0CAN061001, Annual 10 CFR 50.46 Report for Calendar Year 2009 Emergency Core Cooling System Evaluation Changes

Annual 10 CFR 50.46 Report for Calendar Year 2009 Emergency Core Cooling System Evaluation Changes

ML101580218
Person / Time
Site:	Arkansas Nuclear
Issue date:	06/03/2010
From:	David Bice Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
0CAN061001
Download: ML101580218 (5)

Text

Entergy Operations, Inc.

1448 S.R. 333 Russellville, AR 72802 Tel 479-858-4710 David B. Bice Acting Manager, Licensing Arkansas Nuclear One 0CAN061001 June 3, 2010 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001

SUBJECT:

Annual 10 CFR 50.46 Report for Calendar Year 2009 Emergency Core Cooling System Evaluation Changes Docket Nos. 50-313 and 50-368 License Nos. DPR-51 and NPF-6

REFERENCE:

1. Entergy Letter to the NRC, Annual 10 CFR 50.46 Report for Calendar Year 2008 Emergency Core Cooling System Evaluation Changes, dated May 15, 2009 (0CAN050903)

2. Entergy Letter to the NRC, 10 CFR 50.46 Report - Significant Change in Peak Cladding Temperature, dated April 1, 2009 (1CAN040902)

Dear Sir or Madam:

10 CFR 50.46(a)(3)(ii) requires licensees to report annually each change to or error discovered in an acceptable evaluation model or in the application of such model for the emergency core cooling system that affects the peak cladding temperature (PCT). Entergy Operations, Inc. (Entergy) has reviewed the 2009 small and large break loss-of-coolant accident (LOCA) PCT evaluations for both Arkansas Nuclear One, Units 1 and 2 (ANO-1 and ANO-2).

A summary / overview of the information required to be submitted each year is attached to this submittal.

This submittal fulfills the reporting requirements referenced above.

As noted in Reference 1, a notification of a change to the ANO-1 small break LOCA PCT of greater than 50 °F from the previous temperature calculated for the small break LOCA limiting plant transient occurred in 2009 (Reference 2). Also noted in Reference 1, further discussion of this change would be provided in this annual report. This change is discussed in the attached summary / overview.

0CAN061001 Page 2 of 2 This letter contains no new commitments.

If you have any questions or require additional information, please contact me.

Sincerely, DBB/rwc

Attachment:

Summary / Overview of Information for ANO-1 & 2 10 CFR 50.46 Annual Report for 2009 cc: Mr. Elmo E. Collins Regional Administrator U. S. Nuclear Regulatory Commission Region IV 612 E. Lamar Blvd., Suite 400 Arlington, TX 76011-4125 NRC Senior Resident Inspector Arkansas Nuclear One P.O. Box 310 London, AR 72847 U.S. Nuclear Regulatory Commission Attn: Mr. Kaly Kalyanam MS O-8 B1 One White Flint North 11555 Rockville Pike Rockville, MD 20852

ATTACHMENT TO 0CAN061001

SUMMARY

/ OVERVIEW OF INFORMATION FOR ANO-1 & 2 10 CFR 50.46 ANNUAL REPORT FOR 2009

Attachment to 0CAN061001 Page 1 of 2

SUMMARY

/ OVERVIEW OF INFORMATION FOR ANO-1&2 10 CFR 50.46 ANNUAL REPORT FOR CY 2009 Analysis of Record Adjustment, °F As Net PCT @ EOY New Adjustments Net PCT @ EOY (AOR) Peak Cladding of End of Year 2008, oF for Calendar Year 2009, °F Temperature (PCT), °F (EOY) 2008 (CY) 2009, °F Evaluation Model (EM)

Used AOR Date ANO-1(1)

Small Break 1282 N/A 1179.7 102.3 1282 Loss-of- RELAP5/MOD2-B&W (Note 1) (Note 1) (Note 1) (Note 1)

Coolant JAN 2009 Accident (SBLOCA)

Large Break 2008.1 None 2008.1 None 2008.1 Loss-of- RELAP5/MOD2-B&W Coolant AUG 2005 Accident (LBLOCA)

ANO-2(2)

SBLOCA 2111 N/A 2137 Full core Next 2111 S2M (Note 2) (Note 2) Generation Fuel (Note 2)

(NGF)

FEB 2007 (Note 2)

LBLOCA 2144 N/A 2168 Full Core NGF 2144 1999EM (Note 2) (Note 2) (Note 2) (Note 2)

FEB 2007

Attachment to 0CAN061001 Page 2 of 2 NOTES:

1. The ANO-1 Emergency Feedwater (EFW) wetting model utilized in the AOR SBLOCA analyses failed to consider the gap between the 15th tube support plate (TSP) and the shroud in the Enhanced Once-Through Steam Generator (EOTSG) design. The increased gap allows more EFW that is injected above the 15th TSP to run down the shroud and not wet the SG tubes. As a result of the error, the SBLOCA was reanalyzed (new AOR) and the PCT for the Mk-B-HTP SBLOCA spectrum increased 102.3 °F to 1282 °F for the limiting case. The PCT and the LHR limit for the LBLOCA were not affected by the error. This error and its impact on the SBLOCA PCT were previously reported via 1CAN040902(3).

2. ANO-2 completed transition to Combustion Engineering 16x16 NGF fuel assemblies, with Optimized ZIRLO cladding, during its Fall 2009 refueling outage. The net PCT values for EOY 2008 are based on the previous AOR, which were performed for a full core of ZIRLO-clad fuel assemblies using the S2M and 1999EM EMs for SBLOCA and LBLOCA, respectively. With completion of the transition to NGF / Optimized ZIRLO fuel, the ZIRLO fuel PCTs are no longer applicable to ANO-2 and the analyses associated with the NGF fuel performed in 2007 become the new AOR.

REFERENCES:

1. PWROG letter OG-10-171 dated May 13, 2010

2. Westinghouse letter LTR-LAM-10-11 dated February 23, 2010

3. Entergy letter 1CAN040902 dated April 1, 2009