ML22173A162
| ML22173A162 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 06/21/2022 |
| From: | Rasmussen M Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML22173A162 (9) | |
Text
Post Office Box 2000, Decatur, Alabama 35609-2000 June 21, 2022 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:
Unit 3 Replacement Steam Dryer Visual Inspection Results (U3R20)
Enclosed is a summary of the results of the visual inspections of the Unit 3 Replacement Steam Dryer that were performed during the recent refueling outage (U3R20). The inspections are required to be performed in accordance with Operating License Condition 2.C(14)(e) during the first two scheduled refueling outages after reaching full Extended Power Uprate conditions which requires that the results of the inspection be submitted in a report within 90 days following startup. This second report for Unit 3 is being submitted pursuant to Operating License Condition 2.C(14)(f) which requires that the results of the inspection be submitted in a report within 90 days following startup.
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, Matthew Rasmussen Site Vice President p
y M tth R
U.S. Nuclear Regulatory Commission Page 2 June 21, 2022
Enclosure:
Browns Ferry Unit 3 Replacement Steam Dryer (RSD) Inspection Results from the Second Refueling Outage (U3R20) Following Installation of RSD and Implementation of Extended Power Uprate cc (w/ Enclosure):
NRC Regional Administrator - Region II NRC Senior Resident Inspector - Browns Ferry Nuclear Plant
ENCLOSURE Browns Ferry Nuclear Plant Unit 3 Browns Ferry Unit 3 Replacement Steam Dryer (RSD) Inspection Results from the Second Refueling Outage (U3R20) Following Installation of RSD and Implementation of Extended Power Uprate See Enclosed
Browns Ferry Unit 3 Replacement Steam Dryer (RSD) Inspection Results from the Second Refueling Outage (U3R20) Following Installation of RSD and Implementation of Extended Power Uprate
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Purpose This report provides the results of visual inspections of the Replacement Steam Dryer (RSD) as required by the Browns Ferry Unit 3 Renewed Facility Operating License No. DPR-68, License Condition 2.C.(14).(f). This license condition requires that the results of the visual inspections of the RSD be submitted to the NRC within 90 days following startup from each of the first two respective refueling outages.
Summary The Unit 3 RSD was inspected from February 28 through March 12, 2022, during the Spring 2022 refueling outage (Unit 3 Refueling Outage 20: U3R20). This was the second refueling outage following installation of the RSD in March 2018 during Unit 3 Refueling Outage 18 (U3R18) and operation at Extended Power Uprate (EPU) conditions since July 13, 2018. The inspections were performed in accordance with GE Hitachi Nuclear Energy Report No.
003N5663, Revision 2 (Tennessee Valley Authority (TVA) Browns Ferry Nuclear Station (BFNS): Recommendations for Future Inspections - Replacement Steam Dryer). The RSD design and the materials and fabrication processes utilized are expected to result in significantly improved resistance to stress corrosion cracking. Therefore, the inspection recommendations in the GEH report focus primarily on the locations that may be susceptible to fatigue from flow-induced vibration. The locations identified are those indicated to have relatively significant cyclic loading during the dryers operation, as determined by detailed stress analyses.
Tables 1 (Frequency of Recommended Locations Based on Analysis and 2 (Description of Recommended Inspections Locations) of the GEH Report list locations that are considered the most susceptible for fatigue cracking based on BWR dryer experience and stress analysis. All accessible weld and weld heat-affected zone (HAZ) base metal surfaces of the RSD were visually inspected during U3R20, with a total scope of 647 points. The summary results of the inspections can be found in the table starting on the next page.
The following explanations apply to the table:
NRI:
No Relevant Indication RI:
Relevant Indication The parentheses after each Inspection Location refer to the number of points inspected for each.
