ML23171A957

Replacement Steam Dryer Visual Inspection Results (U2R22)

ML23171A957
Person / Time
Site:	Browns Ferry
Issue date:	06/20/2023
From:	Sivaraman M Tennessee Valley Authority
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
Download: ML23171A957 (1)

Text

Post Office Box 2000, Decatur, Alabama 35609-2000 June 20, 2023 10 CFR 50.4 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Browns Ferry Nuclear Plant, Unit 2 Renewed Facility Operating License No. DPR-52 NRC Docket No. 50-260

Subject:

Unit 2 Replacement Steam Dryer Visual Inspection Results (U2R22)

Enclosed is a summary of the results of the visual inspections of the Unit 2 Replacement Steam Dryer that were performed during the recent refueling outage (U2R22). The inspections are required to be performed in accordance with Operating License Condition 2.C(18)(g) 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 2 is being submitted pursuant to Operating License Condition 2.C(18)(h) 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, Manu Sivaram Sivaraman BFN Site Vice President

U.S. Nuclear Regulatory Commission Page 2 June 20, 2023

Enclosure:

Browns Ferry Unit 2 Replacement Steam Dryer (RSD) Inspection Results from the Second Refueling Outage (U2R22) 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 2 Browns Ferry Unit 2 Replacement Steam Dryer (RSD) Inspection Results from the Second Refueling Outage (U2R22) Following Installation of RSD and Implementation of Extended Power Uprate See Enclosed

Browns Ferry Unit 2 Replacement Steam Dryer (RSD) Inspection Results from the Second Refueling Outage (U2R22) Following Installation of RSD and Implementation of Extended Power Uprate 

Purpose This report provides the results of visual inspections of the Replacement Steam Dryer (RSD) as required by the Browns Ferry Unit 2 Renewed Facility Operating License No. DPR-52, License Condition 2.C.(18).(h). 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 2 RSD was inspected from February 20 through March 6, 2023, during the Spring 2023 refueling outage (Unit 2 Refueling Outage 22: U2R22). This was the second refueling outage following installation of the RSD in March 2019 during Unit 2 Refueling Outage 20 (U2R20) and operation at Extended Power Uprate (EPU) conditions since June 2019. 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 U2R22, with a total scope of 646 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.



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Browns Ferry Unit 2 Replacement Steam Dryer (RSD) Inspection Results from the Second Refueling Outage (U2R22) Following Installation of RSD and Implementation of Extended Power Uprate 

Inspection Location Method Inspection Condition Disposition

Result Report(ifRI)

STEAM DRYER ID Divider Plate Welds & HAZs (32) VT-1-89 NRI Trough Side Plate to Base Plate Weld & VT-1-89 NRI HAZs (6)

Hood Vertical / Horizontal Welds & VT-1-89 NRI HAZs (12)

Perforated Plate to Trough Side Plate VT-1-89 NRI Weld & HAZs (22)

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 & VT-1-89 NRI HAZs (12)

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 & VT-1-89 NRI HAZs (4)

Hood Support Stiffener Assembly, VT-1-89 NRI Stiffener to Hood Support Tee Weld &

HAZs, 360-degree weld (16)

Hood Support Stiffener Assembly, VT-1-89 NRI Stiffener to Trough Weld & HAZs, 360 degree weld (16)

Skirt to Lower Support Ring Weld plus 2 VT-1-89 NRI Splice Bars & HAZs (2)

Skirt to Lower Support Ring Weld & VT-1-89 NRI HAZs (6)

Splice Bar Attachment Weld and HAZs VT-1-89 NRI (4)

Trans Brace to Upper Support Ring VT-1-89 NRI Weld & HAZs (2)

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 VT-1-89 NRI (12)

Base Plate to Upper Support Ring Weld VT-1-89 NRI

& HAZs (4)

Base Plate to Upper Support Ring/Latch VT-1-89 NRI Assembly Welds & HAZs (2)

Base Plate to Upper Support Ring/Lifting VT-1-89 NRI Assembly Welds & HAZs (2)

Cover Plate to Upper Support Ring Weld VT-1-89 NRI

& HAZs (2)

Splice Bar to Upper Support Ring and VT-1-89 NRI Trough Welds & HAZs (2)

USR Segment Weld & HAZs (4) VT-1-89 NRI 2



Browns Ferry Unit 2 Replacement Steam Dryer (RSD) Inspection Results from the Second Refueling Outage (U2R22) Following Installation of RSD and Implementation of Extended Power Uprate 

