WBL-21-008, American Society of Mechanical Engineers, Section XI, First 10-Year Inspection Interval, Inservice Inspection Owner'S Activity Report for Cycle 3 Operation

American Society of Mechanical Engineers,Section XI, First 10-Year Inspection Interval, Inservice Inspection Owner'S Activity Report for Cycle 3 Operation

ML21042A021
Person / Time
Site:	Watts Bar
Issue date:	02/11/2021
From:	Anthony Williams Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
WBL-21-008
Download: ML21042A021 (8)

Text

TENNESSEE 1\/4 VALLEY AUTHORITY Post Office Box 2000 , Spring City, Tennessee 37381 WBL-21 -008 February 11 , 2021 10 CFR 50.55a ATTN : Document Control Desk U.S . Nuclear Regulatory Commission Washington, D.C. 20555-0001 Watts Bar Nuclear Plant, Unit 2 Facility Operating License No. NPF-96 NRC Docket No. 50-391

Subject:

American Society of Mechanical Engineers,Section XI, First 10-Year Inspection Interval, lnservice Inspection Owner's Activity Report For Cycle 3 Operation The Tennessee Valley Authority is submitting the Watts Bar Nuclear Plant (WBN), Unit 2, American Society of Mechanical Engineers (ASME),Section XI, Owner's Activity Report for Unit 2 Cycle 3 operation as required by Article IWA-6000,Section XI , Division 1. The report is contained in the enclosure to this letter and is in accordance with the requirements of ASME Code Case N-532-5, "Repair/Replacement Activity Documentation Requirements and lnservice Inspection Summary Report Preparation and Submission ."

The report is an overview of the results from inservice examinations that were performed on components within the ASME Section XI boundary, up to and including the Unit 2 Cycle 3 refueling outage, during the second period of the first inspection interval. The applicable provisions of the ASME Code require that this report be submitted 90 days from the end of the applicable outage, i.e., by February 17, 2021.

There are no new regulatory commitments associated with this submittal. If you have questions regarding this letter, please contact Tony Brown, WBN Licensing Manager, at (423) 365-7720 .

Anthony L. Williams IV Site Vice President Watts Bar Nuclear Plant

U.S. Nuclear Regulatory Commission WBL-21-008 Page 2 February 11, 2021

Enclosure:

American Society of Mechanical Engineers,Section XI, First 10-Year lnservice Inspection Interval, lnservice Inspection Owner's Activity Report for Cycle 3 Operation (Form OAR-1) cc:

NRC Regional Administrator - Region II NRC Senior Resident Inspector - Watts Bar Nuclear Plant NRR Project Manager- Watts Bar Nuclear Plant

ENCLOSURE TENNESSEE VALLEY AUTHORITY WATTS BAR NUCLEAR PLANT, UNIT 2 AMERICAN SOCIETY OF MECHANICAL ENGINEERS, SECTION XI, FIRST 10-YEAR INSPECTION INTERVAL, INSERVICE INSPECTION OWNER'S ACTIVITY REPORT FOR CYCLE 3 OPERATION

FORM OAR-1 OWNER'S ACTIVITY REPORT Report Number U2R3 Plant Watts Bar Nuclear Plant, P.O. Box 2000, Spring City, TN 37381-2000 Unit No. 2 Commercial Service Date October 19, 2016 Refueling Outage No. U2R3 (if applicable)

Current Inspection Interval 1st (1", 2, 3, 4" , other)

Current Inspection Period 2nd ISI/SPT - 2007 Edition, 2008 Addenda Edition and Addenda of Section XI applicable to the Inspection Plans IWE - 2013 Edition ISi - December 10, 2020 / 2-TRl-0-10.1, Revision 006 IWE - September 07, 2018 / O-Tl -100.012, Revision 000 Date/ Revi sion of Inspection Plan s SPT - August 24, 2020 / O-Tl -100.009 Revision 003 Edition and Addenda of Section XI applicable to repair/replacement activities, if different than the in spection plan s 2007 Edition, 2008 Addenda Code Cases used: N-532-5, N-586-1, N-716-1, N-722-1, N-729-6, N-770-5 CERTIFICATE OF CONFORMANCE I certify that (a) the statements made in this report are correct; (b) the examinations and tests, meet the Inspection Plan as required by the ASME Code,Section XI; and (c) the repair/replacement activities and evaluations supporting the completion of U2R3 conform to the requirements of Section XI (refueling outage number)

Signed I>-.__/ John Norman , Repair/Replacement program owner Date 2/3/21 Owner or Owner's Designee, Title CERTIFICATE OF INSERVICE INSPECTION I, the undersigned, holding a valid commission issued by the National Board of Boiler and Pressure Vessel Inspectors The Hartford Steam Boiler of Inspection and Insurance and employed by Company Hartford, Connecticut have inspected the items described in this Owner's Activity Report, and state that, to the best of my knowledge and belief, the Owner ha s performed all activities represented by this report in accordance with the requirements of Section XI.