Browns Ferry Unit 3 Replacement Steam Dryer (RSD) Inspection Results from the Second Refueling Outage (U3R20) Following Installation of RSD and Implementation of Extended Power Uprate
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Inspection Location Method Inspection
Result
Condition
Report(ifRI)
Disposition
STEAM DRYER ID Divider Plate Welds & HAZs (32)
VT-1-89 NRI Trough Side Plate to Base Plate Weld &
HAZs (6)
VT-1-89 NRI Hood Vertical / Horizontal Welds &
HAZs (12)
VT-1-89 NRI Perforated Plate to Trough Side Plate Weld & HAZs (22)
VT-1-89 NRI Trough Spacer Pin Weld & HAZs (6)
VT-1-89 NRI Skirt to Support Beam Weld & HAZs (8)
VT-1-89 NRI Guide Channel to Tee Weld & HAZs (4)
VT-1-89 NRI Skirt to Tee Weld & HAZs (12)
VT-1-89 NRI Drain Pipe to Trough Base Plate Weld &
HAZs (12)
VT-1-89 NRI Drain Pipe to Elbow Weld & HAZs (21)
VT-1-89 NRI Drain Elbow to Pipe Weld & HAZs (11)
VT-1-89 NRI Drain Elbow to Skirt Weld & HAZs (12)
VT-1-89 NRI Collar to Skirt Weld & HAZs (12)
VT-1-89 NRI Cover Plate to Hood Weld & HAZs (2)
VT-1-89 NRI Trough Base Plate to Hood Weld &
HAZs (4)
VT-1-89 NRI Hood Support Stiffener Assembly, Stiffener to Hood Support Tee Weld &
VT-1-89 NRI Hood Support Stiffener Assembly, Stiffener to Trough Weld & HAZs, 360 degree weld (16)
VT-1-89 NRI Skirt to Lower Support Ring Weld plus 2 Splice Bars & HAZs (2)
VT-1-89 NRI Skirt to Lower Support Ring Weld &
HAZs (6)
VT-1-89 NRI Splice Bar Attachment Weld and HAZs (4)
VT-1-89 NRI Trans Brace to Upper Support Ring Weld & HAZs (2)
VT-1-89 NRI Trans Brace Coupler Weld & HAZs (1)
VT-1-89 NRI Trans Brace Plate Welds & HAZs (8)
VT-1-89 NRI Trans Brace Support Welds & HAZs (12)
VT-1-89 NRI Base Plate to Upper Support Ring Weld
& HAZs (4)
VT-1-89 NRI Base Plate to Upper Support Ring/Latch Assembly Welds & HAZs (2)
VT-1-89 NRI Base Plate to Upper Support Ring/Lifting Assembly Welds & HAZs (2)
VT-1-89 NRI Cover Plate to Upper Support Ring Weld
& HAZs (2)
VT-1-89 NRI Splice Bar to Upper Support Ring and Trough Welds & HAZs (2)
VT-1-89 NRI USR Segment Weld & HAZs (4)
VT-1-89 NRI
Browns Ferry Unit 3 Replacement Steam Dryer (RSD) Inspection Results from the Second Refueling Outage (U3R20) Following Installation of RSD and Implementation of Extended Power Uprate
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Inspection Location Method Inspection
Result
Condition
Report(ifRI)
Disposition
Skirt to Upper Support Ring Weld &
HAZs (6)
VT-1-89 NRI
STEAM DRYER OD 000 Degree Pad Welds & HAZs (1)
VT-1-89 NRI Steam Dryer Outer Banks Access Panel Welds & HAZs 000 Side (6)
VT-1-89 NRI Steam Dryer Outer Banks Access Panel Welds & HAZs 180 Side (6)
VT-1-89 NRI Both Sides of the Bank to Divider Plate Weld & HAZs (16)
VT-1-89 NRI Both Sides of the Bank to Exhaust Plenum Plate Vertical Weld & HAZs (20)
VT-1-89 NRI Hood to Cover Plate Horizontal Weld &
HAZs (2)
VT-1-89 NRI Hood to Top Cap Horizontal Weld &
HAZs (6)
VT-1-89 NRI Perforated Plate to Bank Top Cap Weld
& HAZs (6)
VT-1-89 NRI Perforated Plate to Trough Side Plate Weld & HAZs (6)
VT-1-89 NRI Trough Side Plate to Base Plate Weld
& HAZs (6)
VT-1-89 NRI Both Sides of the Hood Support to Trough Weld & HAZs (16)
VT-1-89 NRI Perforated Plate to End Plate Weld &
HAZs (4)
VT-1-89 NRI Perforated Plate to Perforated Plate Weld & HAZs (16)
VT-1-89 NRI Perforated Plate to End Plate Weld &
HAZs from Trough Base Plate to Hood Cap (8)
VT-1-89 NRI Trough Spacer Pin Weld & HAZs (6)
VT-1-89 NRI Bank Tie Rod Bolting Welds & HAZs for all 6 locations on the 000 Deg Side (6)
VT-1-89 NRI Bank Tie Rod Bolting Welds & HAZs for all 6 locations on the 180 Deg Side (6)
