ML16362A213

Supplemental Information - TMI-1 Steam Generator Tube Inspection Report for Refueling Outage T1R21

ML16362A213
Person / Time
Site:	Three Mile Island
Issue date:	12/22/2016
From:	Callan E Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
TMl-16-102
Download: ML16362A213 (2)

Text

Three Mile Island Unit 1 Exelon Generation Route 441 South, P.O. Box 480 Middletown, PA 17057 Telephone 717-948-8000 TMl-16-102 December 22, 2016 U.S. Nuclear Regulatory Commission ATIN: Document Control Desk Washington, DC 20555-0001 Three Mile Island Nuclear Station, Unit 1 Renewed Facility Operating License No. DPR-50 NRC Docket No. 50-289

Subject:

Supplemental Information - TMl-1 Steam Generator Tube Inspection Report for Refueling Outage T1R21

Reference:

Exelon Generation Company, LLC Letter to USN RC TMl-1 Steam Generator Tube Inspection Report for Refueling Outage T1R21, dated May 21, 2016 (TMl-16-015)

In the above reference, Exelon Generation Company, LLC (EGC) provided a report on the completed examination oftubing in the TMl-1 steam generators during Refueling Outage T1R21. An issue was discovered during a subsequent review of the report, determined to be a typographical error. The typographical error occurred when a table was re-created from the original vendor's report.

The total number of plugged tubes was correctly reported. The breakdown by wear mechanism was incorrectly reported for the "B" steam generator.

The attached is a corrected page 13 of 226 for the referenced report. The correction pertains to the table on page 13 titled "Table 3: TMl-1 Tube Plugging History" and under the "TSP wear" and "TIW" columns for "SGB Plug History"; the summation "Total (Tubes)" row should read 192 for "TSP wear" instead ofthe original report listing of 195, and the summation "Total (Tubes)" row should read 3 for "TIW" instead of the original report listing of 0 (zero). All other information in the table is correct.

No new regulatory commitments are established by this submittal. If you have any questions or additional information is needed, please contact Mike Fitzwater at 717-948-8228.

Respectfully, CJ Edw~n n JOJL Site Vice President, Three Mile Island Unit 1 Exelon Generation Company, LLC cc: NRC Regional Administrator - Region I NRC Senior Resident Inspector- Three Mile Island Nuclear Station NRC Project Manager, NRR - Three Mile Island Nuclear Station R. R. Janati, Chief, Division of Nuclear Safety, Pennsylvania Department of Environmental Protection, Bureau of Radiation Protection

Attachment TMl-1 Steam Generator Tube Inspection Report for Refueling Outage T1R21-Corrected Attachment 1, Page 13 of 226 TMI-16-015 (TS 6.9.6.e.) Number of tubes plugged during the inspection outage for each degradation mechanism:

A total of one hundred thirty-four ( 134) tubes were plugged and stabilized during TlR2 I. Three (3) tubes in SG 'A' were preventatively plugged based on engineering judgment due to growth rates and number of indications. One hundred thirty-one (131) tubes in SG 'B' were plugged for TSP wear. Twenty-five (25) of these tubes required plugging based on having indications at or above the Technical Specification limit of 40% Through Wall (TW). The other 106 tubes were preventatively plugged - the majority of these were in the "W-Axis" region of the periphery (Rows l-4). There were no tubes plugged in either SG due to the TTW degradation mechanism.

(TS 6.9.6.f.) The number and percentage of tubes plugged to date, and the effective plugging percentage in each steam generator:

There were no tubes plugged prior to TlRI 9. Table 3 shows the number of tubes plugged during each of the three steam generator inspections and the cumulative number of tubes plugged to date.

Table 3: 'fMl-1 Tube Plugging History SGA Pluiz Historv SGB Plu1* Historv SGA SGB Total Outage TSP TSP TTW Other Total TTW Other Total Plugged Wear Wear Plum!"ed Plu1mcd PSI 0 0 0 0 0 0 0 0 0 T1R19 0 4 0 4 30 3 0 33 37 T1R20 1 0 0 1 31 0 0 31 32 T1R21 3 0 0 3 131 0 0 131 134 Total 4 4 0 8 192 3 0 195 203 (Tubes)

Total(%) 0.051% 1.25% 0.65%

Limit(%) 5.00% 5.00% 5.00%

Limit 779 779 1558 (Tubes)

Note: There are 15,597 tubes per Steam Generator.

There are no sleeves or repairs other than plugs with stabilizers installed in the steam generators.

The effective plugging percentage is the same as the actual plugged tube percentage. Following TIR2l, the effective plugging percentage for SG 'A' is 0.051 % and for SG 'B' 1.25%.

Attachment 1 , Page 13 of 226