L-2021-137, GL 2004-02 Debris Transport Calculation Non-Conservatism

GL 2004-02 Debris Transport Calculation Non-Conservatism

ML21204A052
Person / Time
Site:	Saint Lucie
Issue date:	07/23/2021
From:	Deboer D Florida Power & Light Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
GL 2004-02, L-2021-137
Download: ML21204A052 (4)

Text

July 23, 2021 L-2021-137 GL 2004-02 10 CFR 50.54(f)

U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington DC 20555-0001 RE: St. Lucie Nuclear Plant, Units 1 and 2 Docket Nos. 50-335 and 50-389 Renewed Facility Operating Licenses DPR-67 and NPF-16 GL 2004-02 Debris Transport Calculation Non-Conservatism

References:

1. Florida Power & Light Company letter L-2017-210, Updated Final Response to NRC Generic Letter 2004-02, December 20, 2017 (ADAMS Accession No. ML17362A108)

2. Florida Power & Light Company letter L-2020-165, Supplement to Updated Final Response to NRC Generic Letter 2004-02, December 4, 2020 (ADAMS Accession No. ML20339A501)

In Reference 1, as supplemented by Reference 2, Florida Power & Light Company (FPL) provided an updated final response to Generic Letter (GL) 2004- 02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors, (ADAMS Accession No. ML042360586), for St. Lucie Units 1 and 2 (St. Lucie).

Recently, FPL learned of a non-conservatism in the St. Lucie debris transport evaluation that supported the submittal in Reference 1. Specifically, the non-conservatism occurred when determining the debris transport fractions for postulated reactor nozzle breaks, which incorrectly applied the pool fill-up transport fractions for selected debris types, resulting in non-conservative transported debris quantities. The issue has been entered into the St. Lucie corrective action program (CAP), and the calculations containing the non-conservatism have been revised. The revision increased the overall transport fractions for the fine debris from 97% to 100% for the reactor nozzle breaks. Table 3.e.6-14 and Table 3.e.6-17 of the enclosure to this letter provide the corrected debris transport fraction values for the reactor nozzle breaks for St. Lucie. These tables supersede Table 3.e.6-14 and Table 3.e.6-17 of Reference 1. The non-conservatism did not impact the limiting breaks scenarios evaluated in Reference 1, as shown in existing Table 3.e.6-19 through Table 3.e.6-21 of Reference 1. As a result, the conclusions specified in Reference 1 are not affected.

Florida Power & Light Company 6501 S. Ocean Drive, Jensen Beach, FL 34957

St. Lucie Nuclear Plant, Units 1 and 2 L-2021-137 Docket Nos. 50-335 and 50-389 Page 2 of 2 This letter contains no new regulatory commitments.

Should you have any questions regarding this submittal, please contact Mr. Wyatt Gades, St. Lucie Licensing Manager, at (772) 467-7435.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on 1~tr 23J .20'-i Sincerely, Daniel DeBoer Site Vice President St. Lucie Nuclear Plant DD/jam/res Enclosure cc: USNRC Regional Administrator, Region II USNRC Project Manager, St. Lucie Nuclear Plant, Units 1 and 2 USNRC Senior Resident Inspector, St. Lucie Nuclear Plant, Units 1 and 2 Ms. Cindy Becker, Florida Department of Health

St. Lucie Nuclear Plant, Units 1 and 2 L-2021-137 Docket Nos. 50-335 and 50-389 Enclosure Page 1 of 2 Table 3.e.6-14 (Revised), PSL1 Overall Transport Fractions for a Reactor Cavity Break Debris Type Debris Size 1 Train 2 Train Fines - -

Small Transport as Erosion Fines - -

Pieces Transport as Small Pieces - -

Generic Fiberglass Large Transport as Erosion Fines - -

Pieces Transport as Large Pieces - -

Intact Blankets - -

Fines 100% 100%

Small Transport as Erosion Fines 9% 9%

Pieces Transport as Small Pieces 29% 47%

Nukon Large Transport as Erosion Fines 8% 8%

Pieces Transport as Large Pieces 4% 7%

Intact Blankets 0% 0%

Fines 100% 100%

Small Transport as Erosion Fines 9% 9%

Pieces Transport as Small Pieces 29% 47%

Thermal-Wrap Large Transport as Erosion Fines 8% 8%

Pieces Transport as Large Pieces 4% 7%

Intact Blankets 0% 0%

Fines 100% 100%

Small Transport as Erosion Fines 9% 9%

Pieces Transport as Small Pieces 83% 83%

Temp-Mat Large Transport as Erosion Fines 8% 8%

Pieces Transport as Large Pieces 73% 73%

Intact Blankets 0% 0%

Fines 5% 13%

Mirror RMI Large Pieces 6% 11%

Fines 5% 13%

Transco RMI Large Pieces 6% 11%

Transco RMI (inside Fines 3% 7%

cavity) Large Pieces 0% 0%

Fines 100% 100%

Non-banded Cal-Sil Small Transport as Erosion Fines 17% 17%

Pieces Transport as Small Pieces 6% 14%

Fines 100% 100%

Banded Cal-Sil Small Transport as Erosion Fines 17% 17%

Pieces Transport as Small Pieces 6% 14%

Qualified Coatings Particulate 100% 100%

Unqualified Coatings Particulate 100% 100%

Latent Debris Particulate/Fiber 100% 100%

St. Lucie Nuclear Plant, Units 1 and 2 L-2021-137 Docket Nos. 50-335 and 50-389 Enclosure Page 2 of 2 Table 3.e.6-17 (Revised), PSL2 Overall Transport Fractions for a Reactor Cavity Break Debris Type Debris Size 1 Train 2 Train Fines - -

Small Transport as Erosion Fines - -

Pieces Transport as Small Pieces - -

LDFG Large Transport as Erosion Fines - -

Pieces Transport as Large Pieces - -

Intact Blankets - -

Fines 100% 100%

Small Transport as Erosion Fines 10% 9%

Pieces Transport as Small Pieces 10% 18%

Nukon Large Transport as Erosion Fines 8% 8%

Pieces Transport as Large Pieces 2% 5%

Intact Blankets 0% 0%

Fines 100% 100%

Small Transport as Erosion Fines 10% 10%

Pieces Transport as Small Pieces 5% 8%

Nukon (inside cavity)

Large Transport as Erosion Fines 10% 10%

Pieces Transport as Large Pieces 0% 0%

Intact Blankets 0% 0%

Fines 1% 9%

Mirror RMI Large Pieces 2% 5%

Mirror RMI (inside Fines 1% 4%

cavity) Large Pieces 0% 0%

Fines - -

Transco RMI Large Pieces - -

Fines 100% 100%

Cal-Sil Small Transport as Erosion Fines 17% 17%

Pieces Transport as Small Pieces 1% 7%

Qualified Coatings Particulate 100% 100%

Unqualified Coatings Particulate 100% 100%

Latent Debris Particulate/Fiber 100% 100%