Inspection Location Method Inspection Condition Disposition

Result Report(ifRI)

Skirt to Upper Support Ring Weld & VT-1-89 NRI  

HAZs (6)

 

STEAM DRYER OD 000 Degree Pad Welds & HAZs (1) VT-1-89 NRI Steam Dryer Outer Banks Access Panel VT-1-89 NRI Welds & HAZs 000 Side (6)

Steam Dryer Outer Banks Access Panel VT-1-89 NRI Welds & HAZs 180 Side (6)

Both Sides of the Bank to Divider Plate VT-1-89 NRI Weld & HAZs (16)

Both Sides of the Bank to Exhaust VT-1-89 NRI Plenum Plate Vertical Weld & HAZs (20)

Hood to Cover Plate Horizontal Weld & VT-1-89 NRI HAZs (2)

Hood to Top Cap Horizontal Weld & VT-1-89 NRI HAZs (6)

Perforated Plate to Bank Top Cap Weld VT-1-89 NRI

& HAZs (6)

Perforated Plate to Trough Side Plate VT-1-89 NRI Weld & HAZs (6)

Trough Side Plate to Base Plate Weld VT-1-89 NRI

& HAZs (6)

Both Sides of the Hood Support to VT-1-89 NRI Trough Weld & HAZs (16)

Perforated Plate to End Plate Weld & VT-1-89 NRI HAZs (4)

Perforated Plate to Perforated Plate VT-1-89 NRI Weld & HAZs (16)

Perforated Plate to End Plate Weld & VT-1-89 NRI HAZs from Trough Base Plate to Hood Cap (8)

Trough Spacer Pin Weld & HAZs (6) VT-1-89 NRI Bank Tie Rod Bolting Welds & HAZs for VT-1-89 NRI all 6 locations on the 000 Deg Side (6)

Bank Tie Rod Bolting Welds & HAZs for VT-1-89 NRI all 6 locations on the 180 Deg Side (6)

Hood to Trough Base Plate Horizontal VT-1-89 NRI Weld & HAZs (4)

Both Sides of the Divider Plate to Inner VT-1-89 NRI Plate Welds & HAZs (6)

Drain Channel to Upper Support Ring VT-1-89 RI 1839983 Accepted as-is Horizontal Weld & HAZs (4)

Drain Channel to Support Beam Weld & VT-1-89 NRI HAZs (8)

Drain Channel to Support Ring Tab VT-1-89 NRI Welds & HAZs (20)

Guide Channel to Drain Channel Tee VT-1-89 NRI Vertical Weld & HAZs (4) 3



Browns Ferry Unit 2 Replacement Steam Dryer (RSD) Inspection Results from the Second Refueling Outage (U2R22) Following Installation of RSD and Implementation of Extended Power Uprate 

Inspection Location Method Inspection Condition Disposition

Result Report(ifRI)

Drain Channel to Drain Channel Tee VT-1-89 NRI Vertical Weld & HAZs (8)

Skirt to Drain Channel Tee Vertical Weld VT-1-89 NRI

& HAZs (4)

Doubler Plate to Upper Support Ring & VT-1-89 NRI HAZs (8)

General Overview of the Side Surfaces VT-1-89 NRI (4)

General Overview of the Top Surfaces VT-1-89 NRI (1)

Hood to Inlet End Plate Vertical Weld & VT-1-89 NRI HAZs (18)

Both Hood to Hood Tee Vertical Welds VT-1-89 NRI

& HAZs (4)

Hood to Hood Tee Vertical Weld & VT-1-89 NRI HAZs (18)

Both Sides of the Hold Down Assembly VT-1-89 NRI to Exhaust Plenum Plate Vertical Weld

& HAZs (4)

Hold Down Assembly to Trough Base VT-1-89 NRI Plate Horizontal Weld & HAZs (2)

Lifting Assembly - Support Ring Anchor VT-1-89 NRI Weld & HAZs (4)

Lifting Assembly - Bolting (4) VT-1-89 NRI Lifting Assembly - Lower Bracket and VT-1-89 NRI Welds Plus HAZs (4)

Lifting Assembly - Middle Bracket and VT-1-89 NRI Welds Plus HAZs (4)

Lifting Assembly - Rod to Anchor Weld VT-1-89 NRI

& HAZs (4)

Lifting Assembly - Upper Bracket and VT-1-89 NRI Welds Plus HAZs (4)

Latch Box General Condition for VT-1-89 NRI Evidence of Handling Damage (2)