VT-1-89 NRI Hood to Trough Base Plate Horizontal Weld & HAZs (4)
VT-1-89 NRI Both Sides of the Divider Plate to Inner Plate Welds & HAZs (6)
VT-1-89 NRI Drain Channel to Upper Support Ring Horizontal Weld & HAZs (4)
VT-1-89 NRI Drain Channel to Support Beam Weld &
HAZs (8)
VT-1-89 NRI Drain Channel to Support Ring Tab Welds & HAZs (20)
VT-1-89 NRI Guide Channel to Drain Channel Tee Vertical Weld & HAZs (4)
VT-1-89 NRI
Browns Ferry Unit 3 Replacement Steam Dryer (RSD) Inspection Results from the Second Refueling Outage (U3R20) Following Installation of RSD and Implementation of Extended Power Uprate
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Inspection Location Method Inspection
Result
Condition
Report(ifRI)
Disposition
Drain Channel to Drain Channel Tee Vertical Weld & HAZs (8)
VT-1-89 NRI Skirt to Drain Channel Tee Vertical Weld
& HAZs (4)
VT-1-89 NRI Doubler Plate to Upper Support Ring &
HAZs (8)
VT-1-89 NRI General Overview of the Side Surfaces (4)
VT-1-89 NRI General Overview of the Top Surfaces (1)
VT-1-89 NRI Hood to Inlet End Plate Vertical Weld &
HAZs (18)
VT-1-89 NRI Both Hood to Hood Tee Vertical Welds
& HAZs (4)
VT-1-89 NRI Hood to Hood Tee Vertical Weld &
HAZs (18)
VT-1-89 NRI Both Sides of the Hold Down Assembly to Exhaust Plenum Plate Vertical Weld
& HAZs (4)
VT-1-89 NRI Hold Down Assembly to Trough Base Plate Horizontal Weld & HAZs (2)
VT-1-89 NRI 4 Instrument Tower Pads (1)
VT-1-89 RI 1761661 Accepted as-is Lifting Assembly - Support Ring Anchor Weld & HAZs (4)
VT-1-89 NRI Lifting Assembly - Bolting (4)
VT-1-89 NRI Lifting Assembly - Lower Bracket and Welds Plus HAZs (4)
VT-1-89 NRI Lifting Assembly - Middle Bracket and Welds Plus HAZs (4)
VT-1-89 NRI Lifting Assembly - Rod to Anchor Weld
& HAZs (4)
VT-1-89 NRI Lifting Assembly - Upper Bracket and Welds Plus HAZs (4)
VT-1-89 NRI Latch Box General Condition for Evidence of Handling Damage (2)
VT-1-89 NRI Lower Guide Channel General Condition for Evidence of Handling Damage (2)
VT-1-89 NRI Lower Support Ring to Guide Channel Horizontal Weld & HAZs (2)
VT-1-89 NRI Lower Support Ring to Skirt Horizontal Weld & HAZs (6)
VT-1-89 NRI Lower Support Ring Splice Bar General Condition for Evidence of Handling Damage (2)
VT-1-89 NRI Splice Bar Attachment Weld & HAZs (8)
VT-1-89 NRI Seismic Lug General Condition for Evidence of Handling Damage, also Associated Bolting, Welds & HAZs (2)
VT-1-89 RI 1762156 Accepted as-is Bank Tie Bar Welds & HAZs (34)
VT-1-89 NRI Trough Base Plate Center Horizontal Weld & HAZs (1)
VT-1-89 NRI
Browns Ferry Unit 3 Replacement Steam Dryer (RSD) Inspection Results from the Second Refueling Outage (U3R20) Following Installation of RSD and Implementation of Extended Power Uprate
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Inspection Location Method Inspection
Result
Condition
Report(ifRI)
Disposition
Top Flange to C-Channel to Hood Cover Weld & HAZs (2)
VT-1-89 NRI Upper Support Ring Horizontal Weld &
HAZs (26)
VT-1-89 NRI Upper Support Ring Tapered Pin Seal Weld & HAZs (8)
VT-1-89 NRI Upper Support Ring to Splice Bar Vertical Weld & HAZs (4)
VT-1-89 NRI Upper Support Ring to Guide Channel Horizontal Weld & HAZs (2)
VT-1-89 NRI Upper Support Ring to Skirt Horizontal Weld & HAZs (2)
VT-1-89 NRI Inspection Results Two relevant indications were noted during inspections performed during U3R20. They are described as follows:
(1) BFN3-SD OD Instrument Tower Pads: Steam Dryer Instrument Tower Pads 1, 2, and 3 had twisted crimp collar shafts that were unchanged from their previous inspection during Unit 3 Refueling Outage 19 (U3R19).
