L-MT-13-090, August 2013, 10 CFR 50.46 Thirty-Day Report

August 2013, 10 CFR 50.46 Thirty-Day Report

ML13242A088
Person / Time
Site:	Monticello
Issue date:	08/27/2013
From:	Fili K Northern States Power Co, Xcel Energy
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-MT-13-090
Download: ML13242A088 (6)

Text

U XcelEnergy Monticello Nuclear Generating Plant 2807 W County Road 75 Monticello, MN 55362 August 27, 2013 L-MT-1 3-090 10 CFR 50.46(a)(3)(ii)

U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Monticello Nuclear Generating Plant Docket 50-263 Renewed Facility Operating License No. DPR-22 August 2013, 10 CFR 50.46 Thirty-Day Report

References:

1) GE Report, NEDC-32514P, Revision 1, "Monticello SAFER/GESTR LOCA Loss of Coolant Accident Analysis," dated October 1997

2) GE Report, GE-NE-J1103878-09-02P, "Monticello ECCS-LOCA Evaluation for GE14," dated August 2001

3) GE Notification Letter 2012-01, Revision 1, "PRIME Fuel Properties Implementation for Fuel Rod TIM Performance, replacing GESTR Fuel Properties," dated July 30, 2013

4) NSPM to NRC letter, "2012 Report of Changes and Errors in Emergency Core Cooling System Evaluation Models," (L-MT-12-099),

dated December 20, 2012 Pursuant to 10 CFR 50.46(a)(3)(ii), the Northern States Power Company, a Minnesota corporation (NSPM), doing business as Xcel Energy, is providing this 30-day report concerning a change in the Emergency Core Cooling System (ECCS) evaluation model for the Monticello Nuclear Generating Plant (MNGP). The MNGP Loss of Coolant Accident (LOCA) analyses of record (AORs) are contained in General Electric (GE) reports submitted for the MNGP rerate to the current licensed thermal power (1775 MWt) (Reference 1) and the LOCA analysis for the GE14 fuel type comprising the MNGP core (Reference 2), adjusted for the estimated effect of errors or changes subsequently discovered in the evaluation models or their application.

This 30-day report is being made due to revision one to General Electric Hitachi (GEH)

Nuclear Energy 10 CFR 50.46 Notification Letter 2012-01 (Reference 3), to reflect a reduction in the change in Peak Cladding Temperature (PCT) from 45 0 F to 100 F, due to applying the PRIME fuel properties for fuel rod thermal / mechanical (T / M) performance, which replaced the GESTR fuel properties model. This results in an

Document Control Desk L-MT-13-090 Page 2 of 2 adjusted PCT of 2050'F that is less than that previously reported in Reference 4.

However, this modeling change still results in a cumulative increase in PCT exceeding the 50'F threshold and is being reported in accordance with the regulation.

As prescribed by the regulation a proposed reanalysis schedule or an evaluation is needed to demonstrate the facility remains in compliance with 10 CFR 50.46 requirements. In accordance with 10 CFR 50.46(a)(3)(ii) the following evaluation is provided. The adjusted PCT is 150°F below the 2200°F acceptance criterion of 10 CFR 50.46(b)(1). This provides sufficient margin to justify taking no further action.

No further reanalysis or other actions are planned. provides additional information on the nature of the change, and the previous changes and errors, and their effect on the MNGP LOCA analysis. This information is being submitted in accordance with the requirements of 10 CFR 50.46(a)(3)(ii) for the MNGP.

If you have any questions or require additional information, please contact Mr. Richard Loeffler at (763) 295-1247.

Summary of Commitments This letter proposes no new commitments and does not revise any existing commitments.

