ML020940177

Annual Reporting of Changes and Errors in Emergency Core Cooling System Models or Applications

ML020940177
Person / Time
Site:	Millstone
Issue date:	03/20/2002
From:	Price J Dominion Nuclear Connecticut
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
B18612
Download: ML020940177 (5)

Text

Dominion Nuclear Connecticut, Inc. -Dominion Millstone Power Station Rope Ferry Road Waterford, CT 06385 KAR 20 il0 Docket No. 50-336 B1 8612 RE: 10 CFR 50.46(a)(3)(ii)

U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Millstone Nuclear Power Station, Unit No. 2 2001 Annual Reporting of Changes to and Errors in Emergency Core Cooling System Models or Applications In accordance with 10 CFR 50.46(a)(3)(ii), Dominion Nuclear Connecticut, Inc. (DNC) hereby submits changes to and errors in the Emergency Core Cooling System (ECCS) evaluation models or applications of those models for Millstone Unit No. 2.

Attachment 1 transmits the annual report for the period January 2001 through December 2001. The following is a synopsis of the information provided in Attachment 1.

1. Attachment 1 reports the Framatome ANP (FRA-ANP) modifications in the ECCS models applicable to Millstone Unit No. 2. These modifications have resulted in permanent peak cladding temperature (PCT) margin allocations for Unit No. 2.

2. FRA-ANP identified one change or error in the Small Break Loss of Coolant Accident (SBLOCA) analysis during the 2001 calendar year. As summarized in Attachment 1, assessment of this item resulted in a 0°F change in PCT. The overall SBLOCA PCT is 2064 0 F.

3. FRA-ANP identified six changes or errors in the Large Break Loss of Coolant Accident (LBLOCA) analysis during the 2001 calendar year. As summarized in Attachment 1, assessment of these items resulted in a I°F change in PCT. The overall LBLOCA PCT is 1812 0 F.

4. Considering the changes summarized in Attachment 1, the corrected PCTs for the limiting SBLOCA and LBLOCA remain below the 2200°F limit defined by 10 CFR 50.46(b)(1).

U.S. Nuclear Regulatory Commission B18612/Page 2 DNC believes that this information satisfies the annual reporting requirements of 10 CFR 50.46(a)(3)(ii).

There are no regulatory commitments contained within this letter.

Should you have any questions regarding this submittal, please contact Mr. David W. Dodson at (860) 447-1791, extension 2346.

Very truly yours, DOMINION NUCLEAR CONNECTICUT, INC.

J.,tl1a rice Sitice President - Millstone Attachment (1) cc: H. J. Miller, Region I Administrator R. B. Ennis, NRC Senior Project Manager, Millstone Unit No. 2 NRC Senior Resident Inspector, Millstone Unit No. 2

Docket No. 50-336 B1 8612 Attachment 1 Millstone Nuclear Power Station, Unit No. 2 2001 Annual Reporting of 10 CFR 50.46 Margin Utilization

U.S. Nuclear Regulatory Commission B18612/Attachment 1/Page 1 2001 Annual Reporting of 10 CFR 50.46 Margin Utilization Small Break Loss of Coolant Accident (SBLOCA)

Plant Name: Millstone Unit No. 2 Utility Name: Dominion Nuclear Connecticut, Inc.

Analysis Information EM: EXEM/PWR 2

Small Break Limiting Break Size: 0.06 ft Analysis Date: 03/00 Vendor: Framatome ANP Peak Linear Power: 14.6 kW/ft Notes: None Clad Temp (OF) Notes LICENSING BASIS Analysis of Record PCT 2061 (1)

MARGIN ALLOCATIONS (Delta PCT)

A. Prior Permanent ECCS Model Assessments (Through 12/2000)

1. RODEX2 Corrosion Enhancement Factor in Millstone Cycle 14 SBLOCA Analysis -22

2. Variability in SBLOCA Analysis 25 (2)

B. Planned Plant Change Evaluations

1. None 0 C. 2001 Permanent ECCS Model Assessments

1. Errors Discovered During RODEX2 V&V 0 D. Temporary ECCS Model Issues

1. None 0 E. Other Margin Allocations

1. None 0 LICENSING BASIS PCT + MARGIN ALLOCATIONS PCT = 2064 NOTES:

(1) New Analysis of Record to support Cycle 14 operation with reduced charging flow.

(2) Limiting break size shifts to 0.07 ft 2.

U.S. Nuclear Regulatory Commission B18612/Attachment 1/Page 2 2001 Annual Reporting of 10 CFR 50.46 Margin Utilization Large Break Loss of Coolant Accident (LBLOCA)

Plant Name: Millstone Unit No. 2 Utility Name: Dominion Nuclear Connecticut, Inc.

Analysis Information EM: SEM/PWR-98 Limiting Break Size: 1.0 DECLG Analysis Date: 11/98 Vendor: Framatome ANP Peak Linear Power: 15.1 kW/ft Notes: None Clad Temp(°F) Notes LICENSING BASIS Analysis of Record PCT 1814 (1)

MARGIN ALLOCATIONS (Delta PCT)

A. Prior Permanent ECCS Model Assessments (Through 12/2000)

1. Corrected Corrosion Enhancement Factor -1

2. ICECON Coding Errors 0

3. Setting RFPAC Fuel Temperatures at Start of Reflood -2

4. SISPNCH/ujun98 Code Error 0

5. Error in Flow Blockage Model in TOODEE2 0

6. Change in TOODEE2-Calculation of QMAX 0

7. Change in Gadolinia Modeling 0

8. PWR LBLOCA Split Break Modeling 0

9. TEOBY Calculation Error 0 B. Planned Plant Change Evaluations

1. None 0 C. 2001 Permanent ECCS Model Assessments

1. Inappropriate Heat Transfer in TOODEE2 0

2. End-of-Bypass Prediction by TEOBY 0

3. R4SS Overwrite of Junction Inertia 0

4. Incorrect Junction Inertia Multipliers 1

5. Errors Discovered During RODEX2 V&V 0

6. Error in Broken Loop SG Tube Exit Junction Inertia 0 D. Temporary ECCS Model Issues

1. None 0 E. Other Margin Allocations

1. None 0 LICENSING BASIS PCT + MARGIN ALLOCATIONS PCT = 1812 Notes:

(1) New Analysis of Record with SEM/PWR-98 LOCA Evaluation Model.