ML23093A211
| ML23093A211 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 04/03/2023 |
| From: | Quinn J Tennessee Valley Authority |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| Download: ML23093A211 (1) | |
Text
Post Office Box 2000, Decatur, Alabama 35609-2000 April 3, 2023 10 CFR 50.4 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Browns Ferry Nuclear Plant, Unit 3 Renewed Facility Operating License No. DPR-68 NRC Docket No. 50-296
Subject:
Boiling Water Reactor Vessel Internals Project (BWRVIP) - Notification of Deviation from BWRVIP-138, Revision 1-A, Updated Jet Pump Beam 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-138, Revision 1-A, Updated Jet Pump Beam 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 4, 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 inspection coverage requirement for a UT examination of the BB-1 inspection region on holddown beams for Jet Pumps 2 and 13 stipulated by Section 4.3.1 of BWRVIP-138, Revision 1-A. This deviation is a revision of Deviation Disposition 2019-01 (BWRVIP Designation DD-86) and is being extended to incorporate hydrogen inspection relief being obtained on Unit 3.
During Unit 3 Refueling Outage 18 (U3R18) in Spring 2018 the Jet Pump Holddown Beams were examined using a contact matrix phased array probe. Jet Pumps 2 and 13 had a lack of contact with Probe #1 from one side for the BB-1 examination region. The reason for the
U.S. Nuclear Regulatory Commission Page 2 April 3, 2023 insufficient contact in these two isolated instances appears to be a result of physical interference by the beam trunnion radius profile (desired probe contact point) preventing the probe from making good contact (100% coverage was obtained on the other 18 beams examined). Full contact was achieved on three of the four examination points for the BB-1 examination for Jet Pumps 2 and 13. However, because of this lack of contact the examination did not meet the required BWRVIP inspection coverage criteria for the JP beam BB-1 region.
Thus, the one-sided examination interrogated the BB-1 region and the examination was considered a limited best effort examination (50% inspection coverage obtained for both beams). No relevant indications were noted.
Assurance is provided that jet pump beams 2 and 13 will perform their intended design function and are acceptable for continued operation through Fuel Cycles U3C19 (completed), U3C20 (completed), U3C21 (in progress), U3C22, and U3C23 based on the following:
- 1. The UT examination performed during U3R18 met the intent of BWRVIP-138.
- 2. The holddown beams are fabricated from Alloy X-750, high temperature annealed and aged, and have improved resistance to IGSCC.
- 3. The beam life for a Group 2 beam is 40 years. Unit 3 beams for Jet Pumps 1 through 18 are Group 2 and have been in operation for 24 years (beams for Jet Pumps 19 and 20 are Group 3 and were installed during U3R18 in Spring 2018). At the next scheduled inspection the beams for Jet Pumps 2 and 13 will have been installed for 33 years which leaves significant margin to reach the 40 year beam life. Also, HWC conditions significantly increases this value. Finally, BFN Unit 3 holddown beams are mitigated against the effects of IGSCC as Unit 3 began NMCA (Traditional NobleChem) in 2000 and OLNC (On-Line NobleChem) in 2010.
Although Unit 3 is mitigated against the effects of IGSCC because of HWC and OLNC, BFN will re-inspect the BB-1 region of the jet pump beam at a shorter interval (10-year interval) which is more conservative than the inspection requirements for HWC (12-year interval). The Unit 3 jet pump holddown beams BB-1 region will be re-examined during U3R23 (Spring of 2028) at which time the necessary tooling modifications will be in place to allow 100% examination coverage of Jet Pumps beams 2 and 13.
This deviation is effective for Fuel Cycles U3C19 (completed), U3C20 (completed), U3C21 (in progress), U3C22, and U3C23 (Spring 2018 - Spring 2028). This notification is being transmitted for information only. TVA is not requesting any specific action from the NRC.
U.S. Nuclear Regulatory Commission Page 3 April 3, 2023 There are no new regulatory commitments contained in this letter. Should you have any questions concerning this submittal, please contact Christopher L. Vaughn, Nuclear Site Licensing Manager, at (256) 729-2636.
Respectfully, Manu Sivaraman BFN Site Vice President cc:
NRC Regional Administrator - Region II NRC Senior Resident Inspector - Browns Ferry Nuclear Plant Respectfullyylylyylylyy, Manu Sivaraman