Karen D. Fili Site Vice President Monticello Nuclear Generating Plant Northern States Power Company - Minnesota Enclosure cc: Regional Administrator, Region III, USNRC Project Manager, Monticello Nuclear Generating Plant, USNRC Resident Inspector, Monticello Nuclear Generating Plant, USNRC

ENCLOSURE MONTICELLO NUCLEAR GENERATING PLANT TABLE 1 -

SUMMARY

OF MONTICELLO LOCA CHANGES AND ERRORS INVOLVING CHANGES IN PEAK CLADDING TEMPERATURE (PCT)

(3 Pages Follow)

L-MT-1 3-090 Page 1 of 3 Table 1 - Summary of Monticello LOCA Changes and Errors Involving Changes in Peak Cladding Temperature Licensing Applicable Analysis or Error Description Ref. Basis PCT(°F)

GE14 NEDC-32514P, Rev. 1, Monticello SAFER/GESTR-LOCA Loss of Coolant Accident Analysis GE-NE-J1 103878-09-02P, Monticello ECCS-LOCA 2 < 1960 Evaluation for GE14 Impact of SAFER LevelNolume Table Error on Peak Cladding Temperature (PCT) (Notification Letter 2003-01) 3 -15 Level and volume tables used by SAFER were not updated when a revised initial water level was implemented.

Impact of Top Peaked Power Shape for Small Break LOCA Analysis (Notification Letter 2006-01)

Small Break LOCA analyses had assumed a mid-peaked axial +30 power shape consistent with the Design Basis Accident (DBA) break analyses. It was determined that a top-peaked axial power shape can result in higher calculated PCT.

Impact of database error for heat deposition on the PCT for 1Ox1 0 fuel bundles (Notification Letter 2011-02)

The input coefficients used to direct the deposition of gamma radiation energy produced by the fuel caused the heat deposited 5+ 60 in the fuel channel (post scram) to be over-predicted and the corresponding heat in the fuel to be under-predicted.

(continued)

L-MT-1 3-090 Enclosure 1 Page 2 of 3 Licensing Basis Basis Ref.

Applicable Analysis or Error Description PCT(°F)

GE14 Impact of updated formulation for gamma heat deposition to channel wall for 9x9 and 10x10 fuel bundles (Notification Letter 2011-03)

In the input formulation for SAFER, the method for the contribution of heat from gamma ray absorption by the channel had been simplified so that initially all energy was deposited in the fuel rods prior to the LOCA and then adjusted to the correct heat deposition after the scram. Not accounting for this small fraction of power generation outside the fuel rod tends to suppress the hot bundle power required to meet the initial operating Peak Linear Heat Generation Rate. Also, there is a small effect on the initial conditions for the rest of the core as these are set in relation to the hot bundle condition.

PRIME Fuel Properties Implementation for Fuel Rod T/M Performance, replacing GESTR Fuel Properties (Notification Letter 2012-01, Revision 1)

This change is due to the application of an NRC-approved 7 + 10 procedure to estimate the change in PCT due to the change in fuel properties from GESTR to PRIME primarily to address inaccuracies in fuel pellet thermal conductivity as a function of exposure.

Sum of absolute value of changes during the current reporting period. 10 Sum of absolute value of changes since last Analysis of Record (AOR). 120 Algebraic sum of changes during the current reporting period. + 10 Algebraic sum of changes since last AOR. +90 Current Adjusted Peak Cladding Temperature < 2050

L-MT-13-090 Page 3 of 3 References

1. GE Report: NEDC-32514P, Revision 1, "Monticello SAFER/GESTR-LOCA Loss-of-Coolant Accident Analysis," dated October 1997.

2. GE-NE-J1 103878-09-02P, "Monticello ECCS-LOCA Evaluation for GE14,"

dated August 2001.

3. 10 CFR 50.46 Notification Letter 2003-01, "Impact of SAFER Level/Volume Table Error on the Peak Cladding Temperature (PCT)," dated May 6, 2003.

4. 10 CFR 50.46 Notification Letter 2006-01, "Impact of Top Peaked Power Shape for Small Break LOCA Analysis," dated July 28, 2006.

5. 10 CFR 50.46 Notification Letter 2011-02, "Impact of database error for heat deposition on the Peak Cladding Temperature (PCT) for 10x10 fuel bundles," dated June 10, 2011.

6. 10 CFR 50.46 Notification Letter 2011-03, "Impact of updated formulation for gamma heat deposition to channel wall for 9x9 and 10x10 fuel bundles," dated June 10, 2011.

7. 10 CFR 50.46 Notification Letter 2012-01, Revision 1, "PRIME Fuel Properties Implementation for Fuel Rod T / M Performance, replacing GESTR Fuel Properties,"

dated July 30, 2013.