By signing thi s certificate neither the Inspector nor hi s employer makes any warranty, expressed or implied, concerning the repair/ replacement activities and evaluation described in this report . Furthermore, neither the Inspector nor his employer shall be liable in any manner for any personal injury or property damage or a loss of any kind arising from or connected with this inspection Commissions 15440 Al, I, N, R

~ p e c t o r ' s Signature (National Board Number and Endorsement)

Date 03Feb21 E-lofS

TABLE 1 ITEMS WITH FLAWS OR RELEVANT CONDITIONS THAT REQUIRED EVALUATION FOR CONTINUED SERVICE Examination Category and Item Number Item Description Evaluation Description While performing the enhanced visual examination of the WBN Unit 2 Reactor Vessel Closure Head an area of discoloration was discovered within the 1" annular area of CRDM penetration 57.

In accordance with ASME CC N-729-6, -3140(c) this was documented as a relevant condition.

Previous data of this penetration 57 was reviewed and the condition has existed since U2Rl and has remained unchanged since.

The source of leakage was most likely minor leakage when disconnecting one of the mechanical connections above the head for refueling activities. This was an isolated event that Reactor Vessel occurred multiple operating cycles ago and determination of the N-729-6 / 84.10 Closure Head CRDM source cannot be done conclusively.

Penetration 57 There were no boric acid crystals associated with this indication to be removed. The examiners attempted to remove some of the surface corrosion to evaluate for any degradation. After attempting to scrap some of the corrosion away a subsequent VE was performed and there was no measurable material loss due to corrosion to be evaluated.

Considering this indication has remained unchanged over multiple operating cycles, there was no boric acid residue or crystals observed, and there was no measurable material loss, the indication was not considered indicative of possible nozzle leakage While performing the enhanced visual examination of the WBN Unit 2 Reactor Vessel Closure Head a white material was discovered underneath the degraded head coating. After some mechanical agitation of the head coating the debris was blown away and revea led an additional white spot outside the examination area . A follow-up examination removed additional coating from the annular area of the penetration and confirmed the white substance wa s under the coating and did not appear to have run down the CRDM tube . The condition was declared a relevant condition and an additional assessment was performed Reactor Vessel to determine if the condition was indicative of possible nozzle N-729-6 / 84.10 Closure Head CRDM leak.

Penetration 33 There was insufficient sample quantity to perform any chemical analysis on site. The swabs were analyzed using gamma spectroscopy on site with a 900-second count time, and no gamma activity was detected. The swabs were shipped to Teledyne Brown for additional analysis. No gamma activity was detected using a 3600-second count time. The swabs were analyzed with an extended count (54000 seconds), and Co-58 and Co-60 were detected . Based on the ratio of C0-58/Co-60, this relevant condition was not indicative of an active RCS leak.

After the extended count gamma spectroscopy was performed the samples were sent to a secondary laboratory in an attempt E-2 of 5

to identify the material. The contracted Chemistry Lab, MCL, stated "The sma ll amount of residue on the swabs limited the amount of material available to be removed for analysis. As free-standing values the results offer no interpretable clues as to the identity of the substance on the swabs. The major constituents found are iron, zinc, chloride and sulfate. The proportion of zinc to iron may offer a clue as to the source of the residue ... " However, the lab was unable to provide any conclusive material identification .

After the samples for chemical analysis were taken, the white material was completely removed and a subsequent VE of the affected area was performed . After the material was removed there were no signs of degradation to be evaluated .

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TABLE 2 Abstract of Repairs/replacement Activities for Continued Service Item Description Date Repair/Replacement Code Class Description of Work Completed Plan Number Replace Cooler Coil due 2B-B Penetration Room 3 to through wall tube 7/23/2019 117348693 Cooler Coil leak.

Replace length of pipe 3 2" eves Pipe due to through wall pin 2/18/2020 120394576 hole leak.

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REPORTING REQUIRED BY 10 CFR 50.55a(b)(2)(ix)

ASME Section XI, Subsection IWE Steel Containment Vessel Inspection Program 10 CFR 50.55a(b)(2)(ix) requires the reporting of inaccessible areas and additional examinations identified during the performance of ASME Section XI, Subsection IWE Steel Containment Vessel Inspection Program when conditions exist in accessible areas that could indicate the presence of or result in degradation to such inaccessible areas.

(1) bolted connection that was disassembled, was inspected in accordance with IWE Containment Vessel Inspection Program during this cycle . There were no conditions observed that would indicate the presence of or result in degradation to inaccessible areas of the containment vessel.

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