L-MT-18-055, Thirty (30) Day Notification Pursuant to 10 CFR 72.212, Conditions of General License Issued Under 10 CFR 72.210, for the Storage of Spent Fuel

Thirty (30) Day Notification Pursuant to 10 CFR 72.212, Conditions of General License Issued Under 10 CFR 72.210, for the Storage of Spent Fuel

ML18271A073
Person / Time
Site:	Monticello
Issue date:	09/28/2018
From:	Church C Northern States Power Co, Xcel Energy
To:	Document Control Desk, Office of Nuclear Material Safety and Safeguards
References
L-MT-18-055
Download: ML18271A073 (11)

Text

2807 West County Road 75 Monticello, MN 55362 (l Xcel Energy RESPONSIBLE BY NATURE 800.895.4999 xcelenergy. com September 28, 2018 L-MT-18-055 10 CFR 72.212(b)(2)

U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Director, Division of Spent Fuel Management Office of Nuclear Material Safety and Safeguards Washington, DC 20555-0001 Monticello Nuclear Generating Plant Docket 50-263 Renewed Facility Operating License No. DPR-22 Independent Spent Fuel Storage Installation Docket No. 72-58 Thirty (30) Day Notification Pursuant to 10 CFR 72.212, Conditions of General License Issued Under 10 CFR 72.210, for the Storage of Spent Fuel In accordance with 10 CFR 72.212(b)(2), Northern States Power Company- Minnesota (NSPM),

doing business as Xcel Energy, Inc., is registering the use of two U. S. Nuclear Regulatory Commission (NRG) approved spent fuel storage casks at the Monticello Nuclear Generating Plant (MNGP) Independent Spent Fuel Storage Installation (ISFSI). Registration of a cask is required no later than 30 days after using that spent fuel storage cask to store spent fuel in accordance with 10 CFR 72.212(b)(2). Cask-specific registration information is provided for each NUHOMS-61 BTH dry shielded canister (DSC) in Enclosure 1. of this letter provides a summary of the results of the thermal performance assessment for the highest heat load DSC as required by the General Requirements and Conditions of the Technical Specifications for Amendment No. 10, Revision 1 to Certificate of Compliance No. 1004, Section 1.1.7, "Special Requirements for First System in Place." Enclosure 2 provides the results of the thermal performance assessment for DSC MN P 61BTH-1-B-2-019 and MN P 61 BTH-1-B 020 which have successively higher heat loads to date.

If you have any questions or require additional information, please contact Mr. Stephen Sollom, Regulatory Affairs Sr. Engineer, at (612) 342-8982.

Document Control Desk L-MT-18-055 Page 2 of 2 Summary of Commitments This letter makes no new commitments and no revisions to existing commitments.

'*-~

ris pher R. Church Site Vice President, Monticello Nuclear Generating Plant Northern States Power Company - Minnesota Enclosures(2) cc: Administrator, Region Ill, USNRC Project Manager, Monticello, USNRC Resident Inspector, Monticello, USNRC Minnesota Department of Commerce

ENCLOSURE 1 MONTICELLO NUCLEAR GENERATING PLANT

SUMMARY

OF REGISTRATION INFORMATION FOR THE DRY SHIELDED CANISTERS LOADED DURING THE 2018 LOADING CAMPAIGN 1 Page Follows

L-MT-18-055 Page 1 of 1

SUMMARY

OF REGISTRATION INFORMATION FOR THE DRY SHIELDED CANISTERS LOADED DURING THE 2018 LOADING CAMPAIGN HSM Model HSM Date Placed Number Serial into Service Number Cask Certificate of No. 1004 Compliance:

Cask Amendment Amendment 10, Number: Revision 1 DSC Model NUHOMS-61 BTH Number:

DSC Serial MNP-61 BTH-1-B NUHOMS HSM- HSM-9B 8/30/2018 Number: 019 H MNP-61 BTH-1-B NUHOMS HSM- HSM- 9/13/2018 020 H 10B

ENCLOSURE 2 MONTICELLO NUCLEAR GENERATING PLANT

SUMMARY

OF THE THERMAL PERFORMANCE OF THE MNP-61BTH-1-B-2-019 AND MNP-61BTH-1-B-2-020 DRY SHIELDED CANISTERS 6 Pages Follow

L-MT-18-055 Page 1 of 6

SUMMARY

OF THE THERMAL PERFORMANCE OF THE MNP-61 BTH-1-8-2-019 DRY SHIELDED CANISTER On August 30, 2018 the Monticello Nuclear Generating Plant (MNGP) placed NUHOMS-61 BTH Dry Shielded Canister (DSC) Serial No. MNP-61 BTH-1-B-2-019 into storage. Technical Specification 1.1.7 of Certificate of Compliance 1004, Amendment 10 requires that the heat transfer characteristics of the system be recorded by temperature measurements of the first DSC placed in service and any subsequent DSCs contain ing higher decay heat loads. DSC MNP-61 BTH-1-B 011 was the first DSC placed in service under CoC 1004 Amendment 10 on 09/09/2013. DSC MNP-61 BTH-1-B-2-019 has the highest heat load to date. The thermal performance of the system will be assessed by measuring the air inlet and outlet temperature for normal airflow through the HSM in accordance with Technical Specification 1.2.8b.

Technical Specification 1.1.7 requires that a letter report be submitted to the NRC for the evaluation and assessment of the heat removal characteristics of the loaded DSC in the HSM within 30 days of placing the DSC in service, in accordance with 10 CFR 72.4. This report is being submitted to meet this requirement.