(2) BFN3-SD OD Seismic Lug 005 and BFN-3 SD OD Seismic Lug 185: A relevant indication of wear was observed at the contact point of the Steam Dryer Support Lug for the Steam Dryer Seismic Blocks at 5 degrees and 185 degrees. This wear was the result of mechanical damage incurred by removal and reinstallation of the RSD, and was unchanged from the previous inspection during U3R19.
Disposition of Indications Condition Reports (CRs) were initiated for both relevant indications, and an Engineering Evaluation was prepared as part of the corrective action plan for each CR to disposition the indications. Each disposition is as follows:
(1) BFN3-SD OD Instrument Tower Pads (CR 1761661): Because instrumentation (pressure sensors, strain gages, and accelerometers) was required during the Unit 3 Cycle 19 Fuel Cycle to access in-situ dryer conditions during operation, an instrumentation package was installed. A means was required for the instrumentation leads to exit the vessel via a penetration in the reactor head, so an instrument mast/tower was installed on top of the RSD that was held in place by pads that were welded to the RSD and whose sole function was to hold the mast/tower in place. Inspections performed during U3R19 showed that Steam Dryer Instrument Tower Pads 1, 2, and 3 had twisted crimp collar shafts. Since the instrument package was only required to provide monitoring for the first cycle of EPU operation, the instrument package, as well as the mast/tower, were removed during U3R19. Therefore, the Instrument Tower Pads no longer have a function with the mast/tower removed, and any observed indications were
Browns Ferry Unit 3 Replacement Steam Dryer (RSD) Inspection Results from the Second Refueling Outage (U3R20) Following Installation of RSD and Implementation of Extended Power Uprate
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accepted as-is. During U3R20, inspections were again performed on the Steam Dryer Instrument Tower Pads, and the indications were unchanged from when they were first observed during U3R19. Therefore, the indications were again acceptable as-is.
(2) BFN3-SD OD Seismic Lug 005 and BFN-3 SD OD Seismic Lug 185 (CR 1762156): The main purpose of the Steam Dryer Seismic Blocks is to transfer the lateral load from the RSD to the RPV support brackets. The indications that were observed during U3R19 and U3R20 on the Steam Dryer Seismic Blocks at 5 degrees and 185 degrees were the result of mechanical damage incurred by the removal and reinstallation of the RSD, and are not expected in any way to interfere with the ability of the seismic blocks to perform their required function to transfer the lateral load from the RSD to the RPV support brackets. Therefore, these indications have no bearing on the structural integrity of the seismic blocks and are acceptable as-is with no repair required.
Conclusion A completed second baseline inspection of the Browns Ferry Unit 3 Replacement Steam Dryer (RSD) was performed during the Spring 2022 Refueling Outage 20. This baseline inspection included successful visual inspection of all inspection locations required by the Facility Operating License Condition 2.C.(14).(f) for inspection of the RSD. All observations were acceptable for the locations inspected. There were two relevant indications that were adequately dispositioned. Since two baseline inspections of the RSD have now been completed, future inspections will be performed in accordance with the guidelines specified in GE Hitachi Nuclear Energy Report No. 003N5663, Revision 2.