0CAN061801, Annual 10 CFR 50.46 Report for Calendar Year 2017, Emergency Core Cooling System Evaluation Changes

Annual 10 CFR 50.46 Report for Calendar Year 2017, Emergency Core Cooling System Evaluation Changes

ML18156A313
Person / Time
Site:	Arkansas Nuclear
Issue date:	06/05/2018
From:	Pyle S Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
0CAN061801
Download: ML18156A313 (5)

Text

Entergy Operations, Inc.

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

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 Adjustment as New (PCT), (°F) of End-of-Year Net PCT at the Adjustments for Net PCT at the (EOY 2016), EOY 2016, (°F) Calendar Year EOY 2017, (°F)

Evaluation Model (EM) Used

(°F) 2017, (°F)

AOR Date ANO-1 Small-Break 1459 Loss-of-Coolant 1459 None 1459 RELAP5 / MOD2-B&W None Accident (estimated) (Note 1) (estimated)

(SBLOCA) February 2011 Large-Break 2008.1 Loss-of-Coolant 2008.1 None 2008.1 RELAP5 / MOD2-B&W None Accident (estimated) (Notes 1,2) (estimated)

(LBLOCA) July 2005 ANO-2 2111 2111 2111 SBLOCA S2M None None (analyzed) (analyzed)

October 2007 2144 2144 2144 LBLOCA 1999 EM None None (analyzed) (analyzed)

January 2008

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 reported that LBLOCA analyses performed 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 Framatome 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 Condition 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.