System Information DSC Serial Number: MNP-61 BTH-1-B-2-019 DSC Model: NUHOMS-61 BTH Total Decay Heat Load for 11.716 kW DSC:

HSM Serial Number: HSM-9B HSM Model: HSM-H Certificate of Compliance: No. 1004, Amendment 10, Revision 1

L-MT-18-055 Page 2 of 6 As required by Technical Specification 1.2.8b, inlet and outlet vent temperatures for HSM-9B were taken daily. These readings are shown in Figure 1.

Figure 1- HSM-98 Inlet and Outlet Vent Temperatures 110 100 - ~

90

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80 - - - - - - - - - - - - - - - ... ... ...

70 ..... ~ --- - - - - - - - - .

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so

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8/31/2018 9/1/2018 9/2/2018 9/3/2018 9/4/2018 9/5/2018 9/6/2018 Date

- - HSM-H Inlet - HSM-H Outlet Technical Specification 1.2.8b requires that, if a 61 BTH DSC is placed in the HSM-H with a heat load less than 31.2 kW, the limiting difference between outlet and ambient temperatures shall be determined by a calculation performed by the user using the same methodology and inputs documents in Appendix T of the Standardized NU HOMS FSAR. Transnuclear calculation NUH61 BTH-0425, NUHOMS HSM-H Air Temperature Rise vs. Decay Heat Calculation establishes acceptance criteria for the temperature rise across the HSM-H vents for varying ambient temperatures and decay heat loads.

Data on the Temperature Rise across the inlet and outlet vents of HSM-9B are shown in Figure 2, along with the associated allowable temperature difference from Transnuclear calculation NUH61 BTH-0425.

L-MT-18-055 Page 3 of 6 Figure 2 - HSM-9B Vent Temperature Difference 40 35 30 25 U:-

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20 QJ

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0 I I 8/31/2018 9/1/2018 9/2/2018 9/3/2018 9/4/2018 9/5/2018 9/6/2018 Date Temperature Difference - Allowable The system reached thermal equilibrium on or before September 4, 2018 with additional data collected through September 6, 2018 for trending. On September 6, the temperature difference across the inlet and outlet vents was 14.9°F. This is below the acceptance criteria of 38.6°F.

MNGP has determined the system is functioning as designed.

L-MT-18-055 Page 4 of 6

SUMMARY

OF THE THERMAL PERFORMANCE OF THE MNP-61 BTH-1-B-2-020 DRY SHIELDED CANISTER On September 13, 2018 the Monticello Nuclear Generating Plant (MNGP) placed NUHOMS-61BTH Dry Shielded Canister (DSC) Serial No. MNP-61 BTH-1-B-2-020 into storage. Technical Specification 1.1. 7 of Certificate of Compliance 1004, Amendment 10 requires that the heat transfer characteristics of the system be recorded by temperature measurements of the first DSC placed in service and any subsequent DSCs containing higher decay heat loads. DSC MNP-61 BTH-1-B 020 has the highest heat load to date at the time of loading into the Horizontal Storage Module (HSM). The thermal performance of the system will be assessed by measuring the air inlet and outlet temperature for normal airflow through the HSM in accordance with Technical Specification 1.2.8b.

Technical Specification 1.1 .7 requires that a letter report be submitted to the NRC for the evaluation and assessment of the heat removal characteristics of the loaded DSC in the HSM within 30 days of placing the DSC in service, in accordance with 10 CFR 72.4. This report is being submitted to meet this requirement.

System Information DSC Serial Number: MNP-61 BTH-1-B-2-020 DSC Model: NUHOMS-61 BTH Total Decay Heat Load for 11.719kW DSC:

HSM Serial Number: HSM-10B HSM Model: HSM-H Certificate of Compliance: No. 1004, Amendment 10, Revision 1

L-MT-18-055 Page 5 of 6 As required by Technical Specification 1.2.8b, inlet and outlet vent temperatures for HSM-1 OB were taken daily. These readings are shown in Figure 3.

Figure 3 - HSM-10B Inlet and Outlet Vent Temperatures 110 100

--- ... .. - - - - - - ~

90

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80 70 U:-60 ' '-

QJ

i 50

+-'

....co QJ 40 a.

E

~ 30 20 10 0

9/14/2018 9/15/2018 9/16/2018 9/17/2018 9/18/2018 9/19/2018 Date

- - HSM-H Inlet - HSM-H Outlet Technical Specification 1.2.8b requires that, if a 61 BTH DSC is placed in the HSM-H with a heat load less than 31 .2 kW, the limiting difference between outlet and ambient temperatures shall be determined by a calculation performed by the user using the same methodology and inputs documents in Appendix T of the Standardized NU HOMS FSAR. Transnuclear calculation NUH61 BTH-0425, NUHOMS HSM-H Air Temperature Rise vs. Decay Heat Calculation establishes acceptance criteria for the temperature rise across the HSM-H vents for varying ambient temperatures and decay heat loads.

Data on the Temperature Rise across the inlet and outlet vents of HSM-1 OB are shown in Figure 4, along with the associated allowable temperature difference from Transnuclear calculation NUH61 BTH-0425.

L-MT-18-055 Page 6 of 6 Figure 4 - HSM-10B Vent Temperature Difference 40 35 30 25 i::L

...:::s

';' 20

+-'

~ 15 Q) a.

E

~ 10 5

0 9/14/2018 9/15/2018 9/16/2018 9/17/2018 9/18/2018 9/ 19/ 2018 Date

- - Temperature Difference - Allowable The system reached thermal equilibrium on or before September 19, 2018. At that time the temperature difference across the inlet and outlet vents was 19.9°F. This is below the acceptance criteria of 37.4 °F. MNGP has determined the system is functioning as designed.