ML18156A313

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Annual 10 CFR 50.46 Report for Calendar Year 2017, Emergency Core Cooling System Evaluation Changes
ML18156A313
Person / Time
Site: Arkansas Nuclear Entergy icon.png
Issue date: 06/05/2018
From: Stephanie Pyle
Entergy Operations
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
0CAN061801
Download: ML18156A313 (5)


Text

0CAN061801

June 5, 2018

U.S. Nuclear Regulatory Commission

Attn: Document Control Desk Washington, DC 20555

SUBJECT:

Annual 10 CFR 50.46 Report for Calendar Year 2017 Emergency Core Cooling System Evaluation Changes Arkansas Nuclear One - Units 1 and 2 Docket Nos. 50-313 and 50-368 License Nos. DPR-51 and NPF-6 REFERENCE Entergy submittal to the NRC, "Annual 10 CFR 50.46 Report for Calendar Year 2016 Emergency Core Cooling System Evaluation Changes," dated July 26, 2017 (0CAN071701) (ML17207A163)

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. has reviewed the small-break and large-break loss-of-coolant accident (LOCA) PCT evaluations for both Arkansas Nuclear One, Units 1 and 2 (ANO-1 and ANO-2).

No issues were identified for ANO-1 or ANO-2 in 2017 that impacted the results reported for the calendar year 2016, referenced above.

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.

This letter contains no new regulatory commitments.

Entergy Operations, Inc. 1448 S.R. 333 Russellville, AR 72802 Tel 479-858-4704 Stephenie L. Pyle Manager, Regulatory Assurance Arkansas Nuclear One

0CAN061801 Page 2 of 2

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

Sincerely,

ORIGINAL SIGNED BY STEPHENIE L. PYLE

SLP/rwc

Attachment:

Summary / Overview of Information for Arkansas Nuclear One, Units 1 and 2 10 CFR 50.46 Annual Report for 2017 cc: Mr. Kriss Kennedy Regional Administrator U. S. Nuclear Regulatory Commission, Region IV 1600 East Lamar Boulevard Arlington, TX 76011-4511 NRC Senior Resident Inspector

Arkansas Nuclear One P.O. Box 310

London, AR 72847 U. S. Nuclear Regulatory Commission Attn: Mr. Thomas Wengert MS O-08B1A

One White Flint North 11555 Rockville Pike Rockville, MD 20852

ATTACHMENT TO 0CAN061801 Summary / Overview of Information for Arkansas Nuclear One, Units 1 and 2 10 CFR 50.46 Annual Report for 2017 Attachment to 0CAN061801

Page 1 of 2 Summary / Overview of Information for Arkansas Nuclear One, Units 1 and 2 10 CFR 50.46 Annual Report for 2017 Analysis of Record (AOR)

Peak Clad Temperature (PCT), (°F)

Evaluation Model (EM) Used AOR Date Adjustment as of End-of-Year (EOY 2016), (°F) Net PCT at the EOY 2016, (°F) New Adjustments for Calendar Year 2017, (°F) Net PCT at the EOY 2017, (°F) ANO-1 Small-Break Loss-of-Coolant Accident (SBLOCA) 1459 RELAP5 / MOD2-B&W February 2011 None 1459 (estimated)

None (Note 1) 1459 (estimated) Large-Break Loss-of-Coolant

Accident (LBLOCA) 2008.1 RELAP5 / MOD2-B&W July 2005 None 2008.1 (estimated)

None (Notes 1,2) 2008.1 (estimated) ANO-2 SBLOCA 2111 S2M October 2007 None 2111 (analyzed)

None 2111 (analyzed)

LBLOCA 2144 1999 EM January 2008 None 2144 (analyzed)

None 2144 (analyzed)

Attachment to 0CAN061801

Page 2 of 2 Notes:

1. Framatome (previously AREVA) explicitly updated both SBLOCA and LBLOCA analyses to account for LOCA Swelling and Rupture. There is no estimated net change to PCT for either analysis.

(1) 2. Framatome has previously repor ted that LBLOCA analyses perform ed with the previously approved EM (2) did not adequately account for the effects of thermal conductivity degradation (TCD) on volume average fuel temperatures at later times in life. While short term compensatory measures were put into place to offset the effects of TCD (3), a supplement to the existing EM was developed and submitted to the NRC which contained the methodology developed by Framat ome to perform LBLOCA analyses accounting for TCD. This methodology was contained in the supplement approved by the NRC in 2017 (4). This approval alone does not represent a direct change to the analysis of record (AOR) PCT; however, this does represent a change to the approved LOCA methodology and may result in a change in the PCT once new AOR LBLOCA analyses are performed using the new methodology.

References:

1. Framatome Document FS1-0033526-1.0, "AREVA Conditi on Report 2017-3565, M5 LOCA Swelling and Rupture Model (SRM) Update."
2. Framatome Topical Report BAW-10192PA-00, "BWNT LOCA - BWNT Loss-of-Coolant Accident Evaluation Model for Once-Through Steam Generator Plants."
3. Letter T1.2FAB-FAB15-00217-000, "Arkansas Nuclear One Unit 1 - 2014 10CFR50.46 Annual Report - Emergency Core Cooling System (ECCS) Evaluation Model Changes," Dated March 23, 2015.
4. Framatome Topical Report BAW-10192PA-00_Supplement_1PA-000 "BWNT LOCA - BWNT Loss-of-Coolant Accident Evaluation Model for Once-Through Steam Generator Plants."