Lower Guide Channel General Condition VT-1-89 NRI for Evidence of Handling Damage (2)

Lower Support Ring to Guide Channel VT-1-89 NRI Horizontal Weld & HAZs (2)

Lower Support Ring to Skirt Horizontal VT-1-89 NRI Weld & HAZs (6)

Lower Support Ring Splice Bar General VT-1-89 NRI Condition for Evidence of Handling Damage (2)

Splice Bar Attachment Weld & HAZs (8) VT-1-89 NRI Seismic Lug General Condition for VT-1-89 NRI Evidence of Handling Damage, also Associated Bolting, Welds & HAZs (2)

Bank Tie Bar Welds & HAZs (34) VT-1-89 NRI Trough Base Plate Center Horizontal VT-1-89 NRI Weld & HAZs (1) 4



Browns Ferry Unit 2 Replacement Steam Dryer (RSD) Inspection Results from the Second Refueling Outage (U2R22) Following Installation of RSD and Implementation of Extended Power Uprate 

Inspection Location Method Inspection Condition Disposition

Result Report(ifRI)

Top Flange to C-Channel to Hood VT-1-89 NRI Cover Weld & HAZs (2)

Upper Support Ring Horizontal Weld & VT-1-89 NRI HAZs (26)

Upper Support Ring Tapered Pin Seal VT-1-89 NRI Weld & HAZs (8)

Upper Support Ring to Splice Bar VT-1-89 NRI Vertical Weld & HAZs (4)

Upper Support Ring to Guide Channel VT-1-89 NRI Horizontal Weld & HAZs (2)

Upper Support Ring to Skirt Horizontal VT-1-89 NRI Weld & HAZs (2)

Inspection Results One relevant indication was noted during the U2R22 RSD visual examination campaign. It is described as follows:

(1) BFN2-SD OD DC02 H01: During inspection of the Drain Channel 02 to Upper Support Ring H01 Weld, a relevant indication was observed in the lower heat-affected zone. The indication was measured at 0.389 with a ruler deployed by the vendors inspection services. The inspection data from U2R21 was reviewed and the indication appeared to be present but not as apparent in the video data provided by the standard definition cameras available at the time of the first RSD baseline. High-definition cameras in U2R22 revealed the indication with more clarity.

Disposition of Indications Condition Report (CR) 1839983 was initiated to document and disposition the relevant indication reported on the RSD. The disposition is as follows:

(1) BFN2-SD OD DC02 H01: The indication reported on the Drain Channel 02 to Upper Support Ring H01 Weld was evaluated by the inspection vendor. This document was subsequently reviewed by Asset Management Programs-Materials which concluded that the indication was acceptable as-is without repair for one fuel cycle (U2C23), at which point the indication will be re-inspected in concurrence with vendor recommendations. The Steam Dryer performs no safety function. However, the potential for lost parts generated could pose a threat to safety-related equipment if not considered. Due to the nature of this indication, and the evaluation that concludes the flaw will not result in failure between inspection cycles, lost parts are considered extremely improbable thus further evaluation is not warranted and reinspection will ensure any increase in lost parts probability will be detected prior to an event. The flaw in the Drain Channel 02 to Upper Support Ring H01 Weld will be re-examined during Unit 2 Refueling Outage 23 (U2R23) in Spring 2025 with an emphasis on identifying any signs of change.

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Browns Ferry Unit 2 Replacement Steam Dryer (RSD) Inspection Results from the Second Refueling Outage (U2R22) Following Installation of RSD and Implementation of Extended Power Uprate 

Conclusion A completed second baseline inspection of the Browns Ferry Unit 2 Replacement Steam Dryer (RSD) was performed during the Spring 2023 Refueling Outage 22. This re-baseline inspection included successful visual inspection of all RSD locations required by the Facility Operating License Condition 2.C.(18).(h). All observations were acceptable for the locations inspected.

There was one inspection area with a relevant indication that was subsequently dispositioned by engineering evaluation and will be reinspected in U2R23 per vendor recommendation to confirm stability by assessing the indication for signs of growth or change. Since two baseline inspections of the RSD have now been completed, future inspections (aside from the reinspection of the before described indication) will be performed in accordance with the guidelines specified in GE Hitachi Nuclear Energy Report No. 007N4785, Revision 0 (Tennessee Valley Authority (TVA) Browns Ferry Nuclear Station (BFNS): Recommendations for Future Inspections - Replacement Steam Dryer).



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