausch D. K. Riggs V. D. Schiavone R. L. Seipel J. W. Shea J. R. Sowa C. L. Vaughn ECM